Talk:Evolution

I feel as if it is best for us to move this article to Theory of Evolution for a few reasons. First of all, the name Theory of Evolution is more nuteral than Evolution. Second, many religious people may be a little offended at this being dipicted as if it is a fact. Lastly, Evolution is just a scientific theory, not a fact. Theory of Evolution would be a more correct title for this article. Peace:) --James, La gloria è a dio 22:41, 19 March 2007 (UTC)

Please read Talk:Evolution/FAQ. Wikipedia doesn't, and shouldn't, rewrite articles to prevent offending the religious. illspirit|talk 23:19, 19 March 2007 (UTC)

If you do read Talk:Evolution/FAQ it will send you a very specific article called Evolution as theory and fact. This is the information you should look at. The Law of Gravity is also both theory and fact. Would you have us rename Gravity to Theory of gravity? 23:47, 19 March 2007 (UTC)EdJohnston

Wow, this discussion must be repeated about once every two months. Next should be massive arguments on both sides. Then name calling. Then reverting of edits. Then it all dies down for it to happen all over again. Tiresome. Orangemarlin 00:19, 20 March 2007 (UTC)

As I have said repeatedly, the most popular argument, bar none, is that "evolution is a theory, not a fact". For some reason that resonates in the empty cavities of assorted crania.--Filll 00:31, 20 March 2007 (UTC)

You cannot say "bar none," because I'm stating to you right now, and I'm not going to waste my time arguing about it when you have so many other resources available to enhance your understanding, that evolution is a fact, and even more than a theory. Although for the sake of scientific interests, we label it as only a theory.Valich 08:52, 20 March 2007 (UTC)

Wow. . . Some people can be thick. . . gravity is a law. It is observable. It is testable. It is verifieable. Evolution was something someone thought of to explain why how we got here. It made sense in a time when people didn't know about DNA or that cells aren't little blobs of living substance. To get an idea of what a cell is like, imagine an entire planet ( making example large for purpose of showing intricacies)that has a computer core that directs: machines gathering materials from other planets, the making of electricity from solar energy, a defense system capable of destroying other things of equal size, and a system that starts more of the same machine out on other planets. Basically a cell is pure machinery. Incredibally complicated. Orangemarlin! ! ! Im gonna restate a truth that has been said a lot ( though not enough) evolution has not been verified whatever you say. And if creation is an unintelligent theory, why aren't the 2 arguments put side by side? The theory of evolution is stated as fact in schools by evolutionists. Creation is NOT shown to be wrong, it is only stated to be so. All evolutionists say is "this is an incorrect and stupid belief" (basically all they say about it to science students) Put both arguments side by side for everyone to see!

Orangemarlin do me a favor. ( I don't really expect you to, but im requesting you to anyway)
Please look into a series of movies that are called "Incredible Animals that Defy Evolution"
They give one of the most well organized arguments iv'e heard.
Thank you!
( and by the way I dont intend to revert to namecalling, even if someone else does, nothing destroyes the point of constructive debate as easily)

````oddball 2002

Well, there goes the counter-Wikipedious name-calling. There are scads of instances of the word "theory" in the article, so wherein is the problem? Since this is an article on a scientific topic, the word is properly used as used by scientists (as in 'theory of gravity' -- thanks). There is an article theory, which is not cross-referenced here as far as I see, and contrasts scientific and other uses of the term. Now if you'll excuse me I'm off for a relaxing tour of the global warming discussion. Dfarrar 01:34, 20 March 2007 (UTC)

Evolution does not equal to the theory of natural selection, natural selection is a hypothesis(quite frankly at this point it is just more, much more than a theory) which explains the process of under which evolution happens. Evolution is observable, it is not only a theory. Take the same antibiotic against a bacterial infection, and you will see what happens. The process under which this evolution happened can be a theory and/or a hypothesis, but the fact that an 'evolution' did happen can not be contested. In short, evolution is not a theory. Fad (ix) 00:36, 20 March 2007 (UTC)

IIRC, this is all explained in the article or the various archives of this talk page. There's really no point reiterating it, to be honest. illspirit|talk 00:54, 20 March 2007 (UTC)

Actually, I am agreing with you, you guys even created a FAQ subpage, a great idea. I'll steal the idea for another article. :) Fad (ix) 01:00, 20 March 2007 (UTC)

Fad, your arguments and opinion belong on a talk forum, not here. This discussion section is for how to improve the article, not question its validity and scientific content, or to question what constitutes a hypothesis vs. a theory vs. fact, or to state that evolution does not equal NS (Yes, We all know that evolution is much more complex than just that), or to tell us about your views on taking antibiotics.Valich 08:52, 20 March 2007 (UTC)

You've misread me, check your talk. Fad (ix) 15:18, 20 March 2007 (UTC)

Wikipedia considers evolution an undeniable and undisputed fact and any opposing evidence as 'junk science' regardless and only people with several mental illness (such belief in god) would disagree. You'll have better luck getting Evolution renamed to "The Fact of Evolution." or arguing 1+1=3 Wyatt 20:46, 20 March 2007 (UTC)

You're wrong. And this point has been debated 17 times. Please check the archives. Orangemarlin 00:33, 21 March 2007 (UTC)

Wow. . . Some people can refuse to see the obvious. . . gravity is a law. It is observable. It is testable. It is verifieable. Evolution was something someone thought of to explain why how we got here. It made sense in a time when people didn't know about DNA or that cells aren't little blobs of living substance. To get an idea of what a cell is like, imagine an entire planet ( making example large for purpose of showing intricacies)that has a computer core that directs: machines gathering materials from other planets, the making of electricity from solar energy, a defense system capable of destroying other things of equal size, and a system that starts more of the same machine out on other planets. Basically a cell is pure machinery. Incredibally complicated. Orangemarlin! ! ! Im gonna restate a truth that has been said a lot ( though not enough) evolution has not been verified whatever you say. And if creation is an unintelligent theory, why aren't the 2 arguments put side by side? The theory of evolution is stated as fact in schools by evolutionists. Creation is NOT shown to be wrong, it is only stated to be so. All evolutionists say is "this is an incorrect and stupid belief" (basically all they say about it to science students) Put both arguments side by side for everyone to see!

• Orangemarlin do me a favor. ( I don't really expect you to, but im requesting you to anyway). Please look into a series of movies that are called "Incredible Animals that Defy Evolution". They give one of the most well organized arguments iv'e heard. Thank you! ( and by the way I dont intend to revert to namecalling, even if someone else does, nothing destroyes the point of constructive debate as easily) Oddball 2002 15:30, 21 March 2007 (UTC)oddball 2002

Wikipedia has proof of my staement built into it. The official Evolution FAQ page says the reason that the theory of evolution is well supported by fossil evidence and the like. Its not! But it's an accepted source, and so people quote its falsehoods. Wikapedia is quite biased. but I'm ok with that. . . . . . We're used to it. 71.53.80.206 16:40, 21 March 2007 (UTC)oddball 2002

Let's see, I have a BS in Biochemistry, an MS in Biochemistry, an MD, and nearly 30 years of experience in Science and Medicine, and I'm being lectured about what is a cell? So I probably know more than you how complicated a cell is. And so? Four billion years of evolution will give you complexity and diversity. I'm happy with that, and I don't need to believe that your mythical god had anything to do with it. And I've seen the one part of that boring DVD you mentioned (3 discs to whine about Evolution). It's so filled with incredible statements that it goes without saying, it is a load of BS. Go here if you want to read about the Bombadier Beetle [2]. You can't prove Creationism wrong, because it can't be falsified. No matter what I say, you'll resort to this pathetic notion that your mythical god had something to do with it. It's a boring, exhausting, and nonsense argument that makes no sense to me. I may grant that my G_d established the natural laws of the universe, but everything else follows that law. Every animal on this earth evolved through a series of random events. And that my friend is a verifiable, indisputable fact.Orangemarlin 15:49, 21 March 2007 (UTC)

I agree with you:) --James, La gloria è a dio 23:00, 20 March 2007 (UTC)

Your thoughts are outwith science, which is what this article's about. This article describes what evolution means in biology, not what it means in a faith context. dave souza, talk 23:43, 20 March 2007 (UTC)

Yes, I know. In science evolution is just a fact. Just to let everyone know, I am not going to give up until I see that this article is NPOV. Doing what is right is more important than doing what is popular. --James, La gloria è a dio 23:46, 20 March 2007 (UTC)

Evolution is a fact, I told you, take the same antibiotic everytime you have an infection and see what happens. It is observable, repeatable, measurable etc. Read the articles introduction and see under which context it is used. Fad (ix) 00:52, 21 March 2007 (UTC)

Thank you for your comments. The controversy is already well-covered at Evolution#Social and religious controversies, with links to three sub-articles which more fully explore the issue. Controversial articles per se do not require any tagging. — Knowledge Seeker দ 01:18, 21 March 2007 (UTC)

this social and religious section is not NPOV —The preceding unsigned comment was added by Whoutz (talk • contribs) 16:26, 21 March 2007 (UTC).

Evolution is not a proven fact, rather a theory. It is contested by highly qualifyed scientests. Also it is not believed to be fact by everyone. I am now going to change anywere it says 'evolution is not contested by the scentific community' etc to it is, and if anyone here dosen't like that they have to first read a 'creation' and a 'Jounal of creation'. Dont be idiotic and read out of date ones, or ones not from answers in genisis. If you dont want to do research, dont change mine. There is no evedence for evolution that would turn micro-organsims into men, there is evidence for DE-volution. NuttyProSci-Fi3000 17:25, 21 March 2007 (UTC)

Evolution has nothing to do with religion, Atheism or Richard Dawkins except in your mind. illspirit|talk 17:05, 21 March 2007 (UTC)

As I explained to Wyatt on his talk page, this is simply not relevant here. Also, please read up on what theories and facts are. (The talk archives are an excellent place to start, as is the article itself). Mikker <sup>(...)</sup> 17:24, 21 March 2007 (UTC)

Evolution has nothing to do with religion? you are brilliant. feel free to delete the social and religious sections Wyatt 19:20, 21 March 2007 (UTC)

I'm afraid you misunderstood, Whoutz/Wyatt. Evolution, and science in general, makes no statement about God or the validity of religion, only that there is no evidence of God and that we can develop plausible models to explain the way the universe works and how it has proceeded to this point. However, these explanations may not be consistent with the mythologies of various religions, and this may give rise to controversy. I find the suggestions you make a bit incoherent, but I don't see how claims of teaching religion to be child abuse to be relevant here. If you have some specific suggestions with citations, please feel free to bring them up here. — Knowledge Seeker দ 20:16, 21 March 2007 (UTC)

Let's all remember to maintain civility and assume good faith.  :) Gnixon 12:26, 22 March 2007 (UTC)

Could you try making a more concise edit since it's part of the introduction? I agree it's not right to say "a common ancestor," but I think we should save that level of detail for the body of the article. Maybe instead of getting into lateral transfer, etc., we could just revise the common descent sentence, saying something like "are descended from a few primitive ancestors." Gnixon 10:41, 17 March 2007 (UTC)

How abouts "common ancestry"? Jefffire 11:10, 17 March 2007 (UTC)

Don't you mean "last common ancestor"? garik 11:46, 17 March 2007 (UTC)

Whoever finds a concise way to put it in the intro could try doing the same thing for the mention of common descent in the Controversy section. Gnixon 17:13, 17 March 2007 (UTC)

Also, Common Descent will have to be revised, since it doesn't mention this issue. In fact, it says that biologists agree there was a common ancestor. Changing the intro of the Evolution article is the wrong place to start with this issue. Let's change Common Descent first, with good citations, then change the common descent section of Evolution, and then change the introduction in a concise way. Until then, I think we should revert the change to the intro. I'm not an expert on the issue, so someone else will have to make the major changes. Gnixon 17:32, 17 March 2007 (UTC)

If we say "descended from a few primitive ancestors," this would be too associated with later speciation divergence. Lateral gene transfer occurred during the early origins of life, amongst early single cellular organisms, but there was never any single last common ancestor to "all" species. The last line of the intro has to be changed. I included the supportive sources, so they would be easy to retrieve. How about adding only a one sentence extension with something like this:

"Traditionally, all known species were thought to have descended from a single common ancestor through this process of divergence. However, the current view is that there never was a single [last common ancestor] because of the tremendous amount of gene transfer occurring during the early stages of evolution." Gene transfer would then be linked to the [horizontal gene transfer] article, which is a good continuation of this subject. The Last Common Ancestor article states, "until the new species establishes itself there are going to be some, possibly many, generations of gene-swapping with the parent branch. Depending on the process that gives rise to the species, the LCA can often be better described as the initial small, interbreeding group or clan or founding population, all members of which carry a common species-defining mutation.Valich 20:39, 17 March 2007 (UTC). The last sentence in the intro also contradicts what is later stated in the article under Mechanism of Evolution: Horizontal Gene Transfer: "Horizontal gene transfer complicates the inference of the phylogeny of life, as the original metaphor of a tree of life no longer fits. Rather, since genetic information is passed to other organisms and other species in addition to being passed from parent to offspring, "biologists [should] use the metaphor of a mosaic to describe the different histories combined in individual genomes and use [the] metaphor of a net to visualize the rich exchange and cooperative effects of HGT among microbes".[23] The [Speciation] article also states that, "However, recent research shows that jumping of a gene from one chromosome to another can contribute to the birth of new species [11] This validates reproductive isolation mechanism, a key component of speciation.Valich 18:05, 18 March 2007 (UTC)

Personally, I've always found this terribly confusing: Are we seriously to believe that prokaryotes emerged multiple times from unique events, then exchanged things? It might be a series of convergances and divergences, but an initial single prokaryote seems hugely more likely, and the rest just muddle. Sure, I can see what it's getting at, but unless we presuppose several colonies coming together multiple times too form the proto-prokaryote, I don't see it. Adam Cuerden <sup>talk</sup> 19:56, 18 March 2007 (UTC)

For clarity in confusion and consistency in all Wikipedia articles, please refer to the links added to the Horizontal gene transfer article, Speciation article, as well as the Mechanisms of Evolution section in this article, and the extremeley up-to-date scientific sources cited. Remember, science is progressive. I think it is extremely narrow-minded for us to seriously believe that all species evolved only at one particular instance in all of space and time and only arose from only one prokaryote in our vast enormous universe under all these same earlier environmental conditions, as we similarly like to, or have liked to in the past, entertain ourselves with the notion that there was or is only one God. A different subject, but the point is that there is a psychological bias that exists in the human mind to search for simplicity, and to understand Nature through concepts of simplicity, and "one" is simpler than many. One may be easier for a person to understand, but not always the truth, or, in this case, not the facts. Yes, unicellular organisms emerged from more than one LCA and new such species and strains arise today from gene transfer. Gene transfer amongst species, and not from a common ancestor, played an important evolutionary mechanism in protist evolution and in the origin of life, and still do today. While most higher species do have a common ancestor, there never was a single last common ancestor because of the tremendous amount of gene transfer occurring during the early stages of evolution. This is now an established fact in the scientific community, virtually undebated by any evolutionary biologist anymore, except by creationists: Valich 21:48, 18 March 2007 (UTC)

Lake, James A. and Maria C. Riveral. (2004). "The Ring of Life Provides Evidence for a Genome Fusion Origin of Eukaryotes. Nature. Vol. 431 [[3]]

UCLA Report. (2004) "Ring of Life." [[4]]

Doolittle, Ford W. (February 2000). "Uprooting the Tree of Life." Scientific American. pp. 72-77.

Lake, James A. and Maria C. Riveral. (1999) PNAS (Proceedings of the National Academy of Science) 96:7 pp. 3801-3806 [[5]]

Bapteste et al. (2005). "Do Orthologous Gene Phylogenies Really Support Tree-thinking?" BMC Evolutionary Biology. Vol. 5:33 [[6]]

Gogarten, Peter. (2000) "Horizontal Gene Transfer: A New Paradigm for Biology." Esalen Center for Theory and Research Conference. [[7]]

On the birth of new species today see:

Masly, John P., Corbin D. Jones, Mohamed A. F. Noor, John Locke, and H. Allen Orr. (September 2006). "Gene Transposition as a Cause of Hybrid Sterility in Drosophila." Science. Vol. 313, Issue 5792. pp. 1448-1450

Richardson, Aaron O. and Jeffrey D. Palmer. (January 2007). "Horizontal Gene Transfer in Plants." Journal of Experimental Botany. Volume 58. pp. 1-9 [[8]]

Um...

Forgive me. I'm fully aware of the fusion origin of Eukaryotes. I just see that, combined with the Universal Genetic Code, as further evidence of a last common ancestor: How could a genome fuse if it wasn't using the same language?

I don't at all argue that it's not a simple tree; it's a tree with combinations. Indeed, I'm rather enamoured of the ideas of the larva and imago of insects being a combination of two organisms: the way the imago grows out of cells that have been in the larva te whole time, replacing everything else, is interesting hints at this - provided I understand insect metamorphosis. However, I think that the origin of our genetic code, and probably most of the rest of it - ribosomes, etc - were already fused in the last common ancestor, and the horizontal connections don't, in a meaningful way, change this.

How am I wrong? Adam Cuerden <sup>talk</sup> 22:34, 18 March 2007 (UTC)

Valich, none of the references that you cite actually challenges the idea of a single common ancestor. The fact that Bacteria and Archaea fused at one time to create the Eukaryotes, and that considerable gene transfer occurs between Prokaryotes, doesn't address where the Bacteria and Archaea came from or rule out whether, at one time long before the fusion event(s), they shared a single common ancestor. If anything, they argue against a single common ancestor for all Eukaryotes (although one of the references you provided, the UCLA report, actually references the idea of a "first Eukaryote" on one of its graphics. "Rings of life" don't refute common ancestry.--EveRickert 02:28, 19 March 2007 (UTC)

You are wrong. Read the articles. they all support the view that there was never a least common origin. This is why the tree of life in these articles aren't, and can't be, rooted. If pictures speak a thousan words, then just click on the UCLA Report article. The origins are a ring, not a single root, due to lateral gene transfer. Valich 08:08, 20 March 2007 (UTC)

EveRickert states, "Valich, none of the references that you cite actually challenges the idea of a single common ancestor." Doolittle cited above, and in the article, specifically states: "But extensive [gene] transfer means that trees will differ (although many will have regions of similar topology) and there would never have been a single cell that could be called the last universal common ancestor." This is a fact, and is what I have found again and again through researching this and talking with experts in this field. In particular, I direct you to read Lake's analyses. In the intro, the phrase, "While most species do have a common ancestor..." should be linked to the Common ancestor article, while the phrase "descended from a common ancestor" should be linked to the last common ancestor article. Valich 03:53, 19 March 2007 (UTC)

The Rivera and Lake Nature article you cite does not actually challenge common ancestry, as it is only about Eukaryotic origins. Whether Eukaryotes are descended from one Prokaryote or many doesn't affect the question of whether the Prokaryotic ancestor(s) themselves had a common ancestor. The PNAS Lake article also does not discuss the origin(s) of Prokaryotes, only there relationships to one another well after their origin(s).

You did not provide a full citation to the Doolittle article, so I can't look it up in order to read the sentence you quote from it in context. Even if it is there and is used to mean what you imply it does, it would still not be enough evidence to support your statement that "there never was a single last common ancestor...this is now an established fact in the scientific community, virtually undebated by any evolutionary biologist anymore." Theories like this take decades or more--and more than one citation--to become "established facts." And Scientific American, while an excellent magazine, is not peer-reviewed and so a quote from them would need something more to back it up before saying it was "virtually undebated...established fact."

With respect, your conclusions regarding common ancestry are quite a stretch from the statements made in the articles you cite (those articles that are fully cited and available). It seems to me you are taking valid and active discussions among scientists regarding A. the original of Eukaryotes and B. the "shape" of evolutionary trees (or rings), and stretching them to fit your own ideas on the origin(s) of life--a topic that is hardly as settled as you are trying to make it out to be.

And Adam Cuerden is right in all the logical problems that he's brought up with your stance--none of which seem to have been addressed yet.--EveRickert 05:55, 19 March 2007 (UTC)

It's not my fault that you can't read the full article. Go to the library. It would be ridiculous to expect everyone to only cite sources available at free access to everyone on the internet. The majority of journal articles, and all books, are not available on the internet. So what is your point here? This concept have having more than one life form that all life evolved from was stated by Darwin, has been advocated since his times, and openly expressed through culmination of many scientific studies, mostly with bacteria, over the last fifty years now, and openly promoted and accepted within the evolutionary biology community through scores of articles publish over the last ten years. I cited 10 references dating from 1999 (Doolittle) to the present." Valich 08:08, 20 March 2007 (UTC)

You don't know what you are talking about. Have you even read the Horizontal gene transfer article? No. Because if you had, then you would have read more of Dolittle's article. Go to the library and read it. Do I have to type it ALL in just for YOU to read? That would be inappropriate. You haven't read any of these articles and very clearly you are not up-to-date on the current research and the current state-of-knowledge in this field. I've been spending years on this, and you? Valich 06:20, 19 March 2007 (UTC)

No, you simply need to provide a full citation. You cited a year and page numbers only. As I am sure you are aware,Scientific American is published monthly, not annually.

And please stick to the issues. Your time is better spent logically addressing the challenges to your opinions rather than personally attacking the editors who have challenged them.--EveRickert 06:26, 19 March 2007 (UTC)

I posted the following: Doolittle, Ford W. (February 2000). "Uprooting the Tree of Life." Scientific American. pp. 72-77. I gave the month, year and pages, also Vol 282:90. I did a search, just for you, and see that this article can be downloaded at: [[9]]—The preceding unsigned comment was added by Valich (talk • contribs).

Ah, the missing link: February. Thanks. You will see I have also taken the liberty of adding it to your citation above, where it was missing. Now that I have the issue that the article was published in I can also get it through my own library, but I appreciate your saving my time by providing the PDF. Now, you see how easy that was? I look forward to reading the article.--EveRickert 15:06, 20 March 2007 (UTC)

The taxo box summary to this article at [[10]] states "The exact relationships of the three domains are still being debated, as is the position of the root of the tree. It has also been suggested that due to lateral gene transfer, a tree may not be the best representation of the genetic relationships of all organisms." This citation should be added underneath the tree in the taxo box, as it was created and drawn along with it, and the alternative "Ring of Life" diagram should be added somewhere as well. The farther back you go in the tree, the simpler the species, the simpler the genome, the more lateral gene transfer occurred, to the point till you start debating where and what constitutes life.Valich 03:28, 19 March 2007 (UTC)

For a multiple-origin "Ring of Life" diagram in accordance to early lateral gene transfer - citation listed above - based on previous research projects at UCLA (available to scan and send) see [[11]]. See also the alternative Tree of Life based on 16sRNA by Mitchell L. Sogin of Woods Hole Marine Biological Laboratory at [[12]]. Valich 06:39, 19 March 2007 (UTC)

It is just not possible to provide all the contents of every article cited. Nor is it possible to keep listing multiple citations to satisfy just a handfull of people who for some reason find this commonly accepted knowledge to be deviant or offensive or challenging to them in some way. A person has only so much time in one lifetime to devote to defense or persuasion of what they already know as fact, and actively discuss as fact amongst colleagues, before they must move on and expand in the area of research. The abstract of the last citation by Yi Chuan (2002) PMID. "The Basic Outline of the Evolution of Single Cell Life-Form." Jan;24(1):104-10. Yi Chuan summarizes the last fifty years of research in this area quite nicely [[13]]:

"In 1960s, kingdoms of organisms were charted generally in a five branching form. Later, the endosymbiont hypothesis for the mitochondria and the chloroplast was proposed. The life-form is divided into two forms, the prokaryotes (bacteria) and the eukaryotes. The study of the molecular biology made the progress faster. In 1980s, Woese, CR.asserted that two-domain view of life was no longer true, a three-domain construct, the Bacteria, the Archaea, and the Eukaryotes had to take its place. At first, phylogeny trees based on differences in the amino acid sequences, then among ribosomal RNAs and also nuclear gene from hundreds of microbial species were depicted and many mini phylogenetic trees grouped the species according to their differences in the sequences. It was found that they shared genes between their contemporaries and across the species barriers. At the root of the phylogeny tree, there was not a single common cell, it was replaced by a common ancestral community of primitive cells. Genes transfered rather freely as the transposons swapping between those cells. There was no last universal common ancestor of single cell that could be found in the revised Tree of Life, It was not easy to represent the genealogical patterns of thousands of different families of genes, in one systematic map, therefor there was no trunk at all."

Yes, but that just says that determining the origin became much more difficult, and that HGT muddled the waters so much that it wasn't possible to find the trunk any more using modern methods. That's not the same as saying there never WAS a last common ancestor. Adam Cuerden <sup>talk</sup> 11:10, 19 March 2007 (UTC)

What are you getting at? What do you mean by "determining the origin"? We have never determined the origin, so how has this in any way changed now? Or knowledge of DNA sequencing of primeval organisms has enhanced our ability to determine origins, not inhibited it. And this is why we can now more clearly see that there isn't one. How can you say that HGT has "muddled the waters" when it is something that has always been there. What the realization of HGT has done is to muddle the comprehension of origins for those who cannot understand it. Are you saying that before we were able to say that we found an LCA, but now we can't? We never have and never will. Yi chuan states that there is no universal common ancestor, even now in the new revised tree of life. Read Lake and Doolittle. Portions of which I have provided on my user talk page. The concept of last common ancestor is instructive until you get into single celled microbial organisms. Beyond this, it all changes. What we're trying to do now is to discover the minimal genome species that was an LUCA that consisted of about 260 genes. Beyond this, there was never any LUCA. And even amongst higher level multicellular eukaryotes, there was lateral gene transfer that "muddled the genome," so to speak, so that you cannot anylonger talk about a single LUCA, but must refer to more than one. Where did the chloroplasts and mitochondria in Eukaryotes com from? They were engulfed through endosymbiosis with other species. So shouldn't those other species be included in an analysis of the LUCA? They were part of that organism. You see how the entire concept breaks down here? Yes, it's very helpful to think of a LUCA, but only until you reach that limit. When you start reaching the single cell microbial level, the evolutionary processes, and the notion of a LUCA all change. That's the difference. Valich 08:08, 20 March 2007 (UTC)

Valich, you're simply wrong, here. In the quote above, for example, you chose to highlight this phrase:

There was no last universal common ancestor of single cell that could be found in the revised Tree of Life.

You'll note the final part of this clause - that could be found. That is, it is difficult to identify a LUCA due to HGT and other problems, and we may not be able to reconstruct the root of the existing tree, because it is so confused. This is ENTIRELY different from saying that there was no common origin for living things. This is what Adam is saying and what I think you're failing to understand. There is no tree of life, correct, but that does not mean that life did not have a single point of origin. This has NOT been refuted, and all the references you have posted above simply suggest that it cannot be refuted using phylogenetic methods. If you can plausibly convince us of the origin of genetic code without a LUCA, I think we'd all shut up and listen to you. Graft 16:37, 21 March 2007 (UTC)

I am writing a new article on it. We do not have proof that the genetic code, as we know it on Earth, is "universal" to the universe. There are many alternative possibilities to the current genetic code, and Watson and Crick tried a host of others before finally stumbling on the correct 4-base, 3-code word, double-helix that pertains to life on Earth. There are numerous other genetic codes and the National Center for Biotechnology Information NCBI keeps a listing of all of them that I'm sure you can find somewhere on there extensive website.

Children in Junior High School, and even Elementary School today learn about genetics, and I have even heard of them teaching PCR (Polymerase Chain Reaction) techniques in High School. Please give the up-and-coming younger generation some credit. There is no need to keep this article so simple-minded in thought and terminology that it not only gives innacurate and incorrect concepts, but demotes science. The article should explain evolution, but also challenge the readers' interest with thoughts and ideas and terminology that make her or him want to look up more - to understand more about this exciting field.

The word "Universal Genetic Code" is an old-fashioned name for the standard genetic code and is no longer used. It was once thought that there existed just one, universal genetic code used by all living organisms. However, beginning in 1979, numerous non standard genetic codes have been discovered. Thus there is no universal genetic code and the phrase needs be avoided. "Back in the early 1970s, evolutionary biologists did think that a given piece of DNA specified the same protein subunit in every living thing, and that the genetic code was thus universal. This was unlikely to have happened by chance, so it was interpreted as evidence that every organism had inherited its genetic code from a single common ancestor. In 1979, however, exceptions to the code were found in mitochondria, the tiny energy factories inside cells. Biologists subsequently found exceptions in bacteria and in the nuclei of algae and single-celled animals. It is now clear that the genetic code is not the same in all living things." And this provides some possible evidence that all living things did not have only one single universal common origin, or a single Last Universal Common Ancestor.Valich 04:35, 21 March 2007 (UTC)

Really, Valich, you need to learn a bit about creationism - you've just quoted Jonathan Wells as if he had something relevant to say about biology, when he's said he took a degree in biology at the request of Sun Myung Moon in order to tear apart evolution.

In fact, the code is mostly universal, with a few slight variations in some branches of life, and the term remains in use. Adam Cuerden <sup>talk</sup> 05:22, 21 March 2007 (UTC)

Universal is a euphemism (not universe but earth)for the ubiquitous standard code. The differences that some mitochondria, chloroplast, prokaryotes, etc exhibit is still modified from the standard code. All life ,especially plants and bacteria, demonstrate evidence of HGT, including humans. The concept of the LUCA is a theoretical construct (a grade) that most evolutionary biologist agree (recent evolutionary biology meeting described in Science) was already complex, also gene loss was probably instrumental in the birth of bacteria as well as HGT. HGT makes finding the root impractical, but not impossible. Bapteste E, Brochier C. On the conceptual difficulties in rooting the tree of life. Trends Microbiol. 2004 Jan;12(1):9-13. Review. PMID: 14700546 [PubMed - indexed for MEDLINE Lake JA, Herbold CW, Rivera MC, Servin JA, Skophammer RG. Rooting the tree of life using nonubiquitous genes. Mol Biol Evol. 2007 Jan;24(1):130-6. Epub 2006 Oct 5. PMID: 17023560 [PubMed - in process] Cavalier-Smith T. Rooting the tree of life by transition analyses. Biol Direct. 2006 Jul 11;1:19. PMID: 16834776 [PubMed - in process] Baldauf SL The Deep Roots of Eukaryotes Science 13 June 2003 300: 1703-1706 [DOI: 10.1126/science.1085544] (in Viewpoint) Toward Automatic Reconstruction of a Highly Resolved Tree of Life Francesca D. Ciccarelli, Tobias Doerks, Christian von Mering, Christopher J. Creevey, Berend Snel, and Peer Bork Science 3 March 2006 311: 1283-1287 [DOI: 10.1126/science.1123061] (in Reports) Genomics and the Irreducible Nature of Eukaryote Cells C. G. Kurland, L. J. Collins, and D. Penny Science 19 May 2006 312: 1011-1014 [DOI: 10.1126/science.1121674] (in Review).GetAgrippa 21:46, 21 March 2007 (UTC)

It also makes a useful term for describing evolutionary evidence - "universal genetic code" brings up the right images, if perhaps very slightly too strong of ones. Adam Cuerden <sup>talk</sup> 21:38, 21 March 2007 (UTC)

Pshaw. I think anyone worth their salt would agree that even the variations that make the standard genetic code non-universal are obvious derivations, and that they can't really be called a "different" code apropos of origins. Graft 21:44, 21 March 2007 (UTC)

I think I may be able to add some clarity to the recent discussions of Valich's use of the 16s rRNA Tree of Life figure to support his argument that there was no LUCA.

Valich has, here and in discussions on other users' talk pages, repeatedly brought up the "Tree of Life based on 16s rRNA by Mitchell Sogin of Woods Hill on the TOL Website at [[14]]" as evidence for his statement that "there is not, nor ever will be a LUCA." To quote Valich from Adam Cuerden's talk page:

"Look at the Tree of Life based on 16s rRNA by Mitchell Sogin of Woods Hill on the TOL Website at [[15]]. The three domains are not rooted, nor is the Eukaryote Crown Group rooted to the Archaea and Bacteria Domains. Mention of an unrooted tree, the Ring of Life, or the fact that there is not, nor ever will be a LUCA, should be mentioned somewhere in the introductionValich 04:53, 21 March 2007 (UTC)"

He has mentioned this graphic a number of times, but I believe he is misinterpreting it and the references in the caption to it being "unrooted." To get clarification of this issue and the meaning of the term "unrooted" in the caption to the graphic, I emailed Dr. Sogin, the author of the graphic. My query to Dr. Sogin stated:

"I am writing with a question regarding your 'Universal and Eukaryote Phylogenetic Trees Based on 16s rDNA,' posted at Tree of Life Web at http://tolweb.org/notes/?note_id=54. This graphic is being used by an editor of the evolution article at Wikipedia to argue that there were multiple origins of life and no such thing as a 'Last Universal Common Ancestor.' Specifically, the editor claims that the fact that the caption of the figure says it is 'unrooted' refers to multiple origins of life.

"I believe he is misinterpreting the graphic and the caption. It appears to me that the centerpoints of the graphics indicate where the lineages are branching off from one another, and that the term 'unrooted' in the caption simply means that the exact 'root' is unknown and thus not depicted.

"I find your figure very interesting and I was hoping you could shed some light on this matter.

Dr. Sogin sent me a brief reply via his cell phone, which I initially posted here. He later sent me a longer reply. I am replacing the cell phone message with the longer message, as I think it is this latter that he would prefer to have posted:

"I hope you received my response to this e-mail sent from my cell phone. You are correct about the interpretation of the figure. The tree is unrooted which means no attempt is made to suggest which lineages are deepest branching. It was drawn this way to avoid a controversy that persists to this day regarding the identity of the protists that branched first in the eukaryotic evolutionary lineage. It in no way implies multiple origins of life. I hope you can set the editor of that Wikipedia page on the correct track. You may cite me on this comment."

I hope this is helpful.

(I know you're not typically supposed to delete comments from talk pages; I hope everyone will forgive me in this one case our of respect for Dr. Sogin)--EveRickert 21:23, 21 March 2007 (UTC)

There is an extensive literature that Valich does not mention with other analyses. I mentioned some up above and the paper looking at indels seems an interesting strategy. He also fails to mention articles the last five-seven years examining the LUCA issue. Further, there are plenty of reliable analyses studying bacteria evolution despite HGT. I am with Graft below and his comments "Where's the sex?". A true conundrum. GetAgrippa 20:51, 21 March 2007 (UTC)

There may be a misunderstanding here. The fact that the common ancestor may have been a community, rather than a single well-defined cell, does not imply a "multiple origin of life". Rather, the idea is that in the earlier stages of life (before the bacteria-archaea-eukarya separation), HGT was so rife that no single ancestral cell (indeed, no lineage) can be meaningfully identified; then, at some point, certain cells reach a degree of complexity such that HGT cannot occur to the same extent, creating independent, well-defined lineages for the first time. See Woese's paper, aptly titled "The universal ancestor."[16]: "The universal ancestor is not a discrete entity. It is, rather, a diverse community of cells that survives and evolves as a biological unit. This communal ancestor has a physical history but not a genealogical one. Over time, this ancestor refined into a smaller number of increasingly complex cell types with the ancestors of the three primary groupings of organisms arising as a result." Again, this does not imply that life has appeared independently at several locations. It does not significantly alter the general picture of common descent, either. --Thomas Arelatensis 14:30, 22 March 2007 (UTC)

Thanks Thomas. I really did my best to characterize Valich's arguments as accurately as possible in the context of my query, and I drew on several posts to do so, but I easily could have misunderstood some part of them (wouldn't be the first time!) Anyway your comment is very interesting and thought-provoking. In light of what you say, and the abstract you posted, I do wonder if the whole discussion is really just hair-splitting, at least in the context of the Wikipedia articles.

This discussion has made me think very carefully about the use of phrases like "common descent" and "ancestor." If we see evolution happening at the level of populations, it seems like an oversimplification to imply that the "ancestor" of any species was actually a single individual. For example, let's say there's a brown mouse whose population is split into two, one of which evolves over time into white mice and the other into black mice. The white and black mice would be descendants of the sub-populations of the brown mice, so though we would say the brown mouse is an "ancestor" of the white and black mice, we wouldn't really mean that one brown mouse was the "ancestor." Even though we use jargon like "common ancestor" when discussing trees (or rings, or webs, whatever) that developed well after the origins of life, I think most people who are really familiar with these terms are aware that they are referring to populations, not individuals. For those who aren't, I wonder how important the conceptual difference really is--the more they learn about evolution, the more they will come to understand this before the difference really becomes important. (But then, maybe I'm misunderstanding something).

So does this change as we start looking closer at life's origins? Does the idea of the LUCA as a a "diverse community of cells that survives and evolves as a biological unit" with "a physical history but not a genealogical one," as opposed to the LUCA as a single cell, fundamentally change the idea of a LUCA or of common descent? Thomas, you say it doesn't, at least as it concerns the latter, and I would agree with you. If this is the case, then the distinction may be worth mentioning somewhere deeper within the common descent' and related articles, but would not be worth mentioning in a lead here or elsewhere.

Finally, would you say that this is an issue that is fairly settled yet? I have seen a few articles by Woese, some much more recent than the one you cite, and he does seem to be in the forefront of thinking on this particular hypothesis, but it is hard to say how widely these ideas have been accepted in the scientific community. I see that the article you give has been cited 272 times, and while I have not reviewed most of the citing articles (I do have other things to do!), one of the more recent ones, from last year (Dagan 2006, Genome Biol. 7(10):118)), states in the abstract: "biologists need to depart from the preconceived notion that all genomes are related by a single bifurcating tree." If writers are still feeling the need to making this point, can there be a consensus yet? Many of the more recent abstracts still talk about a LUCA. This very cursory look indicates to me that this is still a subject of debate and study, and far from settled.--EveRickert 16:50, 22 March 2007 (UTC)

Note that what you say above applies to sexually reproducing populations. Asexual organisms (as LUCA must have been) reproduce clonally, and so a single organism MUST be the common ancestor (barring HGT). This, I think, is what Thomas is indicating. I think this is merely a semantic difference between our treatment of HGT and sexual reproduction. The latter, we're willing to accept represents a single organism despite the confused history. The former, because it can jump across species boundaries, we are not. For the record, Doolittle (Curr Opin Struct Biol. 2000 Jun 10(3):355-8) calls Woese a "radical" in this regard; I think most people would be content to say the reconstruction of LUCA is impossible, not that LUCA does not exist. Graft 17:26, 22 March 2007 (UTC)

Ah yes, I see (damn that sex again). And thanks for putting Woese in some context.--EveRickert 17:38, 22 March 2007 (UTC)

Actually, lest I be accused of mischaracterizing Doolittle, I'll note that he goes on to say that Woese's position has considerable support. What he says of relevance to the discussion above is:

How could such a population [of numerous progenitor organisms] give rise to two (and then three) discrete cellular domains without passing through a bottleneck represented by a single cellular universal ancestor? Perhaps in almost the same way that sexually reproducing species speciate, giving rise to daughter species whose gene pools are initially similar to those of the parent species and contain very many more different alleles than are borne by any one genome. (What is crucially not the same is that the genomes of the progenote population — like those of different modern prokaryotes — bore many different genes, not just different alleles.) Thus, there is no more reason to imagine only a single first kind of cell as the progenitor of all contemporary life than there is to imagine only Adam and Eve as progenitors of the human species.

Graft 20:12, 22 March 2007 (UTC)

There is just as much credible scientific evidence to support a "multiple origin of life" as there is to support a "single common ancestor," and if the later is going to be stated in the intro then insert a "POV-Section" tag:

"Using simple stochastic models for diversification and extinction, we conclude: (i) the probability of survival of life is low unless there are multiple origins, and (ii) given survival of life and given as many as 10 independent origins of life, the odds are that all but one would have gone extinct, yielding the monophyletic biota we have now. The fact of the survival of our particular form of life does not imply that it was unique or superior." "Multiple Origins of Life." 2007 [[17]][[18]]

"The possibility for multiple origins of life is an open question with profound implications for detecting life elsewhere in the universe."[[19]]

"There is indeed evidence of multiple origins of life." [[20]]

Wikipedia is accurate, but progressive. Most of the sources cited under single origin of life in the intro support lateral gene transfer: multiple origins, not a "single origin." Do a quick search on the net and you'll come up with over 300 sources that support or suggest the possibility of a "multiple origin" point of view. To quote George Beadle, “I have a persistent feeling that any simple concept in biology must be wrong...but...Do not discard a hypothesis just because it is simple - it might be right.”Valich 04:51, 23 March 2007 (UTC)

The Science article describing the evolutionary biology meeting discussing LUCA stated clearly their was no consensus on what LUCA was but only that whatever it was it was clearly already complex. The origin of life is not the same subject as the LUCA, it is generally accepted the possiblity of life originating more than once given the conditions and being very different, however many also firmly believe that life could not have originated on earth given the conditions. Further there is evidence from metanalysis of tRNA that the genetic code may be as old earth itself (shortly after earth formed). Evolution makes sense, but the origin of life is a personal paradox because I tend to believe that life could not have originated on earth (many of the conditions posited as likely sources of lifes' origin have and still exist on earth today so I can't see life spontaneously evolving on earth least it still does), but then again I don't believe in extraterrestrial life either. In any case if one deletes common descent from the evolution equation then evolution would no longer be fact nor theory. To quote George Beadle, “I have a persistent feeling that any simple concept in biology must be wrong... Hmmm, so much for parsimony and cladistics. Valich I applaud your scholarly contribution of peer reviewed references as usually you just get POV arguments with no attempt to justify an argument with the literature. I don't think it would be appropriate to drop common descent or LUCA but it doesn't have to state it as a single organism (the LUCA Wikipedia article clearly states it could be multiple organisms). GetAgrippa 14:23, 23 March 2007 (UTC)

Well, first, equating "lateral gene transfer" with "multiple origins of life" is pushing things a bit ("multiple origins" would suggest that life sprouted up independently in many separate places - a population LUCA implies no such thing). But, more importantly, this is not related to the question of the existence of a LUCA. The supposed ancestral population of massively gene-swapping "pre-prokaryotic" organisms is not in contradiction with the idea of a LUCA - it is the LUCA. Woese's paper (which is the seminal source of this discussion) makes the point quite elegantly. The fact that the LUCA was a (presumably well-localised) population rather than one single cell does not change the picture for common descent in general.

In other words, the Tree of Life still has a single "origin"; but if we look at it with a magnifier, we see that it is actually a mesh of interconnecting fibers, rather than one single filament. --Thomas Arelatensis 18:08, 23 March 2007 (UTC)

That's basically the same assumptions that I have been making: that there were multiple origins of life - what you are downgrading to "fibers" (whatever that means?) - that combined/evolved with lateral gene transfer to somehow get an outcome of "universal common descent." I'm saying that there were multiple origins of life, and that because of the similarities in environmental conditions and selective pressures, all equated a same genotype-phenotype, combining and interweaving through gene transfer, with an outcome of a universal common ancestor. I find it extremely difficult to believe that in our vast enormous world of space and endless possibilities that in a given extended time frame and the exact same environmental conditions spread out everywhere, that in our universe/Earth only produced one single origin of life organism. Only one? That's ridiculous. But it's part and parcel to our meager human mindset. We look at "one" as being the simplest to understand: one God, one Earth, one Beginning, one Universe, one time frame, 3-dimensions - only because that's all our human eyes and meager human understanding can see. There was more than one universal common ancestor; but still, we are descended from a universal common ancestor. The concept breaks down at the microbial single cell level. When you go beyond that, the way I see it - and they're not fibers - you cannot talked about a LUCA anymore. What we're working on now is the hypothetical smallest genome of the LUCA. When that is realized, then we'll have a "hypothetical LUCA." And what does that mean? It's not real: it's hypothetical. So there is no "real" LUCA.Valich 05:45, 24 March 2007 (UTC)

I suggest offloading most of this discussion to the common descent and LUCA articles, where it belongs. For the purpose of this article, I suggest using a simple phrase like "All modern living beings are descended from a common ancestor (or at least a common ancestral population - see common descent)." This should provide an adequate balance between conciseness and completeness.--Thomas Arelatensis 18:08, 23 March 2007 (UTC)

Thanks Thomas, the voice of reason and a good suggestion. It is well that an article should align with other related articles so there is no confusion and there is continuity. I agree with an adequate balance of concise and precise. GetAgrippa 18:17, 23 March 2007 (UTC)

I agree with Thomas's suggestion. Discussions like these are almost as inappropriate here as the ones debating whether or not evolution is true. It's not our place to debate the subject itself. Let's find a reliable source explaining the current point of view of the scientific community, cite it, and move on. If it takes more than an extra clause to get all the nuances right, save it for the body of the article or the appropriate main article. Gnixon 06:18, 24 March 2007 (UTC)

The source of this debate, I think, and thus the difficulty with just finding "a reliable source explaining the current point of view of the scientific community," and moving on, is that there has been disagreement over what the reliable sources being cited actually mean and contain. Sources were being used to support statements that, in my view, were not supported by those sources, however attempts to address that issue were not leading to fruitful discussions over what statements the sources actually could verify.

My purpose in starting this thread was that there had been so much back and forth over this particular reference, with one editor saying the source said one thing and other editors arguing that it did not. Rather than continue what seemed to be becoming circular arguments, I decided to approach the author of the source itself to learn his true intent. Now we know that Mitchell Sogin's Tree of Life diagram [[21]] was not intended by him to imply multiple origins of life, and that his description of the tree as "unrooted" only means that the root is not known, not that it doesn't exist, so this source should not be used to support a multiple origin argument, and certainly not to support a statement that this is the scientific consensus. That isn't to say that there might not be other good sources.

Of course, I don't want to get into a round-robin argument on each and every source over whether it does or does not support that point of view. There must be an easier way! Like Gnixon and GetAgrippa, I approve of Thomas Arelatensis's proposed solution and suggest we leave it there.--EveRickert 23:03, 24 March 2007 (UTC)

Not sure if you saw this in the clutter of your talk page in the last few days, but Why is evolution described as though it is a fact, though it is just a theory? article sums this up quite nicely. In the context of this article, it describes the observed process, which is indeed fact. The theory itself, however, is indeed a theory. --Hojimachong<sup>talk</sup> 01:10, 22 March 2007 (UTC)

Not sure he cares. But, I read those sites, and 3 out of 4 are christian or creationist sites. One of them misuses the term "theory" to imply a theory is less than a fact. Lastly, I'll chime in first, that I know MUCH more than your science teacher about this field, especially if her answer to "is Evolution a theory" being yes. Others will add their two-cents worth soon, I'm sure. I can't wait to read Filll's response. 66.17.1.189 01:21, 22 March 2007 (UTC)

James, please also read Evolution as theory and fact in addition to Hojimachong's FAQ link. These words are defined in science in a different way than you are using them, which is likely the source of your confusion. — Knowledge Seeker দ 01:46, 22 March 2007 (UTC)

I feel that the lead of the article should mention the fact that evolution is a theory in light of the above sources. Note, in the field of science, the word theory conveys a different meaning than when it is used colloquially. Thanks, Anupam<sup>Talk</sup> 01:53, 22 March 2007 (UTC)

Those sources are 1) mostly christian propaganda, 2) amateurish, and 3) ranks way below better written and peer-reviewed articles. Evolution is a fact and a theory at the same time. The POV and canard that James is foisting onto us is trying to lessen the level of Evolution to that of ID and Creation Science, both of which are classified as pseudoscience, and neither qualify as a theory in the scientific sense of the word. This debate was done several times over, but people don't want to read back in the archives. It's honestly a waste of typing time. Orangemarlin 03:40, 22 March 2007 (UTC)

Please do not respond verbosely to creationist claims. It is unnecessary to debunk them in detail here. All that is needed is to cite the appropriate reference from The Index to Creationist Claims, a well-sourced reference on the subject. In this case, the "theory not a fact" fallacy is Claim CA201. --FOo 08:29, 22 March 2007 (UTC)

Even better is to just refer them to this page's FAQ, which explains why such issues are no longer debated here. Gnixon 12:19, 22 March 2007 (UTC)

blah blah blah blah blah blah

You're an idiot. You don't even know what those words mean. Evolution is true, no matter what a bunch of stupid religious people say. User:DarwinFishEatsYou

Screw you! Evolutionists are just atheists trying to promote their anti-faith as science. They ignore clear evidence for design. User:GenesisTellsAll

Die in a fire! To refute you, I'm going to write ten pages of text proving my point, and add ten more pages of quotes from my favorite people who agree with me. User:DarwinFishEatsYou

So am I. Ready, set, go! GenesisTellsAll

...

Mandaclair recently made some interesting edits to the introduction. They were quickly reverted because they changed the lead significantly, adding a lot of detail, but her paragraph defining evolution seemed useful, and I wonder if we could work it in somewhere without making the lead too unwieldy:

Strictly speaking, biological evolution is the process of change over time in the heritable characteristics, or traits, of a population of organisms. Heritable traits are encoded by the genetic material of an organism (usually DNA). Evolution generally results from three processes: random mutation to genetic material, random genetic drift, and non-random natural selection within populations and species. In common vernacular, evolution is also used more generally to refer to the greater outcomes of these processes, such as the diversification of all forms of life from shared ancestors, and observable changes in the fossil record over time.

The way she enumerates three processes and separates the technical definition from the vernacular could guide the introduction and first few sections of the article, especially if we can find a way to avoid getting too technical too early. By the way, she also made several good small changes to the intro that were reverted with the others. It'd be nice if someone went through the history and copied some of the changes back in. Gnixon 16:58, 27 March 2007 (UTC)

I'm not an evolutionary biologist, nor play one on TV, so it really sounds good. I don't like "biological evolution", for no other reason than I'll bet some creationist will beat up on the point that it's not really "evolution". But I could be paranoid after several months of bickering with creationists on here. Furthermore, I would like one of our more scientific types to review the sentence. Sometimes someone might simplify technology so much, that the essential meaning is lost or confused. Mandaclair is a new editor, so I'm always wary until they have gone through several rounds of discussion on these pages. But, for a first pass, I'm pretty impressed. Orangemarlin 17:32, 27 March 2007 (UTC)

Hi. Thanks for listening. As I mentioned on a user talk page somewhere, there is nothing "creationist" about specifying "biological evolution" as a way of distinguishing life from other systems that evolve, such as languages, societies, or the universe as a whole. And in general, I recommend not worrying too much about what creationists will (or won't) "beat up" upon, because very little progress is to be made in those [rhetorical] dialogues, anyway. Don't write this article with "defense against creationists" in mind. The only sensible thing to do is ignore them, and write the best article you can. (Comment from User:Mandaclair.)

I very, very, very strongly agree. Gnixon 02:39, 28 March 2007 (UTC)

Sounds good to me. Suggest changing "common vernacular" to "everyday speech." I will see what I can do about incorporating some of the other edits.--EveRickert 18:35, 27 March 2007 (UTC)

If "bold editing" was a bit easier to accomplish, I might recommend the following (Comments by User:Mandaclair):

• strip down some of the basic genetics in the article. Keep it streamlined toward Evolution. Much of the article seems like it should be a genetics article, or population genetics article. Those topics definitely play into Evolution, but in my opinion, this article gives them too much space.

Strongly agree. Gnixon 02:38, 28 March 2007 (UTC)

• include a new section entitled "common misconceptions about evolution". These can be documented, and such a section is extremely valuable to persons approaching this subject for the first time.

What misconceptions do you have in mind? A similar section once existed, but it sort of turned into "Why Creationists' objections are wrong because they don't understand stuff." That caused lots of problems. Gnixon 02:38, 28 March 2007 (UTC)

(Discussed in its own subsection below.)

• Stabilizing selection, directional selection, and DISRUPTIVE SELECTION [left out in the current version] are the three MODES of natural selection, and they are not really correctly described here (for example: all three of them favor the "beneficial" alleles and select against "harmful" ones.) Artificial selection should not be invoked in this section -- it is trivial (arguably meaningless) in the grand scheme of things, and probably better discussed in the section about the history of Evolutionary thought, since Darwin began his treatise with an examination of artificial selection, and reasoned: if humans can produce breeds and varieties (as he called them), then why couldn't nature?

• As mentioned, reduce the adaptationist language as much as possible. Adaptations certainly can and do occur, and they are important, but it is also very important to get across that "the race is not always to the swift, nor the battle to the strong", etc. "Fitness" has nothing to do with "strength" or "being better" (although it can). Fitness is reproductive output -- pure and simple -- and nothing else. It's important to keep these concepts separated.

• The discussion of speciation can be improved, mainly by introducing the problem of species concepts (and how no species concept is universally useful), and how the most important thing in speciation of sexual organisms is not necessarily geography (allopatry or sympatry), but reproductive isolating barriers of ANY kind. They may be geographic, but they could also be ecological, biochemical, behavioral, etc.

• The Huxley graphic showing the skeletons of hominids is all right, but it unfortunately resembles all-too-closely the kind of iconic left-to-right linear evolutionary "progress", that doubtlessly causes Steve Gould to roll over in his grave, and will cause me to do so as well when my time comes. The image presented here is not exactly the kind of "linear progress" graphic that is so common, but I am sure we could find a much better graphic to illustrate the concept of *homology* being the signature of evolutionary descent.

• A lot more can be said in the "History of Evolutionary Thought" section -- specifically, on the kinds of *observations* that had been around for years, that were consistent with Darwin's explanation. For example, the Linnean system of classification predates Darwin and knows nothing of common ancestry and descent, yet its structure as a set of "nested groups" very neatly reflects the true branching nature of the history of life.

Even the main article on this subject looks like it could use some work. There seems to be confusion about what evolutionary ideas predated Darwin and how fast his ideas were accepted. Gnixon 02:38, 28 March 2007 (UTC)

• Some fleshing-out of the very true statement that "evolution is the organizing principle of all biology" would be justified on this page.

Here's the sort of topic that could really benefit from an expert's perspective. Gnixon 02:38, 28 March 2007 (UTC)

There are some ideas. Take 'em or leave 'em. I'm willing to help, as long as the debate and round-&-round is kept to a minimum. Kind regards, Mandaclair 19:53, 27 March 2007 (UTC)

Excellent suggestions from an expert in the field. Thanks, Mandaclair. Let's get to work! Gnixon 20:20, 27 March 2007 (UTC)

Thanks. (Mandaclair)

A final note, for now (from User:Mandaclair): The main reason I have taken an interest in this article, is because University students are using Wikipedia more and more as an authoritative source -- a fact that is potentially exciting on one hand, and terrifying on the other. As someone who interacts with biology majors on a daily basis, it would make my job (and my colleagues' jobs) much easier if we helped out in making popular resources (like Wikipedia) as accurate as possible. Otherwise, we spend a lot of time helping students "unlearn" what they thought was true about Evolution (such as: it's all adapation, or it's all a directional process of improvement, or the notion that simply because we refer to "evolutionary theory", that therefore evolution must be some kind of tentative hypothesis that has not been "proven" one way or another... you get the picture.)

Unfortunately, I am sure that many academics in many fields are deterred by the too-many-cooks environment at Wikipedia, and yet, they may feel compelled to help out in some way -- especially if their students use Wikipedia. All of that being said, the Evolution article (as it stands now) does cover most of the main points, and is a decent introduction to the field and its concepts. It could just be a lot clearer, a lot more accurate on some fundamental points, and it could cite more (and better) examples, in many places.

There really are a lot of cooks stirring this pot, but a little word of mouth around the department could go a long way toward increasing the proportion of master chefs. I've wondered sometimes about the idea of creating, for example, a "HarvardBiologyProf" account on Wikipedia that could be shared by a number of experts who each have limited time available. (BTW, I'm not a Harvard bio prof.) Gnixon 04:22, 28 March 2007 (UTC)

Thanks, and for now I think I'll leave most of the editing to the more passionate editors here -- I'm happy to help upon request, Mandaclair 20:54, 27 March 2007 (UTC)

Here are some of the other changes I made last night, and the rationale (Comments by User:Mandaclair.):

• Natural selection, one of the processes that drives evolution, is a self-evident mechanism that results from the difference in reproductive success between individuals in a population. Natural selection occurs due to two biological facts; 1.) the existence of natural variation within populations and species, and 2.) the fact that all organisms are superfecund (produce more offspring than can possibly survive.) In any generation, successful reproducers necessarily pass their heritable traits to the next generation, while unsuccessful reproducers do not. If these heritable traits increase the evolutionary fitness of an organism, then those organisms will be more likely to survive and reproduce than other organisms in the population. In doing so, they pass more copies of those (heritable) traits on to the next generation, causing those traits to become more common in each generation; the corresponding decrease in fitness for deleterious traits results in their become rarer.[1][2][3]

The important thing about selection is that it is a *self-evident* process, in that: given the undeniable, observable biological facts that 1.) organisms vary, 2.) most variation is heritable 3.) organisms produce more offspring than can possibly survive, and 4.) some heritable traits will influence reproductive success, it *necessarily follows* that heritable traits that increase reproductive success will increase in frequency, while heritable traits that do not increase reproductive success will decrease in frequency or disappear entirely. This is why a very common reaction in the scientific community to the publication of The Origin, was basically along the lines of: "well, DUH, how come *I* never thought of that?" It is self-evident to any thinking, rational human.

Also, it is tempting to think of all evolution and natural selection as "adaptation to the environment", but that is a somewhat naïve point of view, mainly in that it is incomplete (many traits are preserved due to random factors, or evolutionary constraints that prohibit their disappearance, i.e. genetic linkage or developmental constraints. Adaptation need not enter into the preservation of traits over time.) I strongly recommend toning down the adaptationist tone of this article in general. Natural selection is perhaps best understood if reduced to the self-evident mathematical outcome of perpetuation of certain heritable forms due to the simple fact that there are more copies available to reproduce, and they are better at reproducing. Yes, adaptation occurs, but it is not the driving force. Mutation, drift, and selection are the driving forces.

Also, any discussion on drift *must* point out that drift applies to sexually reproducing organsisms, since drift is generally understood as a result of random matings. Thus:

• In sexually-reproducting organisms, random genetic drift results in heritable traits becoming more or less common simply due to chance and random mating.

Again, with the concept of speciation and divergence, sexual reproduction must be assumed if you're going to invoke "interbreeding". Many organisms (including eukaryotes) are asexual, and so the ability to interbreed cannot define or describe the divergence process. Thus:

• With enough divergence, two populations can become sufficiently distinct that they may be considered separate species, in particular if the capacity for interbreeding between the two populations is lost.

Great suggestions. Two things I'm a bit uncertain of: one is superfecundity - organisms certainly don't always produce more offspring than can possibly survive, and that's certainly not required for selection to take place. All that's required is that you do better than your neighbor, as in any race. And two is the above misconceptions section. I was never a fan of its inclusion before, and I don't want to see it making a prominent return. It hurts the article. Graft 19:12, 28 March 2007 (UTC)

Hi Graft -- you are right about "doing better than your neighbor", but superfecundity is absolutely, indispensably part of the mechanism of Natural Selection. It is the reason that survival and struggle for existence becomes an issue. Remember Darwin's argument about the elephants: he picked the LEAST fecund animal he could think of, and reasoned that if all elephants ever born survived and reproduced, the earth would be swamped by them. Here:

The elephant is reckoned to be the slowest breeder of all known animals, and I have taken some pains to estimate its probable minimum rate of natural increase: it will be under the mark to assume that it breeds when thirty years old, and goes on breeding until ninety years old, bringing forth three pair of young in this interval; if this be so, at the end of the fifth century there would be alive fifteen million elephants, descended from the first pair. (Darwin. On the Origin of Species. Ist Ed. Ch 3.)

Even though it was shown later that Darwin got the calculations wrong, his point is still true and *fundamental* to natural selection. And this is elephants! Think of the superfecundity of arthropods, marine non-vertebrates, bacteria, fungi, rodents, plants that reproduce by wind-pollination... the fact of Superfecundity is fundamental to life on earth, to Natural Selection, and to Evolution. In "Recapitulation and Conclusion" (Chapter 14) Darwin also calls superfecundity "a ratio of increase so high as to lead to a struggle for life".

Not sure how related this is, but evolutionary biologists have a term called LRS, "Lifetime Reproductive Success", which is an additive function of the probability of surviving to any given age, times the potential number of offspring that could be produced in each unit of time (such as a year), added up over the entire lifetime of the organism. LRS can never reach infinity, because of selection, deleterious mutations, evolutionary trade-offs, etc. It may help to think of superfecundity at the species level rather than at the level of the individual. You can also think of it this way: if organisms were NOT superfecund, and did NOT produce more offspring than could possibly survive, then there would be no struggle for existence. Selection might result in the *increase* of your neighbor who is "doing better" but without superfecundity it won't result in the *extinction* of those that "do worse". (Comments from User:Mandaclair.)

Ah - as to elephants. This is true and good, but populations frequently do explode and grow in size exponentially, and we can still see the influence of selection in this context - that is, allele frequencies can change as a result of differential fitness (or reproductive ability) in an exploding population. So why would we then say that superfecundity is *indispensible* for selection? Graft 20:58, 28 March 2007 (UTC)

Superfecundity is indispensible because 1.) it is a blatantly obvious fact of biology, and the mechanism of Natural Selection is firmly rooted on this and other biological facts (variation, heritability, superfecundity, survivorship) -- and 2.) superfecundity is the primary reason for the "struggle for existence" in the first place. Also, consider gene flow in a world where there is no superfecundity and thus no struggle for existence. If all variants that are born (hatched, germinated, etc.) *could* survive and reproduce, and there is no struggle for existence, it is hard to imagine how allele frequencies are going to change significantly over long periods of time. Sure there are population explosions but eventually, something's got to give, and it "gives" because THERE ARE TOO MANY INDIVIDUALS, MORE THAN CAN POSSIBLY SURVIVE, GIVEN THE AVAILABLE RESOURCES. Selection *means* selection of certain individuals out of a pool of individuals who can't all "make it" because there are too many of them to all "make it". This is what Darwin believed and what he stated explicitly, and should be included on this page, if only for that reason. It is in Darwin's Introduction, and my quick inspection shows (not surprisingly) that his quotation is already included in the Wiki entry about Darwin:

As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.

Here is a lovely link I found showing Ernst Mayr's schematic of Natural Selection. Note that Superfecundity is first principle.

www.scepscor.org/outreach/bio2010/workshop-summary-files/supplemental-material/naturalselection.pdf

Mandaclair 23:11, 28 March 2007 (UTC)

This may be how Darwin defined selection, but as far as I've ever seen it defined, technically, it entirely in terms of differential reproductive success, and nothing else. That's all that's encoded in the idea of fitness. So, while I agree that superfecundity exists and is a fact of nature, I don't see how it is *necessarily* related to selection. Anyway, this is getting abstruse and maybe out of the scope of this article in general. Graft 15:47, 29 March 2007 (UTC)

Well, Ernst Mayr was arguably the most important Evolutionary Biologist of the 20th century, and his schematic of selection (as in the link I've given) has superfecundity as a first principle of selection. Also: technically, Darwin never spoke of reproductive fitness in The Origin using that word (fitness), although differential reproductive success is certainly implied. Note however that fitness is *not* a "differential" (relational) concept in itself. Finally (and this shouldn't be news to anyone), "Survival of the Fittest", in Darwin's time (and meaning) was not a statement of fitness as we define it now -- in The Origin, he really meant survival of competition and, that word you hate, struggle.Mandaclair 23:21, 29 March 2007 (UTC)

Hi -- the last thing I'd like to reply to, is Gnixon's request for more details about "common misconceptions" about evolution. Here's the short list -- some of these may *seem* targeted for the creationists, but they're really not. Even atheists sometimes misunderstand the true meaning of the word "theory". I also realize that many of these issues are addressed piecemeal throughout the article as it stands, but a "bold rewrite" attempt might want to consolidate them into a single section. I think that would be extremely valuable. (From User:Mandaclair.)

• Evolution is [only] a "theory" that remains to be "proved"
• Survival of the fittest means survival of the best
• Human evolved "from" apes (or, any extant X evolved "from" any extant Y)
• Most of an organism's traits are adaptations for some beneficial function
• Humans/mammals/vertebrates are the "most advanced" organisms -- everything has been "leading up" to us
• Evolution always optimizes organisms and improves them over time
• Evolution is usually a slow, gradual, evenly-paced process
• The historical path that evolution took was obvious and unavoidable, and how things will evolve in the future can be somewhat predicted

Please e-mail me for questions or details. Thanks, Mandaclair 18:18, 28 March 2007 (UTC)

The only reason I suggest the misconceptions section, is because Evolution is probably the most misunderstood science of all, because it is so prominent and conspicuous in the popular, public eye. Thus Evolution is in a unique position of having to deal with public misconception, more than any other science has to. There is a way to compose a section like this that does not appear like it's catering to creationists, but rather, caters to the very real need to educate and adjust what many people erroneously believe the position of Evolutionary Science to be.Mandaclair 19:37, 28 March 2007 (UTC)

Hi Mandaclair,

I take your point, and believe me I am sympathetic, but this is not an advocacy site; I don't really see the justification for including what's undoubtedly aimed at countering a specific cultural trend here, no matter what the views of the editors. I know others feel differently here, but I think that we should be true to WP, here, not our selves. Graft 20:54, 28 March 2007 (UTC)

Hmmm, I'm not sure how education = advocacy... most of the points I raised are not about advocacy at all, as much as they are about misconceptions people have of Evolution as an optimizing, directional, gradual process of increasing complexification where X evolves "into" Y. I don't need to argue this point any further, but it's a fact that most people view Evolution that way (regardless of their personal "advocacies")... and that view of evolution is thoroughly incorrect.Mandaclair 21:19, 28 March 2007 (UTC)

Misconceptions=Misunderstandings. We used to have a 'Misunderstandings' section but it was thought by many to be WP:POV to have such a section, so it was removed by consensus, on 22 February. There is a separate article called Misunderstandings about evolution, which survived a vote for deletion in January, but its future is still unclear. User:Silence has referred to the title Misunderstandings as 'unacademic and unneutral'. EdJohnston 00:35, 29 March 2007 (UTC)

Interesting... Well, at least this information is still posted somewhere. Cheers, Mandaclair 00:47, 29 March 2007 (UTC)

I support implementing the bulleted points made by Mandaclair above. I also think some mentions of the misunderstandings are needed. As a complex and touchy issue, many people have preconceived notions or blatantly wrong information about evolution, which is a big reason why it has encountered so much opposition. --Hojimachong<sup>talk</sup> 01:02, 29 March 2007 (UTC)

Heads up -- I'm going to make a few changes, but none should come as a big surprise. Questions? See archive above.Mandaclair 18:00, 29 March 2007 (UTC)

Wow! Drastic improvement to the intro (also finally corrected the definition to include "time" or "successive generations"). I'd just leave out the last paragraph about history for later. The speciation section could really use the same hand as it is sadly lacking. GetAgrippa 19:46, 29 March 2007 (UTC)

Thanks -- will be tackling Speciation next.Mandaclair 19:49, 29 March 2007 (UTC)

Question, Graft: I see by your edit comment that you "hate the word struggle", but I wonder how much bearing your personal hatred of the word has, given the fact that Darwin consistently used the phrase "struggle for existence" throughout The Origin, and this "struggle" is very much viewed as fundamental to Natural Selection. Seems to me that any description of selection ought to be true to Darwin, at least...Mandaclair 23:07, 29 March 2007 (UTC)

Maybe, but the sentence doesn't really add anything other than flavor. Since you've already expressed an aversion to the adaptationist tone of the article, I'd think you'd be in favor of trimming such sentences. I'm actually quite pleased with the fact that this article has, in general, managed to avoid the "struggle to survive" cartoon of evolution in its language. Most of the positive selection that goes on does not take the form of a visible struggle - it is totally invisible to any observation and can only be detected via statistics or genetics. I dislike that language because it leads people to expect competition - lions snarling over meat, etc. This both presents a distorted picture of evolution and results in misconceptions (like "there is no selection going on in humans right now", because we can't see it). Also, I'll point out that this article has taken great pains to move past Darwin in its language and in its treatment of ideas. Origin of Species is, after all, almost 150 years old now. Graft 03:03, 30 March 2007 (UTC)

The undeniable fact that all organisms struggle for survival (think about it for just a moment -- think about all the energy that is required for all the vital processes. It's no cakewalk) -- has nothing to do with adaptation. The adaptationist perspective is not one of "constant competition and struggle", but one of "every trait is an optimized adaptation for the function it currently serves, and evolution is an optimizing process". Also, even though the Origin of Species was only written about 150 years ago... the principles go back at least 3 and a half billion years. ;-)Mandaclair 03:50, 30 March 2007 (UTC)

Another short note: I find it patently odd that Graft is so opposed to the inclusion of principles that have always been integral to the mechanism of natural selection: namely superfecundity and struggle for existence. I am not aware of any academic reference from a working evolutionary author, alive or dead, that purports to give a complete explanation of natural selection without citing superfecundity and struggle. I think the concept that may be slipping through the cracks here is: natural *selection*, like artificial *selection*, means perpetuation of a *select subset* of the individuals from the previous generation. This *selection* occurs because they cannot all survive. There are too many of them (superfecundity), and life is tough (struggle). This is why it is *selection*. Darwin began his argument for natural selection by thinking and talking about artificial selection. Dachschunds are long and squat because only the long and squat individuals were *selected* for breeding in that lineage, despite the existence of plenty of puppies that weren't long and squat enough. Those other puppies did not become part of the Dachschund lineage. Out of all the bizarre Cambrian animals we find in the Burgess Shale, only a few types were *selected for* and became the modern animal phyla. The rest didn't make it. Superfecundity and struggle. They are part of the process and always have been.Mandaclair 04:11, 30 March 2007 (UTC)

My point about Darwin being 150 years old is that our understanding of these issues has certainly evolved since his time. Case in point, selection. You suggest that *selection* means a select subset of individuals from the previous generation are perpetuated, but this is wrong. *Selection* acts on traits, and more properly acts on allele frequencies. It is an allele that is being *selected* for, and the change in frequency of an allele as a result of differential reproductivity is all that is meant by selection. As I've said before (and which I've yet to see a reply to), superfecundity has nothing to do with this idea. Unless I'm missing something, which it's perfectly possible I am.

At this point it seems to me we're talking about very different things - you're talking about species selection and I'm talking about selection within a species. How to resolve this, I'm not sure, other than to outline both of these ideas.Graft 04:51, 30 March 2007 (UTC)

Selection acts on whole organisms -- not genes, not traits. Yes, traits and genes can be selected FOR or AGAINST, and yes it's all about changing allele frequencies over time, but all of this happens only through the vehicle of the organisms that live, reproduce (or not), and die. There is no other way. Even the "selfish gene" needs the organism to be the phenotypic vessel exposed to natural selection. I will agree that citing the Cambrian was a poor example for me to give, since that is more about interspecific competition, but it was the first thing that came to mind. The principles are clearly applied to the "within a species" level, but I really can't spend any more time trying to justify the rock-solid-established fact that superfecundity and struggle for existence are integral elements of selection, both within a species and for life on Earth in general. The artifical selection example I gave for Dachshunds is perfectly analogous to selection within a species. I am sorry if you don't "see" this point, but you don't have to go 150 years back to Darwin to learn about it. Try looking to Mayr -- he only died a few years ago. I often rode the elevator with him in the Museum of Comparative Zoology... You should have seen him wearing pipe-cleaner ant antennae in the audience on the day of Ed Wilson's last lecture before he went Emeritus...Mandaclair 05:06, 30 March 2007 (UTC)

Also, there's no need to address me in the third person - I can follow along just fine. Graft 04:51, 30 March 2007 (UTC)

Sorry, didn't mean to offend. But since this is the public talk page and not your user page, I figured other folks would be involved in this discussion. My apologies,Mandaclair 05:06, 30 March 2007 (UTC)

I agree with Graft on the issue of "struggle for survival" - it's a metaphor from an earlier age, and it's about as dated as "nature red in tooth and claw". No one talks about species interactions in those terms any more. Guettarda 05:33, 30 March 2007 (UTC)

The funny thing is, I am modern enough to agree with this point of view as well, but only to a certain point. I will be the last person hopping up to paint a picture of "nature red in tooth and claw" and I certainly do not think that "struggle for survival" needs to be *emphasized* greatly when talking about evolution. But it is an *inseparable part* of selection, and of evolution -- not a mere metaphor. That is all I'm saying -- that I can't see justification for leaving it out, but I am 100% on the same page with you that evolution shouldn't be emphasized as some vicious competitive battle out there... although frankly, it really is. This may be hard for humans in industrialized nations to perceive, but do not doubt for a minute that competition for resources among humans worldwide is deadly and fierce. Do not doubt for a minute that organisms by the millions die in floods, droughts, and frosts, that they are consumed by herbivores and predators, that they are driven from their habitats by invasive species, and that they starve to death when a more efficient predator or forager comes along. This shouldn't be emphasized as the central theme of evolution, but it's sheer insanity to deny that it's true.Mandaclair 05:43, 30 March 2007 (UTC)

I'm not saying that the effect of inter- and intra-specific species interactions should be left out, just that calling it a "struggle for survival" is too Victorian, too Marxist, too anthropomorphic a presentation. It also points people in the wrong direction - to think about drastic and dramatic floods, rather than far more mundane features like being shaded out by another individual or killed by a pathogen. Big events don't structure populations nearly as much as do a whole lot of small ones. Guettarda 06:14, 30 March 2007 (UTC)

I dunno, I think pathogens are pretty dramatic too... I may have listed some big dramatic struggles above to make a point, but there are large struggles and small struggles -- even being "shaded out" by another... the main point being that life is never a walk in the park, and there is no free lunch. That's all, and I certainly do agree that we should steer clear of anthropomorphism...but what is another way to word this central concept, other than using the traditional wording "struggle for survival"? Like I said, it doesn't need to be emphasized (at all, and I have never argued for emphasizing it), but it is a key element that I just can't see any reason to justify its exclusion. Any alternative wordings you want to suggest?Mandaclair 06:38, 30 March 2007 (UTC)

It is an old metaphor and the naive also equate it with the survival of the fittest metaphor, but the point I think Mandaclair is making is that biotic competition is a fact of life and superfecundity relates as organisms tend to reproduce more than can survive in any given ecological setting. The terminology maybe a contention but the point does need to be made. I think we would be remiss not to mention both as this is an encyclopedia and the audience needs the basics. Introductory text and books (Gould, Mayr, etc)all mention it to my recollection.GetAgrippa 14:33, 30 March 2007 (UTC)

Yes, I am only arguing for its inclusion for the sake of accuracy and completeness. It is not our fault if readers want to misconstrue this as an "only the swift and the strong shall survive" statement. But just because the concept of a "struggle for existence" may be out of fashion, does not make it untrue.Mandaclair 16:51, 30 March 2007 (UTC)

Sorry to keep harping on this, but I simply don't find this apt in many instances. For instance, let's take skin color. There's strong selective pressures to maintain the right amount of melanin, but they're entirely about reproductive success and nothing else - there's no competition for resources involved, and there's no struggle against other members of the same or any other species. I don't think struggle is an appropriate metaphor for evolution *in general*, and the language above doesn't make me any more inclined to believe it's a useful way of phrasing things. Graft 18:33, 30 March 2007 (UTC)

Graft, "struggle for existence", or whatever you'd like to term the fact that "life is not easy and requires a great investment of energy", is a first-principle because of superfecundity: more offspring are produced than can survive in a world with limited resources. It is as simple as that, the concept has always been central to Selection and Evolution (and Ecology: please recall K, carrying capacity) -- and I personally am tiring of this argument. Achieving any kind of reproductive success always implies struggle, in terms of energy expenditure, acquiring resources, access to mates (in sexual organisms), and biological investment in reproduction. Whether the trait you're looking at is skin color or anything else: if selection favored it, it necessarily implies that individuals carrying the trait were selected FOR and those that didn't carry it were selected AGAINST, and not because life is a bowl of cherries available for the taking. Whether or not you like the word struggle or the concept of struggle: maximizing your fitness IS AN UPHILL BATTLE, and individuals that are better at it persist, while others will not. It doesn't require invoking hand-to-hand combat, tribal wars, and "quarreling over the kill" as being connected to every single trait. Can we please table this topic until we hear a few more views, and until someone bothers to review the primary modern literature that describes Natural Selection. And may I please remind you: nobody is suggesting including anything in this article about "struggle", other than mentioning it briefly as one of the first principles of natural selection. Thanks Mandaclair 19:35, 30 March 2007 (UTC)

Proposed solution:

In an attempt to dress up an old concept in less Victorian/anthropomorphic language, I have gone ahead and replaced the classic "struggle for existence" phrase with some roundabout verbage that, to my mind, means exactly the same thing: "organisms in a population are not all equally successful in terms of survivorship and reproductive success". Conceptually, it is identical to "struggle for existence" -- does this wording satisfy the dissenters?Mandaclair 19:58, 30 March 2007 (UTC)

Good edit, Graft -- I dig, Mandaclair 20:22, 30 March 2007 (UTC)

I kind of feel like the short "Variation" and "Heredity" sections don't belong here (mainly because the way they are written does not really address Evolution). What do folks think about deleting these sections -- keeping in mind that there will be embedded links to the variation and heredity articles, throughout this one?Mandaclair 04:24, 30 March 2007 (UTC)

I would agree with a rewrite of Variation and Heredity, but variation (mutations and recombinations)and heritable need to be explained just like superfecundity should be mentioned. It doesn't have to have a separate section. I tend to agree with your analysis of adaptation, but that is a POV issue (I can see the Gouldian influence in your education)as many authors emphasize adaptation. I do agree that exaptations should be mentioned. I am curious how evolution is taught nowadays (it has been over twenty years since I taught an introductory biology course and molecular biology and genomics has drastically altered the state of affairs).GetAgrippa 14:33, 30 March 2007 (UTC)

Here's how evolution is (mostly) taught today: phylogeny, phylogeny, phylogeny! Students get the fundamentals and the history of the field... but then a lot about evolutionary genomics, evo-devo, gene & genome duplications, etc. As you might expect...Mandaclair 17:05, 30 March 2007 (UTC)

I have now made some bold(ish) edits to the Selection and Adaptation section, a bit more consistent with the way these concepts are taught in Evolution courses for biology majors. The previous version of this section was really a bit off... for example, the 3rd mode of selection is disruptive selection (not artificial selection), and all 3 modes could be argued to select against harmful traits and select for beneficial ones. I also tried to improve the description of sexual selection a bit, and removed the distinction of "ecological selection" because it seemed a bit redundant with the existing description of natural selection in general. "Ecological selection" is not a term I hear used a lot... it makes sense, sure, but I don't think it's any kind of standard category of selection... As I go through this article, though, I am generally very impressed with its quality. My intention here is just to tidy-up, not do any drastic rewrites! Thanks, Mandaclair 05:20, 30 March 2007 (UTC)

I also have to disagree with you on ecological selection. I'd say it has a lot of use in the last 5 years. I'd say it's at the very least presented as a distinct type of selection - e.g., [26], p.127. Guettarda 06:16, 30 March 2007 (UTC)

I know Patrick, and in fact worked with people in the Shaw lab for many years. In that paper, I think the term "ecological selection" is used mainly as a convenience (in context) to distinguish it from sexual selection in the argument they are making. That's just my opinion, but I do have to say that, although the term "ecological selection" certainly makes sense, I don't hear it used often as *its own term* (most people just say natural selection and sexual selection, or talk about the 3 modes). I do note, as you say, a lot more recent usage of this term... My only objection was the prior categorization scheme in the article, which divided selection first into "ecological" and "sexual", and then later into "directional", "stabilizing", and "artificial"... the divisions were somewhat confusing. But if more people here think ecological selection belongs in the article in some way, I say put it back, as long as it is implemented in a way different from that previous categorization. In my opinion "ecological selection" is not in such common use that it warrants status as a category of selection in this article... (e.g. ecological selection, in quotes, gets about 20,000 google hits, while sexual selection in quotes gets over 900,000... not really terms or categories in equal usage) Thanks, Mandaclair 06:38, 30 March 2007 (UTC)