Talk:Evolution/Archive 60

Archive 55

←

Archive 58

Archive 59

Archive 60

Archive 61

Archive 62

→

Archive 65

New focus?

Although the results of the above straw poll were clear enough to take action, there were specific points raised by Thompsma and seconded by Slrubenstein and others regarding the focus of the entire section and the possibility of updating it. There seems to be enough tentative agreement to merit further discussion in a new section. I support the idea in general, but lack the background to address the issue with competence, hence I've started this section for others to do so. Enjoy, Doc Tropics 15:13, 26 September 2011 (UTC)

I believe the section being referred to is History of evolutionary thought. Editors interested in improving what Wikipedia has to say on this subject should also keep in mind that we have a daughter article History of evolutionary thought. Both the section and the daughter article have been worked on recently, but they should also be the subject of on-going attention. Overall of course, what gets into the Evolution article itself has to be a bit shorter than what gets into all its many daughter articles.--Andrew Lancaster (talk) 16:32, 26 September 2011 (UTC)

...which is why daughter articles re the ideal places to work out these issues, including the incorporation of new sources, which can lead to reorganization or reframing. Once daughter articles are stable, then it should not be that hard to summarize their main points (sometimes just by using the lead paragraph, with minor modifications or more references=) in this article. Slrubenstein | Talk 17:55, 26 September 2011 (UTC)

I think it can work both ways. Writing in a compressed way helps get a structure for the expanded version too.--Andrew Lancaster (talk) 18:04, 26 September 2011 (UTC)

I don't like the argument that daughter pages should be written first and then summarised. It leads nowhere, it just moves the problem to another page - while we wait for someone to fix that page this one will be stale. We are a group of editors discussing this here and now. Here and now is always the right time to fix problems, not another place or another time. We have momentum here and we have to use it.·ʍaunus·snunɐw· 18:09, 26 September 2011 (UTC)

If others agree with you, then I would propose that provisionally we should stop worrying about length (howevermuch I understand Andrew's concern). The point is: to work on it until editors who watch this page are satisfied that the contents clearly provide a good account of what the mainstream sources say, including accounts of significant debates. If, once we have achieved this, we also agree that the section is too long, at that point we can decide how best to summarize it. My point either way is to break this into two stages - doing justice to the best sources, and then editing down the size. In my experience it is virtually impossible to do a good job at both of these tasks if one attempts to do them at the same time.Slrubenstein | Talk 18:16, 26 September 2011 (UTC)

Yes, I think it is a much better idea to write a section here that is too long and too detailed and then subsequently spin it out into a daughter article leaving a summary in place.·ʍaunus·snunɐw· 18:24, 26 September 2011 (UTC)

I do not think we need an agreement on one particular method here. All edits which are improvements are good, and that is true for both articles. The only concern I have is that I think the Evolution article is already very bloated. I would be careful about any idea of trying out anything that expands sections a lot just to see what they look like. We've recently done some trimming of the section in question and we took our time and used the talk page a lot. I am not saying it always needs to be that way, but let's try not to go too far above 150,000 bytes?--Andrew Lancaster (talk) 18:40, 26 September 2011 (UTC)

We could certainly work on the section hereon the talkpage before inserting it into the article. And I also agree that we don't need to agree on one method.·ʍaunus·snunɐw· 18:57, 26 September 2011 (UTC)

Recommended change to the lead, again

I believe that the first few paragraphs in the lead belongs in evolutionary genetics, or we need some way of distinguishing between the two articles. I think this can be accomplished through the introduction of homology among lineages in the biological hierarchy. I'm working on the following proposal to replace the first two paragraphs in the hopes that it will permit a new section to be added to this article on phylogenetics and evolutionary trees in an effort to systematically organize and reduce the size of this article:

Evolution (or more specifically biological or organic evolution) is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically. In his landmark scientific text on evolution, "On The Origin of Species", Charles Darwin refers to the "great tree of life", "a web of complex relations", and he includes a single illustration of an evolutionary tree. The tree represents common ancestry among lineages that branch and diversify into "endless forms most beautiful and most wonderful". Lineages form through recursive generations of biological reproduction among all individuals in the biological hierarchy, including genes, cells, organisms, and species. A core theory of evolution proposed by Charles Darwin is natural selection. Natural selection applies to all lineages that interact in the biological hierarchy and is formulated on three recurrent facts, including 1) heritability, 2) variation, and 3) the overproduction or superfecundity of offspring. Heritability is the faithful expression of certain characters from one generation to the next. Homologous characters play a central role in evolutionary theory. A homologous character is similar in form, similarly located anatomically or positionally relative to other characters, and they share similar biological functions. Homology is explained by a common line of heritable descent.

Evolutionary novelties originate by various means, including changes in behaviour, sexual recombination, developmentally, symbiogenetically, environmentally, and through genetic mutation. The outward physical expression of a lineage's traits is its phenotype, whereas the heritable information encoded at its molecular level is its genotype. The genotype refers to all the genes that interact in a complex hierarchical network regulating the development of the phenotype. Phenotypic variation can result as a complex developmental and physiological response to different environments. There is rarely a one-to-one readout from the smallest heritable unit, the gene, to the emergent phenotypic pattern. Variation within a lineage may evolve by random chance or become adapted by means of natural selection. Genetic mutations, for example, appear with regular frequency. In larger populations their minute effects may be of such little consequence that they drift through populations in a stochastic manner. Adaptations, however, are not random as features of certain characters may confer a slight advantage to increase reproductive output or evolutionary fitness.

Scientific evidence for common ancestry is overwhelmingly observed in the anatomy of organisms, during development, in genomes, in the universal genetic code, in the geographic distributions of species and their genes, in behaviour, in breeding experiments, and in the fossil record. Common descent stretches back over 3.5 billion years during which life has existed on earth. Evolution reveals diverse kinds of evolutionary transitions over short and vast dimensions of space and time. From genes to morphology, homologous characters are used to construct evolutionary trees or, more precisely, phylogenetic networks for positing, framing, testing, and illustrating evolutionary hypotheses about genealogical relations. The genealogical affinity among lineages is illuminated by comparative analysis on the measured form of characters, their presence, and their varied states among lineages. This kind of evidence clearly reveals that evolution is the cause of speciation, whereby a single ancestral species splits into two or more different species lineages.Thompsma (talk) 05:19, 29 September 2011 (UTC)

Current lead	Thompsma proposal	Thompsma revision/cuts
Evolution (or more specifically biological or organic evolution) is the change over time in one or more inherited traits found in populations of individuals.[1] Inherited traits are distinguishing characteristics, for example anatomical, biochemical or behavioural, that are passed on from one generation to the next. Evolution requires variation of inherited traits within a population. New variants of inherited traits can enter a population from outside populations, and this is referred to as gene flow.[2][3][4][5] Alternatively, new variants can come into being from within a population in at least three ways: mutation of DNA, epimutation (a change inherited in some way other than through the sequence of nucleotides in DNA), and genetic recombination. Natural selection, where different inherited traits cause different rates of survival and reproduction, can cause new variants to become common in a population.[1] Other evolutionary mechanisms can cause a variant to become common even if the variant does not directly cause improved survival or reproduction. These mechanisms include genetic hitchhiking, genetic drift,[6][7] and recurrent biased mutation or migration. Evolution has led to the diversification of all living organisms from a common ancestor, which are described by Charles Darwin as "endless forms most beautiful and most wonderful".[8] For example, evolution is the cause of speciation, whereby a single ancestral species splits into two or more different species. Speciation is visible in anatomical, genetic and other similarities between groups of organisms, geographical distribution of related species, the fossil record and the recorded genetic changes in living organisms over many generations. Common descent stretches back over 3.5 billion years during which life has existed on earth.[9][10][11][12] Both evolution within populations and speciation between them are thought to occur in multiple ways such as slowly, steadily and gradually over time or rapidly from one long static state to another. The scientific study of evolution began in the mid-nineteenth century, when research into the fossil record and the diversity of living organisms convinced most scientists that species evolve.[13] The mechanisms driving these changes remained unclear until the theory of natural selection was independently proposed by Charles Darwin and Alfred Wallace in 1858. In the early 20th century, Darwinian theories of evolution were combined with genetics, palaeontology and systematics, which culminated into a union of ideas known as the modern evolutionary synthesis.[14] The synthesis became a major principle of biology as it provided a coherent and unifying explanation for the history and diversity of life on Earth.[15][16][17] Evolution is currently applied and studied in various areas within biology such as conservation biology, developmental biology, ecology, physiology, paleontology and medicine. Moreover, it has also made an impact on other disciplines such as agriculture, anthropology, philosophy and psychology. Evolutionary biologists document the fact that evolution occurs, and also develop and test theories that explain its causes.	Evolution (or more specifically biological or organic evolution) is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically. In his landmark scientific text on evolution, "On The Origin of Species", Charles Darwin refers to the "great tree of life", "a web of complex relations", and he includes a single illustration of an evolutionary tree. The tree represents common ancestry among lineages that branch and diversify into "endless forms most beautiful and most wonderful". Lineages form through recursive generations of biological reproduction among all individuals in the biological hierarchy, including genes, cells, organisms, and species. A core theory of evolution proposed by Charles Darwin is natural selection. Natural selection applies to all lineages that interact in the biological hierarchy and is formulated on three recurrent facts, including 1) heritability, 2) variation, and 3) the overproduction or superfecundity of offspring. Heritability is the faithful expression of certain characters from one generation to the next. Homologous characters play a central role in evolutionary theory. A homologous character is similar in form, similarly located anatomically or positionally relative to other characters, and they share similar biological functions. Homology is explained by a common line of heritable descent. Evolutionary novelties originate by various means, including changes in behaviour, sexual recombination, developmentally, symbiogenetically, environmentally, and through genetic mutation. The outward physical expression of a lineage's traits is its phenotype, whereas the heritable information encoded at its molecular level is its genotype. The genotype refers to all the genes that interact in a complex hierarchical network regulating the development of the phenotype. Phenotypic variation can result as a complex developmental and physiological response to different environments. There is rarely a one-to-one readout from the smallest heritable unit, the gene, to the emergent phenotypic pattern. Variation within a lineage may evolve by random chance or become adapted by means of natural selection. Genetic mutations, for example, appear with regular frequency. In larger populations their minute effects may be of such little consequence that they drift through populations in a stochastic manner. Adaptations, however, are not random as features of certain characters may confer a slight advantage to increase reproductive output or evolutionary fitness. Scientific evidence for common ancestry is overwhelmingly observed in the anatomy of organisms, during development, in genomes, in the universal genetic code, in the geographic distributions of species and their genes, in behaviour, in breeding experiments, and in the fossil record. Common descent stretches back over 3.5 billion years during which life has existed on earth. Evolution reveals diverse kinds of evolutionary transitions over short and vast dimensions of space and time. From genes to morphology, homologous characters are used to construct evolutionary trees or, more precisely, phylogenetic networks for positing, framing, testing, and illustrating evolutionary hypotheses about genealogical relations. The genealogical affinity among lineages is illuminated by comparative analysis on the measured form of characters, their presence, and their varied states among lineages. This kind of evidence clearly reveals that evolution is the cause of speciation, whereby a single ancestral species splits into two or more different species lineages. The scientific study of evolution began in the mid-nineteenth century, when research into the fossil record and the diversity of living organisms convinced most scientists that species evolve.[13] The mechanisms driving these changes remained unclear until the theory of natural selection was independently proposed by Charles Darwin and Alfred Wallace in 1858. In the early 20th century, Darwinian theories of evolution were combined with genetics, palaeontology and systematics, which culminated into a union of ideas known as the modern evolutionary synthesis.[14] The synthesis became a major principle of biology as it provided a coherent and unifying explanation for the history and diversity of life on Earth. Evolution is currently applied and studied in various areas within biology such as conservation biology, developmental biology, ecology, physiology, paleontology and medicine. Moreover, it has also made an impact on other disciplines such as agriculture, anthropology, philosophy and psychology. Evolutionary biologists document the fact that evolution occurs, and also develop and test theories that explain its causes.	Evolution (or more specifically biological or organic evolution) is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically. In his landmark scientific text on evolution in 1859, "On The Origin of Species", Charles Darwin refers to the "great tree of life", "a web of complex relations", and he includes a single illustration of an evolutionary tree. The tree represents common ancestry among lineages that branch and diversify into "endless forms most beautiful and most wonderful". Lineages form through generations of recursive biological reproduction creating an ancestral-descendant sequence of populations across the biological hierarchy, including genes, cells, organisms, and species. A core theory of evolution proposed by Charles Darwin is natural selection. Natural selection applies to all lineages that interact in the biological hierarchy and is formulated on three recurrent facts, including 1) heritability, 2) variation, and 3) the overproduction or superfecundity of offspring. Heritability is the faithful expression of characters passing from one generation to the next. Homologous characters have a central role in piecing evolutionary history together. They are similar in form, similarly located positionally relative to other characters, share similar biological functions, and are explained by common lines of heritable descent. Novel (non-homologous) evolutionary traits originate by various means of induction, including genetic mutation, sexual recombination, behaviourally, developmentally, symbiogenetically, environmentally, and generally through modification of pre-existing foundations. The full physical expression of a lineage's traits is its phenotype and all the heritable information encoded at the molecular level is its genotype. Phenotypic variation is the product of a complex hierarchical, regulatory, and developmental network of genes that interact responsively to the environmental context. There is rarely a one-to-one readout from gene (the smallest heritable unit) to emergent phenotype. Variation within a lineage may evolve by random chance or become adapted by means of natural selection. For example, genetic mutations may have minute to no phenotypic effect and can drift stochastically in larger populations. Character adaptations, however, are non-random conformations of traits that confer a functional advantage securing or increasing reproductive output and consequent fitness. Common descent stretches back over 3.5 billion years since the origins of life on earth. Scientific evidence for common ancestry is overwhelmingly observed in the anatomy of organisms, genomes, the universal genetic code, the geographic distributions of species and their genes, behaviour, breeding experiments, during development, and in the fossil record. There are diverse kinds of evolutionary transitions over short and vast dimensions of space and time. From genes to morphology, the genealogical affinity among lineages is illuminated by comparative analysis of characters and their varied states among lineages. Character data is systematically analysed when framing, testing, and illustrating evolutionary hypotheses about genealogical relations. This kind of evidence reveals that evolution is the cause of speciation, whereby a single ancestral species branches into different species lineages. The scientific study of evolution began in the mid-nineteenth century, when research into the fossil record and the diversity of living organisms convinced most scientists that species evolve. In the early 20th century, Darwinian theories of evolution were combined with genetics, palaeontology and systematics, which culminated into a union of ideas known as the modern evolutionary synthesis. The synthesis became a major principle of biology as it provided a unifying explanation for common ancestry and diversification of life on Earth. Evolution applies universally to all fields in biology and has had a significant impact in the way that we view and practice science in natural resource management, medicine, computation, and philosophy in general.

Thompsma I tend to agree that a lot of what we have in the lead does not really need to be there. We are trying to summarize a lot there, and it is difficult sometimes to feel comfortable with it. At a certain point, when it is not possible to summarize in a way which is really short, like a summary is meant to be, it is best to just move stuff to sub-sections. Many busy articles have this problem, because people tend to want there favorite things right near the top of the article. Anyway, however, looking at your draft next to the current version, I do not see it is yet achieving your aims? It is longer, and also the sentences in it are longer. Also there a bits which would require further expansion before any person without specialist training could read them. I've done my normal comparison table trick below.--Andrew Lancaster (talk) 07:51, 29 September 2011 (UTC)

I agree with Andrew that the proposed alternative lead is too long, and the further edits that it needs to become acceptable would make it still longer. I think the real issue Thompsa is identifying is the balance between microevolution (sections 2-4) and macroevolution (section 6) in this article. Evolutionary genetics was irrelevant as a now-deleted stub, microevolution is the article that overlaps with, but is current inferior to, the evolution page in the ways that Thompsa identifies. I am open to changing this balance, but I think the way to do it to is to focus on strengthening the macro parts, not attacking the micro parts, which have finally become rather good.

Moving current content to microevolution and leaving a shorter summary here is certainly an option. (In fact, simply copying content to microevolution so it is identical on the two pages would at least help the microevolution page. Are there any rules against that sort of word of word replication?)

Thompsa, you do not need to first change the lead to "permit a new section to be added to this article on phylogenetics and evolutionary trees". Just write the new section. The lead should summarise the current article, which the current lead does. After the new section has been added, we will make the lead reflect that. When the macro parts are as strong as the micro parts of this article, we will reassess their balance, eg putting the macro parts first and the micro second might help. But I cannot support such a move right now, not until the macro parts are stronger. Please help make section 6 better, and let's have this discussion about the lead and the article as a whole after that has happened. Joannamasel (talk) 14:51, 29 September 2011 (UTC)

I second Joanna's recommendations. danielkueh (talk) 16:30, 29 September 2011 (UTC)

I agree that the suggested change was too long. I worked on it for a while and thought it was ready to post so that we could work together to cut it down and integrate. I am working on a phylogenetics section as well and hope to bring that over soon. In the meantime, my main concern with the lead was not really about micro v. macro evolution - although it could be interpreted in this way. I was partly thinking of the work by Kevin de Quieroz and his work on the lineage concept, which goes back to Simpson (which I also revisited when putting this together) - see [1], and [2]. If we can bring in the concept of lineages, homology, and tree-like thinking into the lead, then this will cover the whole hierarchy of evolution, from gene lineages to species lineages - the full scope of evolution is introduced. The current lead actually parallels very closely with a chapter that John Maynard Smith has in one of his classical books on evolution under the heading of evolutionary genetics and in a subsequent edition titled molecular evolution. When you read through the classical texts, most evolutionists covered subjects that went well beyond the concept of genetic mutation and the way natural selection is introduced seems too simplistic. The difficult part about lineages, evolutionary trees, and phylogenetic networks - I found - is finding way to bridge the tree-like metaphor to the modern network perspective, which is why I brought in Darwin's quote on "web of complex relations". I added mutualism in my lead sentence, because the topic of evolution has certainly expanded from the notion of 'struggle' for existence to one that also recognizes the cooperative aspect, with symbiogenesis being a major player in evolutionary novelty - as important as recombination and genetic mutation. I am open to moving sections to microevolution to help that page along. I think that we should work on the lead now and then bring the phylogenetic lineage perspective into the core of this article as we move along.Thompsma (talk) 16:55, 29 September 2011 (UTC)

I think at minimum that the lead should introduce: natural selection, genetic drift, evolutionary tree/lineage, genotype/phenotype, mutualism/symbiogenesis, homology, adaptation, heritability, & variation. The current lead spends a lot of space on explaining genes and mutation, which is not broad enough in my opinion.Thompsma (talk) 17:02, 29 September 2011 (UTC)

I'm new - but interested in evolution. I haven't posted in here before, but thought I would offer my 2 cents. The proposal by Thompsma seems to cover the topic more broadly, although it is a little complicated for the average reader. The proposal is an improvement, but some of the wording may be too advanced???142.207.42.142 (talk) 22:03, 29 September 2011 (UTC)

Does anyone have anything else to add about the recently cut version in the third column? Thanks for the table trick Andrew - it helps for the comparison. Can you think of any way to simplify the text any further? I think I have simplified it a bit further.Thompsma (talk) 01:35, 30 September 2011 (UTC)

I posted the previous comment (142.207.42.142), but now have an account. I like that the recent cut version by Thompsma starts out with Darwin and how it flows from the start to the end. The ending is improved, because I don't understand in the current version how agriculture, psychology, or any of the other lists in the final paragraph are not associated with biology? That paragraph stumbles a bit over the long lists of terms were thrown together at the end. I like that Thompsma's version focuses on lineages, it is a much more traditional description of evolution. "Novel (non-homologous) evolutionary traits" is a mouthful. Could it be changed to "Novel or derived evolutionary traits"? This sentence: "For example, genetic mutations may have minute to no phenotypic effect and can drift stochastically in larger populations" - is a little advanced, I think "stochastically" could be deleted: "many genetic mutations drift silently and under the radar of natural selection with minute to no change on the phenotype." Otherwise, I like the layout and the way it ends.Claviclehorn (talk) 04:36, 30 September 2011 (UTC)

OK, as there is now one supporter of the proposal, a bit more detail about my concerns:-

• It is all about common descent, which is a related but separable subject, not exactly the same as "evolution".
• It is longer.
• It does not have a clear flowing structure which gets to the point of explaining what evolution is. It seems to be about lots of other things.
• The wording is very awkward. (Some parts of the change proposal basically just make the wording more awkward.)

Instead of going through the whole thing, just the first sentence:-

Current lead	Thompsma proposals (both)
Evolution (or more specifically biological or organic evolution) is the change over time in one or more inherited traits found in populations of individuals.[1]	Evolution (or more specifically biological or organic evolution) is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically.

• Defining evolution as a change in "descent of lineages" is odd wording, but even when you spend time thinking about it, it is wrong. Descent of lineages is a process involving change over time. Evolution is that change, and not change in that change. (Or maybe, if we philosophize a bit, it can be used to refer to both, but it is certainly primarily the change itself, and can not only be change in the change.)
• The words "that form complex relations as they compete for existence, reproduce, and interact mutualistically" do not appear to be part of any definition. Or it is unclear if they are intended to do so, and if they are intended to do so, it is unclear how that can be justified. A bacteria living on its own can evolve.
• The word "mutualistically" is a weird word and not adding anything here because "interactions" and "complex relations" already are implied to be mutual. (Maybe this seems picky, but I think it is worth picking on this word a bit as an example of a bigger problem, because there are various strange wordings throughout the proposal.)

Just my 2 cents!--Andrew Lancaster (talk) 09:10, 30 September 2011 (UTC)

I second Andrew's concerns. Joannamasel (talk) 15:39, 30 September 2011 (UTC)

Well I think you are completely off base Andrew Lancaster - and this blockage on evolutionary ideas beyond bean bag genetics is to be expected. We have a current lead written mostly by you and Joannamasel - if memory serves me correctly, and you have jointly been defending the evolutionary genetic line for quite a while in here. This is not a personal attack and I do assume best intentions on both your roles, but it is a natural default of our psychology (mine included!) to favour our own ideas - you've introduced this notion before in your statements that everyone wants their favourite idea to go into the lead. It is to be expected that both of you would get cold feet on an introduction that goes into dark territory beyond the gene, but that territory was illuminated by Charles Darwin and thousands of evolutionary biologists after him. Please let others illuminate those corners and don't restrict this article on evolution down to the simple notion that evolution "is the change over time in one or more inherited traits (genes - one-to-one correspondence problem going on here) found in populations of individuals" = Beanbag Genetics. Evolution has a much larger canvas and it is painted with a cast of lineages that are not included in the current lead. Andrew's quote: "Descent of lineages is a process involving change over time. Evolution is that change, and not change in that change." Huh? Can you go over that again? That truly makes no sense and I have taken quite a few courses in philosophy. What was Darwin thinking when he wrote "Let us see how far these several facts and inferences accord with the theory of descent with modification" (i.e., evolution). Modification and change are synonyms and this "decent with modification" or "change in the descent of lineages" is qualified later in that sentence by introducing evolutionary concepts that have direct bearing on the modification of lineages.

Next part: "The words "that form complex relations as they compete for existence, reproduce, and interact mutualistically" do not appear to be part of any definition." Perhaps you are unfamiliar with the work of Charles Darwin who used the words "complex relations" repeatedly in The Origin, "compete for existence", also Darwin (although, he used "struggle for existence" and "compete" in other instances of the same meaning), "reproduce", goes without saying, and mutualism is NOT the same as interaction. Is parasitism mutualistic? Mutualism has a specific definition and it holds a special place in evolutionary theory. Lynn Marguilis has had a central role in writing on the importance of mutualism in evolutionary theory and many, many, many authors have taken up this issue. John Thompson is of particular note in this context and his writing on geographic mosaics and coevolution is very important in this context. Coevolution and symbiosis are interrelated terms that are broadly covered under mutualistic interactions. Coevolution is the nature of a host that harbours any other entity, the associate. Hosts and associates coevolve through diverse forms of interaction, which has been called a continuum and written about by many evolutionary authors (e.g., [3]) - the continuum runs from parasitism (covered under "compete for existence") to mutualism. "Symbiosis, as understood by de Bary and most modern biologists, includes outright mutualism only as a special case; what makes a relationship between different organisms symbiotic is that they include each other in their lifecycles (metabolic or reproductive) in some regular way."[4] The coevolution of lineages is a central theme in evolutionary biology throughout history, Darwin and Huxley highlighted the struggle (not exclusively), others have since expanded on the central role of mutualism in evolution. Here are some other example quotes highlighting the central role of mutualism in evolution:

• "Symbiosis is arguably not only an important adaptation but a source of evolutionary novelty that could be at least as important as mutation and recombination."[5]
• "From the algae that help power reef-building corals, to the diverse array of pollinators that mediate sexual reproduction in many plant species, to the myriad nutritional symbionts that fix nitrogen and aid digestion, and even down to the mitochondria found in nearly all eukaryotes, mutualisms are ubiquitous, often ecologically dominant, and profoundly influential at all levels of biological organization"[6]
• "Organisms interact with members of other species and clades all the time. Competition, predation, parasitism, and mutualism have been documented in all major environments..."[7]
• "Recent advances in our knowledge of parasitic and mutualistic associations have confirmed the central role of coevolutionary interactions in population and community ecology."[8]
• "Coevolution is one of the major processes organizing the earth’s biodiversity."[9]Thompsma (talk) 16:31, 30 September 2011 (UTC)

The threshold for inclusion of any material is WP:V. To resolve the issue of the definition of evolution in the lead would be to list definitions taken from a variety of secondary sources such as introductory or graduate level biology or evolutionary biology textbooks. I think once we have a list of how evolution is normally defined in the field, then I think a consensus can emerge as to how best to represent it faithfully here. danielkueh (talk) 16:44, 30 September 2011 (UTC)

This is not only a verifiability issue, but also very much a wording issue. We are not just transcribing blocks of texts, but actually trying to write a compact and flowing text which will be comprehensible for a wide readership. This aim is not necessarily the same as someone writing a textbook, a journal article, or indeed (in the other direction) a highschool textbook. (Yes, of course it should all be verifiable also.) Many of my concerns with the newest proposal are just that the wording is no longer clear, flowing and easy to read. I know it is not easy of course. We all find it difficult.--Andrew Lancaster (talk) 17:14, 30 September 2011 (UTC)

I agree. I am not disputing the need to be concise. In fact, I am all about concision. You should know me by now. :)

At the moment, the discussion on the definition of evolution in this article is heading towards a dead end. I would like to know if the definition proposed by Thompsma is indeed the prevailing definition of many secondary or tertiary sources, i.e., biology or evolutionary biology texts (high school, undergraduate, graduate, etc) or peer-reviewed review articles. If it is, then we should work to include it. If not, then we should just forget about it and move on, rather than quibble about its logic, coherence, etc. That was my point. :) danielkueh (talk) 17:20, 30 September 2011 (UTC)

OK, maybe I should state my point differently. I would like to see a clearly worded version of Thompsma's definition before I can comment on anything else like verifiability. I simply can't make it parse. This is possibly partly because of my lack of specialist training in biology, but maybe that is a good thing sometimes! :) --Andrew Lancaster (talk) 17:35, 30 September 2011 (UTC)

I am going to concur with Thompsma here. The current lead seems biased toward genetic evolution and it appears to set the tone for the remainder of this article, which is very gene centered - albeit it does branch into other areas. The current lead sentence: " change over time in one or more inherited traits found in populations of individuals." seems to only cover anagensis as Ernst Mayr addresses in his book - "What Evolution is". He states that Darwin saw two aspects to evolution, anagenesis (change) and cladogenesis (branching). "The study of cladogenesis is one of the major concerns of macroevolutionary research. Anagenesis and cladogenesis are largely independent processes." Thompsma's definition covers both these aspects and so it seems more consistent with a view held by a very prominent evolutionary biologist on what evolution is.

I am also confused by Andrew's statement "Evolution is that change, and not change in that change" - I'm sorry mate, but I am having a difficult time following your logic here. I'm new here, but reading through the editorial help pages to get some idea on the process. I found this information on the lead WP:Lead_section#Length and for an article this size four paragraphs seems reasonable. Thompsma's version is slightly longer, but the current lead accomplishes its short length in the final paragraph where it takes a shotgun approach to net all the ideas, "Evolution is currently applied and studied in various areas within biology such as:

1. conservation biology
2. developmental biology
3. ecology
4. physiology
5. paleontology
6. medicine.

Moreover...

1. agriculture
2. anthropology
3. philosophy
4. psychology

Phew!! That's a long list of terms that are not well integrated. My students use this kind of approach and squeeze a bunch of ideas in at the end of their papers. I suspect that this is what allows the current lead to gain its advantage in shortness. The final sentence: "Evolutionary biologists document the fact that evolution occurs, and also develop and test theories that explain its causes", is hanging out there very oddly. The current lead has a very narrow focus. Thompsma's version is better in my mind, because it but it could use a bit of work to shorten and simplify.Claviclehorn (talk) 19:15, 30 September 2011 (UTC)

Thanks for the support Claviclehorn! I didn't cite the host/associate distinction made in my previous comment, but it comes from Roderick Page's paper in Systematic Biology: "In this paper, I use the term "host" to mean any entity that in some sense harbors another entity, which I call the "associate." Examples of hosts (and their associates) are organisms (genes), host organisms (parasitic organisms), and areas (organisms)."[10] I put his quote up here, because this outlines a trend in evolution in general. Most evolutionary biologists do not just think of gene lineages, as this article presents. Page's quote is quite indicative of evolution in general - it is hierarchical. You can have gene lineages, cellular lineages, lineages of populations, and species lineages and these co-evolve. The coevolution is what is so important in context of Gould's (and others) concept that replication is not really the crux of evolution, but it is the interaction among parts where natural selection exerts its forces. The current lead does not capture this broader aspect to evolutionary biology, it is an attempt to distil evolution down to genetic fitness using a one-to-one correspondence between gene to trait and it does little justice to the diversity of lineages and work of evolutionary biologists working on topics other than population genetics. This is unacceptable.Thompsma (talk) 19:56, 30 September 2011 (UTC)

If we go to Matt Ridley's textbook on evolution, he states:

"Most of the processes described in this book concern change between generations within a population of a species, and it is this kind of change we shall call evolution. When the members of a population breed and produce the next generation, we can imagine a lineage of populations, made up of a series of poulations through time. Each population is ancestral to the descendant population in the next generation: a lineage is an "ancestor-descendant" series of populations. Evolution is then change between generations within a population lineage...Lineage: An ancestor-descendant sequence of: (i) populations; (ii) cells; or (iii) genes."

The last part defining lineage is taken from the glossary - lineage was emphasized in the original text. Most of what Ridley describes is microevolution (not surprising, since Dawkin's was his doctoral supervisor), which is why he states most, but he has chapters on macroevolution where he states: "We need to understand developmental evolution in order to understand morphological evolution. The same need not be said of molecular or chromosomal evolution: we do not need to study development in order to study molecular and chromosomal evolution. Some other kinds of evolution, such as behavioral evolution, can also have a developmental basis." Populations and lineages cross the hierarchical scale, such as cell lineage, or species lineage. You can find many references to "populations of" genes, cells, organisms, and species in evolutionary journals.Thompsma (talk) 20:24, 30 September 2011 (UTC)

(edit conflict)@claviclehorn; There might be a misunderstanding. I should not perhaps speak for Joanamasel and Daniel but I think we are all sympathetic to at least some of the principles being proposed. But there is no use putting in a new lead if it does not achieve those principles. It is very hard to write a lead for this article to suit everyone, but it is much easier to name some principles to be followed, and then write a lead which fails to achieve those aims. I think better drafts would get more positive responses, but no one is trying to say this is easy. We are in a long slow un-ending process ourselves here. Let's just keep looking at options. No one is trying to close the discussion.--Andrew Lancaster (talk) 20:29, 30 September 2011 (UTC)

@Thompsma. I like Ridley's writing, but his definition is nothing like your proposal. I'd say it is much closer to the one we have.--Andrew Lancaster (talk) 20:32, 30 September 2011 (UTC)

Andrew's first concern is: "It is all about common descent, which is a related but separable subject, not exactly the same as "evolution"." I would argue the opposite, the current lead does this. Thompsma's lead is about common descent and divergence. For example, "lineages that branch and diversify". This third paragraph begins with common descent, but then ends with speciation and divergence. The current lead talks much less about divergence and how divergence comes about. Another concern of Andrews: "It does not have a clear flowing structure which gets to the point of explaining what evolution is. It seems to be about lots of other things." It seems clear to me and flows nicely. Homology, adaptation, fitness, lineages - those all seem to be things that are clearly evolutionary. Not trying to pick on you Andrew, I just don't see what you are seeing. The last post by Thompsma on Ridley seems like a bit of a stretch to accommodate "his/her?" points, but previous points seem valid. I agree with Andrew that Ridley's definition is closer, but the content of the text covers the topic of evolution more broadly. Ridley admits that most of what the book is about micro-evolution and provides a definition of this, but this is an article about evolution in a broader sense and I think that is what Thompsma is trying to say.Claviclehorn (talk) 20:39, 30 September 2011 (UTC)

Page 1 in Collin Patterson's textbook on evolution [11] is closer to what I have written - a broader introduction to the topic. Ridley's definition is more appropriate for microevolution.Thompsma (talk) 20:51, 30 September 2011 (UTC)

Stearn's textbook on evolution [12] provides a balanced approach - defining both micro- and macro-evolution, which is my aim. The recent edition of Strickberger's evolution states: "Because evolution acts at genetic, organismal and population levels, a defintion ideally should reflect evolution at all three levels. In many respects, Darwin's concept of descent with modification remains an inclusive definition of (biological) evolution. Evolution is descent with modification, encompassing evolutionary change at genetic, organismal and/or poulation levels." - this is also closer to my aim. We have a choice - should we be inclusive or exclusive. My version is inclusive, because the microevolutionary version does not explain evolution broadly across all levels.Thompsma (talk) 21:10, 30 September 2011 (UTC)

This textbook [13] (I give the amazon link, because you can preview it better there) - follows very closely with my proposal.Thompsma (talk) 21:38, 30 September 2011 (UTC)

Just a side note. it is frustrating previewing these text books on Google Books as they cut out glossary pages listing words that start with the letter "E." It would be nice to have access to them so that we can list them all here. I only have ~ 5-6 references on my desk. It would be nice to have a larger and updated sample to view from. Sigh. danielkueh (talk) 21:56, 30 September 2011 (UTC)

The current lead devotes paragraph 1 to microevolution and paragraph 2 to macroevolution. One paragraph each seems a fair balance to me (the other 2 paragraphs are history and the science of evolutionary biology today). The proposed alternative leads attempts in many places to integrate micro and macro, and in other places deals only with macroevolution. It does not treat microevolution separately, eg it does not include the list in the current lead of the mechanisms of microevolution listed in the main article, namely selection, "genetic hitchhiking, genetic drift, and recurrent biased mutation or migration". This is a simple failure to summarise accurately the current content of the main article. Again, I feel that changes should be made to the main article before they are made to the lead. The lead should follow ;-)

To the best of my knowledge, all major textbooks that cover evolution as a whole are split between microevolution and macroevolution chapters. Wikipedia does not seem to be the place to attempt something so radically different. Especially when there are historians / philosophers such as Provine on record saying that no such close integration exists.

If integration cannot be achieved while doing justice to both micro and macro, then of course they should be treated separately, with justice done in turn to each. If so, then what this really comes down to i) which order should macro vs. microevolution go in, and ii) how should evolution be defined (which is different to explained). The proposed new lead relies very heavily on the term "lineage". If somebody is not clear what evolution is, they are going to be even less clear what a lineage is. On that note, I agree with Andrew "change in the descent of lineages" in the new lead parses as "change in change" and is not acceptable. I think the current first sentence is fine. The plural "populations" encompasses much in the definition. The proposed alternative first sentence contains many things that may be true, but which are peripheral to a definition. Joannamasel (talk) 01:58, 1 October 2011 (UTC)

As I stated previously, this is not just about a battle between micro- and macro-evolution. This is about adding core elements in evolutionary theory that are completely missed in this entire article, homology being one of them. If you read Ridley's definition - he states very clearly that "most" of what he covers in his text is microevolution. In his later chapters on macroevolutionary problems (which I interpret to be the other minor part not covered under his most definition) he states that you cannot understand morphological evolution by building up from the genes alone, you need to study development. I disagree with Andrew and Joannamasel that "change in the descent of lineages" parses as "change in change". It is as though you are arguing that Darwin's "descent with modification" is nothing more than "descent with descent" or "modification with modification". Imagine an alternative situation where you have descent of lineages without change (i.e., a static view), i.e., "descent without modification" - making Darwin's statement tautological without meaning, which is absurd. Joannamasel states: "The current lead devotes paragraph 1 to microevolution and paragraph 2 to macroevolution." - I don't see it this way at all. The first paragraph attempts to define the evolution via evolutionary genetics by falsely implying that this explains evolution in general.

Joannamasel keeps trying to deflect this debate by saying we shouldn't work on the lead, but move into the body. I reject this - we are here to edit the article and right now the lead is what concerns us and this is what we are discussing. The issue is the lead and I feel comfortable discussing it at this point in time, because it sets the tone for the rest of the article to follow where the problems from the lead are replicated. The first sentence in the current lead is not fine, because it erroneously misses the generation component - it refers to change over time, but compare this with the definition offered in the following paper in Evolution [14]: "Evolution is change in organisms over time with the minimum time being one generation. Hence evolutionary change is observed between organisms of one generation and their descendants." - so you can see how important it is to clarify that we are dealing with generations and descendant relations (i.e., lineages).

The previously linked paper [15] can help in this debate, because it compares definitions and looks for universal definitions of evolution. The author states: "Evolutionary change is usually defined as genetic which would exclude both cultural and template evolution; hence the qualifying adjective genetic should not be included in the definition of biological evolution." The current lead gives only a genetic definition of biological evolution - the token gesture to expand its scope by placing "trait" in there does not give due credit to evolutionary concepts that look beyond the gene. The third sentence proves my point: "New variants of inherited traits can enter a population from outside populations, and this is referred to as gene flow." - Gotcha! This is the one-to-one correspondence I am talking about. This is not gene flow - "new variants of genes can enter a population" - the current lead oddly describes is 'trait flow', which is something I have never heard of!!

The text by Patterson [16] provides a summary of six evolutionary propositions: Reproduction, Excess (superfecundity), Variation, Environmental Selection, Divergence, Common Ancestry. All are covered in the proposed lead. Mayr offered five propositions of evolution: Nonconstancy of Species, Common Descent, Gradual Evolution, Multiplication of Species, Natural Selection. Most of these points are missed in the current lead - because it provides a gene only perspective in the first paragraph, giving primacy to this notion that it can explain all of evolution. Clearly: "All phyletic evolutionary change, no matter how extensive it may be, never crosses species taxa boundaries; hence it is not possible to distinguish �trans-specific evolution� (evolution beyond or above the level of the species) from evolution within the species level."[17] The proposed lead only misses the proposition of gradualism and gives a generic statement "There are diverse kinds of evolutionary transitions over short and vast dimensions of space and time." - which broadly covers the debate, the finer details can be covered in the article. Moreover, gradualism in Darwin's time did not mean the same thing as it does today - "In Darwin’s day, “gradual” often meant steplike"[18], - there has been lots of debate on Darwin's gradualism with the consensus that he did not discount stasis followed by rapid change.

Joannamasel states: "The proposed new lead relies very heavily on the term "lineage". If somebody is not clear what evolution is, they are going to be even less clear what a lineage is." - Really? You think people are going to be confused on what a lineage is (even though family lineage is a colloquial term that my five year old understands) yet you want to define gene flow by the flow of traits from one population to another and somehow think that this will not confuse the reader? It is really telling when you have a problem with an article on evolution and want to critique a proposed lead because it relies heavily on the term lineage. I'm trying to offer a more inclusive lead and think that this is more in tune with the spirit of wikipedia and the sciences dealing with evolution in general.

We can adopt one of the definitions below that subscribe to the notion that you can have a reductionist account of evolution with genes as the singular level of causality, but then how do we integrate that with the views of Gould and other prominent evolutionary biologists who championed opposing views to this? Gould argued that Darwin was a reductionist in the sense that he viewed organisms as the locus of selection - "Darwin's theory therefore presents, as the primary underpinning for its radical import in philosophy, a "reductionst" account of broadest-scale phenomena to a single causal locus at a low level accessible to direct observation and experimental manipulation: the struggle for existense among organisms."[19] Gould was not alone in this critique. I suggest that instead of accepting a textbook definition, for which there are diverse options - that we give a very general definition that covers the spectrum of thought from Dawkins to Gould (if you want to paint it that way). More than this, however, my main concern is that the current lead is fragmented and misleading in many respects - the sentence on variation is a tragedy.Thompsma (talk) 20:55, 3 October 2011 (UTC)

Two cents on proposed lead

Evolution is far more than what Darwin described. We know now much more than he knew, just consider the New Synthesis etc. Evolution is change over time. Nothing more and nothing less. Restricting this term, or focusing on specific mechanisms at the expense of other mechanisms basically results in a biased article. The proposed new version is way to much focused on one mechanism, namely natural selection. Genetic drift does also result in change, but does that without differential reproduction linked to heritable traits. Despite the fact that Darwin is at the start of our understanding of evolution, his ideas have been superseded multiple times and we should focus on where we are now, not then. So, instead of focusing on definitions that highlight one or the other mechanism or aspect, keep it simple. If we really want to rewrite the lead, I suggest making a bullet list of key word about what is REALLY ESSENTIAL. And that is far less than what most think. -- Kim van der Linde ^{at venus} 21:27, 3 October 2011 (UTC) P.S. The Natural selection article is skewed similarly to evolution by means of natural selection, not natural selection as a process.

Kim van der Linde states: "The proposed new version is way to much focused on one mechanism, namely natural selection." - natural selection is a problem? The sentiment of your critique is false: "Variation within a lineage may evolve by random chance or become adapted by means of natural selection. For example, genetic mutations may have minute to no phenotypic effect and can drift stochastically in larger populations. Character adaptations, however, are non-random conformations of traits that confer a functional advantage securing or increasing reproductive output and consequent fitness." Hence, the lead does not focus too heavily on one mechanism - it explains genetic drift. It offers a more inclusive synthesis beyond genetic reductionism.Thompsma (talk) 21:38, 3 October 2011 (UTC)

No, the focus oin netural selection is the problem. Here is the first paragraph of the blead as proposed by you:

Evolution (or more specifically biological or organic evolution) is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically. In his landmark scientific text on evolution, "On The Origin of Species", Charles Darwin refers to the "great tree of life", "a web of complex relations", and he includes a single illustration of an evolutionary tree. The tree represents common ancestry among lineages that branch and diversify into "endless forms most beautiful and most wonderful". Lineages form through recursive generations of biological reproduction among all individuals in the biological hierarchy, including genes, cells, organisms, and species. A core theory of evolution proposed by Charles Darwin is natural selection. Natural selection applies to all lineages that interact in the biological hierarchy and is formulated on three recurrent facts, including 1) heritability, 2) variation, and 3) the overproduction or superfecundity of offspring. Heritability is the faithful expression of certain characters from one generation to the next. Homologous characters play a central role in evolutionary theory. A homologous character is similar in form, similarly located anatomically or positionally relative to other characters, and they share similar biological functions. Homology is explained by a common line of heritable descent.

I bolded the NS sections, while I do not read ANYTHING about genetic drift. This goes way to fast in specific mechanisms that are only the underlying explanations of evolution. What we have to do is explain biological evolution before going into the processes that result in evolution. -- Kim van der Linde ^{at venus} 18:21, 4 October 2011 (UTC)

The proposed lead covers both genetic drift and evolution by natural selection. It offers a balanced overview in my opinion. I will side with Thompsma that the current lead and article is too gene centered. I also disagree with the following: "Evolution is change over time. Nothing more and nothing less." The topic of this article is biological evolution - the disambiguation pages at the top of the article gives that broader definition of evolution that you are after here. It seems to me that Thompsma is trying to introduce the essential components of evolution, whereas the current lead implies that the essential components of evolution can be explained by micro-evolution scaled up. This is a classic debate in evolutionary theory and it cannot be resolved here. I think Thompsma is on the right track by trying to be more accomodating of the broader principles. Perhaps this is a bias that we share, because I am more inclined to side with Stephen Gould as Thompsma appears to be. My education background is in geology with a minor in paleontology.Claviclehorn (talk) 22:02, 3 October 2011 (UTC)

"Evolution is change over time. Nothing more and nothing less." We are talking about biological evolution here, so to criticize me of not including the word biological is cheap.-- Kim van der Linde ^{at venus} 18:35, 4 October 2011 (UTC)

Hi Kim van der Linde - please take a look at the lead to the current article: "Evolution (or more specifically biological or organic evolution)" - it is not a cheap shot, this issue is already addressed at the front end of this article. This article specifically looks at biological evolution, not evolution in the more general sense.Thompsma (talk) 21:26, 4 October 2011 (UTC)

I experienced as a cheap shot. All the participants at this talk page use the Evolution shortcut for Biological evolution. Or do you always put the biological qualifier in front of it? -- Kim van der Linde ^{at venus} 21:33, 4 October 2011 (UTC)

I wish to remind everyone (myself included) that at the end of the day, it doesn't matter what position you adopt or what your POV of evolution is or who you support. What counts here are WP:NPOV, WP:V, and WP:OR. These policies are fundamental. I myself have had to learn them the hard way. So whatever direction we take here, it must be in line with these three policies. Otherwise, the discussions will get nowhere. danielkueh (talk) 22:14, 3 October 2011 (UTC)

I agree Danielkueh, but unfortunately those guidelines are not helping us out in this debate. There are many citations that support the expanded synthesis and many citations that present the genetical view of evolution. My understanding is that the expanded synthesis is more in tune with WP:NPOV and WP:V because the reductionist genetical view (current lead) cannot encompass the expanded synthesis (new proposal) that was championed by Darwin, Gould, Eldredge, and more recently by other evolutionary biologists such as Pigliucci, Samir Okasha, and many others. If we want to present on this topic "fairly, proportionately, and as far as possible without bias" - it seems that we are obliged to present the expanded synthesis because it accommodates the reductionist genetical view, whereas the alternative cannot be accomplished. There are many WP:V that support this sentiment.Thompsma (talk) 23:03, 3 October 2011 (UTC)

Thompsma, if I have to pick one definition, it would be the one (see below) by Bock (from the reference you gave above). I think it is the best paraphrase of Darwin's Descent with modifications. It is broad, simple, fulfills WP:V, and is consistent with all the other definitions listed below. I agree that the current definition is, for a lack of better word, "half-ass." Either we define the lead definition in gene-centric terms, which allows for a better and more coherent flow to the rest of the first paragraph or we don't at all, which means rewriting the first paragraph. In any event, one question needs to be resolved, "What is the role of the lead?" I may be oversimplifying things but Joanna's position seems to be that it should be a summary or an abstract of the entire article. You prefer a lead that serves as an introductory prelude to the rest of the article. I think this needs to be resolved first, otherwise I suspect people will be talking past each other. danielkueh (talk) 23:33, 3 October 2011 (UTC)

I was afraid that you were going to suggest Bock! He also authored a paper refuting Wallace as a co-discover of evolutionary theory[20] - an argument I support. However, with respect to his definition the unfortunate side to it is that it puts the emphasis back onto the organism, which is what Gould tried so hard to reject. Hence, it is not consistent with all the other definitions - even those listed below. While I accept that Bock's citation is certainly WP:V - it goes back to the core problem:

"In its purest form, theoretical extrapolation goes beyond predictability of outcome to continuity of process, holding that organism-level selection, along with the other canonical forces of microevolution such as drift, is the exclusive focal level of evolution. By contrast, some authors have argued (convincingly, in my view) that the logic of natural selection and other evolutionary forces need not reside exclusively at the organismic level: differential success of heritable variation owing to interaction with the environment, the Darwinian dynamic, also occurs at higher and lower levels."[21]

This is what the expanded synthesis is trying to correct, because the integrative view has been ever persistent in the evolutionary literature, including and since Darwin. I prefer a lead that introduces the topic of biological evolution, not a contrivance of sorts. It is a peculiar thing that some refer to evolution in the most general sense of any form of change, but as soon as they talk about it in biological terms they want to refer to genes or traits as though they are single entities as in the rare case of Mendelian one-to-one gene to phenotype matches. Those kinds of traits are very rare. Evolution is hierarchical and integrative as WP:V articles in the journal of evolution and even mainstream textbooks have noted. Evolution is much more than the population-trait replacement theory that is being introduced in the current lead. It does not matter if people agree or disagree with the expanded synthesis, the point is that key evolutionary concepts from Conrad Waddington, Rupert Riedl, Stephen J. Gould, Niles Eldredge, and a longer list of evolutionary biologists that championed their ideas over the past 100 years are being sidelined in the current lead - including Darwin's own views on evolution. In my view, sidelining these champions gives a biased view on evolution.

I'm not going to abandon the lead and then dive into the article to battle out every little point on genes - tried that already. There are >200 references to genes in the body of the article, 8 references to phenotype (none in the lead), 49 references to trait (mostly genetic), 9 references to fossils, 6 references to morphology, 6 references to anatomy, 2 references to hierarchy, 4 references to homology (never explained), 7 references to tree, 3 references to paleontology, 4 references to lineage. Gene's trump trees in an article on evolution - zero mention of geology - how can that be?! The bias is clear, this article is about genetic evolution missing the rich contextualization that made evolution a unifying theory for biology and I would like to correct that error. There are few editors in here who have monopolized the genetical view of evolution, they are policing it into the lead and the body, and I think that this is wrong. It is my goal to set the tone in the lead for the rest of the article - gene jockey evolution belongs in a separate article. If we can define evolution in the lead in a way that accommodates the perspectives and evidence presented in WP:V, then authors will have a better guide and freedom to move forward. If the lead suggests that evolution is reduced to population level sorting of traits, then it will remain a battle throughout the rest of the article as that perspective will always trump the alternative and integrative theory of evolution in Darwinian terms; speaking from personal experience.

The ideas I'm presenting here are not radical - they exist in the literature (WP:V) of the great champions of evolution, including Darwin who's perspectives oddly seems to be ignored a great deal in lieu of a reductionist genetical theory. Genetic evolution is swamping out the important work of anatomical/morphological (eco-evo-devo) work because it seems impressive, it is technologically 'advanced', and it has become cheaper to sequence a gene.[22] However, those are not reasons to discount the value of evolutionary knowledge that has been obtained otherwise. I'm not trying to create a lead that serves as a comprehensive introductory prelude to the rest of the article, but I am trying to write an abstract in the lead that is more inclusive of the theory as it is presented by Darwin and his evolutionary descendants. Do we want an abstract on evolutionary genetics or an abstract on biological evolution? This does not require that every idea be included in the lead, just an overview that is inclusive and integrative as evolution always has been.Thompsma (talk) 02:06, 4 October 2011 (UTC)

I understand your attachment to Gould et al. I have read his work and liked much of what I read. However, I don't think it is productive to keep referring to them or to frame this discussion as genes/Dawkins vs Gould, etc. Because the reverse can be done and it often leads to more confusion and deadlock. So let's stick to what the sources are saying below WP:V and see how best to represent them here WP:OR. That way, we can make progress in these discussions WP:consensus. danielkueh (talk) 14:14, 4 October 2011 (UTC)

• I find both Thompsma's proposals to be a change for the worse. It is simply bad writing based on rather idiosyncratic jargon. They both turn relatively clear intelligible prose into obfuscating wordiness and overcomplex prolixity. The definition "change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically" is so convoluted that it almost doesn't make sense, and it is unclear that it in anyway constitutes an improvement in precision over the previous wording. Evolution can be defined much clearer in a single simple sentence: "change in the frequencies of heritable traits in a population". The long description of Darwin's original text is completely unnecessary. This could be spent on explaining what evolution is instead of How Darwin explained what he thought it was. We should generally never use quotes in the lead, especially not without very good motivation, such as because the information in them cannot be provided as well otherwise. This is not the case here. What is with the focus on lineages? That doesn't seem justified. "Heritability is the faithful expression of characters" huh? Furthermore the proposed leads doesn't give any impression of the history of evolutionary theories from Lamarckian evolution to the new synthesis OR of the actual history of evolution from simple to complex organisms. Both kinds of history are of course necessary to summarise in the lead. Let's keep working. And my advice to Thompsma is to try to simplify his writing style as if he was writing for a child. This is an encyclopedia written for everybody, not for those who are already experts in the field. And in fact I think most experts would be bothered by that writing style to, the experts I know all appreciate clear concise writing with sparse use of jargon.·ʍaunus·snunɐw· 14:44, 4 October 2011 (UTC)

If that is the case and if that is the general consensus, then the status quo remains. So it is back to doing minor tweaks. danielkueh (talk) 16:59, 4 October 2011 (UTC)

I recently joined wikipedia because I was interested in this particular debate. I have a few concerns with ·ʍaunus's critique. First, I disagree that the proposed lead is filled with jargon. It is filled with traditional evolutionary concepts that are familiar to even myself, a novice: common descent, lineages, reproduction, ancestral-descendant, biological hierarchy, natural selection, heritability, variation, homology, phenotype, genotype, adaptation, and drift are all covered and very reasonable entries. It seems that Thompsma is trying to use "lineages" as a means to create an "integrative" consensus in the way that the Hall (2011) textbook defines evolution below. The proposed definition is not convoluted in my mind, but I agree that mutualistic is novel relative to the other definitions out there. However, I see that Thompsma is trying to balance the classical competitive angle (struggle) with the modern cooperative angle (mutualism), which makes sense in light of all the work that has been published on co-evolutionary relationships. Perhaps the solution might be to break the sentence into two parts: "Evolution (or more specifically biological or organic evolution) is change in the descent of lineages. Lineages form complex relations as they compete for existence, reproduce, and interact mutualistically." This would require moving the definition of a lineage up from the fourth sentence.

·ʍaunus wrote: "The long description of Darwin's original text is completely unnecessary. This could be spent on explaining what evolution is instead of How Darwin explained what he thought it was." This is a peculiar point, the description is not "overly" long and I think Darwin is relevant. It seems like Thompsma is trying hard to reconcile a lot of the modern literature - in this example he refers to Darwin's "web" and "tree", which is a point that has been raised in the literature, is it a tree or a web (e.g., [23],[24])?

"What is with the focus on lineages?" Answer: This is an article about evolution and I hope that you can make the connection. Darwin regularly referred to lineal descent as have many other evolutionary biologists, it seems to be a very common thread in evolutionary writing.

"Heritability is the faithful expression of characters" - this is a classical definition of heritability as I am aware of it, I've seen the use of 'faithful' transmission from one generation to the next being used for heritability and usually it refers to the entire trait. In this case Thompsma chose to use the term that most phylogeneticist use "character". It seems clear to me. "Furthermore the proposed leads doesn't give any impression of the history of evolutionary theories from Lamarckian evolution to the new synthesis" - the current lead is vague in this way as well. Furthermore, the last two paragraphs in Thompsma's proposal summarizes common descent from 3.5 billion years ago and it gives an abstract of the history. Thompsma's proposed lead does not mention geology or the social and cultural responses, that could be added to the very end. I agree that the proposed text by Thompsma can be reworked, but I think Thompsma's lead proposal offers the superior abstract because it presents a broader and more classical view on evolution that is lacking in this article. I realize that I've entered into a long debate, but I've been reading through this and think that Thompsma's ideas have not been given due credit.Claviclehorn (talk) 18:26, 4 October 2011 (UTC)

If I have to think of a parallel to summarize the current discussion, it would something like this. Imagine another editor who is the equivalent of Thompsma when it comes to physics, and wants to introduce the concepts of general and special relativity to the physics page in the lead early on. No one of course would doubt the importance of relativity. But as a matter of communication and style, most physics books and primers do not begin with Einstein relativity but with Newtonian mechanics/Classical physics. Because Newtonian physics, for all present purposes, correct for a wide range of observations. Its limitations become clear of course as one observes objects approaching the speed of light. I see the same thing here. Yes, no doubt, there has been an extended synthesis and that there are more than sufficient amount of literature to support that. So the question I think we are grappling here with is how best to introduce and communicate a fairly complex topic such as evolution. Like Newtonian mechanics, the modern synthesis or Neo-Darwinian view is not complete. Nevertheless, like Newtonian mechanics, the Neo-Darwinian view serves as a foundation that can be build upon, which is no surprise that many textbooks start with it first. I agree with Thompsma that this article needs more than just the bear bones "gene-centric" view. I am just not sure introducing concepts such as trees, webs, etc so early and so quick is the best to do that. Otherwise, it is just unintelligible, except to individuals who are familiar with the literature. I suspect that is what Maunus was getting at when he found the proposed substitutes "convoluted that it almost doesn't make sense" danielkueh (talk) 19:51, 4 October 2011 (UTC)

"I am just not sure introducing concepts such as trees, webs, etc so early and so quick is the best to do that." - Actually, I'm of the opposite opinion. I think that 'tree-thinking' is a cornerstone of evolution and it is precisely that kind of tool that is proposed for teaching evolution to a beginner class. This is the heart of the problem in this article. Too many people are thinking in individualistic terms of evolution acting on genes or traits in replicating isolation instead of thinking and presenting like an evolutionist using trees to organize the clutter that has built up in here. Evolutionary trees are exactly what is needed from the very onset. My contention with the current lead is no so much about micro- v. macro- evolution, it is about the lack of tree-based evolution. Darwin strongly emphasized genealogical relations and phylogenetic trees is the cornerstone of evolution, it is how evolutionary biologists depict, test, and teach evolution. The branches of an evolutionary tree show the different lineages. Evolutionary trees can be used for gene, cell, or species lineages and neatly illustrate the character transformations and patterns through space and time. Evolutionary biologist use trees precisely because they summarize the data so well and it is exactly this kind of tool that will help this article along.Thompsma (talk) 21:26, 4 October 2011 (UTC)

Tree thinking eliminates major swats of what evolution is. Darwin emphasized five different concepts, of which trees (aka common decent) was only one. So, no, limiting a definition to lineage changes is not going to do it. Most evolutionary changes do not result in trees, but in evolutionary dead ends. -- Kim van der Linde ^{at venus} 21:38, 4 October 2011 (UTC)

List of definitions of evolution

In the hope of trying to resolve the discussion of how evolution should be defined in this article, I listed a few definitions taken from the glossary sections of a few textbooks and peer-reviewed journals. If any of you have some spare time and have access to a general biology, evolutionary biology text, or a specialized biology text, please add the definition of evolution from your text, preferably taken from its glossary section, to the list below. I think it will help move the discussion along. danielkueh (talk) 22:42, 30 September 2011 (UTC)

Perhaps it is notable that the two most recent textbooks on evolution (published in 2011, one by Hall and the other by Arthur) diverge from the gene-population based definitions. Arthur (2011) is also as explicit as Hall (2011) about this: "The overly population-based approach to evolution is now giving way to a more integrative approach - one in which the process of development that turns fertilized eggs into adults is seen as being important to the evolutionary process in a variety of ways." Hence, the two most recent textbooks on evolution are adopting what has been the general integrative trend in evolutionary biology of the past century. This is my goal - to present this integrative view, which is more mainstream, modern, and surprisingly consistent with Darwin's original presentation. Thompsma (talk) 23:34, 3 October 2011 (UTC)

General biology books

• Evolution: Descent with modification; the idea that living species are descendents of ancestral species that were different from the present-day ones; also defined more narrowly as the change in the genetic composition of a population from generation to generation. Campbell and Reece (2008) Biology, 8th ed.
• Evolution: Any gradual change. Organic or Darwinian evolution, is any genetic and resulting phenotypic change in organisms from generation to generation. (See macroevolution, microevolution; compare with speciation.) Sadava et al. (2008) Life: the science of biology, 8th ed.

Evolutionary biology books

• Evolution: In a broad sense, the origin of entities possessing different states of one or more characteristics, and changes in their proportions over time. Organic evolution, or biological evolution, is a change over time of the proportions of individual organisms differing genetically in one or more traits. Such changes transpire by the origin and subsequent alteration of the frequencies of genotypes from generation to generation within populations, by the alterations of the proportions of genetically differentiated populations of species, or by changes in the numbers of species with different characteristics, thereby altering the frequency of one or more traits within a higher taxon. Futuyma (1998) Evolutionary biology, 3rd ed.

• Evolution: Darwin defined it as "descent with modification." It is the change in a lineage of populations between generations. Ridley (2004) Evolution, 3rd ed.

Other specialized texts

• Evolution: A change in gene frequencies over time in a population. Evolution can result in adaptation, or can be nonadaptive. Hill et al. (2004) Animal physiology. 1st ed.
• Evolution: Descent with modification; DNA sequence variation and the inheritance of variation. Madigan et al. (2009) Brock Biology of microorganisms. 12th ed.
• Evolution: the accumulation of genetic changes in populations of living organisms through many generations. Stern et al. (2008) Introductory plant biology. 11th ed.

Peer-reviewed review articles

• Evolution: change in organisms over time with the minimum time being one generation. Hence evolutionary change is observed between organisms of one generation and their descendants. Bock WJ (2007) J Zool Syst Evol Res 45: 89-103
• The following article, for those with access [25] contains a table listing many diverse definitions, e.g.:
  • Cumulative changes in the average characteristics of a population generally thought to occur over many generations. Campbell, Loy, and Cruz-Uribe (2006)
  • Process of change within the genetic makeup of a species over time. DeCorse (2000)
  • The systematic change through time of biological organisms or human cultural systems. Feder (2007)
  • Belief that species arose from others through a long gradual process of transformation or descent with modification. Kottak (2006)
  • A change in the genetic structure of a population from one generation to the next; the term is also frequently used to refer to the appearance of a new species. Lewis, Jurmain, and Kilgore (2007)
  • The process of change over time resulting from shifting conditions of the physical and cultural environment, involving mechanisms of mutation and natural selection; human biology and culture evolved during the late Miocene, Pliocene, Pleistocene, and Holocene. Price and Feinman (2008)
  • A change in the frequency of a gene or a trait in a population over multiple generations. Stanford, Allen, and Antón (2008)
  • Change in the frequencies of alleles within a gene pool of a population over time. Stein and Rowe (2006)Thompsma (talk) 22:55, 3 October 2011 (UTC)

Other evolutionary biology textbooks

• Biological evolution (sometimes referred to as organic evolution), however, means change in the characteristics of descendent populations of organisms. Theories of biological evolution set out to explain diversity amongst organisms, the origin and history of that diversity, and the natural processes by which it has developed and by which it is sustained. Skelton (1993)[26]

• Evolutionary biology aims to understand the diversity of life and the processes responsible for shaping it. It does so at two levels and on two timescales. At the level of populations and on a relatively short timescale, it investigates how traits become well adapted to the job of survival and reproduction. On a longer timescale, it investigates the processes that produced the diversity of life now and throughout the fossil record. Stearns & Hoekstra (2000)[27]

• Evolution: the result of an interplay between two things-heritable varation and natural selection-it is not explicable by either of these on its own. Arthur (2011), Evolution: A developmental approach.[28]

• Evolution now is recognized as hierarchical; genes, structures, populations, species and ecosystems all evolve...In many repsects, Darwin's phrase descent with modification...remains an inclusive definition of biological evolution. Evolution as descent with modification encompasses evolutionary change at genetic, organismal and population levels, although integration of all three levles is required to fully comprehend evolution. Hall (2011) Evolution: Principles and Processes[29]Thompsma (talk) 22:38, 3 October 2011 (UTC)

• comment This is a very good way to go about it. It is clear that the definition proposed by Thompsma is not compatible with standard definitions that converge on the gradual process of descent with modification leading to changes in frequencies of heritable traits in a population. We cannot simply adopt the newest definitions without having seen how they are going to fare in the years to come. We have to give a definition that is as close to a general consensus among recent definitions as possible. Also the definitions by Hall and Arthur are not in fact full definitions, they are partial definitions that define a particular perspective on evolution, not the general concept. I particularly like Stearns and Hoekstra's definition because it includes the implications of evolution - micro evolution through natural selection and the macro effects of speciation and diversification of life forms. ·ʍaunus·snunɐw· 14:48, 4 October 2011 (UTC)

·ʍaunus - by the time those definitions arrive in textbooks - they have already 'fared' in previous years. This is the very reason why we turn to textbooks to gain a mainstream perspective. They are not the 'newest' definitions, but textbook summaries of many previous years of peer-reviewed literature. You are also incorrect in your statement that "the definition proposed by Thompsma is not compatible with standard definitions". My definition is entirely compatible - it is more general because gene lineages exist in populations: "change in the descent of lineages", those lineages include gene lineages, cellular lineages, organismal lineages, and species lineages. I also like the Stearns and Hoekstra's definition, but we can't plagiarise a definition either and their definition is too long. The general nature of my lineage proposal solves this problem without explicit reference to micro- v. macroevolutionary distinctions. Lineages are by their very nature hierarchical, gene trees sort within species trees where you find your changes in allele frequencies.[30] This chapter[31] from the "The Major Transitions in Evolution Revisited" outlines this whole debate. Here are some highlights:"That simple picture of the relationship between microevolutionary change and the macroevolutionary pattern has never been completely accepted (for an overview, see Depew and Weber 1995)...The central status of the organism as unit of selection also came under question...But the status of the organism also began to be questioned in broader contexts. One was historical. In 1987, Leo Buss’s Evolution of Individuality argued that individuality was a derived character, and that the unit of selection could itself change over the course of evolution...These issues are still being debated, though with increasing consensus and theoretical clarity (West, Griffin, and Gardner 2007). Perhaps the most important result of this debate was the focus on the importance of cooperation, and its relevance at all levels in the hierarchy of life (Michod and Herron, 2006). In particular, it has become clear that cooperation has played a deep and important role in the evolution of life’s complexity, resulting in alliances both within and across species, and producing stable, reproducing, units that can be treated as individuals in their own right within a Darwinian framework. Last, claims that developmental biology had been “left out” of the modern synthesis began to emerge...So the simple, Fisherian model of variation is slowly being replaced by more realistic alternatives...One response to these challenges, though a dull one, would be to maintain that the standard narrative is essentially true, but with exceptions." The current lead is not only taking the dull route, it is ignoring the most recent and up to date understanding of evolution - developmental modularity in butterfly wing is a great example of evolution that cannot be explained by the current lead, but it is covered under the notion of cell lineages - hence the generality of the lineage concept I am proposing. Two key points not addressed in the current lead are: "Evolution is more than repeated rounds of microevolution"[32] and "the phenotype is not merely, however, a one-to-one readout of the genotype."[33]Thompsma (talk) 15:21, 4 October 2011 (UTC)

"To clarify, here the term lineage refers to an ancestor-descendant series (Simpson, 1961; Hull, 1980) in this case of metapopulations or simply a metapopulation extended through time (cf. Simpson, 1951). It is not to be confused with a clade or monophyletic group, which is sometimes also called a lineage but is generally made up of several lineages (separate branches). The term metapopulation refers to an inclusive population made up of connected subpopulations (Levins, 1970; Hanski and Gaggiotti, 2004)...Finally, a species is not an entire metapopulation lineage but only a segment of such a lineage. The point here is that species give rise to other species, thereby forming (species level) lineages. Any given species is but one of many segments that make up such a species level lineage."[34]Thompsma (talk) 15:31, 4 October 2011 (UTC)

I disagree that because one recent textbooks uses a slightly different definition this means that this is now the general consensus and previous definitions are dismissed. I agree that the lead should give a better picture of the differences between micro and macro evolution and an inclusion of the genotype/phenotype relation including possibly more space for e.g. epigenetics and other gene/environment interactions. I am unsure whether the view of symbiosis as a general factor in evolution is so generally accepted that it needs to be mentioned in the lead - if we can show that it is I do not mind including it in someway, but your inclusion of the phrasing "mutualistic" doesn't really give a good understanding of that anyway.In general I think you could help your self and others by using an approach to writing that adopts the approach of "less is more" - also in your talkpage comments. They are very longwinded and hard to get through, that does complicate communication. Please try to aim for concision, that helps your readers a lot. ·ʍaunus·snunɐw· 15:34, 4 October 2011 (UTC)

snunɐw· - thanks for the feedback on my longwinded comments - point taken. That critique has been given before and I agree with it, but get carried away - so I apologize. The latest textbooks do not 'replace' or 'dismiss' the previous definitions, they accommodate them - this is what the authors of the expanded synthesis have been saying as well. They are not dismissing the population-based genetic view, they are saying that it offers an incomplete picture. Hence, they not only accommodate the previous definitions, they integrate the very issue that you have outlined in your post about the genotype/phenotype relation. Moreover, the Patterson textbook - which is older - offers an integrative approach, so these ideas are not new. My goal here is to offer a general definition of evolution in the lead. The current lead offers a specific definition of evolution that excludes a lot of recent and historical elements. In the spirit of wikipedia we should be giving a more general overview and otherwise direct the reader to more specific pages, such as microevolution. I am also open to the removal of mutualistic or any modifications consistent with a general overview of evolution, but I am not open to a gene-centred only lead.Thompsma (talk) 15:43, 4 October 2011 (UTC)

I think we should be able to find a way to avoid an exclusively "gene-centered" lead, but it requires that we have an overview of how mainstream sources from the last decade handle that task. ·ʍaunus·snunɐw· 17:47, 4 October 2011 (UTC)

With so many slightly different definitions, choosing either of them is going to introduce bias. However, we can distill a generic definition from them. Ultimately, evolution is a change in the heritable component. Yes, there are newer textbooks that focus a bit more about the developmental aspects, but this is a fine-tuning, not a replacement of the gene-based idea. We have to be careful to see fine-tuning of the mechanisms as a change in the underlying basic aspects of evolution, aka change over time. Yes, we realize more and more that development does play a crucial role in evolution (evo-devo for a reason), but development ultimately does come back to under lying genetic variation of some kind. The main difference is a diversion from a gene-centered view to a heritable units point of view which is inclusive of regulatory elements etc. that are important for the regulation of many aspects of development. So, maybe we have to start with separating mechanisms from the effect. -- Kim van der Linde ^{at venus} 18:33, 4 October 2011 (UTC)

Definitely we shouldn't choose one, apart from bias it would introduce plagiarism problems. We have to distill a new formulation from these ones and I am suggesting that the classical gene-frequency definition should be the main stock for such a definition and that the complexities added by the integrative approach and the genotype/phenotype issues should be included as a kind of corollary.·ʍaunus·snunɐw· 19:40, 4 October 2011 (UTC)

Well, I disagree with you. I think there is a lot to say to divert from the gene-centered definitions, specifically because we are moving forward and much of evolution takes place outside of genes but in regulatory elements, miRNA's etc. So, gene frequencies are really not a good substitute for the wide range of genetic elements that change over time. What we want to to go back to the basics. What is evolution, and build up from there. We are writing an encyclopedia, so we have to keep in mind the average reader, which quite frankly is left in the cold with the current definitions debate. So, what is the core of biological evolution? In my opinion only two things, heritable traits and change over time. The first is far more than just genes, the latter is independent of the HOW and should cover both micro and macro. -- Kim van der Linde ^{at venus} 20:32, 4 October 2011 (UTC)

Well I thought I was expressing agreement with you. Whether we think that gene frequencies are not a good definition it is obvious that a lot of people writing textbooks about evolution still think so. That is what I meant when suggesting that we take this as the basic stock. We need to take this basic view into account as a main part of the definition. I think I agree with you that going back to basics and talking about variation in heritable traits leading to changes in populations over time.·ʍaunus·snunɐw· 20:53, 4 October 2011 (UTC)

Okay, fair enough. I responded to the "classical gene-frequency definition should be the main stock for such a definition" aspect of what you wrote, and although many are still using this, this is also because it works for their specific purposes. However, we have to avoid using the many definitions that work for the specific book about topic X, and focus on what currently is used as the definition by those who actually focus on getting this stuff right. I generally (as an ecologist/neurobiologist) do not favour ecology or neurobiology sources for definitions about evolution. As someone moving towards evo-devo, the concept of heritable units becomes rather complex, hence my suggestion to go back to heritability as a key term in the definition and avoiding to define all the heritable units in a comprehensive way simultaneously avoiding using one of the types of heritable unit. -- Kim van der Linde ^{at venus} 21:01, 4 October 2011 (UTC)

·ʍaunus seems concerned that recent textbook definitions on evolution are not mainstream. These recent (and old) textbook definitions present a hierarchical and integrative vision on evolution. Looking at modern literature, we have lots to refer to on the hierarchical perspective, from the evolution of genes[35],[36], morphology[37], [38], and ecosystems[39]. Classical authors/papers on the integrative/hierarchical view include: Science (1945), Regularly mentioned by GG Simpson (e.g., 1959)[40], Journal of Paleontology (1968)[41], Paleobiology (1978)[42], (1982) [43], and (1984)[44] (Includes citations that go back to 1970), Systematic Zoology (1984)[45], Trends in Ecology & Evolution (1989)[46], Proceedings of the NAS (1983)[47], and so on. The intergrative hierarchical perspective is not new - Rupert Riedl also wrote about this extensively in the 1970's.Thompsma (talk) 19:07, 4 October 2011 (UTC)

No I didn't mean to imply that the integrative perspective is not mainstream, but only whether it is generally seen to fundamentally alter the way in which the general concept of evolution should be defined, or whether it is more of a corollary to previous definitions.·ʍaunus·snunɐw· 19:37, 4 October 2011 (UTC)

Evolution was first described by Darwin through his observation and experimentation at the organism level, but he left open a wider opportunity for natural selection to operate hierarchically. He also wrote that developmental ontogeny was the way of the future for the genealogical classification of species. "What is the origin of the levels of selection debate? Like much in evolutionary biology, it traces back to Darwin. Though Darwin primarily discussed individual-level selection, he was aware of other possibilities."[48] The source definition of evolution by Darwin was that natural selection applied on a hierarchical scale and this is a generally accepted view on Darwin's original texts (notably The Descent of Man). Hence, it was George Williams (popularized by Dawkin's) who fundamentally altered the way in which the general concept of evolution was defined by emphasizing the gene as the sole replicating and explanatory unit of evolution. An integrative hierarchical perspective is not the corollary, but it is the other way around. "A corollary is a statement that follows readily from a previous statement." - which would imply that the integrative-hierarchical view is a simple extension of the population-genetic view and this is what the majority of evolutionary biologists have argued against.Thompsma (talk) 20:59, 4 October 2011 (UTC)

Kim, I second your sentiment, hence my preference for Bock's definition or a variant of it. Very generic indeed. danielkueh (talk) 19:20, 4 October 2011 (UTC)

Bock's definition is fatally flawed. "Change in organisms over time with the minimum time being one generation. Hence evolutionary change is observed between organisms of one generation and their descendants." Change, yes, but organism also change between generation without changes in their DNA, for example though plasticity that does not require changes in the DNA but can result in dramatic changes between generations. That is not evolution. -- Kim van der Linde ^{at venus} 20:38, 4 October 2011 (UTC)

I agree that Bock's definition is a very bad choice, it is essential to note that evolution happens on the level of heritable traits and their distribution in populations.·ʍaunus·snunɐw· 20:48, 4 October 2011 (UTC)

I wouldn't go so far as to say that Bock's definition is a 'very bad choice', but I wonder how do you reconcile Bock's definition with other evolutionary biologists who have argued against the focus on the organism? If you read his paper snunɐw· you will see that he directly addresses your concern: "Note that the definition of evolution advocated herein does not include any statement of heredity or genetic change. Several types of variational evolution exist depending on how information is transmitted from one generation to the next."[49] It is essential to read what the authors are saying to get the whole perspective. I will offer that the lineage is the most generic term that can rectify this: "Evolution: change in lineages over time with the minimum time being one generation. Hence evolutionary change is observed between "lineages" of one generation and their descendants." - Replacing organism with lineage makes that definition 100% compatible with the integrative view on evolution. Perhaps we could move in this direction?Thompsma (talk) 20:59, 4 October 2011 (UTC)

I think Bock's definition is a bad choice for us to adopt. It may make perfect sense in the context of his paper, but I was commenting on whether we should adopt this usage. I don't like the idea of exchanging organism with lineage, I think it is leading towards the jargony side. Lineage as an evolutionary concept is not readily understandable to most layfolk and the nuance introduced by that definition will be lost on all but those who already hold an integrative view of evolution. I am reluctant to adopt that definition, although I accept the validity of your argument.·ʍaunus·snunɐw· 21:33, 4 October 2011 (UTC)

I think any definition focusing on lineages is a bad idea. Evolution is far more than that. Bock;s definition was specially wide to include cultural evolution for example, we focus on biological evolution. -- Kim van der Linde ^{at venus} 21:43, 4 October 2011 (UTC)

If we don't use Bock's definition and our focus is on what is heritable, then we are back to adopting a Neo-Darwinian definition. So why even have a discussion on changing the current definition? danielkueh (talk) 21:50, 4 October 2011 (UTC)

I would argue that the current definition is to much micro evolution oriented, and coming up with a better definition that is more inclusive would be better. -- Kim van der Linde ^{at venus} 22:00, 4 October 2011 (UTC)

If that is the case, then I think we should then ask, "Specifically what aspect (or word) of the current definition is too 'micro' or too 'limiting'?" That way, we will get a better sense of what terms to avoid and/or use. danielkueh (talk) 22:07, 4 October 2011 (UTC)

The current definition is: "Evolution is the change over time in one or more inherited traits found in populations of individuals." I would reduce that to "Evolution is the change over time in heritable traits.. -- Kim van der Linde ^{at venus} 22:19, 4 October 2011 (UTC)

By "over time," I'm assuming a minimum of one generation? Should that be specified? I am asking only because I'm assuming we're excluding ontogeny here. danielkueh (talk) 22:24, 4 October 2011 (UTC)

Nop, it can occur within a single generation if you consider for example germline mutations that affect competition between sperm cells.-- Kim van der Linde ^{at venus} 22:44, 4 October 2011 (UTC)

I am using it the term "generation" broadly. So at the cellular level, there is still a generation difference between the mutated sperm and the one before it? No? danielkueh (talk) 23:13, 4 October 2011 (UTC)

I think using the word generation for this specific kind of evolution is weird. And it does not matter as it does not clarify anything. It only restricts unnecessary. If you want a proper definition, you have to be unit of selection independent. -- Kim van der Linde ^{at venus} 23:22, 4 October 2011 (UTC)

I don't think it is weird. Quite the opposite. Evolution occurring "within a generation" is essentially Lamarkian. That would be weird. danielkueh (talk) 23:28, 4 October 2011 (UTC)

Nop. Think epigenetics. Think gene products of slightly different gene copies competing for receptors etc. -- Kim van der Linde ^{at venus} 23:32, 4 October 2011 (UTC)

Epigenetics? Does that not contradict your previous statement "Change, yes, but organism also change between generation without changes in their DNA, for example though plasticity that does not require changes in the DNA but can result in dramatic changes between generations. That is not evolution." Look, we are talking about inherited traits here. Regardless of the mechanism, what you're saying in effect is that changes in an inherited trait within the lifetime of an organism is evolution. If that change can be passed on, then that's Lamarkian. danielkueh (talk) 23:41, 4 October 2011 (UTC)

Well, that remark I made in a specific context of the Bock definition. Epigenetics changes the DNA by for example methylation and passes that on for multiple generations. So yes, it fits both the definition of Darwinian evolution as well as Lamarkian evolution. -- Kim van der Linde ^{at venus} 00:11, 5 October 2011 (UTC)

I have a few comments, but first I want to bring us back to the notion of a lineage, which will also help to solve the discussion on cell lineages and ontogenetic evolution. snunɐw· states: "Lineage as an evolutionary concept is not readily understandable to most layfolk" A family lineage is very understandable to most people. A family lineage is exactly what a lineage is as an evolutionary concept as well - so there can be no confusion here. Kevin de Queiroz (see [50][51], [52]) has been an integral player in the putting together the phylocode. Over the years he has been building on George Gaylord Simpson's idea of the general lineage concept of a species - the term is used in large part because lineage is so generally understood - even by 'layfolk'. This applies to this debate, because we are talking about evolution, to which the origin of species plays a big role. Please bear with me, because this may solve a lot of the debate here:

"On the contrary, the species problem has, for the most part, already been solved. Despite the considerable diversity among contemporary views on species, all are encompassed by a single, general concept that equates species with segments of population level-lineages...I have used the term lineage (de Queiroz 1998; see also Simpson 1961, Hull 1980) for a series of entities forming a single line of direct ancestry and descent. For example, a lineage can be traced from a given organism backward through a parent, grandparent, great-grandparent, and so on, and forward through a child, grandchild, great-grandchild, and so on. Biological entities at several different organizational levels form lineages. Thus, biologists speak of gene lineages, organelle lineages, cell lineages, organism lineages (as described in the above example), and population lineages. Because entities that form lineages often make up, or are made up of, entities at different organizational levels, the same is also true of the lineages themselves. An organism lineage, for example, is (often) made up of multiple cell lineages, and multiple organism lineages make up a population lineage."[53]

I hope this answers a few questions about evolution during the development (ontogeny) of an organism, coupled with a few words from Okasha in his recent book ([54]) on levels of selection:

"A population of entities evolves by natural selection where heritable differences between the entities lead to differences in their reproductive output; reproduction is understood as giving rise to an offspring entity that occupies the same hierarchical level as the parent, unless otherwise stated. Entities satisfying these conditions are units of selection; the level in the hierarchy which the entities occupy is the level of selection."

Now, what kind of entities are we talking about during the ontogeny of a mammal, for example? Mitochondria form population lineages within cells. They compete, reproduce, and do the things that bacteria do - minus free living adaptations. David Rand wrote about this many years ago on the units of selection in mitochondrial DNA - heteroplasmic mitochondria within cells (variation), reproduction, and heredity all occur within the cells.[55] There are also biparental modes of mitochondrial inheritance in some species ([56]). Hence, the mitochondria satisfy the conditions for units of selection - and the level they occupy, within cells is the level of selection. The author and editor of two recent textbooks on evolution, many other textbooks on evo-devo and homology, Brian Hall has written about cellular condensations as the unit of selection in developmental biology.[57] This idea has also been forwarded in the amazing research on the development of butterfly eye spot patterns.[58][59]

The proposed truncation: "Evolution is the change over time in heritable traits.. -- as suggested by =Kim van der Linde, is actually a bit better than the current lead, but heritable traits are nothing on their own - they are contained in a reproducing vehicle of some kind that form lines of descent. Traits are attached to things that evolve and it is also important to remember that Darwin was split between natural selection versus natural preservation. Hence, it is not just the change that is the focus of evolution, it is also the parts that are sustained - remember the second part to Darwin's book title: "or, the preservation of favoured races in the struggle for life." You could argue that heritability is preservation, but then this would be weird: Evolution is the change over time in preserved traits. It is the whole of entities (genomes, cells, organisms, species) that evolve, not their component traits. This is why evolutionary biologist try to keep things real, where traits are in organisms or in populations as they truly exist in nature.Thompsma (talk) 05:41, 5 October 2011 (UTC)

Well, as an evolutionary biologist, I indeed try to keep things real. Stasis, gradualism, and explosive radiations are all part of evolution. Which of them is active at a specific moment varies, and they are exchanged for another all the time. The idea that evolution is all about lineages of varies levels contained in a single vehicle is bogus. Incomplete lineage sorting, horizontal transfer (endo-bacteria, retro-viruses, transposable elements via vectors), hybridization and reticulated networks (and not only in bacteria, think Lake Victoria Ciclids) show that lineages between and within different levels mix and follow their independent evolutionary pathways. The idea to focus on preservation is muddying the waters as far as I am concerned, because we are talking about word use within a context of an idea 150 years ago. We understand much more of how evolution works, and we have preserved traits that are rapidly evolving if you look at the underlying genetics. BTW, your proposed earlier definition (Evolution is change in the descent of lineages that form complex relations as they compete for existence, reproduce, and interact mutualistically.) does not focus on preserved aspects at all. (let alone the singling out of one of the ways organisms interact, aka mutualism.)

Personally, I am not comfortable with the word trait, because that generally understood as a phenotypic trait of an individual, while the reality is that evolution occurs in all units of selection, and on every aspect that has a heritable component. Any suggestions for a better word (not lineage)? -- Kim van der Linde ^{at venus} 13:39, 5 October 2011 (UTC)

Entities? danielkueh (talk) 14:16, 5 October 2011 (UTC)

Kim van der Linde states: "The idea that evolution is all about lineages of varies levels contained in a single vehicle is bogus." - This is why we rely on peer-reviewed literature that suggests otherwise. Based on your review of the situation you do not understand the concept. "Incomplete lineage sorting" = lineage, "horizontal transfer (endo-bacteria, retro-viruses, transposable elements via vectors)" = lineages, "hybridization and reticulated networks (and not only in bacteria, think Lake Victoria Ciclids) show that lineages between and within different levels mix and follow their independent evolutionary pathways." = lineages again, and you even used the word to describe what is going on. "The idea to focus on preservation is muddying the waters as far as I am concerned" - well as far as Darwin was concerned it was important and it remains relevant to many evolutionary biologists to this day (e.g., [60]). My understanding of wikipedia is that we rely on WP:V and your expressed views are inconsistent with this line of reasoning that we must rely on peer-reviewed and other reliable sources for the information we provide. Frankly I don't care if you dislike the term, I am interested in what evolutionary biologists are writing about. So if you can lead us to some WP:V that supports your opinion, then I will entertain these ideas. Until then - I suggest that we stick to the literature. Many, many, authoritative peer-reviewed evolutionary biologists have written extensive works on evolutionary tree based thinking, phylogenies, lineages, and this is the universal language that is used in the literature and in teaching evolution at an introductory level (which I do a lot of in my profession) (e.g., [61]). Evolutionary biologists are completely aware of the bifurcation and horizontal transfers that intersect the hierarchical scales of life (e.g., [62], [63]). Gene trees within species trees - one of the most highly cited papers on this topic [64], discusses lineages in an evolutionary context. So if you are going to continue calling WP:V bogus as a means to win support for your arguments, you are not going to gain any headway in this discussion and you are not being helpful.Thompsma (talk) 15:49, 5 October 2011 (UTC)

Yes, PW:RS and WP:V are important. We value tertiary sources over secondary and secondary over primary. Of all the definitions in text books above, only one uses lineage in the definition. So, forcing that on the definition of this article based on some cherry-picked non-textbook sources would be very much against WP:V. -- Kim van der Linde ^{at venus} 16:21, 5 October 2011 (UTC)

Kim van der Linde - I am also surprised by some of your posted comments and think that you are discounting a lot of WP:V evolutionary literature. The term lineage appears in far more evolutionary textbooks that those few definitions provided above. I challenge you to find a paper published in a book on evolution or in a paper for that matter that does not mention or rely on the term lineage - it is a pervasive evolutionary term and not "cherry-picked". You are not being reasonable.Claviclehorn (talk) 16:31, 5 October 2011 (UTC)

If all those books mentioned above are only providing partial definitions omitting the word or concept of lineage, it will be easy enough to expand those definitions and show me wrong. -- Kim van der Linde ^{at venus} 16:38, 5 October 2011 (UTC)

at venus - I believe the burden of proof rests on your shoulders. I have read most of those textbooks in their entirety for courses I have taught on evolution. John Avise's book "On Evolution" defines it in context of a lineage. Kevin Padian in his paper on macroevolution and education[65] lists lineage as one of the components that every student of biology should understand. You are fighting a losing battle, the literature does not support your opinions on this issue.Thompsma (talk) 16:47, 5 October 2011 (UTC)

I am sorry that you feel entitled to pounce your chest because you taught evolution. However, wikipedia does not rely on authority of their contributors. Having said that, back to your insistence that lineages should be an integral part of the definition. Yes, lineages are important for evolutionary thought, but the question whether it should be a central aspect of the definition is not solved by stating that people mention it as important.-- Kim van der Linde ^{at venus} 17:04, 5 October 2011 (UTC)

Kim van der Linde - you are not being reasonable here and I agree with Claviclehorn on this. This is not about chest pounding - I am stating that I am broadly aware of the literature from those sources and in that context your rationale is not sound. You are not using the sources properly. I provided a resolution to this problem by drawing on a resource - the work by Kevin deQuieroz, a well respected and highly published evolutionary biologist. deQuieroz has been working on consensus building for many years on the species problem and to do this he has drawn upon a classical line in evolution - the general lineage concept. We are having difficulty in these pages with consensus building, so it seems quite prudent to turn to a place within the field of evolutionary biology where success has been made in this respect. For each one of those definitions above you have a lineage: "Descent with modification" - =lineage, "from generation to generation within populations"=lineage, Ridley uses lineage, "A change in gene frequencies over time in a population" = genetic lineage. This is why it is appropriate, because it universally applies to all those definitions. Let's look at the definition provided by John Avise, a notable evolutionary biologist:

"Biological evolution consists of two processess: anagenesis (or phyletic evolution) and cladogenesis (i.e., splitting). Anagenetic change is gradual and usually results from increasing adaptation to the environment. A favorable mutation or other genetic change arising in a single individual may spread to all descendants by natural selection. Cladogenesis results in the formation of independent evolutionary lineages."[66]

Phyletic is a fancy scientific way of referring to a lineage. The next part on cladogenesis he specifically refers to independent lineages. From Darwin to the most modern evolutionary biologist, the lineage concept has a universal presence. You are arguing against it according to a personal dislike, I am arguing for it using literature that is relevant to the topic at hand. If you can find me a WP:V that supports your opinion on this - then I will be happy to listen. However, you have to do better than a personal dislike (i.e., calling something bogus does not work in professional circles) and other editors in here will not (or should not) support that kind of irrational approach to this. I am not saying that we "MUST" use the term, but in this situation where we are seeking a consensus I think it is best to turn to WP:V for this task and de Quieroz is as good a place to start as any. Try to work with us, put your ego asside for a moment, and draw upon rational lines of defence using the literature as others are doing.Thompsma (talk) 18:21, 5 October 2011 (UTC)

The Evolution 101 website from Berkley uses the tree based method and refers to lineage in its approach.[67] Here is a paper[68] on teaching evolution in the journal Evolution: Education and Outreach: "Phylogenetic trees are the most conventional tool for displaying evolutionary relationships, and “tree-thinking” has been coined as a term to describe the ability to conceptualize evolutionary relationships...The evolutionary lineages emerge via cladogenesis (the splitting of a single lineage into two distinct lineages) when a single population or species is split in two." American Biology teacher [69] - same, emphasising lineage and "tree-thinking". David Hillis published in Science "Pick up a random issue of almost any biological journal these days, and you are likely to see one or more phylogenetic trees [HN1]. One of the reasons that these estimates of evolutionary history have become ubiquitous is because they are needed to make biology predictive...Instead, one principal (or “trunk”) lineage survives and gives rise to future lineages of influenza A, whereas the other lineages quickly become extinct." - lineage again. Ryan Gregory [70] - more lineage tree thinking as a means of educating students on the concepts of evolution. I can come up with a list of over 50 citations on educating about evolution and universally the authors suggest starting with tree-thinking with reference to a lineage. You're rebuttal - it's bogus! This isn't the Discovery Institute - this is an article about evolution, so stick to the theme.Thompsma (talk) 18:35, 5 October 2011 (UTC)

Well, you are sinking deep, first chest pounding, now the DiscoInstitute because I oppose your single minded pushing of lineage as the only relevant way to make a definition. It does not make it right. Yes, trees are important, but pick op any biological journal and you will find articles discussing how groups of individuals change without the reliance on lineage thinking. -- Kim van der Linde ^{at venus} 21:33, 5 October 2011 (UTC)

Come on at venus - we're on the same team! I can see from your profile that you are an intelligent person with a shared passion for evolution. Let's not talk past each other. I'm not being single minded in pushing lineage, but I am at a loss for any other term that so aptively encapsulates the full scope of the diversity of definitions that are out there. It seems to be working below, so hopefully we can become a stronger team - two heads are better than one.Thompsma (talk) 21:56, 5 October 2011 (UTC)

• Easy, easy... Let's stay focus on the choices here. We are making great progress. I especially like the minor tweak made to Bock's definition. If we get something like that, I am all for it. danielkueh (talk) 19:50, 5 October 2011 (UTC)

Break - discussing changes to lead

I think we are going off topic here, but I generally agree with Thompsma because he seems to be using the literature and when I click on the links he is supplying (thanks by the way! Learning lots) his reasoning is sound. Kim van der Linde is taking us off track here (sorry Kim, please don't take this personally), let us return to the topic. Does anything ever get changed in the main article with this kind of bickering? It is surprising to me as a new user to read rational and well informed posts by someone like Thompsma who is providing some great reference material and working quite hard toward building a consensus getting trashed in here. I am convinced that lineage is a term that covers all the definitions and think that referring to deQuieroz is a good direction. Can we return to fixing the lead. I liked Thompsma's approach to Bock's definition:

"Evolution: change in lineages over time with the minimum time being one generation. Hence evolutionary change is observed between "lineages" of one generation and their descendants."

Can we revise this so it isn't plagiarized? Perhaps:

"Evolution (or more specifically biological or organic evolution) is the change that occurs in any lineage over time from one generation to the next. A lineage is single ancestral-descendant sequence formed that extends through recursive generations of biological reproduction in the biological hierarchy, including gene lineages, organelle lineages, cell lineages, organism lineages (as described in the above example), and population lineages. In his landmark scientific text on evolution in 1859, "On The Origin of Species", Charles Darwin describes evolutionary lineages in a "great tree of life", "a web of complex relations", and he includes a single illustration of an evolutionary tree. The tree represents common ancestry among lineages that branch and diversify into "endless forms most beautiful and most wonderful". A core theory of evolution proposed by Charles Darwin is natural selection. Natural selection applies to all lineages that interact in the biological hierarchy and is formulated on three recurrent facts, including 1) heritability, 2) variation, and 3) the overproduction or superfecundity of offspring."Claviclehorn (talk) 18:53, 5 October 2011 (UTC)

I like your suggestions Claviclehorn! A gave it a bit of a tweak.Thompsma (talk) 18:58, 5 October 2011 (UTC)

I like the first two sentences. The rest (3rd sentence onwards) needs more work, in terms of style and organization. But that is a discussion for another time. danielkueh (talk) 19:56, 5 October 2011 (UTC)

Maunus' version

• "Evolution is the biological process by which changes between generations within lineages of organisms accumulate and produce biological diversity over time. Modern evolutionary theory originated in the 19th century in the writings of Charles Darwin who argued that the evolution of living organisms was driven by natural selection acting on the biological variation of heritable traits within populations." Here I am trying to make the text more accesible to laypeople, and to include the relevance (that it leads to biological diversity i.e. the relation between micro and macro evolution) of the topic in the first line as well as situating the concept historically. I still think it is a bad idea to quote from Darwin, the concept of the tree structure can be much more effectively summarised in prose I think.·ʍaunus·snunɐw· 19:10, 5 October 2011 (UTC)

Great work snunɐw·! A little tweak:

• "Evolution is a biological process of change between generations within lineages that produces and preserves biological diversity over time. Modern evolutionary theory originated in the 19th century in the writings of Charles Darwin who argued that the evolution of living organisms was driven by natural selection acting on the biological variation of heritable traits within populations."

Putting organism in there once again gets us trapped in the debate on levels of evolution and I think we have to work around that trap.Thompsma (talk) 19:17, 5 October 2011 (UTC)

I put organism in there because my problem with "lineage" is that when it stands alone it requires extra thinking to understand what it is. Is there another simple word that can be used to answer the question "lineages of what?"? Also why did you remove the "accumulate" part? - I think that is what provides the link between micro and macro evolution.·ʍaunus·snunɐw· 19:21, 5 October 2011 (UTC)

I like Maunus' original version - I do not see how the tweaks improve it. Slrubenstein | Talk 19:48, 5 October 2011 (UTC)

He has a point that organisms limit the concept of evolution to exclude evolution occuring on other levels, but I still prefer that than to have the word "lineage" as a bare noun.·ʍaunus·snunɐw· 20:10, 5 October 2011 (UTC)

I like Maunus' original version - I do not see how the tweaks improve it. Slrubenstein | Talk 19:48, 5 October 2011 (UTC)

I like Claviclehorn's definition and I like Maunus's second sentence. I would like the two to be synthesized and made concise so that it reads something like this:

""Evolution is the change in any lineage over time that occurs from one generation to the next. A lineage is a single ancestral-descendant sequence that extends through multiple generations within a biological hierarchy of genes, cells, organisms, and populations. The study of modern evolution itself originated in the 19th century in the writings of Charles Darwin who argued explained that the evolution of living organisms is driven by natural selection acting on variation of heritable traits within populations.

I believe the second sentence clarifies the context of lineage in the first sentence. danielkueh (talk) 20:13, 5 October 2011 (UTC)

Thanks danielkueh - I like this. Looks like we are coming together here! Exciting stuff. I'm a little leery about the use of "argued" - did he argue? Could that be replaced with explained?Thompsma (talk) 20:23, 5 October 2011 (UTC)

Agree. danielkueh (talk) 20:27, 5 October 2011 (UTC)

I don't like the first sentence in that one - it is not explanatory at all, but just confusing, it fails to give the reader any idea of the significance of evolution, it also doesn't establish the fact that the article is only addressing evolution in the domain of biology not for example the evolution of language or culture. It is also almost tautological in the way it redundantly repeats the notion of "change" "over time" "from one generation to the next". It basically just says that evolution is change (all change occurs over time and between generations). I think it is really not a very good choice. ·ʍaunus·snunɐw· 20:57, 5 October 2011 (UTC)

Sigh, here we go again:

Some biological evolution takes place within a generation, or do we see subsequent versions of mitochondria as 'generations' and forming a lineage?

Most macro evolutionary events do take place when a lineage splits (cladogenesis) and when they strengthen the differences through mechanisms such as character displacement.

Micro evolution often results in interbreeding differentiated groups within a single 'lineage'. Or do we call interbreeding lineages separate lineages? Or do we call the difference in the trait between groups a trait?

Most change between generations is phenotypic without a genetic basis. This is traditionally not seen as biological evolution. Where is the heritable component in this definition?

Lineages of cells, genes, regulatory elements, individuals, species, populations etc can be ordered hierarchical based on what encompasses the other, but they follow their independent paths to a degree.

See my other comments above.-- Kim van der Linde ^{at venus} 21:18, 5 October 2011 (UTC)

How about this:

"Evolution (or more specifically biological or organic evolution) is the change that occurs in any lineage that accumulates and produces biological diversity over time. A lineage is a single ancestral-descendant sequence that extends through multiple generations within a biological hierarchy of genes, cells, organisms, and populations. The study of modern evolution itself originated in the 19th century in the writings of Charles Darwin who explained that evolution of living organisms is driven by natural selection acting on variation of heritable traits within populations."Thompsma (talk) 21:06, 5 October 2011 (UTC)

That's better, but how about changing changing it to: "is the cumulative process of change between generations in a lineage that produces biological diversity over time" - I think the "that occurs in any lineage" is a little clumsy. I would also prefer to write: "A lineage is a sequence of ancestors and descendants through multiple generations ..."·ʍaunus·snunɐw· 21:19, 5 October 2011 (UTC)

• I don't mind the reinsertion of organic and biological evolution but I strongly disapprove of " accumulates and produces biodiversity." That would exclude microevolution as biodiversity is a consequence of evolution. When rabbits in Australia for example, became resistant to the myxoma virus, they have evolve [71]. Aside from genetic diversity (I suspect there is less of it), there is no observed functional, ecological, or species diversity that resulted from that. So the definition of evolution has to be broad to apply to a case such as this, which is indeed a "change in lineage from one generation to the next." The issue of tautology is irrelevant because evolution is descriptive. What is explanatory are the mechanisms of evolution such as natural selection, genetic drift, etc. danielkueh (talk) 21:14, 5 October 2011 (UTC)

Of course the issue of tautology is relevant, the whole point of having a definition is that it should explain what the concept is - that means that the definition should include the mechanisms that characterize evolution as opposed to other forms of change between generations.·ʍaunus·snunɐw· 21:23, 5 October 2011 (UTC)

No, a definition just states what a word means. Some words explain and some things don't. For example, scientific theories explain things, scientific laws do not. To say that something evolve is not to explain anything. It is just stating a fact. The explanation comes from asking about the mechanisms, which is NOT intrinsic to the definition as there are multiple mechanisms of evolution that include: artificial selection, natural selection, genetic drift, etc. Should we list all of them? And besides, it is just wrong. Biodiversity (which has multiple levels) is a potential consequence of evolution in the long run. Putting biodiversity in there doesn't explain anything either. This article is about evolution, micro and macro. danielkueh (talk) 21:31, 5 October 2011 (UTC)

• Most evolution does not result in speciation. That is the macro-evolutionary definition at the expense of micro evolution.-- Kim van der Linde ^{at venus} 21:21, 5 October 2011 (UTC)

That can be solved by removing the link to speciation.·ʍaunus·snunɐw· 21:24, 5 October 2011 (UTC)

And explain genetic diversity and other versions of diversity as well? -- Kim van der Linde ^{at venus} 21:28, 5 October 2011 (UTC)

Besides that, not all evolution leads to more diversity, a reduction in diversity is also evolution. -- Kim van der Linde ^{at venus} 21:29, 5 October 2011 (UTC)

I think we are onto something here people, we are so very close. I was also hesitant about the biological diversity component. Can we take the cue from Kim van der Linde and adjust to the following?:

• "Evolution (or more specifically biological or organic evolution) is the change that occurs in any lineage passing that passes heritable traits into descendant populations. A lineage is a single ancestral-descendant sequence that extends through multiple generations within a biological hierarchy of genesmolecules, cells, organisms, and populations. The study of modern evolution itself originated in the 19th century in the writings of Charles Darwin who explained that evolution of living organisms is driven by natural selection acting on variation of heritable traits within populations."Thompsma (talk) 21:35, 5 October 2011 (UTC)

I'm fine with this. I changed "genes" to "molecules" to include protein evolution. danielkueh (talk) 21:39, 5 October 2011 (UTC)

Changed "passing" to "that passes".Thompsma (talk) 21:42, 5 October 2011 (UTC)

Evolution is not active passing things forward, but a passive process that result in change.-- Kim van der Linde ^{at venus} 21:44, 5 October 2011 (UTC)

Perhaps passes is not the right word? I was thinking replicates? It is not entirely passive - there is synergistic feedback and response as organisms actively modify their environments and alter the selective regime for subsequent generations.Thompsma (talk) 21:51, 5 October 2011 (UTC)

Or:

• "Evolution (or more specifically biological or organic evolution) is the change that occurs in any lineage that reproduces heritable traits into descendant populations. A lineage is a single ancestral-descendant sequence that extends through multiple generations within a biological hierarchy of molecules, cells, organisms, and populations. The study of modern evolution itself originated in the 19th century in the writings of Charles Darwin who explained that evolution of living organisms is driven by natural selection acting on variation of heritable traits within populations."Thompsma (talk) 21:53, 5 October 2011 (UTC)

It looks ok. I struck out "that occurs" as it is redundant. danielkueh (talk) 22:04, 5 October 2011 (UTC)

• comment I really believe you are getting it wrong by sacrificing intelligibility and informativity for the sake of precision and achieving a short definition that is so broad that it encompasses all of the aspects of evolution at once. It is not necessary, and it is not useful. Yes evolution does not necessarily lead to speciation, it doesn't occur only organisms, and it doesn't only happen between generations BUT the most common usage of the concept is for the process of biological change by which lineages of organisms diversify into species. We can and should have a definition that takes this as the point of departure and THEN goes on to describe the various ways in which evolution is really also more complex than that common understanding. It is not helpful or necessary to have definition that is over-broad, just to incorporate all of these from the beginning. It is not good writing, and it is outright bad encyclopedia writing. Look for example how the Britannica defines evolution: "evolution, theory in biology postulating that the various types of plants, animals, and other living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations. The theory of evolution is one of the fundamental keystones of modern biological theory." I think we can definitely do it better than this (e.g. by avoiding creepy stuff like "postulates"), but we can also learn about how to write an informative (if not all encompassing) definition. ·ʍaunus·snunɐw· 00:19, 6 October 2011 (UTC)

A very strong comment ·ʍaunus, I like what you have said here. I like the Britannica definition and you have raised some strong points here. However, we have done some great consensus building on the sentence below and think we have achieved much. Perhaps we can build on your ideas here and bring it into the structure. Instead of sacrificing intelligibility and informativity, can we bring this into the framework we have put together "for the sake of precision and achieving a short definition that is" broad as we have achieved below?Thompsma (talk) 00:37, 6 October 2011 (UTC)

I think we can yes, but I was reacting to the way that you, Daniel and KimVL moved a head by continuously broadening the definition to include all known instances of evolution into a single sentence, no matter of how minuscule importance they may have for the average reader. I think the first line of the definition should be general rather than precise but establish the significance of the concept such as the britannica definition does. It could be> Evolution is the biological process by which all life forms have diversified from a single common origin", or Evolution describes the biological process of modification between successive generations, which through interaction with the environment has lead to the current diversity of life forms from a single common origin. Yes, these privileges macro-evolution, but this can be remedied by making the next sentence about micro-evolution. e.g. "Evolution occurs on all levels of the biological hierarchy from the level of the molecule (DNA) to the level of the species: In each case the process of biological reproduction creates lineages characterized by their particular cumulative changes." or something like that. When you deconstruct these suggestions and build on them please think about the fact that also 9 year old children may want to use wikipedia to write their school assigments sometimes, while we of course shouldn't pander for the lowest common denominator we also shouldn't set the bar way too high.·ʍaunus·snunɐw· 00:54, 6 October 2011 (UTC)

There is an introduction to evolution article for the 9 year old children. Otherwise, I partly agree with the points you raise, but I think that we have a good working definition below for the first sentence and I am interested in trying to tweak in some of your suggestions.Thompsma (talk) 01:10, 6 October 2011 (UTC)

Maunus, I disagree with the notion that it is "bad writing." Quite the opposite. In fact, I think it is good writing to keep things simple. I support a verifiable definition that is broad AND true most, if not all the time. Look at the list of definitions above, how many of them talked about "biodiversity?" If you want to include these things, then do so in the next sentence or two. That is the whole point of having multiple sentences and paragraphs in an article. Besides, if what you say is true, then Darwin must be a terrible writer. After all, his definition of evolution consists of only three words. danielkueh (talk) 01:20, 6 October 2011 (UTC)

I am the one arguing for simplicity you are arguing for precision and broadness. Simplicity is to make it general and intelligble. Darwin's definition most certainly didn't take into account all possible contingenicies of what might also be forms of evolution that needed to be taken into account Darwin's definition is a hundred times better than the ones proposed by you and KVL. I am not going to press the point further, but I think it would be a very good idea to wait for more input before hastening towards a new definition proposal. ·ʍaunus·snunɐw· 01:23, 6 October 2011 (UTC)

Maunus, you must have a peculiar understanding of the word "simple." What is simple about your definition? Let's start with "cumulative process." What does it even mean? If a virus mutates once and evolves? Is that cumulative? How is this cumulative process different from say other processes of evolution such as natural selection, genetic drift, etc? Part of your definition is not even grammatical. For example, "changes between generations within lineages?" Huh?!?! And what about "preserves biological diversity over time." First of all, this is not even true. You must first produce biodiversity before you can preserve it. And that is not even the purpose of evolution. There is no purpose. In fact, many times, it leads to less diversity. Plus there are several levels of biodiversity: genes, species, ecological, and functional. Which of the four is being "preserved" here? Since functional refers to the biogeochemical cycles, that part of your definition doesn't even make sense. So tell me again, what is so "simple" about your definition?

For the record, KVL and I did not formulate that definition. It was suggested by Thompsma, paraphrased by Claviclehorn, and edited slightly by me, with a few suggestions from KVL.

With respect to Darwin's definition, I am ok if we adopt it. His definition is broad precisely because he strived to be accurate. Have you actually read "Origin of species?" danielkueh (talk) 01:41, 6 October 2011 (UTC)

The word "preserve" is not a part of any of my proposed definitions. Nor have I ever suggested that evolution has a "purpose". Have you actually read my posts? I am also not suggesting that my definitions are ...definitive I am trying to communicate to you that there is a problem with your approach and the definition you are getting at is so broad and all inclusive as to be uninformative and circular. If you cannot understand the phrase changes between generations within lineages then I fear it is your English that is inadequate. Evolution may result in less diversity but that is relevant only at the microscale on the macroscale one simple organism turned into all known forms of organism - that suggests a rather significant trend towards diversification rather than loss of diversity. Making a definition that sacrifices the big picture to take into account those specificities is bad encyclopedia writing. I am not going to participate more in this discussion, but I think I have made my points sufficiently clear by now.·ʍaunus·snunɐw· 02:11, 6 October 2011 (UTC)

My mistake on the word "preserve." I read the version of your definition that was tweaked by Thompsma. You yourself did not appear to object to that particular change at that time. In any event, I stand by my other comments.

Before you try to comment on my English language skills, I suggest you read "changes between generations within lineages" out loud and think very carefully about you're trying to say here. It is like saying "changes between hands within two hands." It is incoherent. Almost schizophrenic.

By stating that evolution "produces biological diversity over time," and making that an integral part of your definition, you are implicitly stating that biodiversity is the main function or purpose of evolution. Once again, I hate repeating myself, it is a "potential consequence" of evolution in the long long long term. Evolution is just change over time. In this article, it just happens to be biological, not cultural. Nothing more, nothing less. It is just an event, like the sun rising, the earth rotating, or a car moving. Whether the sun rises to produce heat is a "matter of opinion".

One of your statements, which says "Evolution may result in less diversity but relevant only on the microscale" clearly betrays your ignorance. You are obviously not familiar with major extinction events or coextinctions.

Microevolution occurs all the time at all levels and in every single species. In fact, direct evidence and observations of evolution itself came from microevolution experiments (e.g., Endler, Lenski). I don't know why you keep insinuating microevolution is somehow not part of the "big picture."

I brought up the flaws in your definition because you claimed to argue for simplicity. You rightly said that "simplicity is to make it general and intelligible." Yet, relative to the competition, there is nothing "general" or "intelligible" about your definition. I also criticized your definition because it is the proposed alternative. You proposed it and have suggested to Thompsma that parts of it be incorporated into the other definition. No doubt, you do not like other proposed definition. But it's disingenuous to backtrack and make it appear that you don't think yours is better and that you prefer it.

As for my approach on this subject, it is standard and consistent. Academically and logically. Your approach on the other hand is, well, just peculiar.

Anyway, I have said all I need to say and I'm tired of repeating of myself. I say we resolve this issue by putting up the current definition, your definition, and the other definition up for a vote and be done with it. danielkueh (talk) 03:06, 6 October 2011 (UTC)

What is evolution

It looks like we have rather different ideas about what evolution exactly is. The main dispute is between macro and micro evolutionary thought, but I think there are many more. So, the ideal definition needs to be inclusive of:

1. Macro evolution
2. Micro evolution
3. Speciation
4. gene evolution
5. epigenetics
6. heritable components
7. change over time
8. lineages
9. reticulated evolution
10. increase in diversity
11. reducing in diversity
12. Change within groups of individuals, cells, genes, etc.
13. Natural selection
14. Genetic drift
15. Sexual selection
16. Unit of selection
17. adaptation
18. hybridization
19. passive process
20. phenotype/genotype
21. kin selection/group selection

What other items need to be included? -- Kim van der Linde ^{at venus} 21:40, 5 October 2011 (UTC)

Phenotyope/genotype perhaps?·ʍaunus·snunɐw· 21:55, 5 October 2011 (UTC)

Added.-- Kim van der Linde ^{at venus} 13:27, 6 October 2011 (UTC)

Hence, for a near perfect definition, less is more. danielkueh (talk) 21:58, 5 October 2011 (UTC)

Exactly.-- Kim van der Linde ^{at venus} 13:27, 6 October 2011 (UTC)

These are issues that can be expanded upon in the lead. I think that we are onto something above. Ask ourselves, is the current proposal on the table inclusive of all these things?:

• "Evolution (or more specifically biological or organic evolution) is the change that occurs in any lineage that reproduces heritable traits into descendant populations. A lineage is a single ancestral-descendant sequence that extends through multiple generations within a biological hierarchy of molecules, cells, organisms, andpopulations, and species. The study of modern evolution itself originated in the 19th century in the writings of Charles Darwin who explained that evolution of living organisms is driven by natural selection acting on variation of heritable traits within populations."

It might miss speciation, unless you count that under 'the change' (i.e., change is generic for anagenesis/cladogenesis) and this can be clarified later on. Adding species into the hierarchy list might help. A hierarchy can be nested, so it does account for reticulated evolution. The rest seem to check off in my mind.Thompsma (talk) 22:05, 5 October 2011 (UTC)

• Support. danielkueh (talk) 22:10, 5 October 2011 (UTC)
• Oppose.·ʍaunus·snunɐw· 00:05, 6 October 2011 (UTC)
• Oppose.-- Kim van der Linde ^{at venus} 13:27, 6 October 2011 (UTC)

I got ahead of myself in the next part, so I'm deleting it and will move it to my sandbox until we get this sorted out. I have added a few words in an effort to address the concerns that ·ʍaunus raises above (re: intelligibility and informativity):

"Evolution (or more specifically biological or organic evolution) is the change that occurs in the diverse lineages that populate the Earth and reproduce their heritable traits into descendant populations. A lineage is a single ancestral-descendant sequence or a "family-line" that extends over multiple generations. Evolving lineages form a biological hierarchy of molecules, cells, organisms, groups, and species that interact with each other and their environments. The study of modern evolution originated in the 19th century in the writings of Charles Darwin. Darwin explained the process of evolution in living organisms by means of natural selection. Natural selection is formulated on three recurrent facts about life, including 1) the heritability of traits, 2) variation among traits, and 3) the overproduction or superfecundity of offspring.Species evolve because only a select few individuals survive to the age of reproduction where they pass on their heritable traits into descendant populations. New species branch from a single ancestral lineage as populations become geographically or ecologically isolated.Thompsma (talk) 01:04, 6 October 2011 (UTC)

Deleting the next sentence I added - it is getting too long. I'm going to take a break for a while and think this through.Thompsma (talk) 01:21, 6 October 2011 (UTC)

Evolution is not a forward mechanism, it is a passive mechanism. Changes occur now and have occurred in the past. Evolution has literally nothing to say about the future, and so can not change anything in descendant populations. A major change in the environment can suddenly change all the requirements for individuals for the next generation. -- Kim van der Linde ^{at venus} 13:27, 6 October 2011 (UTC)

Oppose. This defines evolution as change IN (sounds like WITHIN to me) a lineage. We are defining lineage as ancestor-descendent relationships, i.e. sibs, cousins etc. don't count. When one heritable type rises in frequency relative to another heritable type, no change has occurred IN the lineages. A change has instead occurred in the frequencies of the descendents of existing lineages. This basic part of evolution is not included in the definition. Also, in the proposed first sentence, lineages "...reproduce their heritable traits into descendant populations". But lineages are defined as the pairing of ancestor and descendent, so this doesn't parse with lineages as the subject. Also, the reference to hierarchy does not make clear that the pattern of descent in a lineage at one level may bear little relationship to the pattern of descent in a lineage at a different level, eg if horizontal gene transfer has taken place.

I support instead the notion that the way forward here with definitions is that less is more. Joannamasel (talk) 15:15, 6 October 2011 (UTC)

I also agree that less is more. The key goal here is to repair the lead and the remainder of the article toward a more integrative and inclusive description of evolution consistent with the broader literature on this topic. The article has become too gene heavy and we have lots of agreement that this is so. Many articles and textbooks, for example, state something to this effect: "Theories of evolution that state natural selection acts on individuals have been modified to include multiple levels of selection."[72] Hence, we are working toward an abstract lead describing evolution in an integrative way. I understood the point that Joannamasel has raised about change in frequencies and I think this is the same point that Kim van der Linde is stating about evolution being passive, although I don't think that is the most apt term to get the point across (see [73]). Moreover, it adds confusion in context of the niche construction perspective "Niche construction, which portrays organisms as active agents that modify their environment rather than mere passive entities selected by their environment, has received increasing attention in ecology and evolutionary biology during the last decade (Odling-Smee et al. 1996, 2003; Laland & Sterelny 2006)." Of course the extinction of lineages and the differential survival is what alters the frequencies in descendant populations, plus added novelty from mutation and epigenetic admixture.Thompsma (talk) 18:52, 6 October 2011 (UTC)

I am very much in favor of the KISS principle. We do not have to encapsulate everything in the first definitional sentence, but that sentence should cover evolution as a whole. That is why I propose something along the line of:

Biological evolution is the change over time in the heritable components of biological agents. Evolution occurs independently and interactively at every level of organization from molecules to cells to individuals to populations and species, and explains all of the biological heritable diversity at each of those levels. Changes in the heritable components within and between lineages arise from mechanisms such as natural selection, genetic drift and gene flow. The theory of evolution was first proposed by Charles Darwin, who realized that species adapt to their environment by passing on favorable traits from generation to generation, ultimately resulting in the tree of life. Since then, it has been expanded, refined and rigorously tested to the point that most scientists accept evolution as a fact.

Just as a start for discussion.-- Kim van der Linde ^{at venus} 19:25, 6 October 2011 (UTC)

Looks good. I dig the KISS principle too. :) danielkueh (talk) 19:29, 6 October 2011 (UTC)

Expanded it. -- Kim van der Linde ^{at venus} 19:31, 6 October 2011 (UTC)

I like it.Thompsma (talk) 19:35, 6 October 2011 (UTC)

Even better. danielkueh (talk) 19:41, 6 October 2011 (UTC)

Biological agents? Evolution is passive so it can't pass, but now it can explain? Is there any kind of change that doesn't happen over time? If you want "short and simple" then what you are writing is equivalent to "Evolution is biological change through descent with modification" which is both clearer and uses Darwin's original language.·ʍaunus·snunɐw· 19:46, 6 October 2011 (UTC)

Not bad, but I would definitely take out the word "independently". Also, I am not sure that a molecule evolves. What evolves is a population of molecules. At every level, evolution is of a population of things. Avoiding the awkward "populations of populations", what about starting with

Biological evolution is the change over time in the heritable components of populations of biological agents. Evolution occurs interactively at every level of organization, involving agents that range from molecules to cells to individuals to species. Evolution explains all of the biological heritable diversity at each of those levels.

As for the following sentences, I continue to oppose any mention of genetic drift in the lead unless it is accompanied by a mention of genetic hitchhiking and/or background selection, given the evidence that we have defined genetic drift as sampling error, and that the evidence supports a greater role for selection at linked sites than for sampling error in explaining random changes.Joannamasel (talk) 19:44, 6 October 2011 (UTC)

Maunus' version would also be OK if we added a definition of "descent" to it. Except what if the modification is environment and not really heritable? Joannamasel (talk) 19:57, 6 October 2011 (UTC)

For an explanation we could link the phrase "Descent with modification". Currently that redirects to Evolution, but I think the concept is significant enough to have its own article.·ʍaunus·snunɐw· 20:22, 6 October 2011 (UTC)

We need to carefully consider the term biological agent - often used in clinical research in reference to an infectious disease.Thompsma (talk) 21:20, 6 October 2011 (UTC)

True, perhaps "entities" is better than "agents?" danielkueh (talk) 21:22, 6 October 2011 (UTC)

I was thinking the same thing. Entity pops up in the literature quite often, but it does sound a bit dry. Comparing our options:

• Biological evolution is the change over time in the heritable components of biological entities.
• Biological evolution is the change over time in the heritable components of biological agents.
• Biological evolution is the change over time in the heritable components of biological lineages.
• Biological evolution is the change over time in the heritable components of species.
• Biological evolution is the change over time in the heritable components of life.
• Biological evolution is the change over time in the heritable components of individual lineages that weave into a hierarchical tapestry of life.

The last option is thrown in for discussion of using a metaphorical approach.Thompsma (talk) 21:42, 6 October 2011 (UTC)

I like "life." If it's chosen, be sure to wikilink it to life. danielkueh (talk) 21:48, 6 October 2011 (UTC)

• biological entities, please. "Lineages" and "species" seem too encompasing, agents as discussed earlier, life though inferred as "life as we know it" seems not definitive enough with advances in technology and entities in fiction. And the last one (again, IMO) fits the "lineages" part I mentioned earlier along with being a bit wordy and flowery. I would pick life as my #2 choice though. Best, ROBERTMFROMLI | ^TK/_CN 21:53, 6 October 2011 (UTC)

I used entities because of the unit of selection issue. Not married to entities, agents would be fine with me. Life would not really work because we do not have populations of life. Taking into account joanna's points about genetic drift, I come to the following:

• Biological evolution is the change over time in the heritable components of populations of biological entities. Evolution occurs interactively at every level of organization, involving agents that range from molecules to cells to individuals to species. Evolution explains all of the biological heritable diversity at each of those levels. Changes in the heritable components within and between lineages arise from mechanisms such as natural selection, genetic drift, genetic hitchhiking, and gene flow. The theory of evolution was first proposed by Charles Darwin, who realized that species adapt to their environment by passing on favorable traits from generation to generation, ultimately resulting in the tree of life. Since then, it has been expanded, refined and rigorously tested to the point that most scientists accept evolution as a fact.

Shoot! -- Kim van der Linde ^{at venus} 21:56, 6 October 2011 (UTC)

It is repetitive to mention "biological" twice, "change over time" is a pleonasm, do any non biological entities have heritable components?·ʍaunus·snunɐw· 22:03, 6 October 2011 (UTC)

I am OK with the first 2 sentences, and have many issues with the remainder. "Explains all" seem like fighting words to me, I don't even know what that really means. Evolution as defined here is a fact, not an explanation. Instead of "gene flow", I prefer the current lead's formulation of "recurrent biased mutation or migration". I am also nervous of just throwing in natural selection without explaining it. The current explanation in the next selection is historically accurate, in that, following Darwin, it includes the inheritance of acquired characteristics. I don't support placing that idea right next to our first reference to adaptation. We should define adaptation if we use the term, as used here it could easily mean plasticity. Also, there were theories of evolution before Chuck, just not very good ones. Also, most scientists accepted evolution as fact shortly after the publication of the Origin. It was natural selection they didn't accept. Joannamasel (talk) 22:08, 6 October 2011 (UTC)

I think Darwin's classic breakdown of variation + inheritance + selection should appear in the lead. Why don't we take these new first 2 sentences, and form a bridge between them and the existing leads, including the parts that include this breakdown? Joannamasel (talk) 22:17, 6 October 2011 (UTC)

Would "subtle implication" work for you then? (no, I am being serious). Perhaps word like this? "...and explains all of the biological heritable diversity at each of those levels." Best, ROBERTMFROMLI | ^TK/_CN 22:19, 6 October 2011 (UTC)

My previous criticisms of the term "lineage" in this context still applies. First, the word is obscure to the typical lead-reader. Second, if you follow the link, then disambiguate correctly, you get the definition of a line i.e. no branching. Changes in frequencies are not included in this definition. The correct word for this sentence is population, not lineage. There is no genetic drift either within or between a lineage, for example. Mutation is the causes of change within and between lineages. These other mechanisms cause change to the extent to which lineages branch out or contract into more or fewer lineages. Joannamasel (talk) 22:23, 6 October 2011 (UTC)

KVL, 1st two sentences look fine. I agree with Maunus that we do not need to repeat "biological" twice. So I suggest that "biological evolution" be trimmed to just "evolution." danielkueh (talk) 22:26, 6 October 2011 (UTC)

Instead of biological entities, could we use "reproductive entities" or "entities that reproduce"?Thompsma (talk) 22:31, 6 October 2011 (UTC)

Next version:

• Evolution is the change over time in the heritable components of populations of biological entities. Evolution occurs interactively at every level of organization, involving entities that range from molecules to cells to individuals to species. Evolution explains the biological heritable diversity at each of those levels. Changes in the heritable components within populations of entities arise from mechanisms such as mutation, genetic drift, genetic hitchhiking, recurrent biased mutation or migration, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that the individuals within a population that survived and produced the largest number of offspring passed their favorable and heritable traits to the next generation, ultimately resulting in the tree of life. Since then, it has been expanded, refined and rigorously tested, while most scientists accept evolution as a fact.'

Trying to fix the objections.-- Kim van der Linde ^{at venus} 22:34, 6 October 2011 (UTC)

KVL - you are doing a great job! My suggestions for the first three sentences:

• Biological evolution is the change over time in the heritable components of populations of entities that reproduce. Evolution occurs interactively at every level of organization, involving entities that range from molecules to cells to individualsorganisms to species. Evolution describes the patterns of explains the biological heritable diversity and the processes that that produce them at each of those levels.Thompsma (talk) 22:46, 6 October 2011 (UTC)

I still don't know what it means for evolution to "explain" diversity. Either Thompsa's version or simply replacing "explains" with "gives rise to" would help. The "ultimately resulting in the tree of life" doesn't follow logically from the previous sentence, whatever Darwin claimed, and in any case for clarity should have its own sentence. But first we should explain that natural selection leads to a particular kind of evolutionary change, namely adaptation. The last sentence is better than before, but how about replacing "while" with "and". I would also strengthen the wording, to make the overwhelming scientific consensus clearer. Joannamasel (talk) 22:54, 6 October 2011 (UTC)

I personally do not line those changes for the following reasons. Entities that reproduce is kind of specific, we really do not talk about gene reproduction but to copying. Same for species. They undergo evolution as a whole, for example in character displacement situations, but they do not reproduce as a whole but as individuals within the species. Most of the biological diversity is phenotypic, so that is why I specified heritable. Evolution is actually mute on the processes, it does not care. I think describe is to static. Tweaking again, we get to this:

• Evolution is the change over time in the heritable components of populations of biological entities. Evolution occurs interactively at every level of organization, from molecules to cells to individuals to species. Evolution gives rise to the biological heritable diversity at each of those levels. Changes in the heritable components within populations of entities arise from mechanisms such as mutation, genetic drift, genetic hitchhiking, recurrent biased mutation or migration, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that the individuals within a population that survived and produced the largest number of offspring passed their favorable and heritable traits to the next generation. Natural selection can lead to adaptations within populations. Speciation occurs once differences between populations result in a reduced exchange of individuals and the repeated process of speciation results in the tree of life. Since then, the theory of evolution has been expanded, refined and rigorously tested, and scientists overwhelmingly accept evolution as a fact.

-- Kim van der Linde ^{at venus} 22:59, 6 October 2011 (UTC)

Some authors have published statements to the effect that "genes reproduce by replication" and species reproduction is also used in species selection literature.Thompsma (talk) 23:03, 6 October 2011 (UTC)

Oh yeah, I know some people use those words in that way. Anyway, I am heading home and see what comments have been left by tomorrow. Signing off for the day. -- Kim van der Linde ^{at venus} 23:11, 6 October 2011 (UTC)

My understanding is that DNA replicates whereas genes reproduce. A gene is the heritable information encoded in the DNA, or as George Williams put it: “A gene is not a DNA molecule; it is the transcribable information coded by the molecule." (Quoted in a paper by Dawkin's [74]). Here are two examples of the reproductive terminology for genes and species by two well known evolutionary biologist/philosopher:

• "The biological species concept - of interbreeding communities - can be supplemented (but not replaced) by a genetic species concept, of species as gene pools in which the genes reproduce asexually (when DNA replicates) and generates phenotypes (organisms) that can reproduce sexually, so producing new mixtures of genes."[75]
• "An organism grows by increasing the number of cells that are part of its body; it reproduces by creating a new functioning entity. The parallel is this: Species reproduce not when the organisms in them grow in number but when they found numerically distinct offspring species. Species selection thus must involve the idea of differential speciation."[76]

Reproduction across the biological hierarchy adds to the definition by stating that the biological entities (i.e., Darwinian individuals - in Gould's terminology) reproduce; a core principle of multi-level selection. Second sentence, I would replace individual with organism - individual can refer to species as readily as organism, a common practice in evolutionary philosophy lit. Compare:

• Evolution gives rise to the biological heritable diversity at each of those levels.
• Evolutionary biologists describe patterns and explain processes at each level that adds complexity to the planets wealth of biological diversity.

I offer the later, "biological heritable diversity" is too wordy. Next:

"Changes in the heritable components within populations of entitiesEvolution is a population level phenomenon where new heritable traits arise from varied mechanisms such as mutation, genetic drift, genetic hitchhiking, recurrent biased mutation or migration, and natural selection."

As an abstract in the lead (even though I sympathize with Joam's point) I think we can leave out hitchhiking and gene flow until the body of the text; a prelude to what will come later? Next:

The theory of evolution by means of natural selection was first proposed by Charles Darwin who realized that the individuals within a population that survived and produced the largest number of offspring passed their favorable and heritable traits to the next generation. and is formulated on three recurrent facts of biological populations, including 1) an overproduction of offspring, 2) traits are varied among individuals leading to differential rates of survival and reproduction, and 3) traits are heritable. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Natural selection can lead to adaptations as the more favorable traits survive in greater number into descendant populations.

I'm not a fan of the last two sentences on speciation and fact of evolution, sorry Kim - but great job otherwise!! I think speciation can be the topic sentence for the next paragraph.Thompsma (talk) 03:36, 7 October 2011 (UTC)

Comparing the progress

Thought I would use the table comparison method for discussion. I'm very impressed with the progress that we've all made with both versions. Great to see intelligent cooperation!!:

Kim van der Linde

Thompsma

Evolution is the change over time in the heritable components of populations of biological entities. Evolution occurs interactively at every level of organization, from molecules to cells to individuals to species. Evolution gives rise to the biological heritable diversity at each of those levels. Changes in the heritable components within populations of entities arise from mechanisms such as mutation, genetic drift, genetic hitchhiking, recurrent biased mutation or migration, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that the individuals within a population that survived and produced the largest number of offspring passed their favorable and heritable traits to the next generation. Natural selection can lead to adaptations within populations. Speciation occurs once differences between populations result in a reduced exchange of individuals and the repeated process of speciation results in the tree of life. Since then, the theory of evolution has been expanded, refined and rigorously tested, and scientists overwhelmingly accept evolution as a fact.

Biological evolution is change over time in the heritable components of populations of entities that reproduce. Evolution occurs interactively at every level of organization, from molecules to cells to organisms to species. Evolutionary biologists describe patterns and explain processes at each level that adds complexity to the planets wealth of biological diversity. New heritable traits arise in populations through various mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin and is formulated on three recurrent facts of biological populations, including 1) an overproduction of offspring, 2) traits are varied among individuals leading to differential rates of survival and reproduction, and 3) traits are heritable. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Traits are the features of biological entities, including molecular, behavioural, developmental, or anatomical differences. Biological entities adapt by means of natural selection as traits that are favorable to environmental conditions survive in greater number into descendant populations.

Thompsma (talk) 04:07, 7 October 2011 (UTC)

• I'm sure they're both very precise, but neither is an example of good writing.·ʍaunus·snunɐw· 14:27, 7 October 2011 (UTC)

Well, we can fix the good writing once we have the key down. Thompsma, I indicated already above that I think you changes are not a improvment. Genes do not reproduce despite that some people somewhere have used it that way. The general view is that they are copied. They generally do not have control even over whether they are copied, so to word it as an active process that includes often a whole range of behaviors is just complicating things.

"Genes do not reproduce despite that some people somewhere have used it that way." - Evolutionary biologists have used that kind of terminology in WP:V - so it is not just some people somewhere, it is experts in the field who have published that kind of terminology. For example, Theodosius Dobzhansky stated: " The existence of all levels is based ultimately on some patterns of physico-chemical reactions, as yet unknown, which result in the self-reproduction of certain molecules', or molecular aggregates, called gene." or "How do the genes reproduce themselves and direct the synthesis of proteins?"[77] - used in context of someone who is working directly in the field of the proteins, RNA and enzymes involved in the process. Or: "Not just organisms can form populations but so can cells, colonies, and chromosomes. Cells are examples of simple reproducers; they have all the reproductive machinery internal to them. Organisms and groups of organisms are collective reproducers; they are made up of parts—simple reproducers—that can themselves reproduce. Chromosomes, genes, and cultural entities fall in the category of scaffolded reproducers; their reproduction depends on some kind of external scaffolding"[78]) Moreover, the sentence does not say directly that genes reproduce, it says that biological entities reproduce. The point is that reproduction can be used broadly to cover that aspect and I think reproduction is an improvement to the sentence because it makes it more biological.Thompsma (talk) 17:07, 7 October 2011 (UTC)

Leaving individuals out eliminates the key level that most people recognize. Most models are descried as individuals within a population. An organism is generally more akin a species, so we just doubled that up.

The key level that most people recognize is organisms. "The proper definition of a Darwinian individual constitutes one of the most challenging and fascinating issues in the formulation of causality under natural selection."[79] There are hundreds of publications in evolutionary and philosophical literature dealing specifically with the notion of individuality (e.g., [80], [81], [82], [83], [84], [85], [86], [87], [88], [89], [90], [91], [92]). Those are just a few links that I could quickly find to citations that specifically refer to the concept of individuality in evolution making a clear distinction between organism and individual. So using the term individual adds confusion. There is nothing wrong with using organism, it has a direct wikilink to something that is tangible to biology, and it is the correct term to use. These papers on the notion of individuality in evolution also highlight that Darwinian individuals reproduce and the gene is a Darwinian individual.Thompsma (talk) 17:07, 7 October 2011 (UTC)

I can live with leaving out gene flow and genetic hitchhicking, I leave that up to others.

I don't like the changes at the end of the paragraph. The first paragraph should capture the whole, and not drift of in details that are not essential to under stand evolution. Hence also my objection to your expansion of what Darwin postulated, which really does not need to be in the first paragraph at the expense of other aspects.

with that said:

• Evolution is the change over time in the heritable components of populations of biological entities. Evolution occurs interactively at every level of organization, from molecules to cells to individuals to species. Evolution gives rise to the biological heritable diversity at each of those levels. Changes in the heritable components within populations of entities arise from mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that the individuals within a population that survived and produced the largest number of offspring passed their favorable and heritable traits to the next generation. Natural selection can lead to adaptations within populations and sustained differential selection between populations can lead to speciation once those differences result in a reduced exchange of individuals. The repeated process of speciation has resulted in the tree of life. Since then, the theory of evolution has been expanded, refined and rigorously tested, and scientists overwhelmingly accept evolution as a fact.

Maunus, suggestions for prose refinement so that it becomes better writing?-- Kim van der Linde ^{at venus} 14:43, 7 October 2011 (UTC)

What makes it un-good writing is the extreme terminological density which is what we get for aiming for precision and concision at the same time. To make it more easily readable it would require us to unpack the phrasings into something less dense - by using less jargon/sacrifice some precision and use more sentences with less information each.·ʍaunus·snunɐw· 14:58, 7 October 2011 (UTC)

But this is an article on a scientific topic. Jargon: "the language, especially the vocabulary, peculiar to a particular trade, profession, or group: medical jargon."[93] We are using evolutionary jargon and you seem to be counting this as a negative.Thompsma (talk) 17:07, 7 October 2011 (UTC)

Yes I am, because while you belong to the particular profession you are writing for people who do not. Your version is basically only informative to someone who already knows the information that it gives. That is rather pointless. ·ʍaunus·snunɐw· 17:22, 7 October 2011 (UTC)

In the discussion on "creation myths" above, Maunus said ""creation stories" is not a technical term, and while it may look more "neutral" to a layperson, it is just fluffy speech that makes wikipedia look unprofessional." I am starting to come round to this point of view and I believe it applies here as well with respect to the use of "technical terms" or "jargon" in evolution. So while I agree that technical language is necessary, I would like to see it explained or used in such a way as to be clear to the reader. And if there is a choice among technical terms, I of course would advocate for the simplest term. danielkueh (talk) 17:46, 7 October 2011 (UTC)

I think you know full well that you are taking a previous statement of mine out of context and thereby misrepresenting my view in a different context. That is not in line with our civilty policy. Those are two different situations and the same argument doesn't apply. Also you are mistaken if you think that I have actually removed any of the technical jargon in my version - I haven't - I have just supplied explanations for it so that it makes sense to people who do not know the concept before hand. I am not inventing my own terminology to replace the established one as you did with your creation stories.·ʍaunus·snunɐw· 17:52, 7 October 2011 (UTC)

This is going into a digression, I'll be brief. You made the point that "creation myth" is a technical term and should therefore not be changed. That was a very striking comment and rationale, which I still remember. That is why I referenced it and applied that same principle here. Terms such as "entities, tree of life, etc" were removed from your proposed text below. The rationale provided was to avoid "technical jargon" as we should write to a "broader audience." A good point, but inconsistent with the above principle. Whatever principle we used, I think we should strive to apply it consistently throughout the article. Nothing personal. danielkueh (talk) 19:24, 7 October 2011 (UTC)

An attempt at lightening the prose:

Maunus

Evolution is any change in the heritable components of biological populations. The evolutionary process gives rise to diversity, at every level of organization, from molecules to cells to individuals and species. New heritable traits in populations are caused by mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population the individuals that live to produce the largest number of offspring passed their heritable traits on to the next generation. Natural selection can lead to adaptations when certain heritable traits provide an advantage for survival and reproduction in a certain environment. Over time divergent selection between populations can lead to speciation, as diverging lineages become unable to interbreed, or become so morphologically dissimilar that they can no longer be considered the same species. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact."

·ʍaunus·snunɐw· 15:14, 7 October 2011 (UTC)

Maunus, it's an improvement, but... "Reduced exchange of individuals" is rather unclear in meaning. Any definition of species and species needs, I am afraid, to include asexual species as well. Yes, I know this is notoriously difficult. The wording also suggests that selection is the only cause of speciation. I also think that "adaptation" requires some sort of definition / explanation. Joannamasel (talk) 15:38, 7 October 2011 (UTC)

I actually inserted an explanation of adaptation, which wasn't there in the original. "reduced exchange of individuals" was in there in the original, but I agree that it needs to be explained. I don't see where it gives a definition of species that doesn't cover asexual species - the only definition given is a wikilink.·ʍaunus·snunɐw· 15:47, 7 October 2011 (UTC)

I see, the "reduced exchange of individuals" relies on the definition of species as breeding populations. Well actually I don't think that it is necessary to explicitly include for example asexual reproduction here, since it can easily be described as an exception to the rule. But if we make the statement more vague - e.g. ", as diverging lineages become unable to interbreed, or become so morphologically dissimilar that they can no longer be considered the same species." - this takes into account different species definitions, and gives an explanation of speciation.·ʍaunus·snunɐw· 16:16, 7 October 2011 (UTC)

I agree with Joanna. Asexual reproduction is huge. Bacterial cells, some invertebrates as well as plants and fungi reproduce that way. Plus, it preceded sexual reproduction. danielkueh (talk) 16:41, 7 October 2011 (UTC)

Her concern already been incorporated into my version.·ʍaunus·snunɐw· 16:45, 7 October 2011 (UTC)

Of the three versions, I like KVL's proposed text the best, followed by Thompsma's. Although Mauna's text is simpler, the wording in several sentences is a little awkward. While I agree with Maunus's sentiment that the texts by KVL and Thompsma are a little dense, I think the best solution would be to "divide up" a few of the sentences and pace ourselves a little bit. Both versions seemed "a little rushed." danielkueh (talk) 16:56, 7 October 2011 (UTC)

Here is an attempt to improve Maunus's version:

Evolution is any change in the heritable components of biological populations. The evolutionary process gives rise to diversity, at every level of organization, from molecules to cells to individuals and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population the individuals that produce the largest number of surviving offspring passed their heritable traits on to the next generation. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split in two and then evolve in divergent directions: this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Joannamasel (talk) 17:39, 7 October 2011 (UTC)

That is what I should have written. support 100%.·ʍaunus·snunɐw· 17:44, 7 October 2011 (UTC)

I support this if: "individuals and species" is changed to "organisms and species". The large wikilink "within a population the individuals that produce the largest number of surviving offspring passed their heritable traits on to the next generation" - is also a little odd. I would put the link elsewhere: "The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population the individuals that produce the largest number of surviving offspring passed their heritable traits on to the next generation."Thompsma (talk) 17:55, 7 October 2011 (UTC)

I can also support those proposed changes.·ʍaunus·snunɐw· 17:56, 7 October 2011 (UTC)

I support those changes. But how about putting the Origin of Species link on the words "first proposed" instead? That seems to me the best place. Joannamasel (talk) 18:09, 7 October 2011 (UTC)

• 'Support' - I think we have it.Thompsma (talk) 18:19, 7 October 2011 (UTC)

(we still need to hear from KimVDL, Daniel and perhaps Slrubenstein and others who have participated)

Of course! That is implied.Thompsma (talk) 18:27, 7 October 2011 (UTC)

• Support with noted change of "individuals" to "organisms", pending comments from KimVDL and others. ROBERTMFROMLI | ^TK/_CN 18:31, 7 October 2011 (UTC)

I do not support the organisms instead of individuals. For the rest I am fine with the version. -- Kim van der Linde ^{at venus} 18:32, 7 October 2011 (UTC)

Support, with a slight preference for organism. danielkueh (talk) 19:37, 7 October 2011 (UTC)

• I think we need to consider the arguments for using either individual or organism here. What are they again?·ʍaunus·snunɐw· 19:12, 7 October 2011 (UTC)

We need to consider the arguments for or against. I would like to hear the rationale for using individual and the objection to organism. Here is my argument for use of organism: Compare individual against organism - the later is very clear and it is biologically orientated. Earlier I provided a list of publications in evolutionary literature that discuss the philosophical importance of the term individual: (e.g., [94], [95], [96], [97], [98], [99], [100], [101], [102], [103], [104], [105], [106]) On page 597 of Gould's book[107] he devotes a chapter on the meaning of individuality in evolution. Obviously - some key players in the discipline feel that this is an important distinction to make and it is near universally understood that Darwin focused on the organism. I would like to hear the rationale or argument to the contrary.Thompsma (talk) 19:16, 7 October 2011 (UTC)

Just go over to the organism article. Organism is one of those relative vague terms that is sometimes is used to mean a species, and sometimes to mean individuals of an organism. -- Kim van der Linde ^{at venus} 19:26, 7 October 2011 (UTC)

"Just go over to the individual article. Individual is one of those relative vague terms that is sometimes is used to mean a species, and sometimes to mean organisms of an individual." Except, we can turn to the peer-reviewed and published literature that gives very clear direction on this. Please address the list of papers that I linked too - we cannot ignore this, it is a huge issue and the WP:V supports organism.Thompsma (talk) 19:30, 7 October 2011 (UTC)

I prefer "organism". It carries fewer non-biological overtones. Joannamasel (talk) 20:00, 7 October 2011 (UTC)

If this deadlock continues, how about "individual organisms?" danielkueh (talk) 20:25, 7 October 2011 (UTC)

I was away for a while, lots has been done here. I am impressed by the new proposal - it reads well. I support "Organism" or "Individual Organism" with a preference for the shorter version. Adding individual in front of organism really adds nothing further. An individual has a much wider meaning in the philosophical sciences, whereas there is no confusing what an organism is.Claviclehorn (talk) 20:32, 7 October 2011 (UTC)

If everybody except me is for organisms, that is sufficient for consensus in wikipedia terms. I made my objection clear. -- Kim van der Linde ^{at venus} 21:41, 7 October 2011 (UTC)

I would like to suggest a few changes (marked bold and strikethroughs) to the following sentence: "who realized that within a population, the individuals that produce the largest number of surviving offspring passed are likely to pass on their heritable traits on to the next future generations." Also replace the colon with a period after "Populations can split in two and then evolve in divergent directions" danielkueh (talk) 21:50, 7 October 2011 (UTC)

I'm fine either way with the punctuation change. But I think the other sentence is correct as written. The probability (likelihood) is that a given heritable trait will lead to a greater number of surviving offspring. Once you have the greater number of surviving offspring, greater contribution to the next generation follows automatically, not with a certain likelihood. Joannamasel (talk) 22:01, 7 October 2011 (UTC)

There are tense, logic, and redundancy problems. Individuals that produce surviving offspring have already contributed to the next generation. The next generation is basically their offspring. The more interesting question is, "how about future generations?" i.e., their offspring and beyond. Assuming that their offspring continues the practice, the individual's heritable traits are likely to be preserved. danielkueh (talk) 22:06, 7 October 2011 (UTC)

So perhaps it should be phrased as follows: Individuals that produce the largest number of surviving offspring are more likely to have their heritable traits preserved in future generations. danielkueh (talk) 22:14, 7 October 2011 (UTC)

Better, but "preserved" is a bit conservative. Eg, in the classic Drosophila bristle number experiment, selection rapidly yields phenotypes more extreme than any seen in the initial population, due to recombination of previously rare alleles. I would rather a wording that stressed change over preservation. Joannamasel (talk) 22:28, 7 October 2011 (UTC)

I guess the more neutral phrase would be to say "passed on to future generations," which does sound a little boring. But I can't think of a better term at the moment. How about "retained, kept, or present?" danielkueh (talk) 22:34, 7 October 2011 (UTC)

How about this:

1. Individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations.
2. Individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear, in varying forms, in future generations.

danielkueh (talk) 22:40, 7 October 2011 (UTC)

Those are both OK, meaning I can't think of anything better, but suspect that better might still exist. Meantime, I want to challenge the link to biodiversity from the word diversity. That word is being made to mean both biodiversity and genetic diversity in the variation + inheritance + selection sense. The link implicitly excludes the latter. I am also not clear why biological links to Unit of selection. New version in new section below, with a few more changes to links. Joannamasel (talk) 23:10, 7 October 2011 (UTC)

Current proposal

Evolution is any change in the heritable components of biological populations. The evolutionary process gives rise to diversity, at every level of organization, from molecules to cells to organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split in two and then evolve in divergent directions. This can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact.

• Support. Great work everyone. No complaints. danielkueh (talk) 23:17, 7 October 2011 (UTC)
• Support I'm liking the evolution of this. Suggestion to write: "every level of biological organization" for added clarity, even though that word also appears in the preceding sentence.·ʍaunus·snunɐw· 23:27, 7 October 2011 (UTC)
• Support. I was going to suggest "heritable traits expressed in future generations.", but fine with either option.Thompsma (talk) 23:28, 7 October 2011 (UTC)
• Support with individuals caveat. -- Kim van der Linde ^{at venus} 23:51, 7 October 2011 (UTC)

I'd like to understand why you maintain the "individual caveat" Kim - curious and it may help me/us to understand better. I read your reason posted above, but didn't find it very convincing. Is there another reason? Have you read the philosophy papers on individuality by Hull, Gould, Ghiselin, Ruse, and others (e.g., [108], [109])? Curious to know and understand. Perhaps you know something that we don't and could share.Thompsma (talk) 05:44, 8 October 2011 (UTC)

Because it remains confusing. When talking about infections for example, we talk about an individual acquiring the organism. We are not talking about a single specimen of the bacteria, but about an undefined number of individuals of a specific organism. We are not talking about how the individual acquired 1000's of organisms, because that sounds like thousands of different species. Yes, I know that there is a whole phylosophical debate out there about what exactly is an individual and what is an organism and what is a species, but we are not here to solve that issue. We are here to write an encyclopedia that is understandable to the average reader who has no clue about ivory tower discussions between philosophers and most likely don't care at all.-- Kim van der Linde ^{at venus} 15:13, 8 October 2011 (UTC)

Still not convinced, but thanks for your post. It isn't just ivory tower philosophers that are writing about individuality, it is discussed in articles published in evolution, systematic biology, and in textbooks where organism is the norm. Organism is actually less confusing. Much of the ecological literature, for example, refers to the organism: "Many biological sciences are fortunate in having the organism as their object of study. Organisms are convenient units, being discrete, of convenient size, and with a life span short enough to be studied as a whole. Of course none of these properties hold with complete generality."[110]Thompsma (talk) 18:28, 10 October 2011 (UTC)

You can keep repeating the same and adding more links of yet another ivory tower researcher, but that does not change that to me it is more confusing despite your assertion. And to most other people I talked about that are non-biologists. And the quote you provide talks about organisms as species. Conceptional unit is a species, not a single individual. Hardly any researcher studies a single individual. -- Kim van der Linde ^{at venus} 22:30, 10 October 2011 (UTC)

I have not had a chance to look at this during the week. I would like to propose some small tweaks:

Current lead	Proposal above	Tweaked
Evolution (or more specifically biological or organic evolution) is the change over time in one or more inherited traits found in populations of individuals. Inherited traits are distinguishing characteristics, for example anatomical, biochemical or behavioural, that are passed on from one generation to the next. Evolution requires variation of inherited traits within a population. New variants of inherited traits can enter a population from outside populations, and this is referred to as gene flow. Alternatively, new variants can come into being from within a population in at least three ways: mutation of DNA, epimutation (a change inherited in some way other than through the sequence of nucleotides in DNA), and genetic recombination. Natural selection, where different inherited traits cause different rates of survival and reproduction, can cause new variants to become common in a population. Other evolutionary mechanisms can cause a variant to become common even if the variant does not directly cause improved survival or reproduction. These mechanisms include genetic hitchhiking, genetic drift, and recurrent biased mutation or migration.	Evolution is any change in the heritable components of biological populations. The evolutionary process gives rise to diversity, at every level of organization, from molecules to cells to organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split in two and then evolve in divergent directions. This can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact.	Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity, at every level of organization, including molecules, cells, organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Such "natural selection" can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split in two or more and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact.

I am not sure if the reasons are self evident or not. Comments welcome.--Andrew Lancaster (talk) 13:35, 8 October 2011 (UTC)

Moving along

I'm moving the proposed first paragraph below and proposing the next paragraphs - recognizing, of course, that these will probably be changed. I thought I would get the discussion started on the rest of the lead through this tentative proposal.

Thompsma 2nd, 3rd paragraph

Evolution is any change in the heritable components of biological populations. The evolutionary process gives rise to diversity, at every level of organization, from molecules to cells to organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split in two and then evolve in divergent directions. This can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Common descent stretches back over 3.5 billion years since the origins of life on earth. The scientific evidence for common ancestry is overwhelmingly observed in the anatomy of organisms, genomes, the universal genetic code, the geographic distributions of species and their genes, behaviour, breeding experiments, during development, and in the fossil record. Evolutionary biologists frame, test, and illustrate evolutionary hypotheses about the history and genealogical affinity of different lineages by sampling and comparing the evidence from their phenotypic and genotypic traits. Traits are the features of biological entities, including molecular, behavioural, developmental, or anatomical differences. The full physical expression of an organisms traits is its phenotype and all the heritable information encoded at the molecular level is its genotype. Evolutionary traits that are transmitted through common descent, that are similar in form, similarly located positionally relative to other traits, and share similar biological functions are said to be homologous characters. From genes to morphology, evolutionary biologists test genealogical hypotheses in the form of an evolutionary or phylogenetic tree, which is illuminated by the meticulous, systematic, and comparative analysis of homologous characters and their varied states. The scientific study of evolution began in the mid-nineteenth century, when research into the fossil record and the diversity of living organisms convinced most scientists that species evolve. In the early 20th century, Darwinian theories of evolution were combined with genetics, palaeontology, developmental biology, and systematics, which culminated into a union of ideas known as the modern evolutionary synthesis. The synthesis became a major principle of biology as it provided a unifying explanation for the patterns and processes that give rise to life on Earth. Evolution applies universally to all fields in biology and has had a significant impact in the way that we view and practice science in natural resource management, medicine, computation, and philosophy in general.

Thompsma (talk) 23:28, 7 October 2011 (UTC)

One thing I like about the new version is how much shorter it is. Proposed paragraphs 2 and 3 have a lot of material that I think belongs in the body of the article. From here I think the discussion should be whether the 1-paragraph lead can stand on its own, and if not, what are the items that absolutely must be added to it. When (or if?) we have a list of them, we should move on to draft text. So far, I am not sure that anything else is really necessary for the new lead. Joannamasel (talk) 23:37, 7 October 2011 (UTC)

Agree, lets make first a list of topics that need to be in the lead.-- Kim van der Linde ^{at venus} 23:53, 7 October 2011 (UTC)

Third. danielkueh (talk) 23:58, 7 October 2011 (UTC)

I like the idea of the stand alone paragraph - because it is a great piece we have written, although it is very short and we might benefit with a bit more of an overview. I'd have to wait and see what sort of ideas are brought up before making a decision on this.Thompsma (talk)

We need to think in line with WP:LEAD if we want the article to remain in FA status. The lead has to summarize all of the article as fully as possible.·ʍaunus·snunɐw· 12:19, 8 October 2011 (UTC)

Topics that absolutely need to be discussed in the lead

Start making the list: -- Kim van der Linde ^{at venus} 00:02, 8 October 2011 (UTC)

I'm not sure if all these items absolutely need to go in the lead, but thought I would start a list. We can sort in order of importance and cross out ones that we think unimportant.Thompsma (talk) 05:24, 8 October 2011 (UTC)

1. Natural selection (Sexual / Artificial?)
2. Adaptation
3. Heredity
4. Trait / Character
5. Genotype / Phenotype
6. Genetics: DNA / Chromosome / Mutation / Recombination
7. Population Genetics: Gene flow / Neutral drift / Genetic hitchhiking
8. Phylogenetic / Evolution trees / Lineages / Genealogy
9. Species / Speciation / Cladogenesis / Anagenesis
10. History of the discipline
11. Key players: Darwin / Wallace / Mendel
12. History of life / Paleontology / Geology (tectonics)
13. Applications - medicine, computing, conservation biology, agriculture, etc.
14. Eco-geography / Biogeography / Phylogeography
    1. Migration / Dispersal / Vicariance
15. Homology
16. Populations
17. Kin selection / Group selection / Symbiogenesis / Mutualism
18. Eco-Evo-Devo
19. Evidence

I would suggest the new proposed first paragraph has the essentials. The article lead does not really need more, although there might be arguments for it. Thompsma, is there any difference between the list of things you think are essential in the lead and the list of things you think are essential to the whole article? :) --Andrew Lancaster (talk) 13:19, 8 October 2011 (UTC)

Thompsma, could you try to make it about those items that if they are not in the lead, it would make it a bad lead? -- Kim van der Linde ^{at venus} 15:54, 8 October 2011 (UTC)

It was just a shot-gun list of items that I felt were fair game for a lead entry. The purpose was to get the discussion started. I have already proposed a scaffold for the article that would expand beyond this (see Talk:Evolution/Archive_57#Impediments_to_progress)Thompsma (talk) 18:32, 10 October 2011 (UTC)

Rather than write down a list of essentials, I think it would be efficient to think in terms of "main point per paragraph" first. I would like to suggest three paragraphs (max) for the lead as follows:

1st current paragraph (What evolution is)

2nd paragraph (The study of evolution and evidence for it)

This is where "evolutionary biology" comes in. Fossil records, microevolutionary studies, homology (molecular and structural)

3rd paragraph (Impact of evolutionary ideas)

Our understanding of evolutionary relatedness of all life on earth. Evo-devo. Impact on other disciplines, e.g., bio anthropology and evolutionary psychology. Sociocultural impacts.

Just a thought. danielkueh (talk) 16:47, 8 October 2011 (UTC)

I think we should stick to just the single-paragraph lead. Daniel's proposed next 2 paragraphs are nice in principle, but they do not really reflect the current main article and its organisation. Evolutionary biology is already acknowledged in the last paragraph of the proposed paragraph: if more is needed, we should first consider tweaking this, or adding one more sentence to it, rather than add a whole paragraph. What is the key point that is missing? Perhaps simply that evolutionary biology remains an active area of current research? I would support adding words to that effect.

Similarly, I feel the "our understanding of evolutionary relatedness of all life on earth" is already in the current single-paragraph lead, while the "broader" material for paragraph 3 seems too small a proportion of the current main article to be worth putting in the lead. On that note, how about moving paragraph 4 of the current lead down to become the last paragraph of the history section?

An alternative is a radical rethink of the whole article to make coverage of evolutionary biology quite distinct from coverage of evolution, with the lead reflecting this rewrite. Right now, I do not support this. I don't think this is what most readers come to the evolution article to find. This article should focus on what is known today, with the process of learning it arising in passing but not being the central focus. If people disagree on this, and want to continue to discuss it, that's fine, but I think we should go ahead and make the current proposed change, creating a 1-paragraph lead for the time being while that discussion continues. I suspect that deciding on the status of evolutionary biology today will be a long and not easily resolved discussion.

I support most of Andrew's tweaks, except for the one leading to the addition of quotation marks around "natural selection.Joannamasel (talk) 18:28, 8 October 2011 (UTC)

With a single paragraph lead the article cannot be an FA or a GA. According to the Manual of Style the Lead has to provide a full summary of the article and should have a number of paragraphs correlating with the size of the article.·ʍaunus·snunɐw· 18:44, 8 October 2011 (UTC)

In that case I propose taking the existing text, splitting it up into multiple paragraphs, and mildly expanding them, starting as below. Joannamasel (talk) 19:11, 8 October 2011 (UTC)

Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species.

Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment.

Populations can split into two or more subpopulations and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact.

A reasonable point of discussion. I suspect it will end up looking like a much improved version of the existing lead. danielkueh (talk) 19:23, 8 October 2011 (UTC)

That would be good. I think it is almost a natural cycle that in busy articles like this, leads get constantly expanded and then occasionally stripped back down to their core again.--Andrew Lancaster (talk) 19:32, 8 October 2011 (UTC)

I added a couple of things to the revised proposal below that I think are too important to omit now that we are going for something very slightly longer. I also think we need one or two more sentences at the end of paragraph 3 about phylogeny construction and/or inference. Joannamasel (talk) 23:30, 8 October 2011 (UTC)

I am generally satisfied with Joannamasel's revised proposal. I would keep the following as two sentences: "Populations can split into two or more subpopulations and then evolve in divergent directions. This can lead to speciation." - otherwise it is a Run-on_sentence. I am not a fan of the following "Evolution by means of natural selection requires heritable variation within a population." In particular, the term requires is a little problematic, because natural selection requires a few things to work. How about, "Evolution by means of natural selection is partly formulated on the heritable variation that exists in populations. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring." It is longer, but if you are going to introduce heritable variation, then heritability needs to be defined. Would anyone object the following addition at the very end:

"Evolution applies universally to all fields in biology and across disciplines, including natural resource management, humanities, medicine, computation, and philosophy in general."

I will summarize my proposal below.Thompsma (talk) 18:53, 10 October 2011 (UTC)

Slightly expanded proposal

Original	Joannamasel's	Thompsma's
Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split into two or more subpopulations and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact.	Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations. Evolution by means of natural selection requires heritable variation within a population. Natural selection can lead to adaptations, which are heritable traits that provide an advantage for survival and reproduction in a particular environment. Populations can split into two or more subpopulations and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Understanding the patterns and processes of evolution are active areas of current research in evolutionary biology.	Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. The theory of evolution by means of natural selection was first proposed by Charles Darwin. Natural selection is partly formulated on the principle of heritable variation. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Heritable traits can change within populations through mechanisms other than natural selection, including mutation and genetic drift. Natural selection, however, can lead to adaptations of traits that are seemingly fitted for the functional roles they perform. Darwin noted that most individuals within biological populations produce greater numbers of offspring that can survive to an age of reproduction. Hence, some adapations are more likely to be expressed in future generations if they enhance survival and reproduction as individuals compete and cooperate in their environments. Populations can split into two or more subpopulations and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Understanding the patterns and processes of evolution are active areas of current research in evolutionary biology. Evolution applies universally to all fields in biology and across disciplines, including natural resource management, humanities, medicine, computation, and philosophy in general.

With very minor adjustments, I am leaning towards Thompsma's version. danielkueh (talk) 19:44, 10 October 2011 (UTC)

I realize (yet again) that my proposal is longer. However, as I was writing this out I realized the error in the following sentence: "The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations." This kinda mixes things up. Adaptations of heritable traits that enhance their function may enhance fitness and this is the causal explanation, not just individuals that produce the largest number of surviving offspring. If an individual produces much more offspring that survive, this does not necessarily translate into fitness unless those that survive have the kinds of trait adaptations that will persist. Moreover, the first proposal does not define heritability and assumes that newcomers will know what this means.Thompsma (talk) 19:40, 10 October 2011 (UTC)

Thanks danielkueh - I realize it needs tweaking and hoping that our team in here can assist to chop it down to its essentials.Thompsma (talk) 19:47, 10 October 2011 (UTC)

I really don't like "partly formulated" at all, I would much rather that my sentence stressing variation were simply deleted again. I don't think there is anything wrong with the sentence "The theory of evolution by means of natural selection was first proposed by Charles Darwin, who realized that within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations." It is an accurate statement of the necessarily true. This necessarily true statement was Darwin's proposed explanation for the empirical observation of adaptation. Following Darwin, the two concepts should be distinct, and should appear in that order. Otherwise one runs into possible tautologies. Thompsa's version does not explain what exactly evolution by natural selection means, only what it is "partly formulated" on and that it leads to adaptation. I very strongly oppose this change. Although I do like the elaboration on the concept of an adaption, but the link to fitness is inappropriate in its context here.

As for the last sentence in Thompsa's version, I don't know what "applies universally" means. Given limited coverage of applications in the main article, I would leave this sentence out of the short lead.

So I propose my version, minus the heritable variation sentence, plus a possible elaboration that adaptations exhibit a "function" in a particular environment for which they are fitted.

I changed the polymorphism link to the more appropriate genetic diversity link in all versions.Joannamasel (talk) 21:48, 10 October 2011 (UTC)

Joannamasel do you not find it in error to suggest that natural selection="individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations"? This is just the numerical component to fitness. It implies an incorrect explanatory cause that natural selection is just a game of numbers, such that those that produce more offspring will numerically overwhelm the future generations; please remember that "selection and sorting cannot be equated"[111]. This sentence describes the replicators component. However, individuals evolve as replicators and interactors - the later being the more important element to the theory. It is in the interaction where the functional aspect to the traits are subject to their 'natural test' - what is their mettle? The adaptation of a trait variety is what gives it some slight functional advantage in survival and reproduction, not its numerical superiority as the sentence implies. I agree, however, that my version needs some help.Thompsma (talk) 21:57, 10 October 2011 (UTC)

Joannamasel states: "Thompsa's version does not explain what exactly evolution by natural selection means, only what it is "partly formulated" on and that it leads to adaptation." - As you can see - this is true for the proposed version, which is why I added partly formulated. We may be forced to explain natural selection more completely.Thompsma (talk) 22:01, 10 October 2011 (UTC)

Richard Lewontin's three principled scheme (read the first page here: [112]) should serve as a guide for defining natural selection. To this, however, I would add: "Heritability of fitness is required if selection is to lead mean population fitness to increase over generations, as Fisher's (1930) 'fundamental theorem' states. But if by evolutionary change one means change in mean phenotype, rather than mean fitness, as Lewontin does, then it is the phenotype differences, not the fitness differences, that must be heritable..Gould's paradox' is a dramatic way of making a valid point, namely that what matters for evolution by natural selection is sufficient parent-offspring resemblance, or heritability; the transmission of replicating particles from parent to offspring is not in itself necessary (cf. Godfrey-Smith 2000a)."[113]Thompsma (talk) 23:53, 10 October 2011 (UTC)

Thompsa, your reference describes what philosophers distinguish as propensity-fitness (selection) and realized fitness (sorting, which includes drift etc.). There is nothing wrong with the sentence in my version as written. The "most likely" puts it squarely in the selection camp, not the sorting. The reference you cite does not identify anything wrong with the sentence. The sentence actually explains natural selection in full, my concern was that it did not sufficiently stress the move from essentialist thinking to population thinking in terms of the fact that heritable variation is a prerequisite for evolution by natural selection. As things stand, this fact is implied but not spelled out. The passage is fine as is, I was just trying to make it better, based on the assumption that many readers with little prior knowledge will think in an essentialist way. Joannamasel (talk) 23:58, 10 October 2011 (UTC)

I think you are in error. Here is the disputed sentence: Natural selection: "within a population, individuals that produce the largest number of surviving offspring are more likely to have their heritable traits appear in future generations." This sentence implies that the more likely is due to largest numbers not due to adapted traits that are heritable as Darwin and others have described - Darwin always referred to the utility of the trait offering a slight advantage, not its numerical superiority. The sentence is in logical error. As Mayr states: "The answer to this question is obvious. Any aspect of the phenotype (or the phenotype as a whole) that favors survival or reproductive success will be favored by selection."[114]Thompsma (talk) 00:14, 11 October 2011 (UTC)

"As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form." (C. Darwin, 1872, 6th ed. [115])

"in any manner profitable to itself" = adaptation - this is in the definition, this is what is being preserved, those that lack the profitable variation perish in the struggle.Thompsma (talk) 00:24, 11 October 2011 (UTC)

The necessary condition is a correlation between survival and reproduction on the one hand, and a heritable trait on the other. If A is correlated with B, it is equally true to say that A makes B more likely as it is true to say that B makes A more likely. The usual formulation that you cite goes from trait to survival and reproduction. The formulation in the sentence goes the other way. It is less common, but equally correct. Stylistically, it works within the short lead, without leading us into complicated territory. Joannamasel (talk) 01:05, 11 October 2011 (UTC)

Your use of A and B is incorrect. If A = "superior numbers" and B = "trait adaptation" (i.e., those that survive in any manner profitable to the individual), then the definition is incorrect, which is what the current proposal states. If, however, A = "phenotype", B = "trait adaptation", and C = "differential survival", then the definition is correct, because the causal reason for the differential survival is the adaptation, not differential fitness. Differential fitness is not what is being selected for. The sentence is in error.Thompsma (talk) 01:51, 11 October 2011 (UTC)

The sentence is not a definition. It says that "Darwin realized that..." followed by a logically necessary truth. It makes no causal statement about what is being selected for. Such causal statements are philosophically problematic, a problem that the sentence avoids dealing with by not making one. Joannamasel (talk) 02:24, 11 October 2011 (UTC)

Joannamasel states: 1) "The sentence actually explains natural selection in full", 2) "The sentence is not a definition." Hence, the confusion. The definition is implied. Why not just give an honest definition when we have the capability to do so?Thompsma (talk) 03:12, 11 October 2011 (UTC)

Sorry to pick on you Joannamasel, nothing personal: "Such causal statements are philosophically problematic" - hmmm...I disagree. My understanding is that causal relations are very useful in science and philosophy. "To detect causal relations between the phenotypic level and the genic level in this model, operational criteria in the form of statistical tests are applied."[116] "If evolution is a statistical process, covariance is surely its engine. The fundamental aspect of inheritance, genetic or cultural, is phenotypic covariance across generations. The translation of genetic information to phenotypic variation (the genotype-phenotype map) reduces to covariance between genes and phenotype. Selection itself, the fundamental adaptive force in the Darwinian algorithm, is simply a covariance between phenotypes and fitness (Price 1970)." [117] (See [118] to see the relationship between covariance and causal relations.Thompsma (talk) 03:56, 11 October 2011 (UTC)

How about this as a substitute for the paragraph in my proposal:

Thompsma

Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. The theory of evolution by means of natural selection was first proposed by Charles Darwin. Natural selection is formulated on three recurrent principles of biological populations, including 1) more offspring are produced than can possibly survive, 2) traits are varied among individuals leading to differential rates of survival and reproduction, and 3) traits are heritable. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Heritable traits can change within populations through mechanisms other than natural selection, including mutation and genetic drift. Natural selection, however, can lead to adaptations of traits that are seemingly fitted for the functional roles they perform. Adapations are more likely to be expressed in future generations if their varieties enhance survival and reproduction as individuals compete and cooperate in their environments. Populations can split into two or more subpopulations and then evolve in divergent directions. This can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Understanding the patterns and processes of evolution are active areas of current research in evolutionary biology. Evolution applies universally to all fields in biology and across disciplines, including natural resource management, humanities, medicine, computation, and philosophy in general.Thompsma (talk) 04:07, 11 October 2011 (UTC)

In response to Joannamasel question: "As for the last sentence in Thompsa's version, I don't know what "applies universally" means" - My meaning is interpreted from Theodosius Dobzhansky's famous quote: "Nothing in Biology Makes Sense except in the Light of Evolution"[119][120][121] - hence it applies universally as the "antonym" to nothing. It is applied in the sense that it directs how biologists raise questions and give recommendations in their respective disciplines. Conservation biologists, for example, would apply evolutionary principles in the manner in which protected areas might be designed. I think we should close off with a statement similar to Dobzhansky's quote. Any further objections to the proposal?Thompsma (talk) 04:39, 11 October 2011 (UTC)

Dobzhansky's quote doesn't use the word "applies", so this is a non sequiteur re the proposed wording.

Are you going to argue that evolution does not apply to all of biology? I included other citations - the pnas series (e.g., Avise, J.C. and F.J. Ayala (eds.). 2010. In the Light of Evolution, Volume IV. The Human Condition. The National Academies Press, Washington, D.C. (411 pp.).) inspired by that quote discusses the various applications of evolution. My sentence is part inspiration, part interpretation of Dobzhansky's quote and coupled with the literature that discusses that very quote, I think my statement is fairly self evident. The expression "applies universally" is used quite often in scientific literature - can even be found in evolutionary journal articles: e.g., [122]Thompsma (talk) 05:45, 11 October 2011 (UTC)

How about the following merger of the two proposals, with more hopefully useful edits cutting out unnecessary words along the way. Also, do check out the definition of adaptation on that page: I have edited to make the lead consistent with it, which Thompsa's proposed paragraph is not currently.

• I think it would probably have been a better idea not to have kept on presenting changes to the first paragraph of the lead after we had arrived at a compromise on that one. I think the version by andrew lancaster that has the broadest support still stands as the best base to work from. Following paragraphs should be added without changing that one.·ʍaunus·snunɐw· 15:11, 11 October 2011 (UTC)

Another attempt

Thompsma

Joannamasel

Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. The theory of evolution by means of natural selection was first proposed by Charles Darwin. Natural selection is formulated on three recurrent principles of biological populations, including 1) more offspring are produced than can possibly survive, 2) traits are varied among individuals, leading to differential rates of survival and reproduction, and 3) traits are heritable. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Heritable traits can change within populations through mechanisms other than natural selection, including mutation and genetic drift. Natural selection, however, can lead to adaptations of traits that are seemingly fitted for the functional roles they perform. Adapations are more likely to be expressed in future generations if their varieties enhance survival and reproduction as individuals compete and cooperate in their environments. Populations can split into two or more subpopulations and then evolve in divergent directions. This can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Understanding the patterns and processes of evolution are active areas of current research in evolutionary biology. Evolution applies universally to all fields in biology and across disciplines, including natural resource management, humanities, medicine, computation, and philosophy in general.Thompsma (talk) 04:07, 11 October 2011 (UTC)

Evolution is any change in the heritable characteristics of biological populations. The evolutionary process gives rise to diversity at every level of organization, including molecules, cells, organisms and species. Heritable traits change within populations due to mechanisms such as mutation, genetic drift, and natural selection. The theory of evolution by means of natural selection was first proposed by Charles Darwin. Evolution by natural selection is a consequence of three widely accepted premises: 1) more offspring are produced than can possibly survive, 2) traits vary among individuals, leading to differential rates of survival and reproduction, and 3) traits are heritable. Heritability is a measure of how reliably a trait is transmitted or correlated from parent to offspring. Natural selection can cause adaptation of a population to its environment, through the evolution of traits that are seemingly fitted for the functional roles they perform. Populations can split into two or more subpopulations and then evolve in divergent directions, and this can lead to speciation. The repeated process of speciation is the process by which all known life forms have evolved from a common ancestor. Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact. Understanding the patterns and processes of evolution are active areas of current research in evolutionary biology.

Joannamasel (talk) 04:54, 11 October 2011 (UTC)

I'm sorry Joannamasel, but I do not like your version and how it is worded around adaptation. It is a clunky sentence and it is peculiar in the sense that it is saying that a population is adapted to its environment? That is kinda novel. You would prefer to link to teleonomy instead of Fitness (biology)?Thompsma (talk) 05:53, 11 October 2011 (UTC)

I used Gould and Vrba's (1982) review of adaptation for my definition.[123] The paper provides an overview on the definition of adaptation and is notable for its landmark contribution on exaptation - HUGE # of citation hits. Kevin Padian cites this [124] as a recent example of its definition used in courts in defense of evolution in the ID cases. The definition in that paper is adopted widely.Thompsma (talk) 06:05, 11 October 2011 (UTC)

I followed up on the adaptation article, which shouldn't be used as a resource - it is an internal wikipedia article and it is incorrect in its definition. The two citations it provides give very different definitions. It is unreliable.Thompsma (talk) 06:07, 11 October 2011 (UTC)

For both of these I don't like: "Since Darwin, the theory of evolution has been expanded, refined and rigorously tested, and scientists today overwhelmingly accept evolution as a fact." This sentence goes against our generally agreed principle - less is more. I don't like the appeal to scientific consensus and don't understand why that has priority in the lead. This is confrontational in a "in your face" kinda way. It does a disservice to its goal and we can do better than this.Thompsma (talk) 06:19, 11 October 2011 (UTC)

The same adaptation-as-process vs. adaptive-trait disambiguation is used in the body of the evolution. The lead should be consistent with the main article. Yes, adaptation is used with multiple meanings in the literature. So is genetic drift. It is not a question of any of these definitions being "incorrect". We have chosen, I believe rightly, to use only one of the definitions for the sake of clarity and internal consistency. As for fitness (biology), it considers subclasses (relative vs. absolute) of a strictly mathematical definition, and it is completely inappropriate to link to that article from a trait-based non-numeric statement as you do. "Seemingly fitted" is virtually a definition of teleonomy, so what is your problem with that link?

As for "evolution applies", substituting in our definition of evolution, this parses as "change in the heritable characteristics of biological populations applies...to computation and philosophy in general." I cannot make sense of this. This is not a question of content, so please do not keep giving citations. This is a question of wording.

"This is a question of wording" - that you inserted! You are inserting text to make the translation meaningless. Have you never heard of evolutionary based computing? Have you not come across evolution in philosophy in general? Of course evolution applies in those fields - metaphorically and directly. We are biological agents and the way that we interact with our technology is an evolutionary phenomena in itself - and I can provide citations that discuss our evolutionary relations with technology, but you don't want me to do this so will refrain. If you don't understand something, that is no reason to reject it. Think of it as an opportunity to learn - but you want to censure citations that could enlighten us on this topic, so we are stuck to rely on our opinions, which do not conform to Wikipedia:SOURCE#Reliable_sources.Thompsma (talk) 16:27, 11 October 2011 (UTC)

This 2-way conversation seems unproductive. You have rejected every single one of my changes to your text, including the deletion of unnecessary words. For example, "compete and cooperate" is both unnecessary and incorrect as a non-exclusive list. Another eg: "traits are varied" is suggestive of an agent, my "traits vary" is more neutral as well as shorter. I will bow out of this conversation for some days until others have a chance to comment on the two versions. Meantime, I made a few more tweaks to my version. Joannamasel (talk) 15:07, 11 October 2011 (UTC)

Joannamasel - I am not rejecting your text on baseless grounds, I am providing citations that back-up my posts. The adapatation definition that you give is completely wrong and you cannot use wikipedia as a resource Wikipedia:NOTRELIABLE#Sources_that_are_usually_not_reliable! I am following protocol for Wikipedia:SOURCE#Reliable_sources, yet you are complaining because I keep giving citations that adhere to this guiding Wikipedian principle? If you are going to put up definitions like so: "Natural selection can cause adaptation of a population to its environment, through the evolution of traits that are seemingly fitted for the functional roles they perform." - then expect a citation to a reliable source out of me. Nothing personal, but clearly you do not understand what an adaptation is and yet you want to write and argue a lead to this article on evolution? In all kindness (I would advise the same to my students), I suggest you spend a bit of time learning about adaptation and I will refrain from providing modern literature citations for this point and will leave it to you to find your way.

"Yes, adaptation is used with multiple meanings in the literature." - Please point me to those resources, I am prepared to do the research, but as it stands I have a comprehensive understanding of both historical and contemporary reviews on the concept of adaptation. "Seemingly fitted" is virtually a definition of teleonomy, so what is your problem with that link? I have no problem with teleonomy, but it is a rather obscure or pedantic term relative to the concept of fitness in this lead article on evolution - stick to the basics. Moreover, seemingly fitted is not teleonomy - seemingly means "from appearances alone", hence on the basis of appearance a trait can appear adapted for its function, such as the correspondence between a hummingbird beak and a flower, but testing for an adaptation requires much more rigorous methods - such as cladistics - to determine if the trait was indeed shaped by historical factors, if there is a covariance between the trait and survival, and if it is currently maintained by natural selection. Are you familiar with the adaptationist programme?

"Another eg: "traits are varied" is suggestive of an agent, my "traits vary" is more neutral as well as shorter." - I have no issue with this change, it is a simple grammatical switch and if your version is shorter I support this, but I have no idea what you are saying by suggestive of an agent (weird)?

"For example, "compete and cooperate" is both unnecessary and incorrect as a non-exclusive list." - I admit that I was hesitant on this part and wasn't sure of how to go about this. How do we capture the elements of Darwin's struggle/competition narrative with the more modern cooperative/mutualistic context that has been brought to the fore of evolutionary theory; although Darwin also saw the value in cooperative evolution/group selection in the Descent of Man? Organisms can compete for survival, but mutualistic cooperation is also a tactic that has ensured survival - so you are incorrect in your review of these terms as non-exclusive, but I am willing to discuss options.Thompsma (talk) 16:27, 11 October 2011 (UTC)

I am using the Dobzhansky definitions of adaptation and related terms, all fully cited already in the current evolution article. The competition vs. cooperation list is non-exclusive. If one organism eats another, which of the two is it, competition or cooperation? If two organisms do not interact in any way, which of the two is it? I do not intend to appeal to credentials with regard to my edits, but I recommend that you google my name and maybe even glance at my papers before making any more condescending remarks. Joannamasel (talk) 16:50, 11 October 2011 (UTC)

I am familiar with Dobzhansky - read all his books and his process orientated adaptation concepts in terms of norm of reaction and co-adapted gene complexes. I am familiar with adaptation as a process, versus the state of being adapted. I am not making condescending remarks - I am speaking directly to your posts. Re-read your definition on adaptation - I could care less about your credentials, your posts must stand on their own legs and as a professional academic you should appreciate this more than anyone. "Evolutionary adaptation concerns a relative concept and the study of adaptations is directed to structures of individuals. The concept is devoid of any meaning when it is applied to species or populations."[125]Thompsma (talk) 17:11, 11 October 2011 (UTC)

I don't mean to intrude in this intellectually stimulating discussion. I would like to suggest that we don't use the word "adaptation" in the lead since it does have multiple meanings (e.g, Futuyma, 1998). It is perhaps best explained in the main text. My suggestion is "less is more." danielkueh (talk) 17:15, 11 October 2011 (UTC)

I disagree danielkueh that we should avoid terms because they are complex with multiple meanings. This would leave the entire lead empty of meaning. We must face the challenges and work toward an integrative solution. Adaptation is integral to evolution - natural selection in particular. A quote from Dobzhansky (1956) should highlight the importance of this concept: "The basic postulate of the modern biological theory of evolution is that adaptation to the environment is the guiding force of evolutionary change." If we avoid it, then we are not describing evolution. My concern with Joannamasel's wording is that several of his Joannamasel's posts are inconsistent with and cannot be backed up by the facts (as I've demonstrated in several 'check-mate' posts above). HeJoannamasel makes the claim: "I am using the Dobzhansky definitions of adaptation and related terms" - let's see if this is true:

• Joannamasel (essentially taken from an earlier Wikipedia version that I corrected this morning): "Natural selection can cause adaptation of a population to its environment, through the evolution of traits that are seemingly fitted for the functional roles they perform."
• Dobzhansky: "A trait is an aspect of the whole or of a certain portion of the developmental pattern of the organism. An adaptive trait is, then, an aspect of the developmental pattern which facilitates the survival and/or reproduction of its carrier in a certain succession of environments."(Dobzhansky, 1956,[126] )

I don't see the similarity at all, which is why I kindly request that Joannamasel provide sources so that we can be diligent in our research. I'm quite familiar with the works of Dobzhansky and quite partial to his ideas that traits are part of a developmental constellation that do not work in isolation. However, I also understand in modern evolutionary studies that there are examples of modular based gene-regulatory networks - such is the case in eye-spots of butterfly wings: "Our results show that differences in response among directions of selection are minor and demonstrate high potential for independent evolution of eyespot sizes. The developmental and evolutionary independence of different wing regions has been demonstrated in other insects (e.g., ref. 44). In butterflies, such flexibility is probably related to the compartmentalization of each of these iterated homologous pattern elements within wing regions bounded by veins (45). This individualization might involve the lack of physical communication between such compartments and/or compartment-specific genetic compositions that regulate the expression of the eyespot-forming genes (20, 46)."[127] Hence, the definition that I provide is general enough to cover a basic overview that is consistent with Dobzhansky and others that have written on this topic - even the dual nature of adaptation as a static concept in the sense that a trait is adapted, versus the process orientated concept that a trait is being adapted. This is covered in the historical context of Gould & Vrba's (1982) aptation, adaptation, and exaptation and I see no disagreement with what I have proposed and what exists in those texts. There is a very clear contradiction (actually many) between Joannamasel's posts and what is found in the actual literature. This is not a personal attack, it is an objective stance on the posts that I see right here in front of me. I fully appreciate Joannamasel's contributions and am very pleased to have the help - but we must work together and be co-vigilant to make sure we are posting reliable information.Thompsma (talk) 19:07, 11 October 2011 (UTC)

Joanna Masel is a woman. I pretty much for the same reasons as she indicates have left the discussion. -- Kim van der Linde ^{at venus} 19:45, 11 October 2011 (UTC)

Could you elaborate Kim van der Linde? I don't see any reference to gender in this discussion. Thompsma always refers to Joannamasel directly as far as I can see - gender neutral.Claviclehorn (talk) 19:57, 11 October 2011 (UTC)

Quote from above (which you have know if you had read it): My concern with Joannamasel's wording is that several of his posts are inconsistent with and cannot be backed up by the facts (as I've demonstrated in several 'check-mate' posts above). He makes the claim: "I am using the Dobzhansky definitions of adaptation and related terms" - let's see if this is true: I rest my case. -- Kim van der Linde ^{at venus} 20:03, 11 October 2011 (UTC)

Good catch!! However, I'm sure that this was an honest mistake and Thompsma could offer an apology. Is that really a reason for leaving? I happen to be a woman - if that makes any difference.Claviclehorn (talk) 20:07, 11 October 2011 (UTC)

No, the reason is that the discussion is tense and terse, with many long posts figiting over details by trowing around selected references.-- Kim van der Linde ^{at venus} 20:22, 11 October 2011 (UTC)

Ouch!! I do apologise for this mistake Kim and Joanna!! I have found myself going back and trying to correct spots where I have placed a gender based pronoun by copying and pasting the user names. I actually never know who is a man or a woman in these discussions - and so there has been no (intentional) discrimination on that basis, nor would I accept or condone that kind of behaviour. This was an honest mistake as I posted in haste and will work more diligently to ensure that it does not happen again. Please accept my sincere apologies!!Thompsma (talk) 20:12, 11 October 2011 (UTC)

No problem.-- Kim van der Linde ^{at venus} 20:22, 11 October 2011 (UTC)

I am not disagreeing with the importance of the various concepts of adaptation in evolution. My question is, can you say whatever it is that you need to say without using the term, "adaptation?" I'm noticing that both proposals are getting longer and longer. Much of this increased length is due to increased explanations of specific terms and processes. If you can get the point across without using the term "adaptation," I think you would be just as, if not, even more effective in communicating the important points of the lead. danielkueh (talk) 19:29, 11 October 2011 (UTC)

There is a lot of debate going on in here, but I am also surprised by Joannamasel's proposal. Joannamasel's section on natural selection is incorrect and cannot be supported. I like Thompsma's proposal and suggest that we go with this. It seems to address all the concerns that have been laid out and it was a collaborative effort that put that together. Everyone in here has done a great job and should all be commended!!!Claviclehorn (talk) 19:57, 11 October 2011 (UTC)

I am particularly impressed with the way that Thompsma identified the inherent flaw in the previous proposal in the way it implied that natural selection was a process of numerical superiority. That was a difficult error to see and, of course, the emphasis should and always has been on the phenotype!! Natural selection acts on the phenotype - plain and simple. Thompsma gives a "correct" (or at least consistent) interpretation of natural selection from what I can see. I am confused as to Kim van der Linde's and Joannamasel's discomfort or desire to leave this discussion - I would think that they would appreciate that we are all working in here to present an accurate picture of evolution. We should not hold onto our ideas or posts due to our personal attachments, but accept that many ideas are going to be knocked down - this is the norm of process in any academic forum. I like that Thompsma provides citations - why would academic minded people critique that kind of diligence? We should work together.Claviclehorn (talk) 20:05, 11 October 2011 (UTC)

Both proposals are shorter than the current version. We cannot accept Joannamasel's proposal with its erroneous definition of adaptation. My question is, can you say whatever it is that you need to say without using the term, "adaptation?" - Why? If we do that - we might as well not say evolution for fear of being misinterpreted. We can't get caught in these kinds of semantic traps. We all worked together to create the version that I have proposed. My question is - does anyone have a problem with the version as it is proposed? It was a collective venture to get this far and I think we have a comprehensive lead that lays out the foundations of evolution. If Joannamasel wants to cut out the last sentence in my proposal (i.e., "Evolution applies universally...") and others agree that this is what it will take to get this posted, then I am fine with this. However, I think it is a shame that we can't introduce some of the wider applications that evolution offers - perhaps someone can rephrase that sentence? This debate on adaptation is a bothersome distraction, because we have one contributor here who is debating this on an erroneous definition and understanding of adaptation and should not let this lead us astray. We can't let an erroneous post prevent us from including information that is essential and correct. Let's stick to the facts - we have a definition of adaptation in the lead that works. Do you (or does anyone else) have any major issues with the proposed lead?Thompsma (talk) 20:09, 11 October 2011 (UTC)

The definition of adaptation used in Joanna's version is not erroneous. Here is a definition of adaptation taken from Futuyma (1998):

Adaptation: A process of genetic change of a population, owing to natural selection, whereby the average state of a character becomes improved with reference to a specific function, or whereby a population is thought to have become better suited to some feature of its environment. Also, an adaptation: a feature that has become more prevalent in a population because of a selective advantage owing to its provision of an improvement in some function. A complex concept; see Chapter 12.

Joanna's version uses the former while your version uses the latter. Both are correct. There are three definitions of the word adaptation. Hence, why not make a small adjustment and just say "adaptive traits" instead of adaptation for example? It would make the text more understandable to a nonspecialist reader. Besides, little changes like these could have save a lot of time and heartache (discussions above). Anyway, this is not something I want to spend time quibbling about. It's a suggestion. danielkueh (talk) 20:26, 11 October 2011 (UTC)

Sorry, I meant adaptation was in error - the previous collaborative entry on natural selection was in error.Claviclehorn (talk) 20:34, 11 October 2011 (UTC)

Thanks danielkueh for the citation! Now we have something tangible to work with. My concern was that Joanna stated that she was referring to Dobzansky - but your post brings us to Futuyma, so now we have a clear direction. I took issue with using Wikipedia as a resource. Is Joanna's definition consistent with Futuyma's version? It is unclear from Futuyma's definition if he is talking about the population as a whole or the genetic variations within the population? I'll have to check with my copy when I get home. Joanna's definition suggests that the population itself is what adapted. I'm not sure if these are inconsistent, just noting that it isn't entirely clear. This brings us back again to the multi-level selection debate. I have no problem in principle with the notion of a population level adaptation in the same way that you can have a species level adaptation or any group-level adaptation. However, I think that a multi-level definition is something that should go in the body of the text.Thompsma (talk) 21:26, 11 October 2011 (UTC)

I did a bit of research in Futuyma this evening and re-read chapter 11 and 12 of his textbook. His glossary definition is confusing and possibly contradictory with what is stated in the text. For example:

• "All biologists agree that an adaptive trait is one that enhances fitness compared with at least some alternative traits. However, some authors include a historical perspective in their definition of adaptations, and others do not...We have already stressed that the probability of extinction of a population or species does not in itself constitute selection on individual organisms, and so cannot cause the evolution of adaptations."

Hence, my interpretation of Futuyma's glossary definition is that he is referring to populations of individual organisms - he is not talking about population level adaptations. In no other place in his textbook does Futuyma mention population level adaptation. However, here is a multi-level selectionist perspective from Wilson and Wilson (2007):

• "In biological hierarchies that include more than two levels, the general rule is “adaptation at any level requires a process of natural selection at the same level and tends to be undermined by natural selection at lower levels.” All students of evolution need to learn this rule to avoid the errors of naive group selectionism"[128]

Therefore, shouldn't the sentence be reworded: "Natural selection can cause adaptation of individuals in a population to their environment"?Thompsma (talk) 03:39, 12 October 2011 (UTC)