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Ok, this is getting interesting. Basically, when a species goes extinct because it is maladapted, it is not Natural Selection that is causing it, but other processes. That is just to weird... What are those processes and how are they different from NatSel. -- Kim van der Linde at venus 04:27, 9 July 2006 (UTC)
If we have a few children left in a sexually reproducing population and they are all eaten by a predator before reproductive age I fail to see how this could be drift. Since the predator didn´t select any particular children to eat, it just ate them all, it is arguably not selection either. — Axel147 14:00, 9 July 2006 (UTC)
Basic problems: 1) whatever natural selection is, we'll all agree that there is no intelligent designer behind it. So how does natural selection "know" whether there are only a few individiuals or just one individual or many? 2) how do we know the predator didn't select children to eat? Who should we ask? Gleng 21:26, 9 July 2006 (UTC)
How do you know there are no fitness differences except by who survives? Gleng 20:23, 10 July 2006 (UTC)
I think you're trapped in endless paradoxes. If you want to keep natural selection as meaning the theory of evolution by natural selection, OK, this may be common useage. But if so, don't try to use this also as a rigorous definition that you can use coherently in a logical argument. Gleng 09:54, 11 July 2006 (UTC)
Suppose we have two individuals in a population. Let´s call them Adam and Eve (just to play devil´s, or god´s, advocate). The point I am making is whether they go extinct or have children has nothing to do with natural selection. But is what happens next caused by divine intervention? No, of course it isn´t, I haven´t suddenly turned creationist — it is just evolution by a different mechanism!
If Adam and Eve´s reproductive success are tied together they must both have equal fitness. (And this is true even if Eve is susceptible to disease and Adam is not.) So Adam and Eve and all their traits have equal chance of reproducing. Natural selection cannot occur because it has no material to act on. There is no variation. It is only when they have children that fitness differences arise.
Clearly what happens does depend on the liklihood of Adam and Eve surviving the prevailing conditions and that is influenced by their characteristics. But we are not forced to label all natural processes that impinge upon reproductive success as 'natural selection'.
Natural selection requires variation in fitness before it can occur at all (and it requires heritable variation in fitness for it to produce evolutionary response).
(I realise we could puncture this argument by trying to 'force' fitness differences. We could argue Adam is fitter because he might reproduce with his daughter. Or we could talk about cheating during meiosis. But this is not the point. The point is that we are not obliged to name all process that influence reproductive success as 'natural selection'. Natural selection is the set of processes that bias reproductive success according to phenotypic differences.) — Axel147 14:43, 11 July 2006 (UTC)
"Natural selection requires variation in fitness before it can occur at all" I think we've probably played this out, and it has been fun :) As a last riposte I'd just say that natural selection requires that some survive and some do not, and fitness simply is an estimate of who is likely to survive. If we had enough knowledge, our estimate would be certain knowledge of who would survive and who would not; as our knowledge is imperfect we can only make a guess, and the value we give to fitness depends on how much knowledge we have. For Adam and Eve, their fitness is 1 or 0. Now while we know that there are only Adam and Eve, they don't know that - and for all we know there might have been a million others who somehow failed to find the apple. Now my only point is that you cannot sensibly describe what happens to them as natural selection or not depending on whether there are many others or no others. What happens and why it happens to them is the same, unless you think that the mere existence of other people somewhere in the garden alters the nature of the influences on A and E.
So I'd say that natural selection is simply to be understood as the absence of artificial selection - it is the assertion of the absence of a God, a designer, a directing intelligence. It is whatever happens that means that some die and some don't. And that this, this absence of direction, this absence of intelligence, when there is variation and heritability, is enough to result in adaptive evolution, is the radical idea
Gleng
15:57, 11 July 2006 (UTC)
The problem we are faced with (Kim´s orginal concern I think) is that if a lion happens to eat one of a species it probably doesn't know or care whether it is the last one. From its perspective the process is the same whether or not it causes extinction. The only answer I have to this is that from nature´s perspective there is no choice to make between individuals of the same species if we are down to just one. (One way round this problem is by dropping the word 'process' out of the definition as many authors do e.g. Futyama. But I not suggesting we do this.)
I agree that in a sense nature is still 'selecting' whether an individual survives or not, but I don´t think this is what we mean by 'natural selection'. The distinction is important to separate (conceptually at least) processes that may change gene frequencies in a predictable direction, from those which alter gene frequencies at random. Here is a published view on this. Once again Sober p159:
— Axel147 17:42, 12 July 2006 (UTC)
For completeness I suppose I should add that if one considers 'differential speciation' to be a form of higher level natural selection e.g. Gould, extinction could count as a form of natural selection after all! (If we have more than one species.) — Axel147 13:19, 22 July 2006 (UTC)
According to Wiki 'In biology, a trait or character is a genetically inherited feature of an organism.' If this is true why does the article say 'but only the heritable component of a trait will be passed on to the offspring'. Which is correct? Is a trait by definition heritable? — Axel147 20:20, 16 July 2006 (UTC)
We are using trait in the original, normal language definition, as a distinguishing characteristic of an individual rather than the more recent more specialised sense. Science has a way of hi-jacking common words; I've no idea what we should do - maybe a footnote? Gleng 20:42, 16 July 2006 (UTC)
In the fitness entry we still have the other use! 'If differences in individual genotypes affect fitness, then the frequencies of the genotypes will change over generations; the genotypes with higher fitness become more common. This process is called natural selection.'
Similarly, ecological selection (commonly natural selection excluding sexual selection)....
These articles seem stable but inconsistent. I am no longer fresh to this so don't know if it's important to do anything about it! — Axel147 17:08, 10 August 2006 (UTC)
There is a critically important distinction between artificial selection and natural selection, which I think is fundamental and essential not to blur. In Darwin's sense artificial selection involved design, directed intent. Natural selection does not. Gleng 19:22, 12 August 2006 (UTC)
It's not ideal. It was and is obvious that artificial selection can change the form of species, but this process involves intent to produce that particular change, it is a deliberate exploitation of variation and inheritance by an intelligent designer. Darwin's insight was that no intent is necessary. I agree with you, that in the broad scheme of things then artificial selection is just part of our extended phenotype, but appreciating this requires both subtlety and rewriting Darwin even more extensively. I thnk it's important not to blur Darwin's insight that no designer is needed, so the distinction between artificial selection and natural selection is a useful one. Take away this and you don't need the word "natural" . Gleng 07:57, 14 August 2006 (UTC)
I hadn't seen that, and I agree with you; I think it is just silly not to see humans as part of the natural world. Gleng 14:08, 15 August 2006 (UTC)
The last time that I read this article, some idiot had written something about the new Kim Possible season. If the vandal is reading this, please note that we don't care about Kim Possible and that this page is about NATURAL SELECTION, just in case you haven't noticed that already. -- 71.140.114.12 19:45, 11 February 2007 (UTC)
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)
My thoughts what need to be done before considering FA:
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)
would sympathtic editors consider a positive vote here? [3] Slrubenstein | Talk 15:34, 23 August 2006 (UTC)
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)
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 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)
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 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)
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)
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)
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)
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)
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"
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)
Natural selection is a theoretical deduction of perceived evolutionary changes in species.
We must, however, remember that correlation does not imply causation. Moreover, the correlation evident between species does not specifically imply causation. And until natural selection, and more importantly, macroevolution can be proven in the laboratory, they will both remain theoretical.
Science is the pursuit of causes, both natural and unnatural [intelligent]. To completely disregard the possibility of intelligent causes is negligent. This article should not present this concept as if it were completely 100 percent proven. I fear no change will be made by the evidently biased authors/administrators of this article that are bent on making this science appear as if it has been fully observed. Remember, due to certain lapses in knowledge, even the scientific process makes certain presuppositions that requires philosophy/faith. Futuremore, we're not just primordial slime, meaning cannot be fomented through evolution.
Nothingness to Ameba to Brain through time, which only leads to entropy. Come on, every worldview is exclusive and closeminded.
( 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)
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.
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.
Given enough time, this passive process results in adaptations and speciation (see evolution).
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, [1] by analogy with artificial selection, by which a farmer selects his breeding stock.
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 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)
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." [2] 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)
It was added again. I have removed it, again. The Times review on 20 May 2002 puts this book in its proper perspective, "Cranks are an occupational hazard that every scientist eventually faces. Fortunately, these characters are usually easy to spot. If someone claims to have a grand theory that overturns centuries of scientific knowledge—especially when the theory spans unrelated fields like physics and biology and economics—the odds are good that he or she is a crank. If the author publishes not in standard scientific journals but in a book for general readers, watch out. And if the book is issued by the author rather than a conventional publisher, the case is pretty much airtight." Since the peer review didn't occur before publication, we'll have to see how it fares after publication. Genetics411 01:36, 20 January 2007 (UTC)
"The evolutionary process of divergence, which ultimately leads to the generation of new species, is thought to occur usually without any gene exchange between the diverging populations. However, until the recent growth of multi-locus datasets, and the development of new population genetic methods, it has been very difficult to assess whether or not closely related species have, or have not, exchanged genes during their divergence. Several recent studies have found significant signals of gene flow during species formation, calling into question the conventional wisdom that gene flow is absent during speciation."Curr Opin Genet Dev. 2006 Dec;16(6):592-6. Epub 2006 Oct 19. Recent advances in assessing gene flow between diverging populations and species.Hey J. Further while I agree gene flow is homogenizing, it can be useful as gene loss is significant in many examples of speciation and HGT and Hybridization can rejuvenate a genome and generate novelty and speciation. The last year has been a boom for HGT and hybridization studies. I guess we need to address this for NPOV. GetAgrippa 20:46, 15 January 2007 (UTC)
Before you remove Wolfram again, be aware that there is a 3 revert rule in effect. Enough of the nonsense that Wolfram hasn't been peer reviewed for he has been and I've provided the link. Furthermore, though his views might not be popular with some biologists, his views are popular in other circles (bioinformatics for example). Also recall that the views of Darwin himself, have not been popular in the past. If you can show that Wolfram has been misquoted, or that his views of natural selection have been proven wrong, you may remove my contribution under Information theory.
Why are Wolfram's views noteworthy and worthy of inclusion here? Wolfram's criticisms of Natural Selection are noteworthy because few other scientists have been successful in critiquing the problems with the theories of Natural Selection but he has not only exposed errors in the field (such as the ones he showed about Stephen Jay Gould's work), but he has also presented a fairly detailed criticism of natural selection which has to date gone unanswered. It possible Wolfram's views go furthest in finding the weakness with natural selection, but his counter suggestion, shows that complexity and diversity arise by mechanisms other than natural selection and also make it possible to formulate abstract theories about evolution apart from natural selection! The only way this would not be worth noting in this article would be if Wolfram was wrong, or if there is more incentive to hold old ideas rather than adopt new.
He notes that traditional mathematical models have never even come close to capturing the kind of complexity found in biological systems, as a result biologists have treated evolution through natural selection as the foundation of this complexity. He notes that the theory of natural selection has implied complexity in biological systems, but has never actually showed exactly how natural selection requires it. This is a very significant criticism indeed, and if true more than noteworthy except by some who do not welcome debate. Searching the literature of the field - I think his criticism holds, and certainly no biologists has responded.
True. Wolfram's mathematical views of complexity have been criticized. Specifically his theory of the Equivalence of Computational Complexity have met with the most resistance and debate, but that does not undermine in any way his response to natural selection, and for this reason, I have restored his criticism. WikiRat1 17:23, 20 January 2007 (UTC)
The place you have put this is inappropriate for the material, even if it is true. You have completely swamped a section on information theory with criticism of natural selection in general. Genetics411 17:30, 20 January 2007 (UTC)
<reduce indent> He's hardly undermined the theory – he appears to have shown a possible source of variation for natural selection to act on. Try writing an article that covers his ideas on their own, citing relevant critiques. .. dave souza, talk 18:30, 20 January 2007 (UTC)
You're presenting a brief quote from a popular book taken out of context, and adding to this a great deal of your own opinion that this is a noteworthy criticism of the tenets of natural selection. This looks very much like original research. How does it bear on organisms being fitted to their environment? A mathematical explanation of complexity arising from simple sources overcomes a common objection to natural selection rather than overthrowing its tenets – if "complexity and order both can both appear in natural systems as a simple matter of reproduction with no other influences", that provides the variation for selection. However his mathematics also appear to need a great deal of work to become generally useful in the field – your statements imply that it's unused. What you call "his competing explanation of diversity through simple rules" could some day provide useful support and development of natural selection theory, but we need to see your assertion being made by reliable sources and not just your interpretation of his theory of everything. ... dave souza, talk 20:17, 20 January 2007 (UTC)
Has Wolfram published in biological journals more appropriate for the topic? Not much of a debate when you don't invite evolutionary biologist in peer review. Natural selection does not mean evolution. You have evolution by natural selection. Even if natural selection were proven completely in error (which it hasn't plenty of examples in nature) it does not disprove evolution and it would probably be replaced by a more comprehensive or refined mechanism that would deal with the complex multifaceted nature of biological systems. " Natural Selection is solely responsible for the survival of traits and genetic diversity - instead he argues that living things are capable of self organization." Self organization is already dealt with in the article. Natural selection is not solely responsible for the survival of traits or genetic diversity-facial patterns in humans is due to genetic drift and are completely neutral. GetAgrippa 00:20, 21 January 2007 (UTC)
dave souza, alright, this seems kind of desperate (for me to post a bunch of page numbers), but at your request here are some citations which you can check out yourself …
p.14 “Evolution Theory. The Darwinian theory of evolution by natural selection is often assumed to explain the complexity we see in biological systems – and in fact in recent years the theory has increasingly been applied outside of biology. But it has never been at all clear just why this theory should imply that complexity is generated. And indeed I will argue in this book that in many respects it tends to oppose complexity.…..”
p.383 – 432. Most of Chapter 8 starting with Fundamental Issues in Biology showing something other than Natural Selection as responsible for adaptations.
p.383 “… And in fact what I have come to believe is that many of the obvious examples of complexity in biological systems actually have very little to do with adaptation or natural selection. And instead ….”
p.391-392 “ … So why should this be? My guess is that in essence it reflects limitations associated with the process of natural selection. For while natural selection is often touted as a force of almost arbitrary power, I have increasingly come to believe that in fact its power is remarkably limited. And indeed, what I suspect is that in the end natural selection can only operate in a meaningful way on systems or parts of systems whose behaviour is in some sense quite simple. …”
He goes on to justify his belief natural selection is a force of limited power into the next pages arguing that natural selection is not sufficient to produce complexity we see in nature.
p.393 “In a sense it is not surprising that natural selection can achieve little when confronted with complex behaviour. ….”
“It has often been claimed that natural selection is what makes systems in biology able to exhibit so much more complexity than systems that we explicitly construct in engineering. But my strong suspicion is that in fact that main effect of natural selection is exactly the opposite: it tends to make biological systems avoid complexity and be more like systems in engineering.”
p.397 Criticism of Natural selection as a predictive theory … p.400 Constructing growing plants by means other than natural selection … p.402-404 Constructing the shape of leaves by means other than natural selection … p.408-410 Constructing the arrangement of leaves by means other than natural selection .. p. 411 Constructing plant geometries by means other than natural selection … p.414-417 Constructing the Shape of Shells by means other than natural selection …
Just a comment on Wolfram’s views of Biological Evolution found on p. 414-417: It was Stephen Jay Gould who argued in his doctoral thesis on shells that natural selection is necessary to pare down the evolution of thousands of potential shell shapes in the world to only about the half dozen that actually exist in shell forms. He used this as evidence of natural selection. In these 3 pages Wolfram proves mathematically that in fact there are only six possible shell shapes possible in the world, and all of them exist proving Gould wrong.
p.423-425 Constructing pigment patterns by means other than natural selection …
p.842 when a process repeatedly makes random modifications and then applies natural selection, only fairly simple aspects are yielded (i.e. diversity does not result).
p.861 Natural Selection is identified as the basis of many phenomena in biology …. But biology still continues to concentrate on very specific observations with no serious theoretical discussion on complexity.
p.1001 In the history of Natural Selection (Fundamental Issues of Biology) Wolfram comments that continuing controversies with religious accounts of creation have caused biologist’s to adamantly refuse to consider anything other than natural selection in shaping biological systems.
p.1001 cont. In the late 1980’s natural selection had become firmly enshrined as a force of practically unbounded power, assumed-through without specific evidence to be capable of solving almost any problem and producing almost any degree of complexity.
p.1002 Genetic programs: “… there is no uniform correspondence between sophistication of organism and length of genetic program …”
p.1002 Natural Selection section suggests that more work needs to be done to map out the exact limits of the usefulness of the theory of natural selection.
p.1104 Growth in plants section asserts that diversity in plant growth patterns in best explained by rules (not natural selection)
p.1104 Branch patterns in plants suggests the same ….. p.1007 Shape of Cells, Symmetries in Nature, Isotropic growth …… p.1008 Shape of Antlers also ….. p.1008 Shapes of shells suggests the same again … p.1009 Embryonic Development …. p.1011 Growth of Tumours, Pollen, Animal Behaviour … p.1012 Pigmentation patterns does too …. Etc. through for hundreds of pages (not all dealing with natural selection)
1185 Molecular Biology: … DNA as biological artifacts having very simple origins .. (Same with some animals traits such as the mollusc shell, or the radiolarian skeletons etc)
I’ve provided at least some evidence that Wolfram is not glossing over natural selection. To be fair he is equally rigourous with other fields. Clearly, he was critically examining natural selection - and this makes his views pertinant. My point again, is that a credible scientist has raised criticisms about the value of, and placed limits on the subject of this article. Reading it over the not a single critical viewpoint is included. This is either because natural selection is beyond criticism or their are none. I don't know about the former, but I do now about the latter. So I suggest at least let us include Wolfram’s view as being possibly the only valid criticism raise so far. WikiRat1 03:48, 21 January 2007 (UTC)
Good call Dave, the article does belong in an Information theory article. Wolfram uses POV language in his book from what you were saying. Further Natural selection is said to encourage adaptive evolution not complexity. GetAgrippa 14:51, 21 January 2007 (UTC)
I've put in NPOV until this issue is resolved. I recognize that the NPOV policy states that minority opinion doesn't necessarily have to be included in an article, but in this case there are no other views being represent which are critical of natural selection, and few others have gone into their criticism as deeply as Wolfram.
The NPOV policy does permit the minority opinion to be included when it provides balance, which I believe it does. Since the only critical view of natural selection is the minority position, it should be included. WikiRat1 04:05, 21 January 2007 (UTC)
Due mention given as requested. This is a general article about a large and complex field, any further detail can go in a linked article as suggested. .. dave souza, talk 08:55, 23 January 2007 (UTC)
WikiRat you are confused. I never said you misquoted Wolfram another editor did. I don't have a problem with Wolfram. I think his work will be useful for biologist and evolution modeling. I just don't think his ego and POV and a mathematical model discredit over a hundred years of biologist in every field demonstrating natural selection in thousands of publications. Further he may be a brilliant mathematician, but he has not engaged biologist or evolutionary biologist in peer review to debate the merits of his ideas or in a step wise fashion dismiss ALL the published evidence of natural selection. He has been mentioned in the article in an appropriate place and in context. GetAgrippa 14:35, 23 January 2007 (UTC)
I haven't read much of Wolfram I admit, but from quotes above he only says things such as "my guess is that ... it reflects limitations associated with the process of natural selection" and "my strong suspicion is that in fact that main effect of natural selection is exactly the opposite: it tends to make biological systems avoid complexity...". That on the face of it sounds like conjecture so is it supported by theory or evidence? Wolfram seems to claim he has a better way of looking at things: one which may provide more insight and additional explanation of functional design. This in itself does not undermine natural selection, and may happily co-exist with it. Whereas other times Wolfram seems to claim natural selection is oversold? At the moment I think there's insufficent weight. — Axel147 15:58, 23 January 2007 (UTC)
Complexity seems a somewhat subjective term. I see the bacteria or yeast as extremely complex. The thickness of shells is determined by environmental cues-predation. Wolfram maybe on to something considering parallel and convergent evolution, that given certain molecular tools that only certain paths will be favored. It is difficult to discount the impact environment has on development and the life cycle of any organism. Does Wolfram just ignore these facts or does he eliminate the possiblity of environmental influence and go with a model of internal cues? It seems his model is in a vacuum. Cooperation is said to increase complexity-Novak. GetAgrippa 16:05, 24 January 2007 (UTC)
Just a reply to all this talk about Wolfram, and self-organisation in general. It is a fact that rich, complex dynamics do arise "spontaneously" in certain systems, without any natural selection or evolution. It's called self-organisation, and it is not new. At any rate, it certainly doesn't make natural selection "unnecessary" to explain the complexity of living beings, because it does not explain adaptation. Under the proper conditions, brute matter will spontaneously create a range of diverse forms - but very, very few of them will result in anything useful. Complex, well-adapted organs cannot be explained by spontaneous assembly. Self-organisation makes it easier for natural selection to come up with complex designs, but does not replace it.
Complexity is not just the result of evolution by natural selection alone, or self-organisation alone. If there were no natural selection, adaptive complexity would be unheard of. If there were no self-organisation, then the amount of complexity available for evolution to "play" with would be vastly diminished; for example, building well-organised regulatory networks would be much more difficult without the "self-organising" properties of random boolean networks discovered by Stuart Kauffman.
In any case, I'm not sure this page is the place to mention these things. This is an article about natural selection, not about the emergence of complexity in nature. The respective roles of self-organisation and natural selection could be discussed in other pages. No? -- Thomas Arelatensis 14:05, 26 January 2007 (UTC)
The review gives the impression he tends to bloviate, he is dogmatic with narrow views discounting other concerns with weak arguments, and fails to provide few real advancements or real proof. Although they do say positive things that his research is useful. Just not grandiose as Wolfram suggests. I guess we need to add some kind of statement and references to detract from Wolfram's beliefs for NPOV. GetAgrippa 05:45, 3 February 2007 (UTC)
I don't know after reading more of these reviews. I don't think Wolfram's assertions about Natural selection are mature enough to pass muster as a valid concern. I am for keeping the Information theory section and its usefulness, but Wolfram's assertions are just his belief as he offers no real proof or detail just conjecture. At least we should drop his comments about Natural selection as they are not reliable or supported by secondary sources and really just constitute his orignal research. He offers no more proof than creationist arguments. GetAgrippa 13:32, 3 February 2007 (UTC)
I rewrote the Wolfram mention of natural selection but now it sounds idiotic. Any suggestions? GetAgrippa 16:21, 3 February 2007 (UTC)
Samsara noted in edit :"I like the previous one if it can be supported by a reference; what does it matter whether they are biologists, so long as their argument is sound?)" . I don't think it matters what his discipline is but it is not about a sound argument of his opinion but offering some description and some detail what he means and is there any proof to support his claims. It is a nebulous claim and others have noted that even as a hypothesis some aspects are untestable. I am deferring to the criticisms of others about his work. Pete Hurd found a useful site and I offered a Science article review of his book. I am not saying his mathematical model is incorrect in producing complex patterns, and I am just saying he offers an opinion that this could replace natural selection and offers nothing to support or substantiate or explain the statement. GetAgrippa 20:47, 3 February 2007 (UTC)
Axels edits seems to reflect he thinks it is red herring. Not that I'm putting words into his mouth. I think we could mention his work in reference to information theory without any mention of an egomaniacal rant about natural selection. Sound fair? Of course now if it is not related to Natural selection so why have it? Axel's argument appears to have merit. GetAgrippa 22:10, 3 February 2007 (UTC)
I must admit I'm a bit confused (perhaps because I'm too lazy to read it all) whether Wolfram's ideas, if substantiated, challenge natural selection or whether they have little or no bearing on it. I see Wolfram's ideas and NS as alternative ways of explaining the complexity of life. If one is important, it seems to me the other would become less important. (Though NS explains more than just complexity.) But yes I do think it's a Red Herring and don't think Wolfram's arguments are fleshed out clearly enough. — Axel147 02:12, 5 February 2007 (UTC)
Sorry to be a bit slow here, but when registering to look at the website I tactfully asked a couple of questions and forgot to check that mail account for a while, Here's the first response:
Comments:
> Does NKS reject natural selection,
No.
> or reject misunderstandings about the extent to which it creates complexity or produces optimal solutions?
Basically, yes.
Probably most important is that it suggests an actual mechanism for generating complexity in biology, that happens to have essentially nothing to do with natural selection. It also argues that finding "optimal solutions" probably has little to do with generating complexity.
For more information see:
They helpfully sent a more detailed response:
Mr. Souza,
You asked "Does NKS reject natural selection, or reject misunderstandings about the extent to which it creates complexity or produces optimal solutions?" Definitely the second.
NKS knows that natural selection happens and is important, but doubts that it is fundamental to explaining the specific phenomenon of complexity in living organisms. First and most simply, complexity is more general than living organisms so its overall cause is unlikely to be a principle operating (for the most part or as originally meant) only within life. If dendritic drainage patterns or fracture patterns are complicated without having undergone millions of years of natural selection, vein systems may be complicated for entirely similar reasons etc.
Second, formal modeling shows iterative improvement schemes are excellent at "honing"a simple system by tweaking a small number of continuous variables toward some single optimum, but are lousy at finding global optima in a large space of discontinuous changes. On the other hand, point changes to simple programs rapidly explore a wide variety of formal behaviors, including as a matter of course some very complicated ones, on the output side.
The classic Darwinian formula says "descent with variation" is the input to natural selection. NKS sees that "with variation" as much more important than at least some biologists suppose, because it expects a wider range of phenomenal variations from readily imaginable changes to underlying programs, whether those are (simple protein) genetic or developmental or regulatory etc. Wolfram thinks that natural selection is more likely to produce optimizing simplicities than complexity. And overall, it more likely to operate as a "net winnower" of a possibility space explored by algorithmic variation of underlying biological programs, than as the driver of that variation in the first place.
None of which means natural selection isn't happening or isn't important. Just that specifically variety (the harder of the two claims) and complex morphologies (the easier one) do not require it as an explanation, and can be better accounted for by factors operating at the previous, "descent with variation" stage, in Darwin's formula.
To me this appears to account for bits of history like the Cambrian rather better than the usual accounts. Instead of imagining that a whole bunch of separate "niche attractors" arose and ramified in a tiny space of time, and were all filled, one need only imagine that a body-shape or development program innovation occurred, and systematic variation in elements of that program then rapidly "tried everything". Some "stuck", in natural selection terms, and some did not - as adequate rather than optimized. A long but slow period of optimization and winnowing then follows in the variety already formed - that would be natural selection working.
Others have since noted that the two explanations - niche optimality "pull" and algorithmic variety "push" - make different predictions about things like species variety distribution across latitudes. Native mutation rate is higher where temperature is higher. Little more seems to be needed to account for the greater variety seen in the tropics. Not anything like a proof, just a suggestive "fit data point". Analyzing point mutations is an obvious place to try to confirm the idea. E.g. can one make simple vs. complex seashell shadings vary from one to the other with a few point mutations, without any selective forces operating?
I hope this is interesting, and thanks for your interest and the question.
Sincerely,
Jason Cawley, Wolfram Research
Hope this helps, dave souza, talk 19:03, 20 February 2007 (UTC)
Let's talk about something slightly more important than the degree to which we should massage Stephen Wolfram's ego, shall we?
I really dislike the placement of the example as the first section of this article, preceding even the 'general principles' section that would provide context and background. A long time ago, I moved it toward the end of the article, but I see it's drifted back again. I don't much like the section in general - it's written in a very simplistic, tutorial style more suited to a textbook than a reference work, and its placement at the beginning makes the article read like chapter 2 in 'introduction to evolutionary biology'. It doesn't make sense to me, from an encyclopedia perspective, to place the example of a phenomenon before the description of the phenomenon. The lead doesn't do that job either. I imagine it's there for 'accessibility' purposes, but without preceding discussion it's just a blob of text before you get to the actual article.
Does anyone have an objection to demoting it, or a good reason it should be where it is? Opabinia regalis 06:18, 7 February 2007 (UTC)
I don't have any objection. (I think the original reason was that example was the best way of explaining it without diving into the detail.) As a separate point I'm always confused by the sentence "Natural selection can act on ... any aspect of the environment". Maybe I've pulled it out of context but could it be worded more clearly? — Axel147 17:58, 7 February 2007 (UTC)
Natural selection still does not have any criticism of the idea in it. There should at least be on paragraph near the bottom labelled criticism. Steven Wolfram is not the only critic. I have heard complaints such as Selection just reduces the genetic diversity in a population. Even if a criticism is wrong, if it common it deserves a mention. GB 10:03, 12 February 2007 (UTC)
-- Thomas Arelatensis 13:45, 13 February 2007 (UTC)
Also the example of antibiotic resistance in golden staph is not that great an example. Much of antibiotic resistance in bacteria is the result of horizontal gene transfer between different bacteria, rather than by mutation. GB 10:03, 12 February 2007 (UTC)
I had added a section addressing that but I removed because it is just an example for an encyclopedia. I agree HGT is more significant than mutations in antibiotic resistance. GetAgrippa 11:47, 12 February 2007 (UTC)
How in the world is propagation of resistance (even with massive HGT) not an example of natural selection? You still have a perfect example of certain alleles out-competing others (sorry for going all Dawkinsian on you, but that's what natural selection is all about). It would fail to be an example of natural selection if the gene in question did not carry any advantage, or if its propagation was unrelated to this advantage (e.g. genetic drift). Surely nobody argues that this is the case in this particular instance! -- Thomas Arelatensis 13:29, 13 February 2007 (UTC)
Natural selection is certainly not a process; it is patently an unproven theory. Let us try to remove the strong POV slant in this article through consensus NOT through reverting good NPOV edits. And less proprietorial disputes please. Peter morrell 12:41, 23 February 2007 (UTC)
<reduce indent> Three questions:
Many thanks...unfortunately your Ragoletis example, which you said was compelling, only "constitutes a possible example (sic) of an early step towards the emergence of a new species by the mechanism of sympatric speciation," you seem to be bending over backwards to believe all this. I prefer to remain sceptical because I am not a rank believer. You point to the connections where I see only the holes in the same woven fabric of ideas. sorry to disappoint you. I will check out your other references, however. What I meant above about genetic drift was merely that random changes in populations do not necessarily illustrate NS. It is just when viewed through that particular lens that they seem that way. However, what is good about the Ragoletis case is that it shows how adaptable organisms are to subtle changes in the key components of their life cycles, which is fascinating but is not necessarily such compelling grist to the believer's mill as you suppose. My problem is with the curious way these things are pounced on as evidence when they seem wide open to other interpretations. Bad science, as I'm sure you know, is hunting down data to support a pet theory. That is precisely what NS seems like to me. Peter morrell 20:11, 23 February 2007 (UTC)
It is a process. The mechanism is undeniable. Samsara ( talk • contribs) 13:15, 27 February 2007 (UTC)
Overly long, disproportionately footnoted... reeks of old edit war. Can anyone who's been active on this article longer than I've been watching recall why this is and whether it needs to stay as long as it is? Opabinia regalis 07:53, 6 March 2007 (UTC)
In case anybody misses it in the thicket of header banners, I've put this article up for peer review. I've been picking at it for the last couple of weeks, but I really think it could use some fresh eyes, especially from non-biologists. Opabinia regalis 03:45, 18 March 2007 (UTC)
I know I have raised this before but there seems to be inconsistency in the use of phenotype/genotype now in the opening paragraph.
This implies an organism has one phenotype (not one for each characteristic) which is mapped to a single genotype. But how can the genotype increase in frequency unless I am producing clones of myself? Surely it's clearer to say genes (or alleles) increase in frequency? — Axel147 05:17, 21 July 2007 (UTC)
The Fitness section has some problems. Firstly no quotes, no sources, no citations. Secondly "Modern evolutionary theory defines fitness in terms of reproduction rather than survival." -This should be changed. Dawkins proposed DNA "gene reproduction" as a better explainer, and others in "modern evolutionary theory" have also moved away from simple "reproduction". Here's one reason why- in ants and bees and termites and other haplodiploid insects, the colonies are mainly composed of "sisters." The female workers and soldiers forgo reproduction so that their queen will produce sisters instead (brothers too, but relatively few). In other words, Evolution works for family members other than direct offspring. In fact in any creature, uncles and aunts, even cousins, can pass genetic material and their associated traits without reproducing.(through survival of nephews and nieces, etc) While it may seem a minor point at first, as stated now in the article, the whole theory breaks down the when any example of any creature forgoes reproduction for any reason(including humans) Thirdly the sickle-cell anemia is potentially offensive as well as factually incorrect. "as in extreme examples include many human genetic disorders like sickle-cell anemia"-- Sickle-cell anemia turns out to have great survival value in areas with high malaria infection. This is why many descendants of Africans who lived in malaria ridden areas have sick-cell anemia. Sickle cell disease is the most common inherited blood disorder in the United States, affecting 70,000 to 80,000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1,000 to 1,400 Hispanic Americans. ( http://ghr.nlm.nih.gov/condition=sicklecelldisease) So to call it an extreme example is, at best, misleading, and unfortunately, one could read into it a racist bias. This could be easily avoided. I am going to edit out "extreme," for now, but the example itself isn't very good (unless someone wants to greatly expand upon how sickle-cell relates to "genetic fitness") 76.19.28.24 15:17, 23 July 2007 (UTC)
I too think this needs re-writing because it misrepresents the original use of "fitness" and the phrase "survival of the fittest". Wallace to Darwin,
It is clear that "survival of the fittest" was intended to apply to variations not to individuals. (Or perhaps it could be viewed as applying to lineages or 'races' consistent with Darwin's title of the Origin describing natural selection as 'the Preservation of Favoured Races in the Struggle for Life'.) It is so obvious that being the fittest individual, if this simply means living a long time, is not sufficient per se to propagate characteristics to the next generation it is hardly worth mentioning the point! Darwin in any case clears the matter up, 'I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including dependence of one being on another, and including (which is more important) not only the life of the individual, but success in leaving progeny.' — Axel147 12:03, 25 July 2007 (UTC)
The last sentence of the "Fitness" section contains very bad writing. It reads:
Since fitness is an averaged quantity, however, it is possible for a favorable mutation may arise in an individual that does not survive to adulthood for unrelated reasons, or unfavorable mutations to have a for unrelated reasons.
Could someone who understands this better than I please rewrite it? It's embarrasing. —Preceding unsigned comment added by 74.225.65.124 ( talk) 02:44, 1 September 2007 (UTC)
I have a question about this recent edit adding "The second was Adam Smith who, in The Wealth of Nations, identified a regulating mechanism in free markets, which he referred to as the " invisible hand", which suggests that prices self-adjust according to supplies and demand <ref>[[David Orrell|Orrell, David]] (2007) ''Apollo's Arrow'' Toronto: HarperCollins Publishers Ltd. [http://www.apollosarrow.ca/]</ref>. Thus for Darwin, the disaster that was supposed to occur according to Malthus was kept in check and constantly improved by competition (or law of selection)." I don't have the Orrell book, but does it support the assertion that Adam Smith's The Wealth of Nations inspired Darwin in the way claimed? Is there another reference to support the claim? The Malthus influence is well-known, is an equivalent influence from Smith supported by reliable sources? Pete.Hurd 21:14, 15 August 2007 (UTC)
See Inception of Darwin's theory#Malthus and Natural Law for more on the context. The statement that "Thus for Darwin, the disaster that was supposed to occur according to Malthus was kept in check and constantly improved by competition (or law of selection)." seems out of line with the sixth edition having allowed other alternatives to his bleak forecast. There's an indirect connection in that Malthus on p 2 says "The only authors from whose writings I had deduced the principle, which formed the main argument of the Essay, were Hume, Wallace, Adam Smith, and Dr. Price". It's interesting that on p 11.3 Malthus writes:
Browne makes a passing reference on p 389 to Darwin, musing after conceiving of the theory, envisaging an "invisible hand" selecting. However, she puts a lot of emphasis on the Whig thinking all around Darwin, particularly from Harriet Martineau. In summary, the addition of info on Smith is very dubious, and while his ideas undoubtedly were taken up by people who influenced Darwin, he had other more direct inspirations for the idea. .. dave souza, talk 10:29, 16 August 2007 (UTC)
I note that this article doesn't even link to the slightly broader article selection, which is in a fairly poor state. Do we want to have this broader article? I'd probably be in favour of keeping it since heaping everything into this article and having nothing linking the other forms together is probably a bad idea. Selection can provide an overview of the subject, such as classification e.g. natural vs. artificial, stabilizing vs. directional etc, as well as levels of selection and other related topics. Another much smaller article is evolutionary pressure. Should this one be merged into selection? I'm not very familiar with the finer details of evolutionary biology so I'm not sure exactly how much potential this one would have. If it is kept as is, perhaps we should look at whether evolutionary pressure or selective/selection pressure is more commonly used, and consider moving it. Richard001 04:11, 28 August 2007 (UTC)
The Darwin's hypothesis section contains a fraudulent misquotation: I have called this principle, by which each slight variation, if useful, is preserved.
I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. and the next paragraph But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient. We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses, through the accumulation of slight but useful variations, given to him by the hand of Nature. But Natural Selection, we shall hereafter see, is a power incessantly ready for action, and is as immeasurably superior to man's feeble efforts, as the works of Nature are to those of Art.
Darwin seems to imply that Natural Selection as some sort of nature selection force is superior to mans "feeble" efforts. His intent with the phrase Artificial selection also alludes to this. What confuses the matter is that nobody knows what was his or Spencer's intent with Survival of the Fittest. It could mean anything you want it to mean. Natural selection must be discussed in terms of Artificial selection and Survival of the Fittest since Darwin said SoF is more "accurate" and how it relates to "feeble man" and "nature's power of selection" as he put it in the passage dealing with Artificial Selection. It is not clear what was Darwin's intent with these three phrases and how they relate. He seems to be invoking nature as some sort of conscious "selection" force, unless there are passages that proves that it is not so.
Slow though the process of selection may be, if feeble man can do much by artificial selection, I can see no limit to the amount of change, to the beauty and complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may have been effected in the long course of time through nature's power of selection, that is by the survival of the fittest.
I propose that we at least cite the full sentence as written down by Darwin? TongueSpeaker 14:27, 12 September 2007 (UTC)
This sentence appears in the 'Fitness' section. I don't understand what the very last 'or unfavorable...' clause is supposed to mean. " Since fitness is an averaged quantity, however, it is possible a favorable mutation may arise in an individual that does not survive to adulthood for unrelated reasons, or unfavorable mutations to have a for unrelated reasons." Johnor 01:50, 1 October 2007 (UTC)
It is trying to say that since fitness is a probabilistic quantity (like life expectancy) a mutation could increase an individual's fitness and still not increase its actual reproductive success. This is just like stopping smoking would increase my probability of living longer but I could still get hit by a bus tomorrow. It is is important to distinguish what fitness actually means (expected reproductive success) from the way it is measured or estimated (by averaging actual reproductive success). Maybe the article does not makes this point clearly enough and needs amending. —
Axel147
21:51, 2 October 2007 (UTC)
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Ok, this is getting interesting. Basically, when a species goes extinct because it is maladapted, it is not Natural Selection that is causing it, but other processes. That is just to weird... What are those processes and how are they different from NatSel. -- Kim van der Linde at venus 04:27, 9 July 2006 (UTC)
If we have a few children left in a sexually reproducing population and they are all eaten by a predator before reproductive age I fail to see how this could be drift. Since the predator didn´t select any particular children to eat, it just ate them all, it is arguably not selection either. — Axel147 14:00, 9 July 2006 (UTC)
Basic problems: 1) whatever natural selection is, we'll all agree that there is no intelligent designer behind it. So how does natural selection "know" whether there are only a few individiuals or just one individual or many? 2) how do we know the predator didn't select children to eat? Who should we ask? Gleng 21:26, 9 July 2006 (UTC)
How do you know there are no fitness differences except by who survives? Gleng 20:23, 10 July 2006 (UTC)
I think you're trapped in endless paradoxes. If you want to keep natural selection as meaning the theory of evolution by natural selection, OK, this may be common useage. But if so, don't try to use this also as a rigorous definition that you can use coherently in a logical argument. Gleng 09:54, 11 July 2006 (UTC)
Suppose we have two individuals in a population. Let´s call them Adam and Eve (just to play devil´s, or god´s, advocate). The point I am making is whether they go extinct or have children has nothing to do with natural selection. But is what happens next caused by divine intervention? No, of course it isn´t, I haven´t suddenly turned creationist — it is just evolution by a different mechanism!
If Adam and Eve´s reproductive success are tied together they must both have equal fitness. (And this is true even if Eve is susceptible to disease and Adam is not.) So Adam and Eve and all their traits have equal chance of reproducing. Natural selection cannot occur because it has no material to act on. There is no variation. It is only when they have children that fitness differences arise.
Clearly what happens does depend on the liklihood of Adam and Eve surviving the prevailing conditions and that is influenced by their characteristics. But we are not forced to label all natural processes that impinge upon reproductive success as 'natural selection'.
Natural selection requires variation in fitness before it can occur at all (and it requires heritable variation in fitness for it to produce evolutionary response).
(I realise we could puncture this argument by trying to 'force' fitness differences. We could argue Adam is fitter because he might reproduce with his daughter. Or we could talk about cheating during meiosis. But this is not the point. The point is that we are not obliged to name all process that influence reproductive success as 'natural selection'. Natural selection is the set of processes that bias reproductive success according to phenotypic differences.) — Axel147 14:43, 11 July 2006 (UTC)
"Natural selection requires variation in fitness before it can occur at all" I think we've probably played this out, and it has been fun :) As a last riposte I'd just say that natural selection requires that some survive and some do not, and fitness simply is an estimate of who is likely to survive. If we had enough knowledge, our estimate would be certain knowledge of who would survive and who would not; as our knowledge is imperfect we can only make a guess, and the value we give to fitness depends on how much knowledge we have. For Adam and Eve, their fitness is 1 or 0. Now while we know that there are only Adam and Eve, they don't know that - and for all we know there might have been a million others who somehow failed to find the apple. Now my only point is that you cannot sensibly describe what happens to them as natural selection or not depending on whether there are many others or no others. What happens and why it happens to them is the same, unless you think that the mere existence of other people somewhere in the garden alters the nature of the influences on A and E.
So I'd say that natural selection is simply to be understood as the absence of artificial selection - it is the assertion of the absence of a God, a designer, a directing intelligence. It is whatever happens that means that some die and some don't. And that this, this absence of direction, this absence of intelligence, when there is variation and heritability, is enough to result in adaptive evolution, is the radical idea
Gleng
15:57, 11 July 2006 (UTC)
The problem we are faced with (Kim´s orginal concern I think) is that if a lion happens to eat one of a species it probably doesn't know or care whether it is the last one. From its perspective the process is the same whether or not it causes extinction. The only answer I have to this is that from nature´s perspective there is no choice to make between individuals of the same species if we are down to just one. (One way round this problem is by dropping the word 'process' out of the definition as many authors do e.g. Futyama. But I not suggesting we do this.)
I agree that in a sense nature is still 'selecting' whether an individual survives or not, but I don´t think this is what we mean by 'natural selection'. The distinction is important to separate (conceptually at least) processes that may change gene frequencies in a predictable direction, from those which alter gene frequencies at random. Here is a published view on this. Once again Sober p159:
— Axel147 17:42, 12 July 2006 (UTC)
For completeness I suppose I should add that if one considers 'differential speciation' to be a form of higher level natural selection e.g. Gould, extinction could count as a form of natural selection after all! (If we have more than one species.) — Axel147 13:19, 22 July 2006 (UTC)
According to Wiki 'In biology, a trait or character is a genetically inherited feature of an organism.' If this is true why does the article say 'but only the heritable component of a trait will be passed on to the offspring'. Which is correct? Is a trait by definition heritable? — Axel147 20:20, 16 July 2006 (UTC)
We are using trait in the original, normal language definition, as a distinguishing characteristic of an individual rather than the more recent more specialised sense. Science has a way of hi-jacking common words; I've no idea what we should do - maybe a footnote? Gleng 20:42, 16 July 2006 (UTC)
In the fitness entry we still have the other use! 'If differences in individual genotypes affect fitness, then the frequencies of the genotypes will change over generations; the genotypes with higher fitness become more common. This process is called natural selection.'
Similarly, ecological selection (commonly natural selection excluding sexual selection)....
These articles seem stable but inconsistent. I am no longer fresh to this so don't know if it's important to do anything about it! — Axel147 17:08, 10 August 2006 (UTC)
There is a critically important distinction between artificial selection and natural selection, which I think is fundamental and essential not to blur. In Darwin's sense artificial selection involved design, directed intent. Natural selection does not. Gleng 19:22, 12 August 2006 (UTC)
It's not ideal. It was and is obvious that artificial selection can change the form of species, but this process involves intent to produce that particular change, it is a deliberate exploitation of variation and inheritance by an intelligent designer. Darwin's insight was that no intent is necessary. I agree with you, that in the broad scheme of things then artificial selection is just part of our extended phenotype, but appreciating this requires both subtlety and rewriting Darwin even more extensively. I thnk it's important not to blur Darwin's insight that no designer is needed, so the distinction between artificial selection and natural selection is a useful one. Take away this and you don't need the word "natural" . Gleng 07:57, 14 August 2006 (UTC)
I hadn't seen that, and I agree with you; I think it is just silly not to see humans as part of the natural world. Gleng 14:08, 15 August 2006 (UTC)
The last time that I read this article, some idiot had written something about the new Kim Possible season. If the vandal is reading this, please note that we don't care about Kim Possible and that this page is about NATURAL SELECTION, just in case you haven't noticed that already. -- 71.140.114.12 19:45, 11 February 2007 (UTC)
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)
My thoughts what need to be done before considering FA:
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)
would sympathtic editors consider a positive vote here? [3] Slrubenstein | Talk 15:34, 23 August 2006 (UTC)
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)
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 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)
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 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)
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)
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)
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)
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)
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"
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)
Natural selection is a theoretical deduction of perceived evolutionary changes in species.
We must, however, remember that correlation does not imply causation. Moreover, the correlation evident between species does not specifically imply causation. And until natural selection, and more importantly, macroevolution can be proven in the laboratory, they will both remain theoretical.
Science is the pursuit of causes, both natural and unnatural [intelligent]. To completely disregard the possibility of intelligent causes is negligent. This article should not present this concept as if it were completely 100 percent proven. I fear no change will be made by the evidently biased authors/administrators of this article that are bent on making this science appear as if it has been fully observed. Remember, due to certain lapses in knowledge, even the scientific process makes certain presuppositions that requires philosophy/faith. Futuremore, we're not just primordial slime, meaning cannot be fomented through evolution.
Nothingness to Ameba to Brain through time, which only leads to entropy. Come on, every worldview is exclusive and closeminded.
( 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)
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.
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.
Given enough time, this passive process results in adaptations and speciation (see evolution).
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, [1] by analogy with artificial selection, by which a farmer selects his breeding stock.
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 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)
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." [2] 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)
It was added again. I have removed it, again. The Times review on 20 May 2002 puts this book in its proper perspective, "Cranks are an occupational hazard that every scientist eventually faces. Fortunately, these characters are usually easy to spot. If someone claims to have a grand theory that overturns centuries of scientific knowledge—especially when the theory spans unrelated fields like physics and biology and economics—the odds are good that he or she is a crank. If the author publishes not in standard scientific journals but in a book for general readers, watch out. And if the book is issued by the author rather than a conventional publisher, the case is pretty much airtight." Since the peer review didn't occur before publication, we'll have to see how it fares after publication. Genetics411 01:36, 20 January 2007 (UTC)
"The evolutionary process of divergence, which ultimately leads to the generation of new species, is thought to occur usually without any gene exchange between the diverging populations. However, until the recent growth of multi-locus datasets, and the development of new population genetic methods, it has been very difficult to assess whether or not closely related species have, or have not, exchanged genes during their divergence. Several recent studies have found significant signals of gene flow during species formation, calling into question the conventional wisdom that gene flow is absent during speciation."Curr Opin Genet Dev. 2006 Dec;16(6):592-6. Epub 2006 Oct 19. Recent advances in assessing gene flow between diverging populations and species.Hey J. Further while I agree gene flow is homogenizing, it can be useful as gene loss is significant in many examples of speciation and HGT and Hybridization can rejuvenate a genome and generate novelty and speciation. The last year has been a boom for HGT and hybridization studies. I guess we need to address this for NPOV. GetAgrippa 20:46, 15 January 2007 (UTC)
Before you remove Wolfram again, be aware that there is a 3 revert rule in effect. Enough of the nonsense that Wolfram hasn't been peer reviewed for he has been and I've provided the link. Furthermore, though his views might not be popular with some biologists, his views are popular in other circles (bioinformatics for example). Also recall that the views of Darwin himself, have not been popular in the past. If you can show that Wolfram has been misquoted, or that his views of natural selection have been proven wrong, you may remove my contribution under Information theory.
Why are Wolfram's views noteworthy and worthy of inclusion here? Wolfram's criticisms of Natural Selection are noteworthy because few other scientists have been successful in critiquing the problems with the theories of Natural Selection but he has not only exposed errors in the field (such as the ones he showed about Stephen Jay Gould's work), but he has also presented a fairly detailed criticism of natural selection which has to date gone unanswered. It possible Wolfram's views go furthest in finding the weakness with natural selection, but his counter suggestion, shows that complexity and diversity arise by mechanisms other than natural selection and also make it possible to formulate abstract theories about evolution apart from natural selection! The only way this would not be worth noting in this article would be if Wolfram was wrong, or if there is more incentive to hold old ideas rather than adopt new.
He notes that traditional mathematical models have never even come close to capturing the kind of complexity found in biological systems, as a result biologists have treated evolution through natural selection as the foundation of this complexity. He notes that the theory of natural selection has implied complexity in biological systems, but has never actually showed exactly how natural selection requires it. This is a very significant criticism indeed, and if true more than noteworthy except by some who do not welcome debate. Searching the literature of the field - I think his criticism holds, and certainly no biologists has responded.
True. Wolfram's mathematical views of complexity have been criticized. Specifically his theory of the Equivalence of Computational Complexity have met with the most resistance and debate, but that does not undermine in any way his response to natural selection, and for this reason, I have restored his criticism. WikiRat1 17:23, 20 January 2007 (UTC)
The place you have put this is inappropriate for the material, even if it is true. You have completely swamped a section on information theory with criticism of natural selection in general. Genetics411 17:30, 20 January 2007 (UTC)
<reduce indent> He's hardly undermined the theory – he appears to have shown a possible source of variation for natural selection to act on. Try writing an article that covers his ideas on their own, citing relevant critiques. .. dave souza, talk 18:30, 20 January 2007 (UTC)
You're presenting a brief quote from a popular book taken out of context, and adding to this a great deal of your own opinion that this is a noteworthy criticism of the tenets of natural selection. This looks very much like original research. How does it bear on organisms being fitted to their environment? A mathematical explanation of complexity arising from simple sources overcomes a common objection to natural selection rather than overthrowing its tenets – if "complexity and order both can both appear in natural systems as a simple matter of reproduction with no other influences", that provides the variation for selection. However his mathematics also appear to need a great deal of work to become generally useful in the field – your statements imply that it's unused. What you call "his competing explanation of diversity through simple rules" could some day provide useful support and development of natural selection theory, but we need to see your assertion being made by reliable sources and not just your interpretation of his theory of everything. ... dave souza, talk 20:17, 20 January 2007 (UTC)
Has Wolfram published in biological journals more appropriate for the topic? Not much of a debate when you don't invite evolutionary biologist in peer review. Natural selection does not mean evolution. You have evolution by natural selection. Even if natural selection were proven completely in error (which it hasn't plenty of examples in nature) it does not disprove evolution and it would probably be replaced by a more comprehensive or refined mechanism that would deal with the complex multifaceted nature of biological systems. " Natural Selection is solely responsible for the survival of traits and genetic diversity - instead he argues that living things are capable of self organization." Self organization is already dealt with in the article. Natural selection is not solely responsible for the survival of traits or genetic diversity-facial patterns in humans is due to genetic drift and are completely neutral. GetAgrippa 00:20, 21 January 2007 (UTC)
dave souza, alright, this seems kind of desperate (for me to post a bunch of page numbers), but at your request here are some citations which you can check out yourself …
p.14 “Evolution Theory. The Darwinian theory of evolution by natural selection is often assumed to explain the complexity we see in biological systems – and in fact in recent years the theory has increasingly been applied outside of biology. But it has never been at all clear just why this theory should imply that complexity is generated. And indeed I will argue in this book that in many respects it tends to oppose complexity.…..”
p.383 – 432. Most of Chapter 8 starting with Fundamental Issues in Biology showing something other than Natural Selection as responsible for adaptations.
p.383 “… And in fact what I have come to believe is that many of the obvious examples of complexity in biological systems actually have very little to do with adaptation or natural selection. And instead ….”
p.391-392 “ … So why should this be? My guess is that in essence it reflects limitations associated with the process of natural selection. For while natural selection is often touted as a force of almost arbitrary power, I have increasingly come to believe that in fact its power is remarkably limited. And indeed, what I suspect is that in the end natural selection can only operate in a meaningful way on systems or parts of systems whose behaviour is in some sense quite simple. …”
He goes on to justify his belief natural selection is a force of limited power into the next pages arguing that natural selection is not sufficient to produce complexity we see in nature.
p.393 “In a sense it is not surprising that natural selection can achieve little when confronted with complex behaviour. ….”
“It has often been claimed that natural selection is what makes systems in biology able to exhibit so much more complexity than systems that we explicitly construct in engineering. But my strong suspicion is that in fact that main effect of natural selection is exactly the opposite: it tends to make biological systems avoid complexity and be more like systems in engineering.”
p.397 Criticism of Natural selection as a predictive theory … p.400 Constructing growing plants by means other than natural selection … p.402-404 Constructing the shape of leaves by means other than natural selection … p.408-410 Constructing the arrangement of leaves by means other than natural selection .. p. 411 Constructing plant geometries by means other than natural selection … p.414-417 Constructing the Shape of Shells by means other than natural selection …
Just a comment on Wolfram’s views of Biological Evolution found on p. 414-417: It was Stephen Jay Gould who argued in his doctoral thesis on shells that natural selection is necessary to pare down the evolution of thousands of potential shell shapes in the world to only about the half dozen that actually exist in shell forms. He used this as evidence of natural selection. In these 3 pages Wolfram proves mathematically that in fact there are only six possible shell shapes possible in the world, and all of them exist proving Gould wrong.
p.423-425 Constructing pigment patterns by means other than natural selection …
p.842 when a process repeatedly makes random modifications and then applies natural selection, only fairly simple aspects are yielded (i.e. diversity does not result).
p.861 Natural Selection is identified as the basis of many phenomena in biology …. But biology still continues to concentrate on very specific observations with no serious theoretical discussion on complexity.
p.1001 In the history of Natural Selection (Fundamental Issues of Biology) Wolfram comments that continuing controversies with religious accounts of creation have caused biologist’s to adamantly refuse to consider anything other than natural selection in shaping biological systems.
p.1001 cont. In the late 1980’s natural selection had become firmly enshrined as a force of practically unbounded power, assumed-through without specific evidence to be capable of solving almost any problem and producing almost any degree of complexity.
p.1002 Genetic programs: “… there is no uniform correspondence between sophistication of organism and length of genetic program …”
p.1002 Natural Selection section suggests that more work needs to be done to map out the exact limits of the usefulness of the theory of natural selection.
p.1104 Growth in plants section asserts that diversity in plant growth patterns in best explained by rules (not natural selection)
p.1104 Branch patterns in plants suggests the same ….. p.1007 Shape of Cells, Symmetries in Nature, Isotropic growth …… p.1008 Shape of Antlers also ….. p.1008 Shapes of shells suggests the same again … p.1009 Embryonic Development …. p.1011 Growth of Tumours, Pollen, Animal Behaviour … p.1012 Pigmentation patterns does too …. Etc. through for hundreds of pages (not all dealing with natural selection)
1185 Molecular Biology: … DNA as biological artifacts having very simple origins .. (Same with some animals traits such as the mollusc shell, or the radiolarian skeletons etc)
I’ve provided at least some evidence that Wolfram is not glossing over natural selection. To be fair he is equally rigourous with other fields. Clearly, he was critically examining natural selection - and this makes his views pertinant. My point again, is that a credible scientist has raised criticisms about the value of, and placed limits on the subject of this article. Reading it over the not a single critical viewpoint is included. This is either because natural selection is beyond criticism or their are none. I don't know about the former, but I do now about the latter. So I suggest at least let us include Wolfram’s view as being possibly the only valid criticism raise so far. WikiRat1 03:48, 21 January 2007 (UTC)
Good call Dave, the article does belong in an Information theory article. Wolfram uses POV language in his book from what you were saying. Further Natural selection is said to encourage adaptive evolution not complexity. GetAgrippa 14:51, 21 January 2007 (UTC)
I've put in NPOV until this issue is resolved. I recognize that the NPOV policy states that minority opinion doesn't necessarily have to be included in an article, but in this case there are no other views being represent which are critical of natural selection, and few others have gone into their criticism as deeply as Wolfram.
The NPOV policy does permit the minority opinion to be included when it provides balance, which I believe it does. Since the only critical view of natural selection is the minority position, it should be included. WikiRat1 04:05, 21 January 2007 (UTC)
Due mention given as requested. This is a general article about a large and complex field, any further detail can go in a linked article as suggested. .. dave souza, talk 08:55, 23 January 2007 (UTC)
WikiRat you are confused. I never said you misquoted Wolfram another editor did. I don't have a problem with Wolfram. I think his work will be useful for biologist and evolution modeling. I just don't think his ego and POV and a mathematical model discredit over a hundred years of biologist in every field demonstrating natural selection in thousands of publications. Further he may be a brilliant mathematician, but he has not engaged biologist or evolutionary biologist in peer review to debate the merits of his ideas or in a step wise fashion dismiss ALL the published evidence of natural selection. He has been mentioned in the article in an appropriate place and in context. GetAgrippa 14:35, 23 January 2007 (UTC)
I haven't read much of Wolfram I admit, but from quotes above he only says things such as "my guess is that ... it reflects limitations associated with the process of natural selection" and "my strong suspicion is that in fact that main effect of natural selection is exactly the opposite: it tends to make biological systems avoid complexity...". That on the face of it sounds like conjecture so is it supported by theory or evidence? Wolfram seems to claim he has a better way of looking at things: one which may provide more insight and additional explanation of functional design. This in itself does not undermine natural selection, and may happily co-exist with it. Whereas other times Wolfram seems to claim natural selection is oversold? At the moment I think there's insufficent weight. — Axel147 15:58, 23 January 2007 (UTC)
Complexity seems a somewhat subjective term. I see the bacteria or yeast as extremely complex. The thickness of shells is determined by environmental cues-predation. Wolfram maybe on to something considering parallel and convergent evolution, that given certain molecular tools that only certain paths will be favored. It is difficult to discount the impact environment has on development and the life cycle of any organism. Does Wolfram just ignore these facts or does he eliminate the possiblity of environmental influence and go with a model of internal cues? It seems his model is in a vacuum. Cooperation is said to increase complexity-Novak. GetAgrippa 16:05, 24 January 2007 (UTC)
Just a reply to all this talk about Wolfram, and self-organisation in general. It is a fact that rich, complex dynamics do arise "spontaneously" in certain systems, without any natural selection or evolution. It's called self-organisation, and it is not new. At any rate, it certainly doesn't make natural selection "unnecessary" to explain the complexity of living beings, because it does not explain adaptation. Under the proper conditions, brute matter will spontaneously create a range of diverse forms - but very, very few of them will result in anything useful. Complex, well-adapted organs cannot be explained by spontaneous assembly. Self-organisation makes it easier for natural selection to come up with complex designs, but does not replace it.
Complexity is not just the result of evolution by natural selection alone, or self-organisation alone. If there were no natural selection, adaptive complexity would be unheard of. If there were no self-organisation, then the amount of complexity available for evolution to "play" with would be vastly diminished; for example, building well-organised regulatory networks would be much more difficult without the "self-organising" properties of random boolean networks discovered by Stuart Kauffman.
In any case, I'm not sure this page is the place to mention these things. This is an article about natural selection, not about the emergence of complexity in nature. The respective roles of self-organisation and natural selection could be discussed in other pages. No? -- Thomas Arelatensis 14:05, 26 January 2007 (UTC)
The review gives the impression he tends to bloviate, he is dogmatic with narrow views discounting other concerns with weak arguments, and fails to provide few real advancements or real proof. Although they do say positive things that his research is useful. Just not grandiose as Wolfram suggests. I guess we need to add some kind of statement and references to detract from Wolfram's beliefs for NPOV. GetAgrippa 05:45, 3 February 2007 (UTC)
I don't know after reading more of these reviews. I don't think Wolfram's assertions about Natural selection are mature enough to pass muster as a valid concern. I am for keeping the Information theory section and its usefulness, but Wolfram's assertions are just his belief as he offers no real proof or detail just conjecture. At least we should drop his comments about Natural selection as they are not reliable or supported by secondary sources and really just constitute his orignal research. He offers no more proof than creationist arguments. GetAgrippa 13:32, 3 February 2007 (UTC)
I rewrote the Wolfram mention of natural selection but now it sounds idiotic. Any suggestions? GetAgrippa 16:21, 3 February 2007 (UTC)
Samsara noted in edit :"I like the previous one if it can be supported by a reference; what does it matter whether they are biologists, so long as their argument is sound?)" . I don't think it matters what his discipline is but it is not about a sound argument of his opinion but offering some description and some detail what he means and is there any proof to support his claims. It is a nebulous claim and others have noted that even as a hypothesis some aspects are untestable. I am deferring to the criticisms of others about his work. Pete Hurd found a useful site and I offered a Science article review of his book. I am not saying his mathematical model is incorrect in producing complex patterns, and I am just saying he offers an opinion that this could replace natural selection and offers nothing to support or substantiate or explain the statement. GetAgrippa 20:47, 3 February 2007 (UTC)
Axels edits seems to reflect he thinks it is red herring. Not that I'm putting words into his mouth. I think we could mention his work in reference to information theory without any mention of an egomaniacal rant about natural selection. Sound fair? Of course now if it is not related to Natural selection so why have it? Axel's argument appears to have merit. GetAgrippa 22:10, 3 February 2007 (UTC)
I must admit I'm a bit confused (perhaps because I'm too lazy to read it all) whether Wolfram's ideas, if substantiated, challenge natural selection or whether they have little or no bearing on it. I see Wolfram's ideas and NS as alternative ways of explaining the complexity of life. If one is important, it seems to me the other would become less important. (Though NS explains more than just complexity.) But yes I do think it's a Red Herring and don't think Wolfram's arguments are fleshed out clearly enough. — Axel147 02:12, 5 February 2007 (UTC)
Sorry to be a bit slow here, but when registering to look at the website I tactfully asked a couple of questions and forgot to check that mail account for a while, Here's the first response:
Comments:
> Does NKS reject natural selection,
No.
> or reject misunderstandings about the extent to which it creates complexity or produces optimal solutions?
Basically, yes.
Probably most important is that it suggests an actual mechanism for generating complexity in biology, that happens to have essentially nothing to do with natural selection. It also argues that finding "optimal solutions" probably has little to do with generating complexity.
For more information see:
They helpfully sent a more detailed response:
Mr. Souza,
You asked "Does NKS reject natural selection, or reject misunderstandings about the extent to which it creates complexity or produces optimal solutions?" Definitely the second.
NKS knows that natural selection happens and is important, but doubts that it is fundamental to explaining the specific phenomenon of complexity in living organisms. First and most simply, complexity is more general than living organisms so its overall cause is unlikely to be a principle operating (for the most part or as originally meant) only within life. If dendritic drainage patterns or fracture patterns are complicated without having undergone millions of years of natural selection, vein systems may be complicated for entirely similar reasons etc.
Second, formal modeling shows iterative improvement schemes are excellent at "honing"a simple system by tweaking a small number of continuous variables toward some single optimum, but are lousy at finding global optima in a large space of discontinuous changes. On the other hand, point changes to simple programs rapidly explore a wide variety of formal behaviors, including as a matter of course some very complicated ones, on the output side.
The classic Darwinian formula says "descent with variation" is the input to natural selection. NKS sees that "with variation" as much more important than at least some biologists suppose, because it expects a wider range of phenomenal variations from readily imaginable changes to underlying programs, whether those are (simple protein) genetic or developmental or regulatory etc. Wolfram thinks that natural selection is more likely to produce optimizing simplicities than complexity. And overall, it more likely to operate as a "net winnower" of a possibility space explored by algorithmic variation of underlying biological programs, than as the driver of that variation in the first place.
None of which means natural selection isn't happening or isn't important. Just that specifically variety (the harder of the two claims) and complex morphologies (the easier one) do not require it as an explanation, and can be better accounted for by factors operating at the previous, "descent with variation" stage, in Darwin's formula.
To me this appears to account for bits of history like the Cambrian rather better than the usual accounts. Instead of imagining that a whole bunch of separate "niche attractors" arose and ramified in a tiny space of time, and were all filled, one need only imagine that a body-shape or development program innovation occurred, and systematic variation in elements of that program then rapidly "tried everything". Some "stuck", in natural selection terms, and some did not - as adequate rather than optimized. A long but slow period of optimization and winnowing then follows in the variety already formed - that would be natural selection working.
Others have since noted that the two explanations - niche optimality "pull" and algorithmic variety "push" - make different predictions about things like species variety distribution across latitudes. Native mutation rate is higher where temperature is higher. Little more seems to be needed to account for the greater variety seen in the tropics. Not anything like a proof, just a suggestive "fit data point". Analyzing point mutations is an obvious place to try to confirm the idea. E.g. can one make simple vs. complex seashell shadings vary from one to the other with a few point mutations, without any selective forces operating?
I hope this is interesting, and thanks for your interest and the question.
Sincerely,
Jason Cawley, Wolfram Research
Hope this helps, dave souza, talk 19:03, 20 February 2007 (UTC)
Let's talk about something slightly more important than the degree to which we should massage Stephen Wolfram's ego, shall we?
I really dislike the placement of the example as the first section of this article, preceding even the 'general principles' section that would provide context and background. A long time ago, I moved it toward the end of the article, but I see it's drifted back again. I don't much like the section in general - it's written in a very simplistic, tutorial style more suited to a textbook than a reference work, and its placement at the beginning makes the article read like chapter 2 in 'introduction to evolutionary biology'. It doesn't make sense to me, from an encyclopedia perspective, to place the example of a phenomenon before the description of the phenomenon. The lead doesn't do that job either. I imagine it's there for 'accessibility' purposes, but without preceding discussion it's just a blob of text before you get to the actual article.
Does anyone have an objection to demoting it, or a good reason it should be where it is? Opabinia regalis 06:18, 7 February 2007 (UTC)
I don't have any objection. (I think the original reason was that example was the best way of explaining it without diving into the detail.) As a separate point I'm always confused by the sentence "Natural selection can act on ... any aspect of the environment". Maybe I've pulled it out of context but could it be worded more clearly? — Axel147 17:58, 7 February 2007 (UTC)
Natural selection still does not have any criticism of the idea in it. There should at least be on paragraph near the bottom labelled criticism. Steven Wolfram is not the only critic. I have heard complaints such as Selection just reduces the genetic diversity in a population. Even if a criticism is wrong, if it common it deserves a mention. GB 10:03, 12 February 2007 (UTC)
-- Thomas Arelatensis 13:45, 13 February 2007 (UTC)
Also the example of antibiotic resistance in golden staph is not that great an example. Much of antibiotic resistance in bacteria is the result of horizontal gene transfer between different bacteria, rather than by mutation. GB 10:03, 12 February 2007 (UTC)
I had added a section addressing that but I removed because it is just an example for an encyclopedia. I agree HGT is more significant than mutations in antibiotic resistance. GetAgrippa 11:47, 12 February 2007 (UTC)
How in the world is propagation of resistance (even with massive HGT) not an example of natural selection? You still have a perfect example of certain alleles out-competing others (sorry for going all Dawkinsian on you, but that's what natural selection is all about). It would fail to be an example of natural selection if the gene in question did not carry any advantage, or if its propagation was unrelated to this advantage (e.g. genetic drift). Surely nobody argues that this is the case in this particular instance! -- Thomas Arelatensis 13:29, 13 February 2007 (UTC)
Natural selection is certainly not a process; it is patently an unproven theory. Let us try to remove the strong POV slant in this article through consensus NOT through reverting good NPOV edits. And less proprietorial disputes please. Peter morrell 12:41, 23 February 2007 (UTC)
<reduce indent> Three questions:
Many thanks...unfortunately your Ragoletis example, which you said was compelling, only "constitutes a possible example (sic) of an early step towards the emergence of a new species by the mechanism of sympatric speciation," you seem to be bending over backwards to believe all this. I prefer to remain sceptical because I am not a rank believer. You point to the connections where I see only the holes in the same woven fabric of ideas. sorry to disappoint you. I will check out your other references, however. What I meant above about genetic drift was merely that random changes in populations do not necessarily illustrate NS. It is just when viewed through that particular lens that they seem that way. However, what is good about the Ragoletis case is that it shows how adaptable organisms are to subtle changes in the key components of their life cycles, which is fascinating but is not necessarily such compelling grist to the believer's mill as you suppose. My problem is with the curious way these things are pounced on as evidence when they seem wide open to other interpretations. Bad science, as I'm sure you know, is hunting down data to support a pet theory. That is precisely what NS seems like to me. Peter morrell 20:11, 23 February 2007 (UTC)
It is a process. The mechanism is undeniable. Samsara ( talk • contribs) 13:15, 27 February 2007 (UTC)
Overly long, disproportionately footnoted... reeks of old edit war. Can anyone who's been active on this article longer than I've been watching recall why this is and whether it needs to stay as long as it is? Opabinia regalis 07:53, 6 March 2007 (UTC)
In case anybody misses it in the thicket of header banners, I've put this article up for peer review. I've been picking at it for the last couple of weeks, but I really think it could use some fresh eyes, especially from non-biologists. Opabinia regalis 03:45, 18 March 2007 (UTC)
I know I have raised this before but there seems to be inconsistency in the use of phenotype/genotype now in the opening paragraph.
This implies an organism has one phenotype (not one for each characteristic) which is mapped to a single genotype. But how can the genotype increase in frequency unless I am producing clones of myself? Surely it's clearer to say genes (or alleles) increase in frequency? — Axel147 05:17, 21 July 2007 (UTC)
The Fitness section has some problems. Firstly no quotes, no sources, no citations. Secondly "Modern evolutionary theory defines fitness in terms of reproduction rather than survival." -This should be changed. Dawkins proposed DNA "gene reproduction" as a better explainer, and others in "modern evolutionary theory" have also moved away from simple "reproduction". Here's one reason why- in ants and bees and termites and other haplodiploid insects, the colonies are mainly composed of "sisters." The female workers and soldiers forgo reproduction so that their queen will produce sisters instead (brothers too, but relatively few). In other words, Evolution works for family members other than direct offspring. In fact in any creature, uncles and aunts, even cousins, can pass genetic material and their associated traits without reproducing.(through survival of nephews and nieces, etc) While it may seem a minor point at first, as stated now in the article, the whole theory breaks down the when any example of any creature forgoes reproduction for any reason(including humans) Thirdly the sickle-cell anemia is potentially offensive as well as factually incorrect. "as in extreme examples include many human genetic disorders like sickle-cell anemia"-- Sickle-cell anemia turns out to have great survival value in areas with high malaria infection. This is why many descendants of Africans who lived in malaria ridden areas have sick-cell anemia. Sickle cell disease is the most common inherited blood disorder in the United States, affecting 70,000 to 80,000 Americans. The disease is estimated to occur in 1 in 500 African Americans and 1 in 1,000 to 1,400 Hispanic Americans. ( http://ghr.nlm.nih.gov/condition=sicklecelldisease) So to call it an extreme example is, at best, misleading, and unfortunately, one could read into it a racist bias. This could be easily avoided. I am going to edit out "extreme," for now, but the example itself isn't very good (unless someone wants to greatly expand upon how sickle-cell relates to "genetic fitness") 76.19.28.24 15:17, 23 July 2007 (UTC)
I too think this needs re-writing because it misrepresents the original use of "fitness" and the phrase "survival of the fittest". Wallace to Darwin,
It is clear that "survival of the fittest" was intended to apply to variations not to individuals. (Or perhaps it could be viewed as applying to lineages or 'races' consistent with Darwin's title of the Origin describing natural selection as 'the Preservation of Favoured Races in the Struggle for Life'.) It is so obvious that being the fittest individual, if this simply means living a long time, is not sufficient per se to propagate characteristics to the next generation it is hardly worth mentioning the point! Darwin in any case clears the matter up, 'I should premise that I use the term Struggle for Existence in a large and metaphorical sense, including dependence of one being on another, and including (which is more important) not only the life of the individual, but success in leaving progeny.' — Axel147 12:03, 25 July 2007 (UTC)
The last sentence of the "Fitness" section contains very bad writing. It reads:
Since fitness is an averaged quantity, however, it is possible for a favorable mutation may arise in an individual that does not survive to adulthood for unrelated reasons, or unfavorable mutations to have a for unrelated reasons.
Could someone who understands this better than I please rewrite it? It's embarrasing. —Preceding unsigned comment added by 74.225.65.124 ( talk) 02:44, 1 September 2007 (UTC)
I have a question about this recent edit adding "The second was Adam Smith who, in The Wealth of Nations, identified a regulating mechanism in free markets, which he referred to as the " invisible hand", which suggests that prices self-adjust according to supplies and demand <ref>[[David Orrell|Orrell, David]] (2007) ''Apollo's Arrow'' Toronto: HarperCollins Publishers Ltd. [http://www.apollosarrow.ca/]</ref>. Thus for Darwin, the disaster that was supposed to occur according to Malthus was kept in check and constantly improved by competition (or law of selection)." I don't have the Orrell book, but does it support the assertion that Adam Smith's The Wealth of Nations inspired Darwin in the way claimed? Is there another reference to support the claim? The Malthus influence is well-known, is an equivalent influence from Smith supported by reliable sources? Pete.Hurd 21:14, 15 August 2007 (UTC)
See Inception of Darwin's theory#Malthus and Natural Law for more on the context. The statement that "Thus for Darwin, the disaster that was supposed to occur according to Malthus was kept in check and constantly improved by competition (or law of selection)." seems out of line with the sixth edition having allowed other alternatives to his bleak forecast. There's an indirect connection in that Malthus on p 2 says "The only authors from whose writings I had deduced the principle, which formed the main argument of the Essay, were Hume, Wallace, Adam Smith, and Dr. Price". It's interesting that on p 11.3 Malthus writes:
Browne makes a passing reference on p 389 to Darwin, musing after conceiving of the theory, envisaging an "invisible hand" selecting. However, she puts a lot of emphasis on the Whig thinking all around Darwin, particularly from Harriet Martineau. In summary, the addition of info on Smith is very dubious, and while his ideas undoubtedly were taken up by people who influenced Darwin, he had other more direct inspirations for the idea. .. dave souza, talk 10:29, 16 August 2007 (UTC)
I note that this article doesn't even link to the slightly broader article selection, which is in a fairly poor state. Do we want to have this broader article? I'd probably be in favour of keeping it since heaping everything into this article and having nothing linking the other forms together is probably a bad idea. Selection can provide an overview of the subject, such as classification e.g. natural vs. artificial, stabilizing vs. directional etc, as well as levels of selection and other related topics. Another much smaller article is evolutionary pressure. Should this one be merged into selection? I'm not very familiar with the finer details of evolutionary biology so I'm not sure exactly how much potential this one would have. If it is kept as is, perhaps we should look at whether evolutionary pressure or selective/selection pressure is more commonly used, and consider moving it. Richard001 04:11, 28 August 2007 (UTC)
The Darwin's hypothesis section contains a fraudulent misquotation: I have called this principle, by which each slight variation, if useful, is preserved.
I have called this principle, by which each slight variation, if useful, is preserved, by the term natural selection, in order to mark its relation to man's power of selection. and the next paragraph But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient. We have seen that man by selection can certainly produce great results, and can adapt organic beings to his own uses, through the accumulation of slight but useful variations, given to him by the hand of Nature. But Natural Selection, we shall hereafter see, is a power incessantly ready for action, and is as immeasurably superior to man's feeble efforts, as the works of Nature are to those of Art.
Darwin seems to imply that Natural Selection as some sort of nature selection force is superior to mans "feeble" efforts. His intent with the phrase Artificial selection also alludes to this. What confuses the matter is that nobody knows what was his or Spencer's intent with Survival of the Fittest. It could mean anything you want it to mean. Natural selection must be discussed in terms of Artificial selection and Survival of the Fittest since Darwin said SoF is more "accurate" and how it relates to "feeble man" and "nature's power of selection" as he put it in the passage dealing with Artificial Selection. It is not clear what was Darwin's intent with these three phrases and how they relate. He seems to be invoking nature as some sort of conscious "selection" force, unless there are passages that proves that it is not so.
Slow though the process of selection may be, if feeble man can do much by artificial selection, I can see no limit to the amount of change, to the beauty and complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may have been effected in the long course of time through nature's power of selection, that is by the survival of the fittest.
I propose that we at least cite the full sentence as written down by Darwin? TongueSpeaker 14:27, 12 September 2007 (UTC)
This sentence appears in the 'Fitness' section. I don't understand what the very last 'or unfavorable...' clause is supposed to mean. " Since fitness is an averaged quantity, however, it is possible a favorable mutation may arise in an individual that does not survive to adulthood for unrelated reasons, or unfavorable mutations to have a for unrelated reasons." Johnor 01:50, 1 October 2007 (UTC)
It is trying to say that since fitness is a probabilistic quantity (like life expectancy) a mutation could increase an individual's fitness and still not increase its actual reproductive success. This is just like stopping smoking would increase my probability of living longer but I could still get hit by a bus tomorrow. It is is important to distinguish what fitness actually means (expected reproductive success) from the way it is measured or estimated (by averaging actual reproductive success). Maybe the article does not makes this point clearly enough and needs amending. —
Axel147
21:51, 2 October 2007 (UTC)