| Revision as of 14:53, 31 March 2007 editGnixon (talk | contribs)2,977 editsm →Heredity← Previous edit | Revision as of 14:57, 31 March 2007 edit undoGnixon (talk | contribs)2,977 edits →Suggestions from Mandaclair: refactoringNext edit → | ||
| Line 600: | Line 600: | ||
| :I very, very, very strongly agree. ] 02:39, 28 March 2007 (UTC) | :I very, very, very strongly agree. ] 02:39, 28 March 2007 (UTC) | ||
| ⚫ | {{hab}} | ||
| ⚫ | ===Natural selection=== | ||
| ⚫ | {{hat|reason=Hidden for length. Feel free to continue discussion.}} | ||
| ⚫ | Here are some of the other changes I made last night, and the rationale (Comments by ].): | ||
| ⚫ | *''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.'' | ||
| ⚫ | 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. ] 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 ].) | ||
| ⚫ | 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? ] 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 | ||
| ⚫ | :] 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 ]. 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. ] 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 ] in '''The Origin''' using that word (fitness), although differential reproductive success is certainly implied. Note however that ] 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 ] as we define it now -- in '''The Origin''', he really meant survival of competition and, that word you hate, struggle.] 23:21, 29 March 2007 (UTC) | ||
| {{hab}} | {{hab}} | ||
| Line 690: | Line 645: | ||
| 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, ] 20:54, 27 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, ] 20:54, 27 March 2007 (UTC) | ||
| ⚫ | {{hab}} | ||
| I think these suggestions are really useful, and I hope we can incorporate them. ] 16:39, 28 March 2007 (UTC) | |||
| ⚫ | ===Natural selection=== | ||
| ⚫ | {{hat|reason=Hidden for length. Feel free to continue discussion.}} | ||
| ⚫ | Here are some of the other changes I made last night, and the rationale (Comments by ].): | ||
| ⚫ | *''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.'' | ||
| ⚫ | 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. ] 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 ].) | ||
| ⚫ | 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? ] 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 | ||
| ⚫ | :] 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 ]. 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. ] 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 ] in '''The Origin''' using that word (fitness), although differential reproductive success is certainly implied. Note however that ] 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 ] as we define it now -- in '''The Origin''', he really meant survival of competition and, that word you hate, struggle.] 23:21, 29 March 2007 (UTC) | ||
| {{hab}} | {{hab}} | ||
Revision as of 14:57, 31 March 2007
| Skip to table of contents |
| This is the talk page for discussing improvements to the Evolution article. This is not a forum for general discussion of the article's subject. |
|
| Find sources: Google (books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
| Archives: Index, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67 |
| Important notice: Some common points of argument are addressed at Misplaced Pages's Evolution FAQ, which represents the consensus of editors here. Please remember that this page is only for discussing Misplaced Pages's encyclopedia article about evolution. If you are interested in discussing or debating evolution itself, you may want to visit talk.origins or Wikireason. |
 | Evolution is a former featured article. Please see the links under Article milestones below for its original nomination page (for older articles, check the nomination archive) and why it was removed. | |||||||||||||||
 | This article appeared on Misplaced Pages's Main Page as Today's featured article on March 18, 2005. | |||||||||||||||
| ||||||||||||||||
| Current status: Former featured article | ||||||||||||||||
 | Spoken Misplaced Pages | |||
| ||||
| A summary of this article appears in Natural selection. |
 | This article has not yet been rated on Misplaced Pages's content assessment scale. It is of interest to the following WikiProjects: | ||||||||||
| |||||||||||
|
|
References
I just spent a few hours fixing references on this article. Luckily, I have the flu, so what else am i going to do! I'm going to take a break, but I think an article as scientific and well-done as this one, should have bad references. People make edits, and don't use even the slightest standards for referencing articles. I went along with a few other editors and used the WP:CITET method of references. I happen to like it, because it standardizes the references below. I also found references that were not really worthy of an article like this one; for example, one was essentially a link to a commercial website for seeds. I also dug up the right references in a few cases, fixed some grammar, and put in some commentary about George Bush. OK, I did not do the last one. I thought about it just to see if anyone was reading.
Anyways, can we please keep the references clean. If you notice an edit with just a web link, clean it up using WP:CITET templates. It really takes just a few moments. If you're an editor, spot check references for their usefulness, especially if it's a new edit and reference. I'm trying to be civil, but I think I'm going to make someone recite the Origin of Species backwards if they mess up the references!!!! Yeah, I'm retentive, but you have to be in my career. Orangemarlin 20:53, 17 March 2007 (UTC)
for a picture of a chicken with four legs
for a picture of a chicken with four legs see here.......I will add later to the article in morphological evidence CrystalizedAngels 14:26, 18 March 2007 (UTC)
- Holy S***! MarkBuckles (talk) 14:30, 18 March 2007 (UTC)
- Isn't that more likely to be some sort of siamese twin, though? Adam Cuerden 14:42, 18 March 2007 (UTC)
Cut references
These are excellent references, and would be very good for the HGT section, but are a bit much for the lead.
- Bergthorsson, Ulfar, Aaron O. Richardson, Gregory J. Young, Leslie R. Goertzen, and Jeffrey D. Palmer (December 2004). "Massive Horizontal Transfer of Mitochondrial Genes from Diverse Land Plant Donors to the Basal Angiosperm Amborella". Proceedings of the National Academy of Sciences. 101 (51): 17747–17752. Retrieved 2007-03-18.
{{cite journal}}: CS1 maint: multiple names: authors list (link)Citing numerous additional sources, the article states in the discussion section that, "plant mitochondria frequently fuse, with their genomes recombining, which makes it easy to imagine multiple mitochondrial genes being acquired in a single event involving whole-mitochondrial transfer." This is process is relatively common and well studied in bacteria.
- 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. 313 (5792): pp. 1448-1450. Retrieved 2007-03-18.
{{cite journal}}:|pages=has extra text (help)CS1 maint: multiple names: authors list (link) CS1 maint: year (link)
- Richardson, Aaron O. (January 2007). "Horizontal Gene Transfer in Plants". Journal of Experimental Botany. 58: 1–9. Retrieved 2007-03-18.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help)</ref>
We should definately add these - and the references left in the lead - to the section on gene flow (encompassing HGT, hybridisation, etc) Adam Cuerden 11:49, 19 March 2007 (UTC)
Why are there references in the intro at all? The introduction is supposed to be a summary of the rest of the article and shouldn't contain info that isn't elsewhere in the article. The references should go in the article body. Joe D (t) 16:34, 20 March 2007 (UTC)
- Controversial topics usually end up needing them anyway, as it helps protect them from drive-by POV, by setting a "standard" that must be lived up to. Adam Cuerden 16:38, 20 March 2007 (UTC)
- I cut those three references but I guarantee you that someone will now put in a "need citation" tag. Then I'll put them back in, I guess? The alternative is to add in parentheses :(see: Mechanisms of evolution: New Species below)", and create a new subsection.Valich 22:44, 20 March 2007 (UTC)
- The Richard Dawkins article solved this problem by adding HTML comments stating that the reference was later in the article. Joe D (t) 11:55, 24 March 2007 (UTC)
- I cut those three references but I guarantee you that someone will now put in a "need citation" tag. Then I'll put them back in, I guess? The alternative is to add in parentheses :(see: Mechanisms of evolution: New Species below)", and create a new subsection.Valich 22:44, 20 March 2007 (UTC)
"Sampling Error"
In the lead, can we come up with a way that "sampling error" in relation to genetic drift can be phrased in a more layperson-oriented fashion?--EveRickert 18:29, 19 March 2007 (UTC)
- "...as over large numbers the random changes tend to average out, but, in small populations, the fate of any one individual (and all his genes) matters far more." - A little wordy, but you could always use half of it (large or small).Adam Cuerden 19:16, 19 March 2007 (UTC)
- Hmmm.... nice start, but let's keep working on it.--EveRickert 19:38, 19 March 2007 (UTC)
Sometimes the easiest way to fix a troublesome phrase is to just delete it. I think the simpler sentence still gets the point across, and more detail can be included in the genetic drift article.--EveRickert 18:38, 20 March 2007 (UTC)
- No, I definitely want to keep that idea in there. Drift is hard to understand and important to understand. It is ESPECIALLY important that people understand evolution as a stochastic and not a deterministic process, including selection. I think a second clause simply explaining "sampling error" might work, but I'm also not overly concerned with making the idea of "sampling error" more accessible simply by making genetic drift less so. This is the article on evolution; our allegiance should be first to clarifying ideas relevant to that. Graft 16:41, 21 March 2007 (UTC)
- Remember to balance completeness with conciseness in the introduction. Genetic drift is an important modification to the idea of evolution by natural selection, but I'm not sure it's so important that it needs to be explained in the introduction. Gnixon 18:23, 21 March 2007 (UTC)
- This is not an article about natural selection, it is an article about evolution. Graft 18:43, 21 March 2007 (UTC)
- Sorry, I wasn't clear. If I was introducing evolution to someone who hadn't heard of it, I would say something like... 1) we have all these different species because they evolved into their present forms; 2) they got there over a long period of time, mostly by natural selection picking from among random variations (this is where Darwin and everyone else went Aha!); 3) sometimes statistical effects are important, especially if populations are small (this is an importan issue if you're trying to understand evolution more deeply). I'm just saying that (3) might not make it into my introductory paragraph. I agree with Eve's comment below. Gnixon 21:35, 21 March 2007 (UTC)
- You're right, and Eve's right. I withdraw my objections. Graft 21:39, 21 March 2007 (UTC)
- Woot! Consensus has been reached! (Dontcha just love it when it's that easy?)--EveRickert 02:02, 22 March 2007 (UTC)
- Woot-woot! Yeah, baby, consensus---go all of us. This was a good discussion. Now can we come up with a good edit for the article? Gnixon 13:25, 22 March 2007 (UTC)
- Woot! Consensus has been reached! (Dontcha just love it when it's that easy?)--EveRickert 02:02, 22 March 2007 (UTC)
- You're right, and Eve's right. I withdraw my objections. Graft 21:39, 21 March 2007 (UTC)
- Sorry, I wasn't clear. If I was introducing evolution to someone who hadn't heard of it, I would say something like... 1) we have all these different species because they evolved into their present forms; 2) they got there over a long period of time, mostly by natural selection picking from among random variations (this is where Darwin and everyone else went Aha!); 3) sometimes statistical effects are important, especially if populations are small (this is an importan issue if you're trying to understand evolution more deeply). I'm just saying that (3) might not make it into my introductory paragraph. I agree with Eve's comment below. Gnixon 21:35, 21 March 2007 (UTC)
- This is not an article about natural selection, it is an article about evolution. Graft 18:43, 21 March 2007 (UTC)
- The reader is not going to come to an understanding of genetic drift via the lead. We want to keep them reading so they get to the more detailed sections, not have them stumble early on over unfamiliar jargon. Remember the lead is an introductory overview.--EveRickert 18:54, 21 March 2007 (UTC)
- There is a difference between "simple" and "dumbed-down" ("horse with favoured odds" ??). At least a mention of genetic drift in the lead is necessary, for a simple reason: the uninitiated reader might come to believe that evolution = natural selection, a common misunderstanding that we should combat. Of course this does not mean that we should absolutely fudge a complete discussion of genetic drift in the lead. The current version seems OK to me on this point.--Thomas Arelatensis 14:17, 22 March 2007 (UTC)
- Right... The question wasn't about whether to cover genetic drift, just whether to use jargon, i.e. the term "sampling error," to describe it in the lead.--EveRickert 16:08, 22 March 2007 (UTC)
- Speaking of which, I'm not wedded to that horse analogy. I just thought it was a good way to convey the mix of the action of drift and selective pressure. Feel free to ax it if you have a better notion. Graft 16:21, 22 March 2007 (UTC)
The comments from MandaClair below are relevant to this discussion. Gnixon 17:29, 28 March 2007 (UTC)
Comment: Proposal to move Evolution to Theory of evolution
| This discussion has been closed. Please do not modify it. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
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
|
- Previous commenters have objected to inclusion in this Talk page of questions already answered in the FAQ. There was even a proposal to move them to a special archive called 'Evolution debates'. In lieu of that, to save space here and to maintain visibility of old discussions, how about I 'box up' the above discussion using a Show/Hide pair of templates, such as {{hat}} and {{hab}}. Those names are short for {{Hidden archive top}} and {{Hidden archive bottom}}. I have done so for the above thread so you can see what it looks like. If you disagree, simply remove the pair of templates. I'll wait for feedback before doing this elsewhere EdJohnston 17:18, 20 March 2007 (UTC)
- I like this idea even better than the "Evolution Debates" archive, but others might object to it for the same reasons, i.e., that these discussions should simply be deleted. I'm worried that outright deletion (or moving to users' talk pages) will only stoke more flame wars, so I like the hat/hab archives. It would be nice if the template didn't say the archive should not be edited. By the way, this seems like a nice way to archive all long discussions, as long as the template doesn't say it can't be edited. Maybe we could consider hat/hab archiving all comments between the initial post and the final resolution (if available). Gnixon 14:31, 21 March 2007 (UTC)
Evolution statements
This article states it as fact that evolution happened. It is an unproved theory. It is simply a belief system. Anyone can call me a crazy creationist if they feel like it, but it doesn't change this. And if creation is an idiotic belief that only people who can't or won't think believe in, why not put the arguments for it and against it in schools and musems? (Please don't say that creatonists dont either. Its not true) Are the evolutionists scared of something? I think they are. And despite what evolutionists want us to belive, there are no rock layers of fossils of increasingly complicated organisms. anyone who doesnt like these statements send me a message. ````oddball 2002 —The preceding unsigned comment was added by Oddball 2002 (talk • contribs). 20 March, 2007.
| This discussion has been closed. Please do not modify it. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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!
Misplaced Pages 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
|
- This issue is addressed in the FAQ. Editors should remember to keep a civil tone with each other and avoid reigniting long-settled debates. Gnixon 18:15, 21 March 2007 (UTC)
Controversial
I think this article should be tagged controversial because many people don't believe in evolution.— Preceding unsigned comment added by 68.78.117.139 (talk • contribs)
| This discussion has been closed. Please do not modify it. |
|---|
| The following discussion has been closed. Please do not modify it. |
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) |
- This issue is addressed in the FAQ. Gnixon 18:08, 21 March 2007 (UTC)
...the hell?
The theory of evolution by natural selection was first put forth in detail in Charles Darwin's 1859 book On the Origin of Species. In the 1930s, Darwinian natural selection was combined with Mendelian inheritance to form the modern evolutionary synthesis. With its enormous explanatory and predictive power, this theory has become the central organizing principle of modern biology, providing a unifying explanation for the diversity of life on Earth.
Why on earth has this returned? It's like a hideous vampire, returning from the dead to kill off good writing, and to keep its undead, over-edited corpse alive by feasting on the life of the article. REWRITE NEEDED BADLY!!!! Adam Cuerden 04:09, 21 March 2007 (UTC)
- I agree, but I put it back because rewriting is better than deletion (that is, we all agree Darwin and Mendel, etc., need to be mentioned in the intro). If it's deleted, it'll take forever for it to come back. Its festering corpse will more rapidly encourage rewriting. Graft 16:44, 21 March 2007 (UTC)
- Fair enough, but I do hope we drive the stake of rewriting through its heart soon. Adam Cuerden 18:40, 21 March 2007 (UTC)
- With the exception of the unexplained mention of Mendelian inheritance, I kind of liked it, though I don't think it adds much to the lead as it is now. What specifically don't you like about it, Adam? If there was a discussion of it before, can you link to it?--EveRickert 21:03, 21 March 2007 (UTC)
- Various things - it didn't handle Wallace or earlier evolutionists well, the second half of it about "With its extraordinary explanatory and predictive power... central organising principle of biology, etc." bears no relationship to the first half, and, lastly, it WILL NOT DIE!!! It's the only part of the lead that's identical in phrasing to the ancient lead of a year ago, despite losing all the transition between its halves. We don't need no stinkin' Cytochrome-c in our lead. DIE YE VESTIGE OF THE EVOLUTION ARTICLE'S EVOLUTIONARY PAST! Adam Cuerden 21:18, 21 March 2007 (UTC)
Input appreciated
I would greatly appreciate input in discussions surrounding content of Jewish reactions to intelligent design. My interference appears to have gotten this and Jewish opposition to evolution blocked. I apologise. But I think both articles need serious attention less they waltz into OR and essay gray areas.--ZayZayEM 09:43, 21 March 2007 (UTC)
social and religious controversies
There needs to be a description about the atheist agenda to promote atheism by evolution materialism. Especially since dawkins has labeled teaching children religion is 'child abuse' like my edit that was just undone. its clearly that such a controversial topic is not only driven by passionate religious individuals as well as atheist naturalists. I think this is evidence since gravity is considered a theory and evolution is considered a fact. Wyatt 16:24, 21 March 2007 (UTC)
| This discussion has been closed. Please do not modify it. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
- The issue of theory vs. fact is addressed in the FAQ for this page. I believe the relationship between atheism and evolution is discussed at Objections to evolution, but not all of that article's information will fit in the summary on this page. Gnixon 12:26, 22 March 2007 (UTC)
Single Last Common Ancestor
All species are not descended from a single ancestor as the introduction wrongly states. The origins of life and consequent speciation did not have just one single last common ancestor. Amongst unicellular organisms a tremendous amount of lateral gene transfer took/takes place. Intro needs to be revised Valich 06:07, 17 March 2007 (UTC)
| Comments hidden to save space. Discussion continues under a new heading below. |
|---|
| The following discussion has been closed. Please do not modify it. |
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 19:56, 18 March 2007 (UTC) For clarity in confusion and consistency in all Misplaced Pages 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 ] UCLA Report. (2004) "Ring of Life." ] 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 ] Bapteste et al. (2005). "Do Orthologous Gene Phylogenies Really Support Tree-thinking?" BMC Evolutionary Biology. Vol. 5:33 ] Gogarten, Peter. (2000) "Horizontal Gene Transfer: A New Paradigm for Biology." Esalen Center for Theory and Research Conference. ] 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 ]
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 ]. See also the alternative Tree of Life based on 16sRNA by Mitchell L. Sogin of Woods Hole Marine Biological Laboratory at ]. 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 ]: "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."
Valich, you're simply wrong, here. In the quote above, for example, you chose to highlight this phrase:
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) |
Universal Genetic Code
Please do not use this term. It is extremely out-dated and misleading. Valich 04:35, 21 March 2007 (UTC)
| Comments hidden to save space. Discussion continues under next heading. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
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 Cavalier-Smith T. Rooting the tree of life by transition analyses. Biol Direct. 2006 Jul 11;1:19. PMID: 16834776 Baldauf SL The Deep Roots of Eukaryotes Science 13 June 2003 300: 1703-1706 (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 (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 (in Review).GetAgrippa 21:46, 21 March 2007 (UTC)
|
Valich is right and I'm shocked that anyone would disagree with this, when Genetic Code states clearly that the canonical genetic code is not universal. One defender of "universal genetic code" seems to understand that it is not universal, but says that this term "brings up the right images". If there is no literally correct way to defend the "right image", then its probably not "right" is it? In fact, the wide distribution of the canonical genetic code, though it is not universal, leads to the inference that it is ancestral to all of cellular life. To make this inference seem definitive by loading up the rhetoric with incorrect terms is poor scholarship. Dabs 13:39, 26 March 2007 (UTC)
LUCA and the meaning of the Tree of Life diagram
| Some comments have been hidden to save space. Feel free to continue the discussion below. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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 ]" as evidence for his statement that "there is not, nor ever will be a LUCA." To quote Valich from Adam Cuerden's talk page:
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:
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 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 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.": "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)
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 ]] "The possibility for multiple origins of life is an open question with profound implications for detecting life elsewhere in the universe."] "There is indeed evidence of multiple origins of life." ] Misplaced Pages 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)
|
Based on Thomas's suggestion, I've edited the the intro to say
- Evidence such as the wide distribution of the canonical genetic code indicates that all known cellular organisms are ultimately descended from a common ancestral population.
This is a small change from the text that was there before. Is it satisfactory to everyone? If so, the next task would be to cut most of the 4 billion citations at the end of the sentence. Cheers, Gnixon 15:07, 26 March 2007 (UTC)
- Nice, except I think the phrase "canonical genetic code" is too jargony for the lead. Can we find a phrase that is a little more accessible to the novice reader?
- Also, the last 2 paragraphs of the horizontal gene transfer section of the page could use some reworking in light of the outcome of this discussion.--EveRickert 18:24, 26 March 2007 (UTC)
Not sexy enough
Anyone else find it a bit weird that we include discussion of HGT but not of sexual reproduction? Does this seem to be needlessly privileging phylogenetics? Sure, HGT confounds that, but otherwise I don't see why it's any more or less germane than sex. I seem to recall that we had sex in here in the past and excised it... anyone have any feelings on the subject? Since this is an open(ish) evolutionary conundrum as well, it maybe bears inclusion. Graft 18:53, 21 March 2007 (UTC)
- I suspect that it's because it's presumed sexual reproduction is already understood, but this is probably a bit mistaken. Still, we don't need to go into much detail - how about a paragraph on genetic recombination and independent assortment in the basic processes section? Adam Cuerden 19:10, 21 March 2007 (UTC)
Gah! And then nature goes and does something like this.--EveRickert 17:58, 22 March 2007 (UTC)
- Very good EveRickert! So much for Muller's ratchet. There are always exceptions to the rule in biology. Like bacteria (planctomycetes ) with nucleus like structures, and fish that have evolved placentas. Makes things interesting!! I noted in a recent Science edition talking about the size of genomes and abundance of non-coding DNA that it maybe proportional to the size of the cell or metabolic rate such than natural selection may select for larger genomes. They had good accordance with osteocyte size and genome size and looked at fossils and present life. Plants followed the cell size trend. Interesting reading. It reminds me of Darwin's finches beak differences, which I always assumed that the genetic variation was either influencing neural crest and bone morphogenetic protein so something directly related would be the gene in question, yet calmodulin seems to be the culprit. Examining genes and traits is not always straightforward. Back to the topic SEX! I get off track sometimes-it reminds me of the ole joke-"Meanwhile ,back at the oasis, the Arabs were eating their dates." Oops, sorry about that. I must have calligraphic Tourette's syndrome. Is there no cure??? Hee, hee, hee. GetAgrippa 18:30, 22 March 2007 (UTC)
Theory or Fact
Take a look at the following. All these state evolution is a theory. Let me quote from the last link "Like all scientific theories, the theory of evolution is a current best explanation." It does not say it is a fact, it says it is a theory and like all theories it is the best explaination that we have. Also I have asked a science teacher that I know if Evolution is a theory and her answer was "Yes." I think she knows more about this than many of you. Thanks:) James, La gloria è a dio 00:30, 22 March 2007 (UTC)
| This discussion has been closed. Please do not modify it. |
|---|
| The following discussion has been closed. Please do not modify it. |
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)
|
- This issue has been discussed. Please see the FAQ. Gnixon 12:19, 22 March 2007 (UTC)
Proposed change
This article is a bit long, couldn't we just remove the sections that have their own articles and just link to those articles or just give a brief summary of each? It takes really long to open this on my dialup internet browser. BTW, the talk page should be archived again Ratso 01:40, 22 March 2007 (UTC)
- I don't think it is to long at all. Peace:) --James, La gloria è a dio 01:47, 22 March 2007 (UTC)
- I do ! --Thomas Arelatensis 13:17, 22 March 2007 (UTC)
- Me too! (Notice discussions above about the length issue.)Gnixon 13:20, 22 March 2007 (UTC)
- There has not been a consensus for a further reduction of the length of Evolution since the debate on 8 February. At that time, a number of previous contributors argued that it was already short enough, at around 65kb, and they suggested we not target a specific length. The article shrank a lot between mid-December and mid-January, and I agree with the February 8 consensus that it is now short enough. Though one might argue that there are still some details that might be omitted in specific sections to reduce complexity (the type of items that Silence used to call 'trivia'). The article currently stands at 71kb. EdJohnston 15:31, 22 March 2007 (UTC)
- It's a pretty complex topic: To give a proper overview needs some length, and all those references are probably extending it a fair bit.
- Anyway, I think every section has a subarticle, so that'd reduce it to... the lead and a bit of introductory material for the supergroupings. Adam Cuerden 18:10, 22 March 2007 (UTC)
The problem is that everyone is constantly adding their caveats and extra bits of detail, and they tend to add them too high up in the hierarchy of the article and it's sub-articles. People read the article and see their favorite topic given only brief mention, so they add several paragraphs at a level of detail better suited for a "main article." Or, they glance at the intro, see some nuance missing, and add 10 extra clauses to an already unwieldy sentence. The article naturally swells over time, so it needs to be regularly trimmed back if it's going to stay (become?) readable. (IMHO) Gnixon 15:21, 26 March 2007 (UTC)
Evolutionary pumps
Hi there, I'd like some expert advice on this interesting theory within an article up for GA review. I've moved part of the article onto the talk page, as this doesn't match what I understand by the theory of punctuated equilibrium. Any comments on this talk page would be welcome. TimVickers 03:02, 22 March 2007 (UTC)
Archival
This talk page tends to fill up quickly. Can we agree on a policy for archiving old discussions? I would suggest the following:
- Keep any discussion with a comment less than 2 weeks old. Regularly move older ones to the archives.
- For very long but ongoing discussions, use the hat/hab tags to hide older comments. Use the reason= parameter to explain. For example, {{hat|reason=Older comments hidden to save space. Feel free to continue the discussion below.}} produces
| Older comments hidden to save space. Feel free to continue the discussion below. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
blah blah blah blah blah blah |
- When someone raises a controversial subject that is addressed in the FAQ, leave the original post, but immediately use hat/hab on the inevitable flamewar that follows. For example,
- Evolution is unproven! It's a theory, not a fact! User:GenesisTellsAll
| This issue is addressed in the FAQ. |
|---|
| The following discussion has been closed. Please do not modify it. |
... |
What do you guys think? Gnixon 16:31, 23 March 2007 (UTC)
- An excellent suggestion Gnixon. The warning banners and FAQ do little to stop POV pushing and vandals, so addressing it in the Talk but hiding it seems reasonable. It is difficult enough to get consensus on the topic from evolution enthusiast without wasting time addressing side issues not related to the topic. I have to admit I was initially naive to the depths of concern over creationist and ID vandalisms-I thought the editors paranoid, but was I wrong. Fill spends quite a bit of time refuting such claims from creationist and ID proponents. I am shocked as some seems less than honest (not all I should amend)which does little for their cause. GetAgrippa 18:32, 23 March 2007 (UTC)
- Thanks. Credit where due: the hat/hab archives were EdJohnston's idea. We could all try harder to keep our comments tightly focused and avoid starting off-topic discussions. Gnixon 02:16, 24 March 2007 (UTC)
- I'd propose regular archiving in a simple manner, not topic-by-topic, which is too labor-intensive to be done regularly by a human, and prone to error. It probably requires a bot to do topic-by-topic archiving without tons of work, and the available bots leave something to be desired. The hat/hab scheme for boxing up topics seems fine for questions answered in the FAQ. In general I'd suggest that this Talk page is too large when it gets over 120 kb and that the archiver should leave the most recent 80kb in place. EdJohnston 18:53, 23 March 2007 (UTC)
- Oh yeah. I didn't mean that each topic should be archived separately. I imagined someone glancing at the page and saying, "none of the topics above here have comments within the last two weeks, so they all get archived." As for keeping the page to 80-120 kB, I think it's better to decide a reasonable time since last comment and cut on that instead. (Of course, keeping the page small puts an upper limit on that time.) This page fills up so fast that cutting on size will often remove ongoing discussions. Editors shouldn't miss the chance to comment on recent topics just because they haven't logged onto Misplaced Pages in the last 3 or 4 days. Gnixon 02:16, 24 March 2007 (UTC)
I must have missed when it happened, but this new archiving methodology isn't very useful. I remember there used to be, at the top of the discussion page, a great reference source that had archives of discussions by topic. For example, the "Evolution is only a theory" topic, which happens over and over again, had it's own link. One could go and read it, maybe realize "oh someone's said that, and it's been set aside." Now I can't find all that stuff. Anyways, all IMHO. Orangemarlin 18:16, 26 March 2007 (UTC)
- Archiving by topic is really useful, but also tons of work to maintain. I suspect people switched to the simpler scheme out of laziness. Keep in mind that this talk page generates about an article's length of comments every couple weeks. See also the discussion about an "Evolution Debates" archive and its deletion as a POV fork. Gnixon 18:52, 26 March 2007 (UTC)
- Too bad. It was nice to refer people to old arguments. If they didn't read them, we could beat them up mercilessly. It made my days so much happier. Orangemarlin 17:33, 27 March 2007 (UTC)
- It would be useful if someone created such a table at the top of the page with links to discussions in the archives. Gnixon 17:33, 28 March 2007 (UTC)
intro: suggest removing reference to "types"
The term suggests typological thinking, not required in the context. Also, many would associate speciation with reproductive isolation. I suggest "at some point diverging populations become sufficiently distinct that they may be considered distinct species, in particular if the capacity is lost for interbreeding between the populations. Dfarrar 02:47, 24 March 2007 (UTC)
Theistic Evolution
There is a need for a section about Theistic Evolution. Talk about Evolution's status in big religions such as Islam, and Christianity, and Hinduism, etc. Believe it or not, there are Muslims, Christians, and Hindus who believe in Evolution. Armyrifle 23:21, 25 March 2007 (UTC)
- Believe it or not, Theistic evolution.--Ķĩřβȳ♥♥♥ŤįɱéØ 23:29, 25 March 2007 (UTC)
- Hmm, a link somewhere in the article might be nice. i kan reed 23:38, 25 March 2007 (UTC)
- Please see the Social and religious controversies section. — Knowledge Seeker দ 02:27, 26 March 2007 (UTC)
- Hmm, a link somewhere in the article might be nice. i kan reed 23:38, 25 March 2007 (UTC)
Controversy (2)
The Social and religious controversy section is probably the most neglected one in the article, but it is one of the most important for many of the new posters on this discussion page. The section has long had "citation needed" tags. It discusses both objections to evolution and controversial social theories derived from it, but the two topics are not well-separated. The paragraphs seem to have each been developed independently and don't transition well. Can we try to improve things? Gnixon 16:09, 26 March 2007 (UTC)
I attempted a major revision several days ago. I thought it would be uncontroversial since I only used the previous text and the introductions of the sub-articles, but the change was reverted by someone who preferred to discuss it here first. In response, I've created a Work in Progress page and copied my edit there. I would appreciate if people would take a look, comment at the bottom of the page, and make improvements. Thanks!! Gnixon 16:09, 26 March 2007 (UTC)
Thanks to the users who made comments at the WIP page. I've recently made several edits to the Controversy section, keeping their comments in mind. Particularly, instead of trying to copy in the introductions of related articles, which made the section too long, I've simply organized the section with subsections and cut redundant material. One editor argued for cutting the "Social theories" stuff, but I've left it in for now. I hope this is satisfactory to everyone. Let's work hard to keep this section short, well-referenced, and free of both anti-evolution and anti-creationist POV. Gnixon 16:31, 28 March 2007 (UTC)
Observation
Where are the examples of new species observed to come into existence? I've heard claims about medicines being invented by evolution and things, but I don't know of any where that evolution has actually been observed? This is different than seeing a chain of similar animals, because those animals are actually distant from each other even if they followed a similar path. All I've seen is beaks getting longer or shorter, but no real macro changes or new features. It would be nice to have some statements about it, but I may have just overlooked them. Wyatt 21:28, 26 March 2007 (UTC)
- This issue is addressed somewhat in the FAQ. You'll also find information in Objections to evolution since some have argued that "macroevolution" has not been observed. Gnixon 22:33, 26 March 2007 (UTC)
- Wyatt is right, macroevolution is the main objection in recent memory. On first thought it could be unburied from Objections and placed in its lead, which would then be replicated to Evolution. I could see some objecting to this as too specific for the lead; but to not have macroevolution in the content of the Evolution article (templates at the bottom/side don't count folks) seems to be a glaring blind spot. - RoyBoy 03:11, 28 March 2007 (UTC)
Suggestions from Mandaclair
A number of discussions with a biology professor.
Definition in lead
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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:
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)
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 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.)
|
Recommendations
| Comments hidden for length. Feel free to continue discussion below. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
If "bold editing" was a bit easier to accomplish, I might recommend the following (Comments by User:Mandaclair):
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)
|
Cooks in the pot
| Hidden for length. Feel free to continue the discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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 Misplaced Pages 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 Misplaced Pages) 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 Misplaced Pages, and yet, they may feel compelled to help out in some way -- especially if their students use Misplaced Pages. 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.
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) |
Natural selection
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
Here are some of the other changes I made last night, and the rationale (Comments by User:Mandaclair.):
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:
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:
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)
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)
|
Common misconceptions
| Hidden for length. Feel free to continue the discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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.)
Please e-mail me for questions or details. Thanks, Mandaclair 18:18, 28 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 01:02, 29 March 2007 (UTC) |
Changes implemented
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
|
Struggle to survive
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
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)
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)
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)
|
Heredity
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
|
Selection and Adaptation
| Hidden for length. Feel free to continue discussion. |
|---|
| The following discussion has been closed. Please do not modify it. |
|
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)
|
- Misplaced Pages former featured articles
- Featured articles that have appeared on the main page
- Featured articles that have appeared on the main page once
- All unassessed articles
- Unassessed Evolutionary biology articles
- Unknown-importance Evolutionary biology articles
- WikiProject Evolutionary biology articles
- Misplaced Pages pages with to-do lists