Talk:Evolution/Archive 47

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Archive This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Contents

Lacking substantive clarity

"Though changes between generations are relatively minor,..." is not appropriate imho because it does not explain what this is relative to. The sentence, although understandable, does not adequately or clearly explain what it is attempting to express. --Candy (talk) 21:23, 8 April 2008 (UTC)

Is the simpler phrasing of "small" any better? Tim Vickers (talk) 21:25, 8 April 2008 (UTC)
Yes. It's all "relatively minor" means, and it six times as long to accidentally say something else. Plain English for the win. Robin Johnson (talk) 15:13, 11 April 2008 (UTC)
Changes are minor relative to the distribution of trait values in the population. I.e., the average value of some trait probably isn't going to jump three standard deviations in a single generation. Graft | talk 19:02, 9 April 2008 (UTC)

Please add an interwiki link to la:

la:Evolutio Thanks. --Roland2 (talk) 10:12, 13 April 2008 (UTC)

Done. Tim Vickers (talk) 14:34, 13 April 2008 (UTC)
Thanks --Roland2 (talk) 14:42, 13 April 2008 (UTC)

Implementing "approved version" editing

Hi there, I've been bold and made a rather radical change with this "draft" page, this is being discussed at the administrator's noticeboard. Tim Vickers (talk) 18:44, 31 March 2008 (UTC)

Hi Tim, Been away for a bit. Seems like a bit of re-inventing the wheel discussion before the invasion of the sock puppet. I applaud your idea and experiment to deal with this type of vandalism. It should have been implemented long ago as the incessant interruptions are just childish and disruptive. Many excellent editors have left Wikipedia in frustration or they reluctantly contribute. What is the process to gain approval for such an experiment? Regards GetAgrippa (talk) 01:28, 1 April 2008 (UTC)
I did it on my own, any approval will be retroactive. You would be very welcome to comment in the discussion of what I've done. Tim Vickers (talk) 04:20, 1 April 2008 (UTC)
We ought to ask for other levels of control - e.g., require an arbitrary number of user edits, > some number of days registered, etc. There ARE criteria we could use to recognize and lock out sock puppets, they just aren't implemented in software. Graft | talk 17:41, 4 April 2008 (UTC)
I agreeWacoJacko (talk) 06:43, 14 April 2008 (UTC)

Evolution on a chip

Just this could be worthy of inclusion somewhere here, or in sub-articles as appropriate. Excerpt: "The molecule, which stitches together strands of RNA, became 90 times more efficient after just 70 hours of evolution." - RoyBoy 03:51, 17 April 2008 (UTC)

Tweaks

Two tiny tweaks occur to me ...

  1. The caption on the plot showing simulated genetic drift could perhaps be changed to: "Drift to fixation occurs more rapidly in the smaller population". Qualify with reference to fixation since drift itself occurs at the same rate.
  2. End of second paragraph in "Social and cultural views" could perhaps be changed to: "While other scientific fields such as cosmology and earth science also conflict with literal interpretations of many religious texts, evolutionary biology experiences significantly more opposition from religious believers". The old wording doesn't make sense since the sentence is supposed to be drawing a distinction between evolution and other scientific fields. While they all disagree with literal readings, only really evolution is attacked.

Anyway, use or ignore as you see fit. Cheers, --Plumbago (talk) 15:28, 17 April 2008 (UTC)

Drift doesn't occur at the same rate - that's the entire point. The only factor governing the first passage time of a random walk is the size of the steps, which is a function of population size in our case. Graft | talk 16:05, 17 April 2008 (UTC)
Erm, I think what I was concerned about was that people (who, like me, jump to the figures and only read captions ...) might infer that the process underlying drift was somehow different in a small population. It's not, but the consequences of it are significantly different because of the relative, rather than absolute, importance of a shift in allele frequency. Anyway, notwithstanding me mucking up my explanation (I'm still digging ...), I think my (tiny) amendment could still be useful. Cheers, --Plumbago (talk) 16:14, 17 April 2008 (UTC)
Try working out edits on the draft? Once you've got something you're both happy with I'll copy it over. Tim Vickers (talk) 16:57, 17 April 2008 (UTC)
OK. Done. Sorry, I was just been needlessly (or possibly not given my misunderstandings) hesitant in editing the draft. Cheers, --Plumbago (talk) 17:14, 17 April 2008 (UTC)
Please be bold, it's only there as a sandbox really. I've transferred the edits over. Tim Vickers (talk) 18:29, 17 April 2008 (UTC)

Your experience with the draft and the vandalism...

It would be nice, if editors on this page and the admins, who are maintaining this hopefully temporary solution, could comment here. Thanks, Merzul (talk) 11:12, 18 April 2008 (UTC)

Sexual Selection

I remember being taught at university that sexual selection was a different evolutionary force than natural selection yet I see here that it has been catagorised as a particular type of natural selection. Doesn't sexual selection in fact often oppose natural selection by favouring traits which decrease the probability of survival? It may be that my University education is now out of date. Is there a widely accepted definition of natural selection that enconpasses sexual selection? Rosalspot (talk) 14:18, 18 April 2008 (UTC)

Broadly speaking sexual selection is just the expression of mating choice - that is, who do I want to reproduce with? This hopefully manifests as a measure of overall fitness. E.g. there are many factors that might predispose you to having skin problems. But if your skin is relatively smooth and clear, it suggests you don't have any of them, ergo, your overall fitness is higher. That is, you lack deleterious variation. Expressing mating preference thus improves the overall fitness of the population by selecting against individuals with a relatively high load of bad alleles.
On the other hand there is the idea that traits that impose a high fitness burden may be cues for overall fitness. E.g. I am such an ass-kicker that even with these three hundred pound antlers on my head I can still walk around. This might result in Fisher's "runaway" selection. Whether this can result in fitness decreases I'm not sure. Graft | talk 18:33, 18 April 2008 (UTC)
Err, sorry, had to leave this comment mid-stream. Anyway, the point I was trying to make was: sexual selection is qualitatively different from most forms of selection in that you're not selecting for better fitness for a specific trait, you're selecting for a generally higher level of fitness. (This is arguably a crucial contributor to the fitness of populations - fighting against our genetic load is an important battle for sexually-reproducing organisms to wage, and by some models completely random mating would result in an inordinate mutation burden.) In that sense it is very different from the traditional kind of selection we tend to think of associated with Darwin's finches, peppered moths, etc. Right now the article does at least indicate the special nature of sexual selection, although maybe it needs to be rewritten a little more broadly (since now it seems to be restricted to only certain kinds of sexual selection). Anyway, I'm certainly not an expert here - is there an in-house sexual selection technician? Graft | talk 20:31, 18 April 2008 (UTC)
I'm with Rosalspot here. The first book I pull off the shelf (4th ed of Krebs & Davies Behavioural Ecology has in the first paragraph of Mike Ryan's chapter on "Sexual selection and mate choice" a sentence which reads

"Darwin was convinced that natural selection alone could not bring about such differences, but instead posed an alternative selection force, which[...] (emphasis added - PLH)

It's long been my sense that this is how it is thought of, as an "alternative". I've said this before, see my comments at Talk:Selection#Ecological_selection. Here on Wikipedia these's an alternate classification, shown at Selection#Types_and_subtypes that I've never seen elsewhere, and remains unsupported by references... I would also point out that there is more to sexual selection than mate choice, male-male combat forms the other half (I note that recent edits to sexual selection hold that "biologists today" divide sexual selection into intersexual competition (aka female choice), intrasexual competition (aka male-male combat) and a third category "sexual conflict" which is a new one on me and this statement is also unsupported by references). Thanks to Graft for the prod, there's my 2c. Pete.Hurd (talk) 22:50, 18 April 2008 (UTC)
I'm having a flash-back to some debates (with User:Marcosantezana on talk:Natural selection?) about sources listing sexual selection in the wild as a subset of natural selection... If I remember correctly, Endler's Natural selection in the wild and Andersson's Sexual selection books don't come down emphatically on the "they're different" side. I leave the details to others, but still think Rosalspot's memory serves him well... Pete.Hurd (talk) 23:03, 18 April 2008 (UTC)

Explaining Genetic drift

There seem to two distinct "explanations" in this article as to what drives genetic drift:

1. From the Introduction section:

"Genetic drift results from the role chance plays in whether a given individual will survive and reproduce."

2. From the Genetic drift section:

"Genetic drift is the change in allele frequency from one generation to the next that occurs because alleles in offspring are a random sample of those in the parents."


Process 2. is the better explanation, and ought to replace Process 1. in the introduction, in my opinion. Process 1., after all, need not even occur for genetic drift to take place (consider a hypothetical situation where every individual in the population always survives to produce exactly two viable offspring, every generation: genetic drift will still occur in this population...).
Process 2. is driven by the truly "random" assortment of chromosomes (ie. "allele-sets") during meiosis, which always occurs, and occurs not rarely but at every single reproductive event!

Process 2., then, is both a necessary and a sufficient cause of genetic drift, whereas Process 1. is not necessary, and is only mildly "sufficient" by comparison.

Wikiscient— 19:34, 18 April 2008 (UTC)
Meiosis does not occur in prokaryotes. That is a very limited case. Tim Vickers (talk) 19:39, 18 April 2008 (UTC)
Right. Well, in that case, I guess you ought to change the explanation given in the Genetic drift section, then, huh?!
(Which is a shame, since the drift caused by meiosis is so much more robust, and easier to see...) —Wikiscient— 20:01, 18 April 2008 (UTC)
A few months back whats-her-face and I went back and forth arguing about this issue, with her maintaining that drift was based on random mating (1), and myself maintaining that drift was based on random assortment (2). Both are correct. Either process causes drift. Any process contributing to random variation in reproduction will cause drift. Graft | talk 20:22, 18 April 2008 (UTC)
Even in multicellular organisms producing very few offspring, the number of meiotic events is very large and there is an enormous chance element in which gametes / spores etc. are ultimately successful and which aren't. For example, consider a tree producing trillions and trillions of pollen grains over its lifetime. So many that the overall frequency of each allele is going to be very close to the expected value of 0.5 (assuming unbiased meiosis). On the other hand, very few of those pollen grains will actually result in seeds, and fewer still in seeds that germinate, survive and reproduce (single digits, possibly). The role of meiosis in genetic drift, therefore, seems minimal compared to the role of chance survival of gametes and offspring. --Graminophile (talk) 20:25, 18 April 2008 (UTC)
Yes, yes. I meant meiosis is when the randomization of chromosomes occurs; it is then the recombination of those haploid gametes resulting in a diploidal "viable offspring" that I am saying "happens every time" and is therefore a far more robust driver of genetic drift than "a-rock-falls-on-you" events...
Wikiscient— 20:37, 18 April 2008 (UTC)
This seems to be a statistical fallacy to me - I can roll the dice hundreds of times and get close to a perfect uniform distribution of rolls, but a single event still has a huge amount of variance. So, yes, I have produced billions of sperm in my life, but only three or four of them will ever produce offspring (if I meet the right girl) - and the variance for those three or four meiotic events is very large. So, in our case meiosis IS contributing a lot to drift. This may not SEEM to be the case for clownfish, which produce hundreds of offspring, but even in that case I think assortment plays a role. The early-generation situation (hundreds of babies) is less important for assessing drift compared to the differences in the parental generations (a few dozen surviving reproducers). That is, variance still comes from the fact that my reproducing offspring only received half of my chromosomes. Compare to, for example, everyone reproducing by cloning themselves, and drift arising from random variation in the number of clones we happen to grow up. Graft | talk 20:45, 18 April 2008 (UTC)

Genetic drift is the change in allele frequency from one generation to the next that occurs because alleles in offspring are a random sample of those in the parents, as well as from the role that chance plays in determining whether a given individual will survive and reproduce.

Comments? Tim Vickers (talk) 20:48, 18 April 2008 (UTC)

"the role that chance plays in determining whether a given individual will survive and reproduce" seems to suggest that the survival of organisms needs to be governed by random events in order to allow drift. It does not - it can be entirely driven by selection and we would still have drift. Selection produces variance in the number of offspring reaching the next generation, and it is JUST variance in the number of offspring that is necessary for drift to happen. I.e., say you have 100 individuals. 40 of them contain neutral allele A1, and 60 contain neutral allele A2. Of the former, 21 contain (unlinked) beneficial allele B1, and 19 contain deleterious allele B2. Of the latter, 29 and 31 respectively. Now, selection acts to increase B1 and decrease B2, and just due to the fact that there was some non-uniformity in the random distribution of these alleles, we get drift in the frequency of A1/A2. The same situation would arise, of course, if we simply assumed that # of offspring has some probabilistic distribution. But the sentence above only implies the latter. I suggest:

Genetic drift is the change in allele frequency from one generation to the next that occurs due to the fact that alleles in offspring are a random sample of those in the parents, and also due to variation in the number of offspring that survive and reproduce.

Graft | talk 21:05, 18 April 2008 (UTC)


"...just due to the fact that there was some non-uniformity in the random distribution of these alleles..."
Well, you've built that into your example; how would such a situation arise? Especially if there is no linkage between 'A' alleles and 'B' alleles? It seems to me that such a pre-existing distribution is, itself, in effect, "linkage".
The point about genetic drift is that it is that change in allele frequency which is not accounted for by selection pressure.
I do see your point though; the distinction I'm making is subtle, and admittedly perhaps less rigorously "true". Nevertheless, for the purpose of maximizing clarity in an already over-complicated issue, I'd go with Tim Vickers' proposed wording...
Wikiscient— 21:41, 18 April 2008 (UTC)
The situation of a pre-existing distribution arises due to stochastic variance, and nothing else. You can easily verify this with some dice and some spare time. What the example demonstrates is that the pre-existing variance is exacerbated (that is, allele frequencies change) due entirely to the effect of selection on individuals, NOT due to random variance in their survival. In the subsequent generation there is no particular reason why the pre-existing distribution (number of A1s that are B1s, etc.) would resemble this generation; but it would still result in drift. Graft | talk 21:54, 18 April 2008 (UTC)
As for clarity, what we should try to get across is not that drift is the process that occurs outside of or in the absence of selection (which is wrong), but that drift is a process orthogonal to selection and occurs right alongside it. I agree the point is subtle, but the more we can get people away from the idea that drift is the product of volcanoes or rocks falling on people, the better. Graft | talk 21:57, 18 April 2008 (UTC)
But, drift still occurs even if offspring contain the exact same alleles as their parents, so long as there is variation within the parental generation. What matters is the subsequent random survival of the offspring (ignoring the effects of selection on other genes, as in Graft's example). For example:
(A) 1 plant containing alleles A1 & A2 produces pollen/eggs with either allele A1 or A2. Following self-pollination, seeds are produced with approximately even numbers having genotype A1A1 and A2A2 (plus 50% with A1A2).
(B) 2 plants with genotypes A1A1 and A2A2. Clonal seeds are produced by apomixis, either A1A1 or A2A2.
Drift can occur equally in both cases due to random survival of the seeds. The lack of meiosis in (B) actually increases the rate of drift between A1 and A2, because there are no seeds with A1A2 genotypes (which keep the original 1:1 ratio of A1:A2).--Graminophile (talk) 22:32, 18 April 2008 (UTC)
The error in (A) is "approximately". In a finite population, variation in this process will still result in drift. (B) is correct, except that I'm not sure drift will occur faster. If we have 40 such plants and each one of them faithfully produces a single copy in the next generation, no drift will occur. Anywho, see above - the point is both of these processes contribute to drift. Either is sufficient; neither is necessary. Graft | talk 23:00, 18 April 2008 (UTC)
No, approximately is not an error. My point wasn't that the random allocation of alleles at meiosis doesn't cause drift, but that the effect at the time of meiosis is (much) smaller than the subsequent random survival of the gametes/offspring. E.g. the plant in (A) produces 1000 seeds and only two survive, both of which happen to be A1A1. Sexual reproduction was necessary for producing the different genotypes A1A1, A1A2 and A2A2, but the ultimate change in gene frequency was everything to do with random survival and very little to do with any imbalance in the ratio of A1:A2 at the time of meiosis.
In (B), who said the plants were producing one seed each? Clearly each will produce a large number, but only a few will survive--Graminophile (talk) 09:51, 19 April 2008 (UTC)
Meiosis isn't responsible for less drift than survival, as I explained above. The point is that any process that results in alleles being a random sample of the parental generation - either differential survival or meiosis - suffices to cause drift. There is no "less or more". There is just drift. The amount of drift depends on the sample size, that is it. I seriously suggest you make a toy model and play with some examples. Graft | talk 14:39, 19 April 2008 (UTC)

The larger the population, the smaller the effect of drift. I think it helps to remember that drift is a statistical phenomenon and we can illustrate it with empirical examples but those examples remain illustrations of a statistical phenomenon. Slrubenstein | Talk 10:53, 19 April 2008 (UTC)

Isn't this the encyclopedia that anybody can edit?

Thank you to the admins

Not many users are saying this, but me and my research team greatly appreciate the maintenance of these extremely well established yet somehow "Contraversial" evolution articles. —Preceding unsigned comment added by 128.243.253.112 (talk) 09:10, 22 April 2008 (UTC)

No problem, but this is only temporary until Wikipedia:Flagged revisions/Sighted versions is activated, which should happen this month. Tim Vickers (talk) 15:34, 22 April 2008 (UTC)

Lets hope it can be activated on this before something gets deleted :(

Field guide to genetic programming

This was added as a reference, but since it is self-published by Lulu.com I removed it. As this section already has a reference for this statement, we don't need to include this book as an additinal reference, but do people think it should be added as an external link? On the plus side, it is free-access and has expert authors, but on the minus side it is self-published and might create an problematic precedent on the quality of our sources. Tim Vickers (talk) 15:34, 22 April 2008 (UTC)

Deleting discussion comments!

I would just like to voice my opinion that comments on the talk page should not be deleted, but responded to.

Are you worried that my lack of faith in evolution could stop others believing? If this is how insecure believers of this theory are, it doesnt give a very good advertisement.


No where in this article can I find that evolution is unproven.

This should be at the top of the page in a prominent position to emphasise that the entries are only based on a theory.

And yes I did know that some aspects are controlled by dominant alleles and therefore exist more often. - your blue eyes statement. (to which i could have responded had you not deleted it).

Microsoft Encarta stipulates that it is only a theory in its opening paragraphs, why can we not have that here?

Also, this article, and no other article on wikipedia should be fully protected in this way. It goes against the whole idea of wikipedia, where anybody is free to make a contribution. - maybe impartial moderators should just look at this page more often.

Evolution is a hot topic for debate and always will be. It is unlike an encyclopaedia not to put forward both points of view.

Whilst the article should be about what evolution is, at the present time it could be mistakenly believed to be fact.

Matty2002 (talk) 16:42, 11 April 2008 (UTC)

Your comments have not been deleted but archived (see above). This is an attempt to focus the discussion on the article, rather than having this conversation wind off into a unproductive debate on the topic in general. Tim Vickers (talk) 16:46, 11 April 2008 (UTC)
I suggest you refer to Evolution as fact and theory, which addresses these issues. Snalwibma (talk) 16:52, 11 April 2008 (UTC)
In good faith, we appreciate your interest in improving the article's neutrality. However, your comment reflects a misunderstanding of scientific method. This is understandable, as the terms involved (e.g., "proof", "theory") have different meanings in colloquial contexts. Please review Talk:Evolution/FAQ#But isn't evolution unproven? and Talk:Evolution/FAQ#Why is evolution described as though it's a fact? Isn't evolution just a theory?. In science, something does not stop being a theory once it is "proven"—in fact, it would be more accurate to say that a theory is a "proven hypothesis", depending on how you define "proof". Additionally, this article is actually about the fact/process of evolutionary change, not directly or exclusively about the theory of evolution: the latter topic is more of a historical and metascientific nature than of a directly biological nature, and is covered at modern evolutionary synthesis.
You also seem to misunderstand Wikipedia policy on science articles. An encyclopedia's job is not to report on every point of view in its science articles (else we'd have to give Flat Earth and Round Earth theories equal time on Earth); rather, it is to report on every established scientific point of view in its science articles, which means only reporting on views which have significant representation in peer-reviewed scientific publications. If you wish to insert alternatives to evolution here, you must provide peer-reviewed literature (e.g., a Nature article) to substantiate that view. -Silence (talk) 17:05, 11 April 2008 (UTC)
I am not sure what Matty2000 means by "both points of view." In science as in most fields there are many, hundreds, of points of view. If the question though is simply, is evolution a fact or is it not a fact, there is only one notable view, that held by all scientists who are not beholden to any other dogma, and that view is that evolution is a fact. This is not a matter of opinion, and there is no meaningful scientific argument about it. Now, there may be debates among theologians, but those debates and the various views belong in a different article, not this one. Slrubenstein | Talk 17:29, 11 April 2008 (UTC)

I believe Matty2002 (talk · contribs) is probably referring to his prior talk page comment and my subsequent removal. Perhaps I was a bit brusque, but I felt that the comment was largely a misinformed soapboxing that offered minimal value towards the goal of this talkpage (improving the article) because it presented the classic "it's only a theory" canard that is dealt with in other articles, the FAQ, and past discussions ad nauseum. The point about the current status of article protection may warrant clarification (in the talk page header?), though. — Scientizzle 18:52, 11 April 2008 (UTC)

Folks, I realize this sort of engagement is entertaining and provides a healthy dose of self-gratification, and I readily acknowledge that I have been a prime offender in this regard in the past, but frankly, it just encourages 'em. Keep it short and simple: a single line, a FAQ link, and that's all. That's why the FAQ is there, after all, to keep this page clean. Graft | talk 21:47, 11 April 2008 (UTC)
Err, not to gainsay Scientizzle's point about the protection status - that is definitely an important debate we need to keep going. Graft | talk 21:49, 11 April 2008 (UTC)
It would probably have been better to archive it than delete it. thx1138 (talk) 22:53, 11 April 2008 (UTC)
In retrospect, I agree. I'll be sure to do that in the future.
To Matty2002: Feel free to come by my talkpage if you have further questions regarding the points made in this thread, the linked articles, and the FAQ. Let's end this thread and let MiszaBot put it to bed. — Scientizzle 23:20, 11 April 2008 (UTC)


Thanks for explaining it to me, I am after all only here to help contribute my (minimal) knowledge to improve the encyclopaedia, just like everybody else. Not sure where Graft is coming from "just encourages 'em" - I was only putting forward a point of view to be discussed - which the majority on here have allowed.

Thanks again for the explanation,

Matty2002 (talk) 21:33, 12 April 2008 (UTC)

But...how can something be theory and fact? if indeed a fact is a proven theory, then it would no longer be a theory? 4-25-08 —Preceding unsigned comment added by 98.195.196.19 (talk) 20:16, 24 April 2008 (UTC)

Many people are confused about that, but that's only because they don't know the scientific definition of "fact". Look through Evolution as fact and theory, it specifically addresses this common mistake. In a nutshell, evolution is a fact because it can be seen to happen and to have been happening. Evolution is also the theory describing how science has gathered these observable facts to be working. A proven theory is still a theory, and facts are always facts. Whether or not the fact is different from the theory isn't really relevant. They are in fact completely interdependent: it's not viable to propose a theory of intelligent design to explain the fact of evolution, because there is no fact of intelligent design, only beliefs of intelligent design.--AkselGerner (talk) 20:42, 24 April 2008 (UTC)

Reference number 4

Hi, I have been translating this article into the portuguese Wikipedia, and I am having a little problem with the references that use the wikiref template, because this template does not exist over there. Could someone tell me what is the Gould 2002 reference, please? GoEThe (talk) 09:33, 25 April 2008 (UTC)

  • Gould, S.J. (2002). "The Structure of Evolutionary Theory." Cambridge: Belknap Press (Harvard University Press). ISBN 0-674-00613-5. Tim Vickers (talk) 17:00, 25 April 2008 (UTC)
Thanks! GoEThe (talk) 17:20, 25 April 2008 (UTC)

Evolution is a theory

Phenotypic plasticity

The main article is protected from editing, so I can only recommend to add Phenotypic plasticity to the section "Mechanisms and processes" of the "Part of the Biology series on Evolution" template
Miguel de Servet (talk) 12:59, 25 April 2008 (UTC)

You can add it to the draft article yourself if you want. thx1138 (talk) 17:45, 25 April 2008 (UTC)
As a comment, since phenotypic plasticity does not, by definition, alter allele frequencies, we can't classify it as a mechanism of evolution. Tim Vickers (talk) 17:52, 25 April 2008 (UTC)
I agree with that comment Tim, but the literature is recognizing plasticity as an evolutionary agent for example:Otaki JM.Stress-induced color-pattern modifications and evolution of the Painted Lady butterflies Vanessa cardui and Vanessa kershawi.Zoolog Sci. 2007 Aug;24(8):811-9. Badyaev AV, Oh KP. Environmental induction and phenotypic retention of adaptive maternal effects.BMC Evol Biol. 2008 Jan 9;8:3. However I don't think this material would apply in an encyclopedia. Regards to all the progess being made here. GetAgrippa (talk) 11:11, 27 April 2008 (UTC)
It's certainly part of the nature/nurture process, but it doesn't change what alleles are there in the first place, or cause the frequencies of alleles to change over time. I suppose we could in theory put it in the genetics section, but it doesn't seem to me to be important enough warrant the attention. Tim Vickers (talk) 20:24, 28 April 2008 (UTC)
I agree Tim, but one idea is these epigenetic phenotypes maintained by the environment can later be fixed by an allele shift (interesting backwards way of looking at things)and also there are reports of epimutations and epialleles. Still hypothetical and not suitable for an encyclopedia. The epigenetic world is a layer of regulation that just doesn't paint a clear picture yet, but it's significance in germ line and development in general gives me a sense of its potential. It does bring up the subject of what we measure as evolution-shifts in gene alleles with what evolution has historically been associated-the phenotype. Studies of clonal bacteria,etc. demonstrate genetically identical cells will produce different phenotypes from environmental cues. I think there are a number of varieties of turkey but one species in particular (I recollect) turned out to be a phenotypic variant because it was genotypically identical to another species but the influence of the environment created the illusion. Anyways interesting stuff. I at one time entertained writing a "NeoLamarckism" article to address some of the novel ideas. There are a handful of authors (Jablonka, West-Eberhard,etc.), a number of books, and a growing literature.It is really a misnomer of a title and more a symbolic gesture to Lamarck but it would make an interesting little article.GetAgrippa (talk) 01:03, 30 April 2008 (UTC)

evolution of life

In the Evolution#Evolution_of_life section it says: "Soon after the emergence of these first multicellular organisms, a remarkable amount of biological diversity appeared over approximately 10 million years, in an event called the Cambrian explosion." But the Cambrian explosion article describes it as lasting 70-80 million years: "In the following 70 million to 80 million years, the rate of evolution accelerated by an order of magnitude, and the diversity of life began to resemble today’s." Can somebody explain the discrepancy?Archer3 (talk) 01:29, 30 April 2008 (UTC)

Check the references it uses. This isn't the helpdesk.--Otterathome (talk) 12:44, 30 April 2008 (UTC)
Ok, relax. No need to get snotty. I'll check the references.Archer3 (talk) 14:30, 30 April 2008 (UTC)
You might not be able to access the full text of the reference, so I'll paste the relevant piece here:

Over the past five years, a firm temporal framework has beenestablished in which the early fossil appearances can be ordered. Relatively abundant, mineralized fossil remains that include living phyla appear in the record at about 530 million years ago (Ma), and for the next 9 or 10 million years, phyla make their appearances in geologically rapid succession (Fig. 1; Bowring et al., 1993). By the end of that time, all but one of the phyla with easily fossilizable skeletons had appeared (the Bryozoa appear in the Early Ordovician, but this group is rich in unmineralized representatives today, and the oldest fossils are sufficiently derived to suggest a deeper evolutionary history; P. D. Taylor, personal communication June 1998). It is this relatively abrupt appearance of living phyla that has been dubbed the ‘Cambrian explosion.’ [copied from Valentine et al p851

However, as I remember, there is some debate about exactly how long this process took, so different sources might take different viewpoints on this. Tim Vickers (talk) 15:56, 30 April 2008 (UTC)
Looking at some more papers, there is clear agreement that the cambrian explosion is when most of the animal phyla appeared in the fossil record, but there is disagreement over if this was when they first evolved (since some phylogenetic studies indicate earlier divergence times). I've therefore tweaked the article a little to say that most animals appeared in the fossil record during the cambrian explosion. As the saying puts it, "It is better to be vague than wrong." Tim Vickers (talk) 18:20, 30 April 2008 (UTC)

Dysgenics

This article is currently protected because of an edit war. It is supposedly part of Wikipedia's Evolution Project, and I suspect that the term does have meaning and value in population genetics or evolutionary theory ... maybe not. Anyway, the talk page is in serious need of well-informed comment. As someone else noted, the editors most active on this page have created one of Wikipedia's finest articles. I urge - beg - you to take fifteen or twenty minutes to look at the particle and the past week's talk, and comment. Does this word merit an encyclopedia article (Wikipedia is not a dictionary)? If it is to be an encyclopedia article, is it best thought of as an article about a concept in fringe science (like "irreducible complexity")? Or is this an article on a scientific topic, like the Evolution article - if so, you guys are the ones best suited to advise what shape such an article should have and have the knowledge and experience to make constructive interventions in the conflict. Please? Slrubenstein | Talk 19:03, 30 April 2008 (UTC)

Presented as Fact?

I suggest that those interested in continuing this general discussion of the topic do so at talk.origins Tim Vickers (talk) 20:26, 28 April 2008 (UTC)

It is not intellectually honest to say, in explaining why contrasting theories are not included in the Evolution article, that "an encyclopedia's job is not to report on every point of view in its science articles (else we'd have to give Flat Earth and Round Earth theories equal time on Earth)." This is a very bad analolgy, as the Flat Earth theory was disproved eons ago (and easily proven to be false); whereas the theory of Intelligent Design, for example, has not been disproved. At any rate, to be fair and honest, this article should include a section called "Competing Theories" or some such thing. Also, it should be pointed out that although this article mentions cross-species evolution as fact, there is no evidence in the fossil record that this has EVER happened, to my knowledge (nor is any evidence of this offered in the article itself). It is therefore biased to include cross-species evolution in this article without including a discussion about the overwhelming lack of evidence therein. —Preceding unsigned comment added by Kmommy2 (talk • contribs) 21:41, 1 May 2008 (UTC)

The "theory" of Intelligent Design has not been disproved because no theory has been offered. Currently, there are no competing theories to evolution, so such a section is not warrented. There is an abundance of fossil evidence for speciation so mentioning a lack of fossils would be inaccurate. thx1138 (talk) 19:13, 7 May 2008 (UTC)

"Change in a species over time"

This seems a bit vague to me, is this really a common way of describing evolution? Tim Vickers (talk) 21:45, 1 May 2008 (UTC)

It does seem vague and seems to equate the misnomer that evolution is speciation. There are known examples of phenotypic species (some heritable epigenetic)that are not true evolution-no shift in gene alleles but just environment and epigenetic regulation of expression. Speciation is a byproduct of evolution so evolution occurs and "may" led to speciation. So a change in a species over time maynot be evolution if it is just a heritable epigenetic trait and evolution can proceed without speciation. A species of bacteria may evolve a new trait like eating nylon without becoming a new species. I understand the drift of the statement but it does seem misleading. Sorry I'm rambling-need coffee!!!!GetAgrippa (talk) 13:54, 3 May 2008 (UTC)
I hadn't noticed, but it sounds unusual to me. I think population geneticists define evolution as changes in allele frequencies in a population and of course the distinction between population and species is very important. And of course it need not lead to speciation. Population geneticists also often do distinguish between micro- and macro-evolution. The difference between creationists and such population geneticists is that creationists think microevolution and macroevolution are distinct processes, whereas population geneticists see them as different effects of the eact same processes (macroevolution describing the threshold that is crossed when speciation has occured .... this distinction is what is at issue when lumper and splitter paleontologists and paleoanthropologists debate how to classify fossil evidence). But others in the natural or life sciences may routinely use other definitions. Slrubenstein | Talk 18:28, 3 May 2008 (UTC)
Perhaps make some mention of phenotypic-genotypic maps being used by population geneticist to quantify evolution, and attempts at modeling to explain and make predictions about evolution. That way the emphasis is on phenotypes-traits and genotypes-gene alleles. The distinction between population and species by Slrubenstien is a good one. Even a definition for species is problematic. GetAgrippa (talk) 21:17, 3 May 2008 (UTC)
Maybe I'm wrong but couldn't macroevolution be bumped up to the changing of "kinds" instead of species? I mean, many many organisms can have random minute changes in structure, appearance...etc., that pile up to the extent that they become a new species altogether, but I have two points: should changes like I just mentioned be considered evolution since they weren't self-actuated, and, should some more study be made in the transition from one kind to another? 5-4-08 —Preceding unsigned comment added by 98.195.196.19 (talk) 23:54, 4 May 2008 (UTC)
No, macroevolution cannot be "bumped up" to "kinds" for the simple reason that "kind" is not a a term in Biological nomenclature. Coffeeassured (talk) 07:39, 5 May 2008 (UTC)

"Change in a species over time" rings of a common colloquial simplification--it's probably how most folks without university-level biology training would describe ToE. While I believe this addition is erroneous (for the reasons stated above), I think it could be useful as a springboard from which we can craft wording to more successfully span the gap from common (mis)understanding to the more esoteric definitions used by biologists... — Scientizzle 15:20, 5 May 2008 (UTC)

OK, I've removed this for now. Let's redraft it here. Tim Vickers (talk) 16:17, 6 May 2008 (UTC)

For our use, there are some Google hits for "Change in a species over time". Included are some apparent educational sources:

I think a bridge between this simplification and the more technically correct (and nuanced) definition may even be extractable from the Glossary Definitions of "Evolution" link above...Introduction to evolution simply states: "Evolution is the process of change in all forms of life over generations". — Scientizzle 18:52, 6 May 2008 (UTC)

Article no longer protected?

I see the lock on the page, but there is IP vandalism in the recent history. WTF? --Aunt Entropy (talk) 17:17, 6 May 2008 (UTC)

The page was no longer locked - Tim set it to expire on May 6. Let's see if it works out okay. I locked it for moves only. Graft | talk 17:22, 6 May 2008 (UTC)
I was hoping that the flagged revisions function would be active by now. However the community seem to be moving at a glacial pace. Let's keep at semi for now, that's what it was before. Tim Vickers (talk) 18:50, 6 May 2008 (UTC)
And the vandalism is back again, only two days after the protection was dropped (probably just waiting for the new accounts to mature). *sigh* --Infophile (Talk) (Contribs) 18:00, 8 May 2008 (UTC)
I have restored full protection after a recent flood of vandalism. Fvasconcellos (t·c) 15:45, 9 May 2008 (UTC)

Polyploidy

What is the following sentence from the section on gene flow trying to say?: "Polyploidy is important in hybrids as it allows reproduction, with the two different sets of chromosomes each being able to pair with an identical partner during meiosis." No it doesn't. Haploids and diploids are perfectly capable of reproducing. Facilitation of reproduction is not what it is about, finding identical partners during meiosis has nothing to do with it, and the assumption of TWO sets of chromosomes is incorrect. Everything about this sentence is wrong and out of place, and I strongly recommend it is deleted. Plantsurfer (talk) 20:12, 6 May 2008 (UTC)

Despite theoretical doubts about their importance in speciation, chromosomal rearrangements often contribute to the sterility of hybrid plants (18, 19). Unlike Drosophila (in which hybrid sterility is mostly due to Bateson-Dobzhansky-Muller (BDM) incompatibilities), sterile plant hybrids often recover fertility after chromosomal doubling (18). This is expected if chromosomal rearrangements are the cause of sterility, because chromosomal doubling furnishes an exact homolog for each chromosome, whereas doubling should not affect BDM incompatibilities.

From PMID 17702935. This certainly isn't well-phrased, but it appears to be accurate. I think the idea is that in a diploid hybrid formed from AA and aa parents you have Aa cells trying to go through meiosis and being unable to pair the differing chromosomes. However in a AAaa tetraploid, this isn't a problem. Tim Vickers (talk) 22:32, 6 May 2008 (UTC)

Christ, looks like my view of this is very simplistic, I'm reading through PMID 17361174 but despairing of understanding all the detail. Tim Vickers (talk) 22:51, 6 May 2008 (UTC)

evolution

Please read WP:FORUM. This is not the place for such discussions. --Infophile (Talk) (Contribs) 16:41, 9 May 2008 (UTC)

just a quick question

Picture of male lion

Male lions dont leave the pride when they are born.....--203.192.91.4 (talk) 13:48, 18 May 2008 (UTC)

It doesn't say when they are born, it says WHERE. GoEThe (talk) 15:59, 18 May 2008 (UTC)

Misleading Information

FA status Portuguese

Could someone please add the FA status for the portuguese (pt) version of this article? GoEThe (talk) 20:55, 20 May 2008 (UTC)

Y Done Hut 8.5 20:58, 20 May 2008 (UTC)