Talk:Evolution

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Two major mechanisms

The second paragraph now reads:

There are two major mechanisms driving evolution. The first is natural selection, which is a process causing heritable traits that are helpful for survival and reproduction become more common in a population, and harmful traits to become more rare. This occurs because individuals with advantageous traits are more likely to reproduce successfully, so that more individuals in the next generation inherit these traits.[1][2] Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment.[3] In contrast, genetic drift produces random changes in the frequency of traits in a population. Genetic drift results from the role chance plays in whether a given individual will survive and reproduce. Though the changes produced in any one generation by drift and selection are small, differences accumulate with each subsequent generation and can, over time, cause substantial changes in the organisms.

I am not sure this is entirely clear. How do these mechanisms drive evolution? Arguably random mutation, procreation and environmental duress would be forces driving evolution. Now natural selection is definitely a mechanism, and it gives direction to evolution, so the statement is true in the "steering" meaning of the "drive" verb, but usually the "drive" verb is used in this kind of context as in "the current of the river drives the water mill wheel", so it might be misunderstood. Is genetic drift really a mechanism? Isn't it more of an observable result, a trend or emergent pattern rather than a predictable and/or formalizable mechanism? Genetic drift of course can be said to be an emergent force driving (=causing to move/function, rather than the "steering" meaning) evolution as it allows for accelerated gene-pool change, but then the verb "drive" is used at the same time for two different subjects with two different meanings, which might be a problem. I have studied biochemisty but it's been a while and I haven't dealt with that field for a while so please enlighten me on the specifics if I'm completely off-target. I realize that mechanism might be a conventional term for genetic drift, if so, no problem. I only nit-pick at this because the potential ambiguity offers a point of attack for those who would want to make a mountain out of an anthill.--AkselGerner (talk) 22:14, 21 April 2008 (UTC)

I'd say that since genetic drift is a process like natural selection that alters allele frequencies over time, then it is a mechanism of evolution. Tim Vickers (talk) 19:53, 25 April 2008 (UTC)

I understand, it's just that it's so entropic, I guess it just bugged me that it's not a usual kind of mechanism. It's tricky to do that paragraph better... the drive-verbs semantics I still think is slightly problematic, but it's not major and it's hard to see what would be better. —Preceding unsigned comment added by AkselGerner (talk • contribs) 20:50, 28 April 2008 (UTC)

I would like to add that (at least how it is described here) the evolution theory is a tautology: look at: "natural selection, which is a process causing heritable traits that are helpful for survival and reproduction become more common in a population, and harmful traits to become more rare" It says that natural selection cause helpful traits (defined as the one who help for reproduction and survival) to survive :P —Preceding unsigned comment added by RonanSandford (talk • contribs) 04:49, 11 May 2008 (UTC)

"Natural selection" is just the word given to the process, so the fact that the word does indeed accurately describe the process shouldn't come as a surprise to anybody. See also this article for further discussion of the topic. Tim Vickers (talk) 19:41, 11 May 2008 (UTC)

Theory of evolution is a tautology like F=ma is one. It does not make theory of evolution infalsifiable. —Preceding unsigned comment added by 202.134.182.138 (talk) 04:05, 29 May 2008 (UTC)

Mechanisms of reproductive isolation

I've not been happy with this section for a while, so I've been bold and removed it diff. Firstly, it isn't very well written and is just a list. Secondly, what precisely does this have to do with evolution? The evolution of mechanisms of reproductive isolation are important in speciation, but this seems to be too distant from the speciation event itself for this much detail. These are proximal reasons why speciation occurs, just as the aerodynamics of feathers are proximal reasons why wings evolved. The ultimate reasons are surely the ones that we need to focus on here? Does this make any sense to anybody else, or have I failed entirely to explain what I mean? Tim Vickers (talk) 02:49, 24 May 2008 (UTC)

Perhaps it should be added to the article on speciation as a separate section? Are the mechanisms of reproductive isolation covered anywhere else? Esseh (talk) 23:35, 24 May 2008 (UTC)

Actually, on a quick search, there is an article on reproductive isolation. Perhaps there? Esseh (talk) 23:37, 24 May 2008 (UTC)

Controversies

If nobody has any objections, I'll add, "and controversies", to the "Social and cultural views", as I don't feel that the title rely suggests as much as it should about the section's content. I would, however, be grateful were somebody to come up with a better title, to avoid one quite so clumsily phrased.--THobern 14:33, 29 May 2008 (UTC)

Hmmm. "Controversies" is a dangerous word to use in evolution articles, since it may give the appearance of acceding ground to the likes of creationists, who love to generate the impression of controversy. I would agree that "views" is somewhat anodyne in this context, but perhaps something better than "controversies" can be found. What about more neutral terms like "reactions", "responses" or "reception"? Still, I suppose that "controversies", since it would be pre-fixed with "social and cultural", is clearly not scientific controversy. Cheers, --Plumbago (talk) 14:50, 29 May 2008 (UTC)

What about "effects"? (Note our article is at Social effect of evolutionary theory.) Hut 8.5 15:13, 29 May 2008 (UTC)

As always, I think we should be guided by policies like NOR and V. We should not add new sections just because they sound nice or because we personally are interested in them. We should add sections that cover significant areas of research or debates, found in reliable sources. So my question is, what is the body of literature (the reliable sources and the notable views they contain) you propose to draw on in this new section? once we have a clearer idea of what line of investigation or debate you think the article fails to, but ought to, cover, then it will be easier to discuss an appropriate name for it. Slrubenstein | Talk 15:17, 29 May 2008 (UTC)

The section is already here, at Evolution#Social and cultural views - the proposal is just to retitle it. --Hut 8.5 15:21, 29 May 2008 (UTC)

I'd be fine with "responses", since this section does describe how other groups have responded to the findings of evolutionary biologists. Tim Vickers (talk) 16:05, 29 May 2008 (UTC)

Okay, I agree that the current titles are awkward. Responses is fine. How about "reception?" Slrubenstein | Talk 16:28, 29 May 2008 (UTC)

Eugenics isn't really a "reception", it's picking up the findings of science and running off with them in the direction your prejudices suggest. Tim Vickers (talk) 17:03, 29 May 2008 (UTC)

Agreed. The best title might be longer to be more inclusive: "Reception, responses, applications and appropriations" or something like that but I have no problem with someone picking one word. Slrubenstein | Talk 17:06, 29 May 2008 (UTC)

I'm for "responses". It wasn't my favourite when I suggested it above, but Tim's reasoning is sound. Cheers, --Plumbago (talk) 18:15, 29 May 2008 (UTC)

Done. Tim Vickers (talk) 18:32, 29 May 2008 (UTC)

As a spin-off, the simplistic idea that eugenics=bad evolution is inaccurate. The ideas of Darwin and Galton were to do with heredity rather than evolution, though related, and they were both convinced that it could only be voluntary.[1] There is still "good" voluntary eugenics.[2] Compulory eugenics coincided with the "eclipse of Darwinism" by Mendelian evolution, and developed in the US for various reasons.[3] All rather complex, but commonly misunderstood. . . dave souza, talk 20:26, 29 May 2008 (UTC)

The problem is, it is equally as POV to use euphemisms. "Controversy" really is the fairest way of describing the content of the section. I would agree with you, Tim, that it would normally be a misrepresentation, but this is the social and cultural section, not the scientific.--THobern 07:30, 30 May 2008 (UTC)

Plumbago, who are you talking to?--THobern 07:30, 30 May 2008 (UTC)

Hi THobern. I was originally talking to you, but my second remark was just to confirm that I agree with Tim Vickers' suggestion to alter the "views" in the section heading to "responses". Hope that clears things up. Cheers, --Plumbago (talk) 07:35, 30 May 2008 (UTC)

Talk about DNA

The second paragraph explains in some detail the structure and function of DNA. Wouldn't it be more appropriate to talk about Mendel here?Sikkema (talk) 14:17, 30 May 2008 (UTC)

This section is really about genes, which are critical to evolution. Mendel is just a historical note is a much less important part of the article. Tim Vickers (talk) 16:32, 30 May 2008 (UTC)

This article is trying to be a textbook when it's not

There's a huge amount of peripheral cruft in this article that has no reason for being in an evolution article: e.g.

"Present-day extinction rates are 100-1000 times greater than the background rate, and up to 30 percent of species may be extinct by the mid 21st century." (shocking and true, but how does it relate to evolution? if it does relate to it, there's no mention)

Or lengthy definitions and discussions of related concepts, that just aren't needed to explain "evolution". E.g.

The time for an allele to become fixed by genetic drift depends on population size, with fixation occurring more rapidly in smaller populations.[67] The precise measure of populations that is important here is called the effective population size, which was defined by Sewall Wright as a theoretical number representing the number of breeding individuals that would exhibit the same observed degree of inbreeding.

Yes, but what does it have to do with evolution? I know it's a related concept, but the article is too busy giving a textbook definition of genetic drift to relate it back to the topic.

I only recently discovered the divide between the two evolution articles. The other being Introduction to evolution -- which, far from being a "for dummies" article, it is simply a better article. "Introduction" should simply replace this article. —Pengo 13:28, 6 June 2008 (UTC)

Genetic drift is just as important to evolution as natural selection, perhaps more so. See neutral theory of molecular evolution. I'd also recommend you read the excellent essay Wikipedia:Many things to many people, which explains why we have two classes of articles on these core topics. Tim Vickers (talk) 13:32, 6 June 2008 (UTC)

I agree with Tim - the Intro article is certainly good and has its place, but it's far too simplistic a picture of evolution to serve as an overview article for the past hundred years of history. That article gives a summary of selection and stops at the modern synthesis - hardly satisfactory. This article is far more comprehensive and needs to be, though I would agree it can be made more approachable and better written. Graft | talk 06:03, 7 June 2008 (UTC)

I didn't say that genetic drift or extinction weren't "important" to evolution. I said there's no need to include so much detail in this article, and it fails to tie the concepts to the central topic (evolution). To give an example of what I mean, if the article on stars were structured the same way as this article, it would contain 3 paragraphs on hydrogen, 3 more on helium, and then 3 more on thermonuclear fusion and that would be the end of the article. Note, that it actually has no description of hydrogen or helium even though they are incredibly important to a star. "Important" does not mean "include a mini-essay within the article". —Pengo 22:29, 8 June 2008 (UTC)

Poor analogy Pengo because "Star" is an object and evolution is a process. You could compare "Evolution" with "How Stars Form". In explaining how gene alleles shift with time and a trait and allele dominate a population (Evolution) one has to discuss the processes of genetic drift and natural selection. Seems we would be remiss not to explain these fundamental processes explaining how traits and gene alleles change with time. The size of the population is a critical factor in how gene alleles shift with time. Regards, GetAgrippa (talk) 13:18, 9 June 2008 (UTC)

Heredity

The section on heredity is pure definition cruft. The words "evolution", "evolve" or even "selection" are not mentioned in all 3 paragraphs. The term "heredity" isn't even used elsewhere in the article, and "inheritance" isn't mentioned again until the section on the "History of evolutionary thought". Even the concept of a "trait" that it goes to pains to explain isn't brought back until the reader's seen 6 more headings. Please explain to the reader of the article (not to me) why he or she is subjected to a screen full of definition on heredity when they want to read about evolution -- preferably in the opening sentence of the "heredity" section.

And if you'd like a way to improve this article further, do the same after each and every heading in the article. —Pengo 23:09, 8 June 2008 (UTC)

The link was made in the introduction, I've also added this to the first sentence of this section. Tim Vickers (talk) 23:13, 8 June 2008 (UTC)

One thing I did notice from Pengo's posits is that the Heredity section needs to emphasize that the mutation has to be in the germ line and not somatic mutations in sexual reproducing organisms (perhaps mention asexual organisms appear to use gene or genome duplication then mutation). We wouldn't want to give the impression that somatic mutations an organisms gains in life are passed on in sex rep. organisms-only mutations in the germ line are significant. It does say "Heritable traits are propagated between generations via DNA" but I don't know that a layperson would associate that to meaning germ line in sexual reproducing organisms. Just a thought! GetAgrippa (talk) 14:58, 9 June 2008 (UTC)