Talk:Evolution

WARNING: This is not the place to discuss any alleged controversy or opinion about evolution and its related subjects. This page is for discussing improvements to the article, which is about evolution (not creation science, not creationism, and not intelligent design to name a few), and what has been presented in peer-reviewed scientific literature about it. See Wikipedia:No original research and Wikipedia:Talk page guidelines. Some common points of argument are addressed in the FAQ below, which represents the consensus of editors here. If you are interested in discussing or debating over evolution itself, you may want to visit talk.origins or elsewhere.

Evolution in society

Could or should something like the following video [1] be added? If not, I'm sure my fellow evolution enthusiasts will appreciate the video nonetheless.Thompsma (talk) 05:54, 9 February 2012 (UTC)

No. Also WP:NOTAFORUM--Harizotoh9 (talk) 09:02, 9 February 2012 (UTC)

I agree with "no": the video seems low value (looks like a montage of copyvios from TV documentaries, with an instrumental background). However, significant contributors to this article are entitled to post an occasional dubious link on the talk page, so I removed the collapsing of this section. Johnuniq (talk) 09:57, 9 February 2012 (UTC)

Well, rules are rules. It shouldn't matter if someone has made significant contributions to the article or not. --Harizotoh9 (talk) 12:53, 9 February 2012 (UTC)

It wasn't intended as a forum post - I put it up as a serious question. There are few rules on video content - see Help:Video and [2] and suspect that it may become more common in the future. This video in particular might not have been the best example, but there are others that go into details on evolution. However, the video explains many of the evolutionary concepts by notable experts in the field in a short clip. It is also a modern example a social and cultural response to evolution and science. I doubted that it would be accepted in here, but thought I would post it out of general curiosity on the issue of videos in wikipedia. I can envision some well designed clips that could be used to visually demonstrate key concepts.Thompsma (talk) 17:43, 9 February 2012 (UTC)

Well, the video is meant to be artistic in nature. It's a song auto-tuning various scientists. It can't really be used as a reference. You would use the original video for a reference. --Harizotoh9 (talk) 13:56, 11 February 2012 (UTC)

I raised the question in here of a more general nature, because I have come across other videos that can help to clarify misconceptions - such topics as whale evolution (http://www.youtube.com/watch?v=I2C-3PjNGok&feature=related), or evolution as fact and theory (e.g., [3]). I agree with you Harizotoh9 that the first video is meant to be artistic in nature, which is why it might be an example of evolution in a social cultural context. Anyway, if anyone has information or thoughts on the appropriate use of video in articles, not just about legal permissions, but if they actually help, and if we should seriously consider putting key pieces of video to explain the more complex issues into articles, I am interested in this kind of media related discussion; as it relates to the topic of evolution or its sub-articles.Thompsma (talk) 20:45, 13 February 2012 (UTC)

Error in FAQ

The following statement is in error: "The great majority of modern evolutionary biologists consider macroevolution to simply be microevolution on a larger timescale; all fields of science accept that small ("micro") changes can accumulate to produce large ("macro") differences, given enough time." That statement is absoltely false. A great majority of evolutionary biologist have equivocally rejected this notion, some of the most notable being Stephen J. Gould, Richard Lewontin, Niles Eldredge, Ernst Mayr, and many others. See [4] for a review. Ecologists have also recently been writing about the importance of ecosystem engineering modulating macroevolutionary selection pressures.[5] The subject is still debated, but it is false to say that a "great majority" consider macroevolution to be microevolution writ large. That goes against many of the macroevolutionary theories that have been proposed to date.Thompsma (talk) 08:34, 9 February 2012 (UTC)

I can provide multiple quotes that show that the FAQ statement on macroevolution is false. The reality is that the issue has not been resolved and in some cases there is empirical evidence supporting a distinction (but I'll leave that debate to the peer-review process). Here is a quote from Sean Carroll supporting my claim:

Many geneticists assert that macroevolution is the product of microevolution writ large, but some palaeontologists believe that processes operating at higher levels also shape evolutionary trends...A long standing issue in evolutionary biology is whether the processes observable in extant populations and species (microevolution) are sufficient to account for the largerscale changes evident over longer periods of life’s history (macroevolution). Outsiders to this rich literature may be surprised that there is no consensus on this issue, and that strong viewpoints are held at both ends of the spectrum, with many undecided. (Sean Carrol [6])

Thompsma (talk) 23:38, 9 February 2012 (UTC)

Why not include the conclusion of that piece: "The subdivision of evolution into two scales no longer reflects our understanding of the unity and diversity of evolutionary mechanisms. However, more important than redefining macroevolution is recognizing that discipline- or scale-bound considerations of only one component of evolution, or of solely extrinsic or intrinsic mechanisms, are inadequate. Long-standing boundaries between evolutionary disciplines are dissolving, to allow richer concepts of evolution to emerge."

And the debate is not whether "microevolution" leads to "macroevolution", but rather whether the former is sufficient to lead to the latter without competition between species, and this only from palaeontologists. Palaeontologists of course operate within a structure of differentiating between species rather than the nuances within a species, so that is why they are concerned with what some might call "macroevolution". Ninahexan (talk) 03:28, 10 February 2012 (UTC)

The point was not that Sean Carrol agreed with the hierarchical view. The quote shows that Carrol recognizes that the debate is far from settled. Moreover, the debate is not only about competition between species. Species selection as the mechanism explaining punctuated equilibria is one theory among others. Niche construction is a macroevolutionary theory where ecological inheritance is included in its model.[7] Evo-Devo has also presented macroevolutionary theory,such as the mechanism of Riedl's burden[8] with hypotheses explaining developmental stasis and evolutionary constraints. There are macroevolutionary hierarchical theories of Gould, Niles Eldridge and Elizabeth Vrba[9], [10], which offers an expansion of "the traditional view that equates sorting among organisms with selection upon organisms", sorting as an alternative mechanism (not selection) operating across the hierarchy. There is also multi-level selection theory, which has several mechanisms that bypass the naive group selectionist theory and have offered various mechanisms, including metapopulation dynamics and an expansion of Hamilton's coefficient of relatedness (r)[11]. Templeton, Carson, and Mayr's founder flush mechanistic models that are cladogenic (macroevolutionary) in content[12], and the models and mechanisms on multilevel selection that Samir Okasha[13] has published extends beyond species selection. There are other examples in recent literature still debating, testing, and theorizing about this issue. It is not only paleontologists. "Palaeontologists of course operate within a structure of differentiating between species rather than the nuances within a species" - that is false and irrelevant to the peer-reviewed analyses in the scientific journals where scientists have presented their evidence on macroevolutionary theory. Of course, there are many different theories "above the gene" with different names that the simple distinction micro- to macro- spans, but for the beginner that marks out the polarity between anagenesis and cladogenesis.Thompsma (talk) 05:07, 10 February 2012 (UTC)

Your points seem to relate to taxonomy more than actually addressing whether macroevolution is the product of microevolution. Can you find a reference to either an evolutionary biologist or a palaeontologist who directly suggests that you can have macroevolution without microevolution? Your Sean Carroll reference addressed the issue of whether it makes any sense at all to talk about macro and micro evolution as distinct spheres when the only strong reason for doing so relates to taxonomy (relying on arbitrary demarcation) more than explaining phenomena). In fact that reference pointed out that far from being a debate about whether microevolution leads to macroevolution, the debate was about the inadequacy of using the terms at all as if talking about different things. You said that "a great majority of evolutionary biologist have equivocally rejected this notion", the notion that microevolution leads to macroevolution if given enough time. I'd like to see a reference to support that assertion. The Erwin reference you gave earlier doesn't actually support the claim that macroevolution isn't the result of long-term evolution, what it does say is that the nature of the interaction of the organism and the environment can create a broad variety of organisms. In other words, it is the result of aggressive forces influencing selection (and sorting) as much as long time frames. This matter really does seem to relate more to taxonomy and nomenclature than anything else. Ninahexan (talk) 06:55, 10 February 2012 (UTC)

My opinion is that this issue requires cautious consideration of what the FAQ is trying to say. I think that in its aims it is not in conflict with the papers Thompsma cites. The FAQ was clearly written in order to help less informed readers, who have heard about micro and macro evolution from creationists, to understand that even if biologists ever make such a distinction, they do not make it in such a way that they would ever accept that the theory of evolution could only apply in isolation to one of them. It would be like have different laws of nature at different times. If you accept the distinction between micro and macro as useful, then real biologists would still all say that microevolution has no limit, and can lead to speciation. What the creationists were spreading about was the idea that microevolution can work within some sort of natural fixed limits, and can exist in such a way that macroevolution might still be impossible.--Andrew Lancaster (talk) 07:56, 10 February 2012 (UTC)

Ninahexan states: "Your points seem to relate to taxonomy more than actually addressing whether macroevolution is the product of microevolution." - That is absolutely false and suggests that you have not read through that literature to any great extent. The entire premise of many researchers cited in the literature is precisely that you cannot explain evolution through a simple microevolutionary model, i.e., evolution is change in gene frequencies within populations that diverge. It seems that you are forwarding a myth on this issue, because clearly we all know that the debate between micro- and macro-evolution has not been resolved. Papers are streaming out regularly that address this very problem. "I'd like to see a reference to support that assertion." - OK, try Douglas Erwin's paper titled "Macroevolution is more than repeated rounds of microevolution"[14] (See here[15] for contemporary debates in evolution on this topic). Other examples: this paper[16] has a section titled: "Is macroevolution something special or just cumulative microevolutionary changes?" Eldredge and Cracraft [17] also argue that microevolutionary processes cannot logically be extrapolated to explain macroevolutionary patterns. "A persistent debate in evolutionary biology is one over the continuity of microevolution and macroevolution – whether macroevolutionary trends are governed by the principles of microevolution."[18] "A major question for evolutionary biology is whether the ecological, populational and genetical processes that can be studied in the present (microevolution) are sufficient to explain evolution over timescales of, say, more than 10 million years (macroevolution)."[19] - The debate is ongoing, such as this recent publication in Evolution[20] discussing this problem in context of developmental modularity and macroevolutionary mechanisms involved, or this publication in Journal of Biogeography[21] looking at macroevolutionary explanations from an ecological perspective.

In response to Lancasters post, I disagree that the FAQ as it is currently framed says or implies what you are saying after. "The great majority of modern evolutionary biologists consider macroevolution to simply be microevolution on a larger timescale; all fields of science accept that small ("micro") changes can accumulate to produce large ("macro") differences, given enough time." - That is false - specifically the first component of the sentence, I have no issue with the 2nd clause. Debates in science are part of the productive process. I am not concerned about creationists misinterpretation of the information, what I am concerned about is the honest disclosure of what is really taking place. The sentence in the FAQ needs to be worded in a way that is an honest reflection of what is taking place in the literature. I'd like to see the stats on The great majority of modern evolutionary biologists - sounds like special pleading for a cause rather than a fact about science. That does not sit well with me.Thompsma (talk) 17:51, 10 February 2012 (UTC)

Ninahexan's statement that the points relate primarily to taxonomy issues (less about mechanism) is particularly worrisome when you read in depth the work by Alan Templeton and Hampton Carson's transilience and founder flush models - clearly flagged as a macroevolutionary model by those authors (See [22]). That point is a bit patronizing to the authors that are doing the work who know full well the range of taxonomic issues and have contributed significantly to our fundamental understanding of taxonomy, speciation, and evolution. Templeton has stated that there are three different models for peripatric speciation that cannot be explained solely on the grounds of the simple accumulation of changes in gene frequencies among populations that are separated and then diverge. These authors propose specific mechanisms that leads to cladogenesis that are incompatible with peak-shift conditions and relate to ecological processes (not population gen) leading to relaxed selection constraints in the founder populations. There is also the "functional synthesis" [23]with experimental evidence of macroevolutionary steps [24] that cannot be explained by a smooth transition using microevolutionary population genetic models (for example, see [25]). Thompsma (talk) 19:22, 10 February 2012 (UTC)

Ninahexan is also twisting my comments so that they do not express what I am actually stating. For example "'a great majority of evolutionary biologist have equivocally rejected this notion', that microevolution leads to macroevolution if given enough time" - I am NOT making this claim. Of course microevolution can lead to macroevolution. The point is that not all macroevolution can be explained by microevolution and there are specific models, theories, and experiments supporting this claim that have been cited.Thompsma (talk) 19:34, 10 February 2012 (UTC)

Thompsma, you misquote me above?--Andrew Lancaster (talk) 21:30, 10 February 2012 (UTC)

Hi Andrew - did I? The quote I put in response to your statement is from the FAQ - not quoting you. Is that where the confusion is?Thompsma (talk) 22:02, 10 February 2012 (UTC)

I fully recognize that this is a controversial issue. I have some ideas of my own on macro- v. micro-evolutionary theory, but I'm not interested in forwarding my own ideas rather to express in fairness what others (experts) have published. Just to be clear - my contention is with the following component of the FAQ statement: "The great majority of modern evolutionary biologists consider macroevolution to simply be microevolution on a larger timescale..." That statement cannot be substantiated. It may be that there is a majority, but I would leave it up to the evolutionary biologists to decide and comment on this for themselves. Unless there is a peer-reviewed publication that has done a survey on evolutionary biologists expressing their opinion on this matter, I contest that there is a "great majority" and there is certainly enough evidence to suggest that many evolutionary biologists have given alternative theories that do not "consider macroevolution to simply be microevolution on a larger timescale."

How about: "All fields of science accept that small ("micro") changes can accumulate to produce large ("macro") differences, given enough time. However, a major question for evolutionary biologists is whether microevolutionary processes studied by population geneticists in contemporary populations are fully sufficient to explain all macroevolutionary patterns that paleontologists study in the fossil record."Thompsma (talk) 22:13, 10 February 2012 (UTC)

Given that we are writing an FAQ and not the article itself, I am not sure what the point of the second sentence is. BTW the creationist way of using the term macroevolution means any evolution radical enough to create clear speciation. That is a widely used term, and I am pretty sure we do not want it being mixed up with more meaningful biology.--Andrew Lancaster (talk) 13:39, 12 February 2012 (UTC)

I am not a scientist, but my understanding is that the question among evolutionary biologists is whether speciation (which is what distinguishes macro-evolution from micro-evolution) is a process that requires a distinct explanation, or whether speciation occurs simply by the accumulation of micro-evolutionary changes. I will leave it to the better-informed to correct me. TomS TDotO (talk) 13:52, 11 February 2012 (UTC)

Thompsma is correct in that the Modern Synthesis has always been a limited consensus. Recent articles in Science and Nature relate the sentiment how the Synthesis needs to be continued to incorporate new ideas and information. Whereas I can produce a Science reference to the general consensus at a evolutionary biology meeting that the LUCA was likely already complex (and bacteria likely evolved from gene loss) but that alone doesn't support that all evolutionary biologist agree (just the ones at that particlular meeting). Thompsma has produced a significant literature contrary to the first part of the sentence (in fact there is confusion what Macro and micro mean- some say related to amount of change and others the tme scale or both)-seems a no brainer to tweak the sentence and take a NPOV. GetAgrippa (talk) 14:31, 11 February 2012 (UTC)

TomS TDotO - you are partly correct, there are different kinds of theory and causal levels of explanation in evolution. Willi Hennig (1966), for example, specifically broke his theory into different parts. There is biological systematics of which phylogenetic systematics is a part. Hennig specifically distinguished phylogenetic, tokogenetic, and ontogenic theories of relationship. Phylogenetic relations specifically refer to relations among species and can help to explain how they come to be, i.e., cladogenesis. Tokogenetic relations specifically refers to relations within species and can help explain the distributions of characters within them, i.e., anagenesis. Ontogenetic refers to the developmental biology of organisms. Each one of these hypotheses (phylogenetic, tokogenetic, and ontogenic) has a distinct kind of causal relation: "The significance of pointing out the distinctions between ontogenetic, tokogenetic, and phylogenetic inferences is that the goals of each are different in both the nature of the causal questions asked relative to the effects observed, and the theories invoked for inferring possible answers."[26] There are different semantic issues on the term microevolution. Does it just refer to evolution on a recent "ecological" time scale, or does it refer to tokogenetic relations as a population geneticist might explore; similar semantic issues exist for macroevolution? The key point in the debate, as I understand it, is if microevolution (i.e., tokogenesis of mutations accumulating in populations) can be extended through time to provide a causal explanation for the macroevolutionary patterns we see in phylogenetic relations. I have no doubt, as in the case of ring species, that microevolution can extend out through time to produce different species, but there is sufficient literature (experimental evidence) suggesting that the transition is not always smooth and there are specific circumstances that explain speciation (i.e., claodogenesis) that cannot be explained by changes in gene frequencies and accumulated mutation over time (anagenesis). The FAQ is worded poorly and gives incorrect information on the nature of the science on this particular issue.

In response to Andrew Lancaster's question on the point of the sentence - I imagine it has to do with questions that have been raised on the micro- to macro-evolutionary debate, where some creationists will accept that we can observe evolution on a microscale, but that alone is insufficient to explain the full scope of events we see in the fossil record - hence, they imply that evolution is a "just a theory" that is limited in scope because it cannot provide a universal explanation where ID fills in those gaps. The flaws of ID have been addressed elsewhere in this context and it might be worthwhile drawing on that literature for this particular point. It is also noteworthy that the NAS defines "Microevolution: Changes in the traits of a group of organisms that do not result in a new species."[27] - they do not discuss macroevolution.Thompsma (talk) 21:14, 13 February 2012 (UTC)

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘So the error is still contained in the FAQ. The claim being made is erroneous and I have provided ample evidence proving it false. Take, for example, the perspective given by Fitzhugh[28][29] on the inferential basis of species as hypotheses. As I pointed out in the quote above, there are distinct inferences and explanatory accounts being made at different levels in the biological hierarchy. Hence, it is erroneous to state that a "great majority of modern evolutionary biologists consider macroevolution to simply be microevolution on a larger timescale" for several reasons. Firstly, no survey of this nature has ever been taken to substantiate this claim and second, a survey of the literature shows that many evolutionary biologists who have published explicit claims to the contrary. Causal events related to ontogenetic development of individuals (e.g., heterochrony, semaphorants), tokogeny of events within a species (i.e., anagenesis), and phylogenetics (i.e., cladogenesis) have consistently drawn inferences as separate hypothesis claiming different kinds of causal explanations relative to the specified domain of interrogation. This is how the history of science in evolutionary biology has played out despite the claims by some that their field of explanatory inference (e.g., population genetics or modern synthesis) has dominion over all other explanatory accounts outside of their area of research, whereas many researchers in evolutionary-developmental biology, palaeontology, and phylogenetic systematics have categorically rejected this claim.Thompsma (talk) 20:28, 24 February 2012 (UTC)

Second FAQ concern

"The evolution of the eye and the evolution of flagella are well-understood, and "irreducibly complex" structures can evolve through mechanisms such as exaptation, in which a structure is adapted to serve a different function." -> The preceding sentence has a grammar problem, but my main concern is the "irreducibly complex" link. The way this is put together might suggest that there is some merit to irreducibly complexity. This should be reworded. Perhaps: "The misquoted "irreducibly complexity" of the eye and the evolution of flagella are often used falsely as examples of things that cannot be explained by the mechanisms of natural selection. However, many papers and studies have reported on the exact nature of these structures from the genetic level, from simpler to more complex structures, through developmental biology, and through the fossil record to explain to the range of patterns and transitions spanning the diversity of life. Exaptation, for example, is one mechanism that explains how structures can become adapted to perform new functions as selection builds on the raw material of pre-existing traits of a different kind."Thompsma (talk) 22:43, 10 February 2012 (UTC)

I see the problem, but don't think "misquoted" is the right word. I would suggest a simpler solution: "The term "irreducibly complex", sometimes applied to flagella and to the eye, is not a scientific term. Indeed, the evolution of these structures is well understood and involved such mechanisms as exaptation, in which a structure is adapted to serve a different function." By the way, what's the grammar problem? I see only an orthographical issue (the hyphen in "well-understood"). garik (talk) 18:18, 12 February 2012 (UTC)

Thanks Garik - another suggested tweak: "The term "irreducibly complex", sometimes applied to flagella and to the eye, is not a scientific term. Adherents to the notion of "irreducibly complexity" might argue or ask how you can evolve flight from half of a non-functional wing? Details on the evolution of these structures, however, are well understood to involve the mechanismsmechanics of natural selection. For example, exaptations explain how an ancestral structure having a different utility (e.g., fluffy 'feathers' for warmth) can become selected in descendants for a different kind of adaptation (e.g., strong feathers for flight)."Thompsma (talk) 22:20, 13 February 2012 (UTC)

I think we're better not without the "adherents ... might ask" bit. I'd make the following further tweaks: "The term "irreducibly complex" is not a scientific term. It is sometimes used to imply that such structures as flagella, eyes, or wings, could not be the product of natural selection because they would not be functional at earlier stages in their evolution. However, the details of how these structures evolved are in fact well understood. Through exaptation, for example, a structure having one function (e.g. fluffy feathers for warmth) can come to be used for another function (e.g. strong feathers for flight) in descendants." garik (talk) 15:00, 14 February 2012 (UTC)

Okay Garik...like your changes, however it lacks some of the finer details to give it the explanatory punch that is needed. We may have stripped this back too far that the meaning is being lost. This next proposal extends it out longer to get the precise wording from the arguments that are made by ID proponents: "The term "irreducibly complex" is not a scientific term, but stems from theological arguments that predate the theory of evolution. It is used to argue that natural selection could not account for the step by step stages needed to evolve complex structures, such as the flagella of a bacterium or the vertebrate eye. For example, how could half a non-functional wing become adapted for flight at earlier stages in bird evolution? In contrast, biologists have studied these cases in precise detail in living and fossil forms illustrating evolutionary precursors from the molecular scale, through developmental biology, and up to their full anatomical form. Exaptation, for example, explains how an ancestral structure (e.g. fluffy "feathers" for warmth) can become evolutionarily co-opted in descendants for other functional adaptations (e.g. strong feathers for flight)." --> I put the first "feathers" in quotes, because technically they may not have been a true feather until flight evolved.Thompsma (talk) 17:00, 14 February 2012 (UTC)

OK. I see what you're doing, but I think there's a little more detail than is necessary. And the bit about natural selection accounting for the step by step stages isn't quite right: The people who make this argument don't think that a step-by-step process was involved at all. How about the following? "The term "irreducibly complex" is a non-scientific term that is sometimes used to argue that complex structures, such as bacterial flagella, vertebrate eyes, or wings, could not have evolved through a step-by-step process like natural selection. For example, while the utility of evolving a functional wing is immediately clear, it is not so obvious what advantage the intermediate stages of wing development might have conferred. In fact, biologists have studied these cases in detail, and there is little mystery as to how such structures might have come about gradually. Exaptation, for example, explains how one structure (e.g. fluffy "feathers" for warmth) can become evolutionarily co-opted for new functions (e.g. strong feathers for flight)." garik (talk) 15:48, 15 February 2012 (UTC)

Hi Garik - a few problems I'm catching here. First - "irreducibly complex" is two words, so it is not a term. Second, I have a problem with "there is little mystery" - that goes against the very premise of science going back to Francis Bacon, "Those who have taken upon them to lay down the law of nature as a thing already searched out and understood, whether they have spoken in simple assurance or professional affectation, have therein done philosophy and the sciences great injury" - scientists love to keep the mystery alive. Third, "might have come about gradually" does not sound convincing. Science does not work in absolute terms, but this sounds like we might know or we might not know, but science is about knowing and this puts this on the same playing field as belief as opposed to scientific inference and acceptance of theory. Hope you don't mind my strong critique. My aim is to create a strong statement that can explain the concept while at the same time staying true to the science. Here is my counter offer: "The argument of "irreducibly complexity" is neither scientific nor recent. It is an old theological argument for intelligent design pre-dating the theory of evolution. Its proponents claim that complex structures, such as bacterial flagella, vertebrate eyes, or wings are wholly functional and could not have evolved through intermediate stages in step-wise fashion by means natural selection. The claim to "irreducibly complexity" must instead be the work of an intelligent creator. In contradistinction, biologists continue to probe at these cases by applying the scientific method while gathering detailed factual observations from fossils, genes, and whole organisms. Natural selection has repeatedly proven to explain how these and many other complex patterns evolved through their functional adaptations. Exaptation, for example, explains how primitive structures (e.g. fluffy "feathers" for warmth) can become evolutionarily co-opted for new functions (e.g. strong feathers for flight)."Thompsma (talk) 19:40, 16 February 2012 (UTC)

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘No worries Thompsma, but what makes you think a term can't consist of two (or more) words? In fact, I think calling it an "argument" is less appropriate. People make an argument that a structure is irreducibly complex and a further argument that this means it cannot be the product of evolution. But the term "irreducibly complex" is not itself an argument.

A fair point on "mystery", however, and I see your point about "might", although my intention was not to imply uncertainty. But I still think your version is somewhat too long and, in places, too wordy. For example, I think we want to emphasise that "irreducibly complex" is not a scientific term, but I don't think there's any need to talk about it predating evolutionary theory. In any case, the term doesn't. The related argument does, but I don't think it's necessary to say so. Similarly, I think other sentences, like the one starting "in contradistinction", go into too much detail for the FAQ. In addition, there are a few somewhat unclear phrases and sentences. I would avoid the phrase "wholly functional", for example. First, it's ambiguous ("functional as an irreducible whole" vs. "completely functional, with no non-functioning parts"—indeed, the second seems the more natural meaning, and I don't think it's the one you mean). Second, it could be true of a structure regardless of whether it evolved through step-by-step processes or not. I'm also not quite sure what you mean by "The claim to "irreducibly complexity" must instead be the work of an intelligent creator." That implies to me that God (or aliens, or whoever) came up with the claim that eyes can't have come about through evolution, which I don't think is what you intended.

We need to get clear on what we're trying to do here. And what I think we're trying to do is explain, as concisely as possible, that "irreducible complexity" is not a scientific term, that anti-evolution arguments based on supposed irreducible complexity don't stand up, and that we actually have an evolutionary explanation for structures that are claimed to be irreducibly complex (and therefore inexplicable in evolutionary terms). While staying true to the science. The current version of the FAQ does a fairly good job in two sentences and 75 words. And, as far as I can see, the only real problem with the it is that it implies that irreducible complexity is worth taking seriously (i.e. it's not very true to the science). I don't think we need 63 extra words to solve that problem. If people want to find out about the origins of the notion of irreducible complexity, or about the evolution of bacterial flagella, they can click on the links. The FAQ is not the place for that kind of detail. garik (talk) 22:21, 16 February 2012 (UTC)

In fact, maybe it's time to go back to something closer to the current wording:

1. Evolution can't create irreducibly complex structures like the eye, or the bacterial flagellum.

"Irreducible complexity" is not a scientific term. The evolution of many structures that are claimed to be irreducibly complex, such as the eye or the bacterial flagellum, is well understood and involved mechanisms such as exaptation, in which a structure is adapted to serve a different function. Moreover, it does not follow that, if we do not fully understand the evolutionary history of a biological structure, that it did not come about through evolution a less than full understanding of the evolutionary history of a biological structure is not evidence against evolution, any more than The fact that a less than full understanding of the gravitational orbit of every astronomical body is not fully understood is not is evidence against gravity.

garik (talk) 22:34, 16 February 2012 (UTC) edited by garik (talk) 22:39, 16 February 2012 (UTC)

Thanks Garik...yes I went into too much detail and I see where I made errors. According to Wikipedia, however, it is an argument and the National Academy of Sciences also calls it an argument (see [30]). You can have compound words as a term, but saying it is a term carries far less meaning than saying it is an argument, which it is. More than an argument (and I realize this will be controversial, but readers should visit Kirk Fitzhugh[31] who has written more extensively on this nature of evolutionary scientific philosophy than anyone I know), like ID it is a theory - but, it is not a scientific theory that can be tested. "Beyond Behe’s (2006) admission that an ID theory is not testable, let’s be clear how he has misrepresented the very nature of testing."(See [32]) However, "only natural selection or ‘descent with modification’ has withstood repeated attempts of refutation by way of testing. In other words, the empirical evidence amassed for descent is substantial, whereas no such evidence has yet been provided for causes involving the intelligent agent(s) referred to by ID advocates."[33] I posted these quotes here because I think that we can use this information in the sentence structure. When I compiled my proposal above, I tried to use wording from external reliable sources to avoid my personal bias. I think the definition of exaptation in the proposal is too vague. This paper on the evolution of the eye[34] also provides a nice summary on the evolutionary sequence. It is also my understanding of the IC argument is that a whole structure could not have evolved its functional utility from a sub-set of its parts. How about:

"Evolution can't create "irreducibly complex" structures like the eye, or the bacterial flagellum.

Irreducible complexity" is not a scientific argument. The vertebrate eye or the bacterial flagellum are claimed to be irreducibly complex. In fact, they are adaptations that evolved through a logical sequence of transitions from simple to complex. For example, genes and structures in the development of the vertebrate eye occur in vertebrate ancestors, such as sea squirts having simple photosensory organs called an ocellus that are the basis for more complex eyes.[35] Complex biological traits can evolve as exaptations, where simpler ancestral structures that evolved for different reasons become coopted for new adaptive functions. Moreover, a less than full understanding of the evolutionary history of a biological structure is not evidence against evolution, any more than a less than full understanding of the gravitational orbit of every astronomical body is evidence against gravity. The empirical evidence for evolution is substantial, whereas no evidence has ever been provided for irreducible complexity.

Thompsma (talk) 18:08, 17 February 2012 (UTC)

"Irreducible complexity" isn't a compound noun, it's a phrase composed of an adjective and a noun, but that doesn't mean it's not a term. Both words and phrases can be terms. I also still think argument isn't quite the right word (including in the intro to the Wikipedia article)—indeed, I'm happier with calling it a (pseudoscientific) theory—but none of that's really important. I won't quibble any further over it.

I think the newest version you've suggested is pretty good, by the way, although I still think we can cut it down. For example, we don't need the sentence "The vertebrate eye or the bacterial flagellum are claimed to be irreducibly complex." The reader can get that from the question. I'm also not sure we really need to give as many details about the evolution of the eye. So how about:

"Evolution can't create "irreducibly complex" structures like the eye, or the bacterial flagellum.

Both the vertebrate eye and of the bacterial flagellum are well understood to have evolved from simpler structures. Indeed, simpler eye-like structures (such as the sea squirt's ocellus) can still be found in existing species.[36] Complex biological traits can also evolve as exaptations, where ancestral structures that evolved for different reasons become coopted for new functions. "Irreducible complexity" is not, in any case, a scientific argument is, in any case, neither a scientific concept nor a coherent argument: A less than full understanding of the evolutionary history of a biological structure is not evidence against evolution, any more than a less than full understanding of the gravitational orbit of every astronomical body is evidence against gravity. The empirical evidence for evolution is substantial, whereas no evidence has ever been provided for irreducible complexity.

garik (talk) 03:56, 18 February 2012 (UTC) edited by garik (talk) 18:39, 18 February 2012 (UTC)

I've thought of a good alternative to "scientific argument", which allows us to separate two points that I think were being conflated. garik (talk) 18:39, 18 February 2012 (UTC)

OK, if everyone's happy with this version that Thompsma and I have thrashed out, I'll make the change. garik (talk) 15:21, 22 February 2012 (UTC)

Looks fine to me. danielkueh (talk) 16:01, 22 February 2012 (UTC)

I like it. Good job!!Thompsma (talk) 18:56, 23 February 2012 (UTC)

Other FAQ concerns

My remaining concerns for the FAQ deal with the following sentences:

• "Proof has two meanings: in logic and mathematics, it refers to a proposition that has been shown to be 100% certain and logically necessary; in other uses, proof refers to a proposition that is well-supported by experimental evidence (much like the colloquial meaning of fact)."
• "Evolution, as a fact, is the gradual change in forms of life over billions (1,000,000,000s) of years."
• "So, although the entire evolutionary history of life has not been directly observed, all available data supports the fact of evolution."

Proof

Proof does not refer to a proposition, proof stems from its Latin roots to test or probable. In this way, proof refers to the experiment. There are two aims to a proof, 1) explain the proposition through peer and public review , and 2) to convince others of the facts by means of a rational demonstration of the experimental cause-effect inference. Edward Wilson discusses this in Consilience, and you can read more about this in the following citation: .

Fact

Some evolutionary biologists have claimed that evolution is not a fact. I will post a quote that I put in Evolution as fact and theory that speaks to this matter in a very clear way:

Therefore, we should not call a true factual proposition a 'fact'. (The view that facts are theory-dependent or else empirical data rather than thigs "out there" is rampant in the philosophy of biology...In other words, a well-confirmed hypothesis, such as the hypothesis of descent with modification, is not a fact: it refers to a fact, i.e., a process or, more precisely, a number of processes. Similarly, there are no "scientific facts": only a procedure to attain knowledge can be scientific (or not), not the object of our investigation. Accordingly, scientists neither "collect" facts nor do they come up with or, worse, "construct" facts, but advance hypotheses and theories referring to or respresenting facts. Of course, some of these hypotheses may turn out ot be false, either for referring to purely imaginary objects, or for describing incorrecly realy facts.

Here is a contrast of facts as used by evolutionary biologists:

1. "Confirming evidence cannot change the status of a hypothesis to a fact" (Fitzhugh)[37]
2. "In science, "fact" can only mean "confirmed to such a degree that it would be perverse to withhold provisional assent." (Gould)[38]
3. "US National Academy of Science (NAS) (1998), one of the most prestigious scientific societies in the world, a scientific fact is “an observation that has been repeatedly confirmed, and for all practical purposes, is accepted as ‘true’."(Gregory)[39]

There is a bit of a discrepancy here, because "As we will see next, observation and confirmation are irrelevant to facts (but not vice versa)."[40] It is also important to note that there is no such thing as a scientific fact, facts exist outside the realm of science and they are the worlds data and I have yet to find an evolutionary biologist who disagrees with this claim. We can also be certain that a hypothesis is not a fact, "And facts and theories are different things, not rungs in a hierarchy of increasing certainty."(Gould, [41]) What is being confirmed? Does this mean that the hypotheses has been confirmed? We can't confirm hypotheses, they can be falsified, rejected, or corroborated. Confirming evidence is related to inductive inference. Hence, some researchers can make statement like so: "To say ‘evolution is a fact’ is just an inexact reference to what is thought to have existed, which are organisms and the events in which they were involved. While evolution is not a fact, it is also not a single theory, but a set of theories applied to a variety of causal questions."[42] Darwin's five theories on evolution include four nomonological and a singular historical theory (i.e., common descent)[43]. None of these theories are facts, that's not possible. So what is fact?

Facts refer to events that occur, processes in things, or the states of things. Scientists can observe the facts, but they are represented and referred too by way of theory. Hence, evolutionary theories refer to facts, but it in itself is not a fact. There are many facts that evolutionary biologists refer too, including natural selection, which is a process so it can be a fact. Hence, when scientists say that evolution is a fact, what they are really referring to are processes or states of things. We can observe states of things and our observations refer to those facts, but they also "exist regardless of their being perceived".

Returning to natural selection as a process and facts refer to processes. So is natural selection indeed a fact? Unfortunately, it is not a singular fact, but a deduction based on the three part syllogistic core of natural selection: 1. superfecundity, 2. variation, 3. differential survival, which are facts about populations of organisms that evolutionary theories refer too. Gould, however, sees evolution as a historical fact and natural selection as its mechanism; and by this I believe he is using evolution in short-form ignoring the four nomological theories and focusing only on the historical inference (common descent). He views Darwin's unique enterprise through the use Whewell's consilience of inductions as the proof that Darwin used to claim the historical inferences of evolution as fact. Gould claims that Darwin would refer to a long list of facts to arrive at a reasoned conclusion of descent with modification as a scientific exemplar of consilience. So what is factual? Descent with modification is a two part hypotheses (1. descent, 2. modification) and hypotheses can't be facts. Common descent is a theory, modification is not a thing nor the state nor an event occurring in a thing, so it can't be a fact either. Some evolutionary biologists, like Gould, appear to be using fact in the colloquial sense of referring to statements instead of things and in this sense they claim that evolution is a historical fact without referring to the facts themselves as an inexact short form. Gould is claiming that Darwin's exemplary use of consilience of inductions is a proof of evolution that makes it factual, but once again - we see that there is a discrepancy between Gould and Fitzhugh, because Fitzhugh claims that no amount of proof could ever convert a theory or a hypotheses into a fact. Gould is making a bit of a logical error here, because he has also claimed that facts and theories are different things, but yet he seems to turn theory into fact by means of overwhelming confirmation.

These discrepancies cannot be sorted out here - but I thought I would include some of these comments about evolution as a fact, because at some time people may have to account for Fitzhugh's claim that "evolution is not a fact". I imagine creationists will catch onto this and we need to have an understanding of how to respond effectively. I am not convinced that the FAQ addresses fact well enough. Perhaps other editors could pick through some of this information on fact and contribute their own knowledge to improve the explanation that is given.Thompsma (talk) 22:28, 24 February 2012 (UTC)

Divergent, convergent, and parallel evolution?

I would like to know why there aren't dedicated sections on these topics, or are they already covered within some other sections? Cadiomals (talk) 22:09, 13 February 2012 (UTC)

I agree Cadiomals and those topics would be covered under a section on phylogenetics. I've been tinkering on just such a section for a while and will post it here in the near future. This article is missing a section on evolutionary trees explaining how evolutionary biologists map out characters to retrace (abductively infer) the phylogenetic history of DNA and morphological changes through time.Thompsma (talk) 17:06, 14 February 2012 (UTC)

Thanks Thompsma. I feel like these three topics (as well as coevolution which is already covered) should go under a section called "types of evolution" or something like that, or it go under the current "outcomes of evolution section." I just feel like these four distinct forms of evolution should all go under the same section. Cadiomals (talk) 19:02, 14 February 2012 (UTC)

John Avise appended a sentence to Dobzhansky's quote on nothing makes sense except in the light of evolution, in his now famous book on molecular markers[44] - that "much in evolution makes more sense in the light of phylogeny." All these concepts (divergent, convergent, and parallel evolution) can be explained simply, spanning all scales of evolution, from molecules to morphology, through the convenient use and description of an evolutionary tree and how it works. Convergence or parallel evolution not only occurs in the classic example that comes to mind, that of marsupial vs. mammal morphology (e.g., [45]), but touches on the very foundational notions of homology, homologues, and evolution across the hierarchy of life. It amazes me that after all the debates in the archived threads on this article, for all the ideas that have been thwarted, denied, rejected, argued, and diffused that we still have an article on evolution in 2012 that excludes even the most basic introduction to the systematic tool that evolutionary biologists have used since Darwin to infer pattern onto phylogeny. Only one figure sits prominently in Darwin's Origin and it was an evolutionary tree. This article glances over this in its myopic genetic reductionist slant. Try breaking that barrier and you will be faced with a barrage of editors that will have you writing in circles until you end up with the confusing mess we are faced with. Critique this article in this form and you will have a fleet of editors telling you how well it is written and your ideas are welcomed. Phylogenetic trees are the bread and butter of evolutionary hypotheses and they can help to organize all the principles of evolution, but we wouldn't like to see that kind of organization entered here because this article is already too big. The kind of organization that a phylogenetic perspective can bring is exactly the tool that can simplify the essentials of evolutionary theory to serve as a scaffold for ideas to follow. Unfortunately, there is a fleet of population geneticists guarding the reductionist status-quo of the content of this article.Thompsma (talk) 20:30, 14 February 2012 (UTC)

Gee wiz, dude. i just wanted dedicated sections created for these forms of evolution. I'll do it myself. Cadiomals (talk) 21:00, 14 February 2012 (UTC)

It wasn't directed at you Cadiomals. There is history on this issue.Thompsma (talk) 21:46, 14 February 2012 (UTC)

Need high quality references

The first two sentences in the History section of this article are in need of high quality references. I have access to a few references, but they do not discuss Empedocles or Aristotle's view of "natural things." Plus, I am not an expert on Greek history and I would prefer editors with access to more comprehensive references to take the lead on this. Previous attempts have been made to buttress both statements with a reference to a UC Berkeley website<http://www.ucmp.berkeley.edu/history/ancient.html>. I reverted the addition of this reference for several reasons. While I hold UC Berkeley in high regard, there are several problems with referencing this site. For one, it is a self-published site and is not peer-reviewed. From what I understand, WP:RS does not encourage the use of self-published sources, especially for good or featured articles like evolution. Plus, it sets a dangerous precedent. If we can accept this as a reliable source, then similar arguments can be about the use of self-published sources from say, Bob Jones University. Finally, it is not clear who the authors are for this site. As you follow the links, it points to a webmaster named Ben Waggoner. I have never heard of him. I don't know if he is just responsible for maintaining the site or if he wrote its content as well. Thus, the credentials of the site's author(s) remained unclear. Furthermore, if we take credentials of whoever wrote this site at face value, then similar arguments could be made with respect to quoting the theoretical physicist, Jim Al-Khalili on the contribution of Al-Jahiz to the history of evolutionary thought. See archive for details. danielkueh (talk) 20:06, 20 February 2012 (UTC)

Wikipedia:Verifiability states that "Source material must have been published (made available to the public in some form)". This citation is. Thousands of articles on Wiki have less reliable sources than this, take your crusade there. --Judgeking (talk) 20:16, 20 February 2012 (UTC)

I think you should also read on what constitutes reliable and unreliable sources. danielkueh (talk) 20:23, 20 February 2012 (UTC)

A few more clicks show that the author moved on from Berkley to the U of Central Arkansas He has published dozens of peer-reviewed papers, many of them in Evolution. --Judgeking (talk) 20:30, 20 February 2012 (UTC)

Yes, he does. But I am not sure if the written work on his former website constitutes the widely accepted version of the history of evolutionary thought. Plus, it is still self-published and not peer reviewed. danielkueh (talk) 20:34, 20 February 2012 (UTC)

Agree that higher quality citations are preferable, but disagree that high quality citations are the only citations that can be used. The citation appeared to be acceptable under WP:SPS as the institution is not a personal web-site, but run through a University.--JOJ ^Hutton 20:48, 20 February 2012 (UTC)

Respectfully disagree. Even though it is hosted by an institution, its contents are written by an individual. The content may or may not be endorsed by the institution. Plus, if we follow that logic, then citations from say Liberty University would be just as acceptable. Unless of course we have a policy to decide which institutions are acceptable and which aren't. I suspect such a discussion would open up a whole new can of worms. danielkueh (talk) 20:59, 20 February 2012 (UTC)

I think you're both talking past one-another. Yes, it's probably a reliable source. But we really should aim for better. So, instead of debating things here... Guettarda (talk) 21:03, 20 February 2012 (UTC)

Agree. danielkueh (talk) 21:05, 20 February 2012 (UTC)

Then until or unless another is found,why is the citation being removed?--JOJ ^Hutton 21:08, 20 February 2012 (UTC)

Because this is a featured article that is need of high quality references per WP:FACR. That website is not it. And for the other reasons that I brought up. danielkueh (talk) 21:12, 20 February 2012 (UTC)

The articles on Anaximander and Empedocles themselves (reminder: that's what this discussion is about to those who are just arguing for arguing's sake...) state their views on animal & human origin. Why is there even a need for further citation here? --Judgeking (talk) 21:13, 20 February 2012 (UTC)

I hate to sound repetitive, but see WP:FACR and WP:V. Plus, that article on Anaximander does not even have a reference to support the weasel statement, "...some people consider him as evolution's most ancient proponent." danielkueh (talk) 21:17, 20 February 2012 (UTC)

Then go and start an edit war over there, there's no such statement here. All this citation does is state a fact that seems to be fairly well established. --Judgeking (talk) 21:22, 20 February 2012 (UTC)

You seem to be presenting a moving target. I am assuming you brought up the articles on Anaximander and Empedocles because you wanted to know "Why is there even a need for further citation here?" I responded to that question. Look, if it is a well established fact, then it should not be hard to find high quality sources. danielkueh (talk) 21:28, 20 February 2012 (UTC)

Jojhutton, could you specify the chapter as well for that Bertrand Russell reference that you inserted? I looked at p. 696 of A history of western philosophy and I am not seeing the corresponding text. P. 696 in this pdf version seems to be discussing Rousseau's system of government and social contract. Plus, I don't see explicit mentions of evolution as starting with Empedocles in this book. Granted, I did a quick flip through so I could be wrong. danielkueh (talk) 21:42, 20 February 2012 (UTC)

These citations should suffice. - if anyone requires the specific details, I can cut and paste the pertinent details.Thompsma (talk) 21:52, 20 February 2012 (UTC)

Thanks Thompsma, I will replace the existing Russel reference with these these two references. danielkueh (talk) 21:56, 20 February 2012 (UTC)

Daniel as one of the authors of that section I can say the real source I used for the first sentence, and it is better than a general history. In fact I do not think a better source is possible: Kirk, Raven and Schofield (1983 second ed.) The Presocratic Philosophers , Cambridge University Press. Anaximander is chapter III (pp. 100-142)and Empedocles is chapter X (pp. 280-321). Because each chapter is an overview of fragments with discussions about how to interpret them I believe it is best not to cite individual pages. For the second sentence about Aristotle it is definitely no problem to find a source, but more of a question about what type of source would be best. A general history might in fact be better for that type of sentence? Aristotle's preferred term was eidos, traditionally translated as species, but today most often as form. The form or species though visible to humans as a visible category of thing was actually a cause of natural things such as animals, but outside of the normal physical causality (efficient causes) we study today.--Andrew Lancaster (talk) 22:06, 20 February 2012 (UTC)

Thanks Andrew. I was gonna drop a line on your talk page for this. I inserted the reference you gave me. As for the Aristotle reference, any would do, as long as it is reputable and it matches very closely what the main text in this article is saying. Which book did you or Dave use when you guys wrote that second bit? danielkueh (talk) 22:22, 20 February 2012 (UTC)

I think we were just trying to get the sentence right. It is a fairly general sentence. So I do not recall having one particular source in hand. At the same time we were working on that I had lots of sources in hand for several Aristotle articles I work on, such as potentiality and actuality, but the sourcing for that article is a bit specialized. So if someone has found good biology-relevant articles that is probably the best solution. I do not have access to JSTOR so I can not comment on the specific ones chosen.--Andrew Lancaster (talk) 07:47, 21 February 2012 (UTC)

BTW, as mentioned I can not see the sources for the second sentence. OTOH, I wonder if they also cover the 3rd sentence, which kind of continues the same thought?--Andrew Lancaster (talk) 10:49, 21 February 2012 (UTC)

hey Andrew, the Torrey et al. reference not discuss Aristotle's views of species. Instead, it devotes a lot of effort to interpreting different passages from Aristotle as being "evolutionistic" or not. The Hull reference does discuss Aristotle's views of species, but it does not say that Aristotle viewed objects as "imperfect actualisations of different fixed natural possibilities," at least that is not the impression that one gets from reading that reference. One could potentially come to a similar conclusion like the third sentence based on the Hull reference, but it is a stretch. Terms like teleological have very specific meaning. My suggestion would be to remove third sentence and perhaps modify the second sentence to describe Aristotle's views of "essences" as being fixed and immutable. My two cents. danielkueh (talk) 16:45, 21 February 2012 (UTC)

Unfortunately I have limited time on this at the moment but I will make a perhaps over-obvious remark that we want to make sure we do not change the meaning of a sentence too quickly coming out of a fairly routine request for better sourcing. Improvement is the aim and I don't see anything in the paragraph which should be un-sourceable. I wonder if Dave S has time this week? I am not sure your proposal of saying that Aristotle viewed essences as fixed quite gives the right balance. And the term teleological is actually debated quite a bit when it comes to Aristotle. What you describe sounds a little more like where Aristotelianism ended up by early modern times, but one thing Dave and I were going for was at least a hint of the debate about differences between Aristotle and Aristotelians. Aristotle is interesting, and we should let readers see that with appropriate linking to other articles. He is both the inspiration of modern science and also the man who inspired most of what modern science is opposed to. Perhaps draft ideas can be dealt with here on the talk page so as to keep a conservative pace?--Andrew Lancaster (talk) 22:27, 21 February 2012 (UTC)

Andrew, I think that is a reasonable suggestion -- taking our time on this. I agree that Aristotle is a significant figure. My only concern is that whatever we say should correspond closely with what is said in the sources that we cited. At the moment, it is just not clear if one would come to the same conclusion that is similar to the present text if one read those two sources. That is a potential problem, especially if issues of WP:OR were to be brought up. I will see what I can come up with. Like you, I am terribly busy at the moment, and so will not be able to devote as much time to this for the next couple of weeks. If Dave S. or anyone else wants to take the lead, that would be fine too. danielkueh (talk) 22:37, 21 February 2012 (UTC)

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘I would defer this matter to Andrew who certainly knows more about Aristotle on evolutionary matters than I do. However, I wanted to correct danielkueh that the Torrey et al. reference does discuss Aristotle's views on species on pages 12-13 in particular reference to "forms" with quoted reference to Aristotle's works that specifically addresses the material in the sentences of this article: "Which is not surprising, when it is remembered that to Aristotle species were immutable...Royce has already been quoted as saying that the Aristotelian 'forms' which are responsible for the evolution of individuals are as eternal as the Platonic ideas. They therefore do not evolve...To him [Aristotle] the eternity not only of Matter but also what he called Form,-that is to say, the collection of attributes giving definiteness to natural aggregates, more especially those known as organic species-was an axiomatic certainty. Every type, capable of self-propagation, that could exist at all, had existed, and would continue to exist forever...To the problem of variation Aristotle gave no consideration except as it concerned individual modifications that altered in no essential degree the specific type. " --> Reading carefully through the rest of that article, it was entirely appropriate to include it as a citation for the following sentence: "In contrast to these materialistic views, Aristotle understood all natural things, not only living things, as being imperfect actualisations of different fixed natural possibilities, known as "forms", "ideas", or (in Latin translations) "species"." --> the article has five pages that discuss Aristotle's views on "forms" species and hybrids. I wouldn't put up a random citation unless I had read it first and thought it through.Thompsma (talk) 19:22, 29 February 2012 (UTC)

Thompsma, you are right. I stand corrected. Thanks for pointing that out. danielkueh (talk) 20:48, 29 February 2012 (UTC)

Evolution Template proposals:

• Proposal to Merge Evo and Paleontology templates:
• Articles to add t template

Leave replies at the links above. For some reason no one replies to the talk page for the Evolution template. For that reason, I am posting a notice here. The template is very important because it serves as a gateway for many people for evolution articles and it is featured in this article. It's one of the first things people see when they look at an article. If you do not have the Evolutionary Biology template on your watchlist, add it now. --Harizotoh9 (talk) 00:34, 27 February 2012 (UTC)

Any Change?

The first line of the article: "Evolution is any change across successive generations in the heritable characteristics of biological populations." is incorrect. "Successive" implies consecutive rather than "across many" which was probably the intended meaning. As it stands the change in average size of organisms in a population from one generation to the next could be called evolution evolution, or one could infer that this year's caterpillars are an evolved form of last year's butterflies. 131.251.254.71 (talk) 12:29, 28 February 2012 (UTC) emt1001

Change in individual size is, indeed, a commonly observed and commonly discussed trend seen in evolution. As for your second example, I don't want to sound mean, but it's a stupid concern. Evolution is about heritable changes across generations, and the average reader of this is/should be aware enough that the adults of one generation can not transform into the larvae of the following generation, given as how, among other things, a) adults can not physically revert back to a larval stage, b) and if they could, then they would all be the same generation, and it would not be evolution as evolution is about changes inherited across successive generations.--Mr Fink (talk) 13:38, 28 February 2012 (UTC)

The changes in the sizes of organisms you refer to are surely over many generations, and not, as in my example, from one season to another. The second example was intentionally stupid to make a point. The point is that "ANY change across successive generations" is very different from "heritable changes across generations". Removal of the word any would be better, and make it clearer to the "average reader" (who might be an 15 year old creationist).131.251.254.71 (talk) 16:29, 28 February 2012 (UTC) emt1001

The first line is correct. You don't need many generations for evolution to occur. Technically you only need one generation. Your example of comparing an adult to a juvenile is irrelevant because the sentence specifically refers to "the heritable characteristics" and a juvenile stage has heritable characteristics that would not be compared to other kinds of heritable characteristics in an adult phase, by definition. The sentence refers to the change in heritable characteristics in biological populations. Hence, a population in one generation with its set of heritable characteristics and then a subsequent generation with a different set of heritable characteristics culminates from events (e.g., natural selection / drift) that caused the different population states (i.e., change in the suite of heritable characteristics) in subsequentsuccessive generations, which is evolution.Thompsma (talk) 20:17, 28 February 2012 (UTC)

I think it was JoannaM that wrote that sentence and I'm certain that she knew exactly what she meant by including "successive" in that sentence and I agree with this. It is consecutive because the idea is that the minimum requirement for evolution is from one generation to the next successive generation.Thompsma (talk) 20:28, 28 February 2012 (UTC)

Sorry to labour the point, but, whilst heritable variation clearly is a minimum requirement for evolution, the inheritance of those characteristics from one generation to the next is not evolution, which occurs over a longer time scale. I maintain that the phrase "ANY change across successive generations in the heritable characteristics" implies just that. Removal of the word any would inprove the situation, but the first line should also be more specific about the minimum time scale, to avoid the inference by our "average reader" that he or she has evolved from his or her parents. 131.251.254.71 (talk) 09:29, 29 February 2012 (UTC) emt1001

Can you specify (define) the number of generations required for evolution then? (If a reader believes that individuals evolve, I think the phrasing of this particular sentence is the least of his/her problems when it comes to understanding evolution.) - Soulkeeper (talk) 10:04, 29 February 2012 (UTC)

Can of worms here IMHO. I don't think it is possible to be specific about the time-scale needed for evolution to occur. Acquisition of a mutation may be passed on one generation, = potential evolutionary event, but may be lost again from the population several generations later with no lasting evolutionary impact. The criterion is not that an innovation is passed on to a few individuals of the next generation, but that it results either in heritable change in the population as a whole or in speciation. Isolated populations may evolve (diverge from a parent population, speciate) fairly quickly, while the large, more widespread and diverse parent population will evolve more slowly. Removal of the word ANY makes the statement more generally applicable and therefore less subject to conflict Plantsurfer (talk) 10:22, 29 February 2012 (UTC)

"Heritable change" is the primary requirement for evolution to occur. As for generations, it can take hundreds of thousands of generations before any dramatic changes can be seen or noticed, like how the different populations of apple maggot flies have been genetically isolated from each other for 2, 3 centuries since Europeans imported their domestic fruit tree hosts into North America, but are still morphologically identical to each other, or, it can take only one generation, like how scientists recreated the honeysuckle maggot fly by breeding its ancestors, the blueberry and snowberry maggot flies, in a laboratory setting. In other words, no, it would not be wise at all to define or specify the minimum number of generations needed for evolution.--Mr Fink (talk) 14:01, 29 February 2012 (UTC)

Evolution does not necessarily take place over longer time scales. The mechanisms described by Darwin and the core of the theory of natural selection: superfecundity, variation, differential survival --> only requires at minimum one generation for the effect to take hold. Scale this process over successive generations and this basic mechanism explains much of the diversification of life. Population geneticists run evolutionary models on these principles. There are three factual errors in the statement provided by the user launching this critique: "1) heritable variation clearly is a minimum requirement for evolution, 2) the inheritance of those characteristics from one generation to the next is not evolution, 3) which occurs over a longer time scale." It is fair to say that this is not opening a can of worms, but this thread is going nowhere of value. The first sentence in this article is factually correct.Thompsma (talk) 17:18, 29 February 2012 (UTC)

If there is an: "inference by our "average reader" that he or she has evolved from his or her parents" - I highly doubt that they will gain anything by reading this article. The first sentence does not make this claim. Specifically, it refers to population level processes. This is not only a straw-man argument, but demonstrable incomprehension of the sentence. Please see -> introduction to evolution.Thompsma (talk) 17:24, 29 February 2012 (UTC)

Last attempt: As a definition of evolution, the phrase "any change across successive generations in the heritable characteristics of biological populations" is at best vague, at worst simply incorrect. Short term changes in population numbers, physical characteristics, sex ratios etc, caused by seasonal, predatory, migratory effects etc. all produce "changes across successive generations in the heritable characteristics of biological populations." Evolution concerns the longer term fixation of such changes in populations in the form of adaptations or speciation. A definition that says populations breed and change over time is not good enough. 88.109.39.228 (talk) 22:50, 29 February 2012 (UTC)emt1001

Once upon a time, the definition we provided was something like: changes in allele frequencies in a population over time. Can someone quickly explain toi me why this is wrong or inadequate? But in response to 88, I think "long term" is just a succession of "short terms." Whether changes in a shor period of term have efects over the ong term can only be discovered in retrospect. When studying a population now, how can one know which changes will have what long term effects? Moreover, it sounds like you are talking about the evolutionb of species. Speciation is a very important form of evolution, but I am not sure that it is synonymous with "evolution." You are right that seasonal, predatory, migratory effects all produce changes in heritable characteristics ... but so what? Aren't you simply providing some examples of "natural selection" which certainly is one important mechanism of evolution, no? It is vague, but how is it incorrect? I still do not get the problem you see. Slrubenstein | Talk 23:09, 29 February 2012 (UTC)

This lead was heavily debated and the reasons for using what has been dubbed in the literature as the "standard genetic definition" of evolution (see [46]) was rejected for not being general enough to cover the whole of evolutionary theory as represented in the wider literature (scientific and 2ndary sources). The lead sentence is not vague - it is exacting and precise in its meaning. Moreover, it could only be considered vague (in one sense) if you read the first sentence in isolation - the sentence is part of a paragraph. Read the rest of the paragraph. "A definition that says populations breed and change over time is not good enough." --> Hence, the lead sentence states something else.

To the user/editor launching this thread -> please stop using straw man arguments. Understand the sentence and then launch your counterpoint. Do not make false claims about the sentence and then claim it to be inadequate based on those false claims. Perhaps you are having trouble understanding the rates of evolution in the present versus the effect extended over time as Slrubenstein alludes in relation to speciation? Stephen Palumbi - for example - addresses this conceptual misconception about evolution in his book "The Evolution Explosion"[47]. There are many introductory evolutionary sources that discuss this matter in terms of drug resistance, for example. Douglass Futuyama defines evolution using the standard genetic definition like so: "The changes in populations that are considered evolutionary are those that are inheritable via the genetic material from one generation to the next."(Evolutionary Biology, 1986) Hence, the claim being made by this user that "Short term changes in population numbers...is not good enough" is neither a good description of what the sentence says, nor can the "too short on time" claim be supported. A widely adopted and sourced textbook definition states that things considered evolutionary occur "from one generation to the next". This thread is going nowhere.Thompsma (talk) 23:52, 29 February 2012 (UTC)

It is actually a great lead sentence and we had a huge consensus on this after a really long debate by many of our most experienced editors on evolution. This does not mean that people are not free to try to knock the sentence from its perch, but I would recommend that this would have to be achieved by someone who has a grasp of the concept to begin with. Not intended to be a snide remark or anything (please do feel free to comment), but there are some problems with the users posted reasoning on the way that evolution works that concerns me.Thompsma (talk) 00:01, 1 March 2012 (UTC)

Sorry, but misunderstanding of the concept is not a reason to change it. Evolution does occur from generation to generation. Can we easily observe it? No. But that does not make it absent. If changes do not occur each generation, you cannot accumulate them over generations and you cannot have evolution under that scenario. So, the lead sentence is actually more correct than the older sub-theory specific. 69.244.220.253 (talk) 00:39, 1 March 2012 (UTC)

I think Thompsma hit the nail on the head. 88 comments:"Evolution concerns the longer term fixation of such changes in populations in the form of adaptations or speciation" You are equating evolution as synonymous with adaptations and speciation. That is incorrect as they are just two outcomes of evolution. Evolution is change in heritable traits of a population (genes or memes) over successive generations (the generation time of animals vs bacteria differ so time will differ too, but we can see evolution happen in bacteria, fruit flies and reptiles as has been published)the outcome could also be selection to stablize traits like living fossils that remain mostly the same. Variation within a population will always occur due to sexual reproduction and recombination but then the processes of evolution (drift, selection, gene flow) will filter the population traits to produce outcomes-which may be an adaptation or speciation or the status quo. GetAgrippa (talk) 17:08, 1 March 2012 (UTC)