Talk:Natural selection

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Nominate for FA?

Guys, seeing how little the article has changed in recent weeks, and noting that it is well referenced and well illustrated, and also noting that my recent experience of peer review shows it to be much less active, and therefore much less useful, than FAC, can I ask you all whether you consider that FA status is desirable for this article, and would therefore like to apply for it? (FA has ups and downs - it will bring more people wanting to "improve" the article, but it also carries prestige...)

Many thanks,

Samsara (talk • contribs) 14:48, 16 August 2006 (UTC)

Personally I think that this article is clear and interesting, looking at it now with fairly fresh eyes some time after my last edit; there could usefully be some more illustrations perhaps, certainly a lead figure at the beginning? Maybe the lead picture should show the results of artificial selection that inspired Darwin - think it was the diversity of pigeons if I remember well, which I probably don't, paralleled with finch diversity? Gleng 20:54, 16 August 2006 (UTC)

I seem to remember seeing plates of finch beaks in biology textbooks. Maybe a free example exists or could be created. Unfortunately, drawing is not one of my strengths. I don't recall ever seeing an illustration of domestic pigeon diversification. We could try to polish the antibiotic illustration into something more tangible - many bacteria do have a distinct, recognisable shape. - Samsara (talk • contribs) 21:45, 17 August 2006 (UTC)

On page 18 of The Beak of the Finch are four finches drawn by Darwin from his journals. I don't know if these qualify as PD by now via this route, but I'm with Glen, Finches and Pigeons are the ideal candidates for illustrating this article. Pete.Hurd 22:33, 17 August 2006 (UTC)

If they're his original figures, then yes, c.f. Image:Darwins first tree.jpg. Seeing that you seem to have a copy of the book, could you scan and upload the figure? - Samsara (talk • contribs) 14:21, 18 August 2006 (UTC)

Is it this image? --Fastfission 17:05, 18 August 2006 (UTC)

Aye, that's the one Pete.Hurd 20:09, 18 August 2006 (UTC)

Now all it needs is a compelling caption. - Samsara (talk • contribs) 13:50, 19 August 2006 (UTC)

I was thinking it would be nice to have some text dealing with character displacement, sympatric and allopatric species and beak shape etc. It would make the figure all the more worthwhile, and would probably work best as another example section. What do you think? Pete.Hurd 14:39, 19 August 2006 (UTC)

Sounds good. Would also like to see adaptive radiation mentioned. I was intrigued by the fact that there are 13 main islands in the Galapagos archipelago, and 13 species of finch. I don't know the literature on these finches at all, so I'll leave it at that lest I embarrass myself. - Samsara (talk • contribs) 14:54, 19 August 2006 (UTC)

Actually, no, the speciation is much more complex, and each island has different species, and the interactions between the species is crucial to explain the variation in beak size. -- Kim van der Linde ^{at venus} 15:10, 14 September 2006 (UTC)

My thoughts what need to be done before considering FA:

1. references, more references and even more references. Most of it comes straight out of my mind, but there are references for it.
2. Lead section. To short, slightly incorrect. Individuals -> unit of selection, requires a mind warp to get that right as it becomes mind-numbing complex but needs to be accessable for lay people (that is why I skirted it when I rewrote it). Needs to include more of the main points of the main text.
3. Definition section needs to be rewritten.
4. Aspects like character displacement and adaptive radiation are nice additions to the evolution by means of Natrual selection section. If you want to do NatSel with that, it should be about how changes in the seed size between years affects the fitness of individuals and results in a changed beaksize in the next generation. You can make really perty graphs with that.

maybe I come up with some more things, but this is it for now. -- Kim van der Linde ^{at venus} 15:10, 14 September 2006 (UTC)

embryology

would sympathtic editors consider a positive vote here? [1]Slrubenstein | Talk 15:34, 23 August 2006 (UTC)

definition of natural selection and bacteria example

I apologize for the improper posting, I'm new to this. This whole section of a definition is lacking. I know of no definition that a majority of scientist would agree upon. Natural selection is measured as an outcome of reproductive success of genetic traits or genomic elements. Natural selection is a black box that should be filled with ecological contributions, population biology, neuroethology-animal behavior, proteogenomic interactions, and random chance. It may be better to state that is a measured outcome and the variables that produce it are complex and entail the aforementioned. GetAgrippa 12:48, 30 August 2006 (UTC) AFter closer scrutiny I think this is addressed.GetAgrippa 01:31, 31 August 2006 (UTC)

The bacteria example is too simplestic. Antibiotic resistance can occur by altering phenotypic expression in genetically identical strains, and by inhibition of growth-non-inheritable change so not evolution per se. Horizontal transfer also appears to be a source of antibiotic resistance from the huge reservoir of antibiotic resistance in soil bacteria, so it is not a mutation but gene gain. Science. 2006 Apr 28;312(5773):529.Science. 2006 Apr 28;312(5773):529. Science. 2006 Jan 20;311(5759):342-3. Science 15 April 1994 264: 375-382 [DOI: 10.1126/science.8153624] (in Articles) Science 10 September 2004 305: 1578-1579 [DOI: 10.1126/science.1103077] (in Perspectives GetAgrippa 13:25, 30 August 2006 (UTC)

Natural selection can occur with any mechanism that introduces new variation, or simply on pre-existing variation. In the example is it HGT or other mutations — presumably both? But I don't think it really matters so much from the point of view of giving a simple example of natural selection accessible to the layman. Maybe a slight tweak needed? — Axel147 19:09, 30 August 2006 (UTC)

After reading the reference to phenotypic natural selection ,then I guess the bacteria example holds even if it is just penotypic expression of a subpopulation or inhibition of growth could explain it without a mutation. . HGT is inheritable but an example of gene gain or gene network alteration. I have to admit phenotypic evolution personally bothers me from a developmental biology viewpoint and the fact that inheritable genomic change has historically been a mainstay of evolution theory, but that's personal so Get A grippa!! Hee, Hee. It maybe worthwhile to add that bacteria can acquire antibiotic tolerance by HGT from the soil genomic reservoir and that mutations are not the only mechanism. You could also link phenotypic modulation and non-heritable evolution. That maybe too confusing, but it demonstrates the many pathways of evolution. Axel maybe you could recommend a slight tweak that would be meaningful and cohesive witht the rest? I agree with simple examples, but they should also be complete and true to what is known (maybe a HGT reference?), but I can see how it could create confusion if taken too far. GetAgrippa 11:41, 31 August 2006 (UTC)

In order to make my stance more clear I provide these abstracts for quick review: Five point mutations in a particular ß-lactamase allele jointly increase bacterial resistance to a clinically important antibiotic by a factor of 100,000. In principle, evolution to this high-resistance ß-lactamase might follow any of the 120 mutational trajectories linking these alleles. However, we demonstrate that 102 trajectories are inaccessible to Darwinian selection and that many of the remaining trajectories have negligible probabilities of realization, because four of these five mutations fail to increase drug resistance in some combinations. Pervasive biophysical pleiotropy within the ß-lactamase seems to be responsible, and because such pleiotropy appears to be a general property of missense mutations, we conclude that much protein evolution will be similarly constrained. This implies that the protein tape of life may be largely reproducible and even predictable. Science, Vol. 312, Issue 5770, 111-114. 2006.

The emergence of multidrug-resistant bacteria is a phenomenon of concern to the clinician and the pharmaceutical industry, as it is the major cause of failure in the treatment of infectious diseases. The most common mechanism of resistance in pathogenic bacteria to antibiotics of the aminoglycoside, beta-lactam (penicillins and cephalosporins), and chloramphenicol types involves the enzymic inactivation of the antibiotic by hydrolysis or by formation of inactive derivatives. Such resistance determinants most probably were acquired by pathogenic bacteria from a pool of resistance genes in other microbial genera, including antibiotic-producing organisms. The resistance gene sequences were subsequently integrated by site-specific recombination into several classes of naturally occurring gene expression cassettes (typically "integrons") and disseminated within the microbial population by a variety of gene transfer mechanisms. Although bacterial conjugation once was believed to be restricted in host range, it now appears that this mechanism of transfer permits genetic exchange between many different bacterial genera in nature. Science, Vol 264, Issue 5157, 375-382.1994.

When research labs began churning out the genome sequences of a multitude of microbes in the late 1990s, microbiologists got a big surprise: Many organisms seem to be swapping genes with abandon from strain to strain, even across species. Astonishingly, for example, about 25% of the genome of the gut bacterium Escherichia coli turns out to have been acquired from other species. The realization that gene swapping, or horizontal gene transfer as it is called, is a common phenomenon has thrown the field into a tizzy. The implications, says microbiologist Matthew Kane of the National Science Foundation in Arlington, Virginia, "are very, very broad." Borrowed genes can spread antibiotic resistance from one pathogen to another or help an organism survive new or stressful conditions. And it happens often enough to alter the dynamics of microbial communities and even affect the course of evolution……Science, Vol 305, Issue 5682, 334-335.2004.

Microbial resistance to antibiotics currently spans all known classes of natural and synthetic compounds. It has not only hindered our treatment of infections but also dramatically reshaped drug discovery, yet its origins have not been systematically studied. Soil-dwelling bacteria produce and encounter a myriad of antibiotics, evolving corresponding sensing and evading strategies. They are a reservoir of resistance determinants that can be mobilized into the microbial community. Study of this reservoir could provide an early warning system for future clinically relevant antibiotic resistance mechanisms. Science, Vol. 311. Issue 5759 374-377. 2006

It would seem that HGT should be mentioned as a significant factor or the major factor in antibiotic resistance.GetAgrippa 12:27, 31 August 2006 (UTC)

I think you are right that HGT deserves a mention. But I'm not sure about the spin! Evolution by natural selection is the idea that successful organisms will transmit (some of) their characteristics to other organisms more often than unsuccessful rivals. This is true whether this happens 'horizontally' or 'vertically'. But admittedly if genes can jump freely from one organism to another this might undermine the individual bacterium as the unit of selection in this case. We would have to replace 'differential reproduction' with 'differential transmission'. Or, more sensibly, view this as an example of natural selection of (ultra) selfish genes.

Maybe HGT should be mentioned briefly (so as not to detract from the main point of the example) or the example should be changed? I wonder if anyone else has a view on this, before proposing anything. — Axel147 18:14, 31 August 2006 (UTC)

Thank you Axel for your perspective. The more I read it seems HGT is the prevaling thought, however I agree it would undermine the example to a degree. It should be just a simple straightforward example. The example is accurate and occurs, but the interest in HGT is growing and appears to be significant. I'm like you, it would be nice for some others to chime in. Perhaps I should follow the motto "Keep it simple stupid" and just forget it, or mention HGT further down in a separate area and specifically mention bacteria and HGT antibiotic resistance as new concern?GetAgrippa 19:34, 31 August 2006 (UTC)

I went ahead and added my thoughts on HGT in antibiotic resistance. I stated that mutations ocurr in nature and the significance ,and then went on to mention HGT as a growing reality in nature.GetAgrippa 08:41, 3 September 2006 (UTC)

Phenotypic natural selection

Phenotypic plasiticity is heritable in birds and insects as I recollect from more recent studies. I'll find references.GetAgrippa 19:50, 3 September 2006 (UTC)

Some are phenotypes are heritable and some are not, so "forget about it". GetAgrippa 18:45, 4 September 2006 (UTC)

Grin, selection on phentotypic plasticity can even be phenotypically plastic, just to make it even more complex. In the end, phenotypic plasticity is just a version of an GxE interaction. A good article dealing with this is: Schlichting, C. D. and H. Smith (2002). "Phenotypic plasticity: linking molecular mechanisms with evolutionary outcomes." Evolutionary Ecology 16(3): 189-211. -- Kim van der Linde ^{at venus} 14:57, 14 September 2006 (UTC)

Is the example too technical?

I feel the example has now become too technical and is likely to put off non-biologists. (HGT etc. are subtleties not really key to natural selection). Does anyone else agree? — Axel147 17:51, 11 September 2006 (UTC)

Maybe there is a better example? Antibiotic resistance can be from mutations, phenotypic plasticity exists in genetically identical strains that acquire antibiotic resistance, a hindrance of cell division until the antibiotic environment stops is another mechanism, and HGT a growing and perhaps the major mechanism of antiobiotic resistance so I disagree it is a subtlety. There is not a bacterial genome to date not riddled with HGT sequence events. It is still natural selection- the reproductive success of insertion elements. Why not something like peppered moths, Darwin's finches has numerous examples of natural selection, Ectodysplasin Alleles in stickleback fish, insecticide resistance in drosophila populations, or maybe a yeast example. GetAgrippa 18:58, 11 September 2006 (UTC)

I didn't mean to play down HGT. I just didn't want to scare off the layperson. Maybe it should be mentioned additionally elsewhere in the article? But I don't think the organismic trait 'ability to receive insertion elements' is generally favourable for reproductive success. Insertion elements are preserved, I think, not just because of the reproductive advantage they confer on organisms in which they are housed; they are preserved (partly at least) because of their ability to jump. In other words this is no longer a clear cut example of natural selection acting at the level of the individual phenotype (of the organism). And as such not a clear example of natural selection as described in the opening paragraph? — Axel147 19:55, 11 September 2006 (UTC)

Aye, finches would be my pick. I wish I had time, but I don't. Best Regards, Pete.Hurd 19:30, 11 September 2006 (UTC)

My updates

I have updated my stored version to improve the introduction (see User:KimvdLinde/Natural selection. Feel free to use what you want. I do not care anymore about this article due to the continued fighting about definitions, but I did not want that my rewrite legacy at my own page was substandard. I will probably improve the defintion section of my own version as well by adding some operational definitions as used by specific disciplines (for example the 'differential reproduction of genotypes' definition as used by population genetisists). The current article is not featured article quality, it has a way to short lead section, the definition section is substandard, the additions to the antibiotic section are overkill, and there is a gross lack of appropriate references. The additions to the antibiotics example are true, but are better suited in the article about antibiotic resistance as the purpose of that section is solely to illustrate Natural selection to a general lay public, not to repeat how antibiotic resistance under all conditions arrises. If it ever reaches featured status, please update my list of articles on my user page to reflect that. -- Kim van der Linde ^{at venus} 03:22, 14 September 2006 (UTC)

I agree with your comments on my anal penchant for accuracy concerning the bacteria example. It is a occupational necessity. For that reason I have decided to only edit and write concerns in discusion and never write or directly modify an article. I forget it needs to be a simple encyclopedia. The old adage "Keep it simple stupid" needs to be my personal mantra. I believe like AdamRetchless that expertise is a hindrance to writing a simple, balanced, and informative article. You seemed to be angered over the situation. I hope I have not contributed to that.GetAgrippa 11:59, 14 September 2006 (UTC)

I think most have missed my point in the addition. I was trying to indicate how in the prokaryote world and in plants to some degree that HGT is probably more a source of evolutionary change than mutations. I think mutations are often emphasized too much and fails to recognize the growing contributions from other sources that comparative genomics is demonstrating in all life. GetAgrippa 12:06, 14 September 2006 (UTC)

Ho, stop, take it easy. You do not have to appologize. This is how article development goes, and it was just my thoughts that I expressed (a bit to harsh, my applogies). My frustration is with wikipedia as a whole, the anti-expert atmosphere, the POV-pushers, and the increadable amount of time that you sometimes have to spend to get something fixed. The page was a declared disaster in the past and it was only resolved by me rewriting the page together with Gleng in my userspace. Since then, it has been relative stable. I have always been someone who tries to write for lay people. It is a challenge, but one that I think academics can benifit greatly from if they can master that. I always step back, and ask myself if my mother would understand this (if she could read English). She is not stupid, but uneducated, and it is at times for me a challange to explain her things that I do for work. If anyting at all, before you can write something complex in a simple way, you have to know every detail of your system, and most people do not.

As for leaving, unless there are some good changes in that it becomes much easier to correct POV-pushing and things alike, and in which pages can be concerved and only changed by experts who know where they are talking about, I might come back. But the atmophere here at WP is way to anti-expert, and even when you have written something, it just gets slowly demolished by passer-by's who think they know more than an expert on the details of complex concepts like natural selection. -- Kim van der Linde ^{at venus} 13:56, 14 September 2006 (UTC)

I agree with the anti-expert comment to a degree. It reminds me of teaching an introductory biology course (which I haven't done in years as I have been primarily research). You often present information that you know is not exactly correct or upto date. Such is the nature of the beast as most text are out of date in some areas. I like your comment of would your mother get it. In that regard, would an adolescent get it also. Maybe every article should be divided by age or maturity, so one section would be simple enough for children and another complicated enough for a college student. GetAgrippa 14:39, 14 September 2006 (UTC)

What I always try, and I think this is general practise, is to start with a lead that is general, and if possible, understandable by a large number of people. That has resulted in the current, slightly incorrect lead. The lead rewrite of my preserved version is a first atempt to fix that. It is not yet perfect, but the thinking process is going again. After that, you build up in complexity. Many people do not realise how complex the concept of NatSel actually is, and that is why I (better Gleng and I) have choosen to use an example (which allows you to leave out many of the mind-numbing details) instead of trying to explain the whole concept conceptually correct to a general public. If you look aroudn at the internet, and even in text books, this is how it is done often, precisely because of the complexity of the concept. After having satisfied the general public, the article can run free in complexity. -- Kim van der Linde ^{at venus} 14:53, 14 September 2006 (UTC)

Good advice!!!! GetAgrippa 15:01, 14 September 2006 (UTC)

I think KimLinde is slightly disingenuous in saying she doesn't care about the article due to fighting over definitions. I think she is pushing a slight POV on this and is happy as long as the article is her way. Why (if she knows her stuff) does she say 'Phenotypic selection is a term I never heard yet beyond Endler' and then a few weeks later provide a crucial extract from Lande with the sentence 'Animal and plant breeders routinely distinguish phenotypic selection from evolutionary response to selection (Mayo 1980, Falconer 1981).'?

Sober (who I previously granted as a backer of the phenotypic view) now seems happy with the conventional definition. Sober and Wilson, Unto Others 1998: 'The process of natural selection requires three basic ingredients: (a) phenotypic variation among units, (b) heritability, and (c) differences in survival and reproduction that correlate with phenotypic differences.' — Axel147 15:54, 14 September 2006 (UTC)

Whatever. You had the chance for many weeks to rewrite the horrible article that it was at that time (I even invited you explicitly), but you never did. Finally I did it and it seem to stand solidly until now. Feel free to change it to fit your definition, that is the nature of wikpedia. I have my own conserved version for people who ask me about NatSel. -- Kim van der Linde ^{at venus} 16:08, 14 September 2006 (UTC)

I am not familiar with your discussion. I tried to make a point with the bacterial example, but decided to drop it and removed it. Don't even get me started on the Natural Selection or Evoluton articles. I have decided to avoid these articles, because most comments go on deaf ears despite providing literature to support a point. It would be interesting to have Ernst or Gould if they were alive, or Dawkins to comment on the articles. I doubt there critiques would be welcomed either. However, their arguments shouldn't be welcomed because of their strong POV. It is better to let the article evolve and would probably best be written by someone who has never even heard of either topic. GetAgrippa 16:11, 14 September 2006 (UTC)

It was a very long discussion, see the archives. It has worn me out, and it is part of the reason for me to leave wikipedia. I do not need to get sneers like if she knows her stuff. And to answer that question of Axel: I shared an office with Lande in the past and discussed a lot of these thinsg with him (and other for that matter); Futuyama does not use that term; and I only digged up the exact quote when I really needed it. -- Kim van der Linde ^{at venus} 16:24, 14 September 2006 (UTC)

Omission

There is no mention of what the selection pressures are. I thought it is the fact that organisms tend to expand in size, putting a selection pressure due to an unchanged amount of food.—The preceding unsigned comment was added by 86.20.185.217 (talk • contribs) 18:41, 4 October 2006 (UTC)

Picture

The picture of the peacock contradicts the peacock article which states in the gallery "The White Peacock is frequently mistaken for an albino, but it is a colour variety of Indian Blue Peacock"

The file name has it as an albino. - Samsara (talk • contribs) 21:43, 10 October 2006 (UTC)

Just a theory

It does not state anywhere in the article that this is just a theory and that it has never been proven. That is why I put the weasel word tempelate on it. Everything in the article speaks as if all this is fact and proven when it really has not been proven yet. 69.22.216.252 02:30, 5 November 2006 (UTC)

It isn't just a theory, whatever you mean by that. The scientific evidence for the scientific facts of natural selection are well presented in the article. It would appear that you have a mis-understanding of science - or are simply trying to push some religeous POV? Weasel tag goes as it's placement amounts to little more than vandalism. Vsmith 02:44, 5 November 2006 (UTC)

Actually there are a huge number of studies demonstrating natural selection, so natural selection is a fact. You could argue is it significant in evolution. There are a large number of studies correlating natural selection with evolution, however there are studies indicating other factors can come into play and/or evolution can be unpredictable.GetAgrippa 19:41, 10 November 2006 (UTC)

With all due respect, Vsmith and GA, you are allowing a nobody to waste our time. The article itself explains these things. I would say that any registered Wikipedia editor should have no qualms simply reverting nonsense edits from anonymous users who clearly have neither read nor understood the article itself. Let's save this talk page for talk among people who are serious and deserve to be taken seriously. For me, actually having read the article is an obvious minimum standard. Slrubenstein | Talk 13:42, 12 November 2006 (UTC)

rv - line "Who is charles Darwin?"

( Who is charles Darwin?) Appeared after a heading resulting in the heading not displaying correctly. The line seems meaningless so I removed it Paul Hjul 10:00, 5 December 2006 (UTC)

Lead Section

I think that the lead section is pretty good but needs to be simplified a bit.

---

Natural selection is the process by which individual organisms with favorable traits are more likely to survive and reproduce than those with unfavorable traits.

• not bad

In so far as there is genetic variability for the trait under selection, the genotypes associated with the favored traits will increase in frequency in the next generation.

• In so far???? genotype???? This sentence is too long.

Given enough time, this passive process results in adaptations and speciation (see evolution).

• not defined. One has to look these big words up which is not good for an introductory paragraph.

Natural selection is one of the cornerstones of modern biology. The term was introduced by Charles Darwin in his 1859 book The Origin of Species, by analogy with artificial selection, by which a farmer selects his breeding stock.

• pretty good, except I am not sure about the last phrase. I would reword "by which a farmer selects his breeding stock". Sounds too technical. I would make it simpler.--Filll 14:55, 13 December 2006 (UTC)

Yes, a sentence beginning 'in so far' seems to me to be at least as awkward as the one it replaced. And is it correct? Doesn't a genotype refer to the genetic makeup of the whole individual, not the units that might get passed on? And isn't this a probabilistic process, with no guarantee that favourable genes will increase? (And doesn't this presuppose somthing about mapping between genes and phenotypic trait: in cases of pleiotropy genes associated with favoured traits may NOT have a tendency to increase in frequency in the next generation — if they are also correlated with other unfavourable traits.) — Axel147 15:49, 13 December 2006 (UTC)

You are welcome to improve the wording. However, remember this is an introduction. There is no need to get bogged down in exceptions and nuances. At some level of simplification, the statements should be true (which they are). There is no way that you can write a few simple sentences that incorporate epistasis, cytoplasmic inheritance, genetic maternal effect, imprinting, balancing selection, drift, etc. Those topics can be discussed in the remainder of the article. Genetics411 16:44, 13 December 2006 (UTC)

Another nuance if you like is that you've removed the word heritable. Heritability is key. One problem is that it is possible for traits to have a genetic basis without being heritable. Another is that some authors prefer not to limit the concept of heritability to genetic mechanisms. So I'm not suggesting anything complex — just reverting to the original sentence I think (which I didn't write myself). But I'm interested to see what other people think... — Axel147 02:28, 14 December 2006 (UTC)

I understand that Wikipedia has different conventions than normal, so I may be way off. An introduction should serve three basic purposes:

1. It should serve as a summary of the field for people who will only read the introduction. It should give them an accurate "flavor" for the field, but not get bogged down in details or exceptions. It should be something that any intelligent reader of whatever (scientific) background can understand and come away feeling they know a little bit.
2. It should serve as a teaser for the main body of the article, to entice the reader to read more.
3. It should be true to the field so that experts don't automatically reject the entire thing. On the other hand, it should also be uncontroversial -- there is time for that later. This should also include a hint of criticism, if there is significant amounts.

Now, what is it that you want people to come away with if the introduction is the only thing they will read? Really, the original version was pretty bad. If nothing else, it uses heritable in two different ways in the same sentence, one of which is absolutely incorrect. Is the difference between genetic and heritable essential for an elementary understanding of natural selection? Is that how we want to spend valuable introduction space, particularly if it has to be spelled out for the non-expert? I am probably way off base for Wikipedia. My apologies. Genetics411 03:15, 14 December 2006 (UTC)

The criteria above are fine, I'm not disputing those. But the original sentence has received good consensus if you look through the history of this talk so I was wondering if it could be tweaked if you're not happy with it? How about 'It works on the whole individual, but only heritable traits will be passed on to the offspring, with the result that favorable heritable traits tend to become more common in the next generation' ? Anyway that would be my vote. — Axel147 04:34, 14 December 2006 (UTC)

Can we just introduce the first paragraph with the following sentence: "Natural selection is the process in which heritable characters which affect survival and reproductive success will be differentially propagated within a population of reproducing individuals" ? We could leave much of the present paragraph as an explanation of this succint definition. In modern treatises, natural selection is very much understood as the process of differential transmission of characters, rather than as the processes which affect the survival or reproductive success of individuals (and thereby cause differential character transmission). At the extreme, Dawkins define natural selection as "the process through which genes out-replicate each other", but we need not go there in an introduction.

I personally think the path of wisdom is to leave the first paragraph alone and improve the rest of the article, particularly with references. Samsara (talk • contribs) 13:07, 18 December 2006 (UTC)

Yeah, but you weren't arguing this before Genetics411 change. What makes 'heritable' jargon and 'genetic variability' not jargon? — Axel147 19:05, 18 December 2006 (UTC)

Evolution without natural selection

I began to write a section about the effects of natural selection not taking place, but I realized some of the examples I intended to use were natural selection. Here I'm talking about situations where natural selection has little impact on a trait due to it being of neutral fitness contribution. One example I planned to use was the eyes of moles - how they have diminished due to lack of use. Really it's more a case here of natural selection favoring the removal of the eye as 1) It can be infected by all the dirt and debris in the mole's environment, and to a lesser extent 2) Construction and maintenance of the organ uses up precious energy (here a much weaker force than that of infection, no doubt). However, even without these forces of natural selection favoring the absence of the eye, there is still the force of entropy which simply tends to favor randomness - general loss of orderly arrangement. Even without natural selection there is a tendency to break down progress made in a certain direction, so for example mutations of the eye that were not injurious in other ways would make no difference to the survival rate and hence the careful order of the eye would tend to break down over time without any selective forces acting on it.

(Another force I've neglected to mention is sexual selection, which would act as a backup against the forces of entropy because animals seldom choose partners with strange mutations, even if they aren't deleterious to the species).

I'll try to compose a better section when I have some time, hopefully with some more examples. Comments on the topic are most welcome. Richard001 09:39, 2 January 2007 (UTC)

Agree in principle, but please don't equate entropy with randomness: as the linked article states, "Spontaneous changes tend to smooth out differences in temperature, pressure, density, and chemical potential that may exist in a system, and entropy is thus a measure of how far this smoothing-out process has progressed." The "orderly arrangement" is part of a nineteenth century analogy attempting to visualise the motion of energetic molecules as "disorder", and is completely superseded by quantum mechanics. .. dave souza, talk 11:00, 2 January 2007 (UTC)

Be careful of introducing material the "seems" correct, but isn't. It turns out that in lab colonies of Drosophila, at least, there is mate selection favoring the oddballs. I have not looked for other examples of this phenomenon, so cannot say how common it is. Genetics411 15:10, 3 January 2007 (UTC)

I don't really agree in principle. By defintion this is not natural selection but evolution by another mechanism. I think it is better to cover this in the evolution page rather than here. — Axel147 13:21, 8 January 2007 (UTC)

Removed from the article

However, Stephen Wolfram claims to have shown simple rules of cellular automata create complex forms, which organisms evolve outwardly, filling all the possible forms available to them by the initial rule set. Natural selection then becomes both unnecessary and impossible for paring down evolution to robust forms. "Complexity is destiny—and Darwin becomes a footnote. "I've come to believe," says Wolfram, "that natural selection is not all that important." By showing this trend towards complexity in natural systems, Wolfram believes he has not only shown the limits of selection, but also that complexity and order both can both appear in natural systems as a simple matter of reproduction with no other influences.

I've removed the preceding passage from the article because of undue weight; it is represents a tiny minority view. Wolfram's ANKOS (A New Kind Of Science) has not been well received in the scientific community at all: [http://www.math.usf.edu/~eclark/ANKOS_reviews.html A Collection of Reviews of ANKOS and Links to Related Work]. FeloniousMonk 17:04, 14 January 2007 (UTC)