Definition of Evolution

So Ray. Thanks for picking out one of the posts that strayed from the topic -- the definition of evolution -- for comment (I also notice that you paid no attention to the refutations of his several errors and misrepresentations). Can we get back on topic?Do you agree that the definition of evolution is: If not why.Enjoy.

And yet Ernst Mayr "contributed to the conceptual revolution that led to the modern evolutionary synthesis of Mendelian genetics, systematics, and Darwinian evolution, and to the development of the biological species concept" and he also defined evolution as:

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Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species.

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Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.157

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My personal preference is Because the naturalist can measure and document changes in hereditary traits, as Mendel did, without needing genetic analysis. But I don't see that as being significantly different from In either case we get change that is hereditary and that is passed from one generation to the next based on relative reproductive success. I suppose you think gravity is just an observation, an inference.Sorry ray, but this is not a definition either, it is just a way for you to avoid confronting the evidence. Perhaps you should read Mod's Message 122 and the links he provided.Enjoy.

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Right where I left it (after concept). He is known for both.Ernst Mayr - Wikipedia

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Ernst Walter Mayr (July 5, 1904, Kempten, Germany - February 3, 2005, Bedford, Massachusetts U.S.), was one of the 20th century's leading evolutionary biologists. He was also a renowned taxonomist, tropical explorer, ornithologist, historian of science, and naturalist. His work contributed to the conceptual revolution that led to the modern evolutionary synthesis of Mendelian genetics, systematics, and Darwinian evolution, and to the development of the biological species concept.

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He comes from the side of naturalist (ornithologist) and taxonomist and he had reservations about a "gene centric" view.He is also known for inconsistency. I suggested you read Mods Message 122 and follow the links: apparently you haven't done that. One of them was Sandwalk: What Is Evolution?

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The Gene Centrist Objection

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Ernst Mayr wrote an entire book on the subject of this little essay. One might expect some insight from one of the original founders of the Modern Synthesis but, unfortunately, we aren't going to get any help from Mayr. On page 157 he says,

Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species.

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Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.157

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This is good stuff. It restricts the changes to genetic changes and it clearly identifies the population as the unit that evolves. There's no mention of any particular mechanism. But”and you knew there was going to be a "but" didn't you?”good things never last. In his chapter on macroevolution Mayr describes the work of his colleagues Rensch and Simpson. These workers were able to study macroevolutionary events without referring to allele frequencies in a population. Mayr coments,

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This approach was consistent with the modern definition of evolution as a change in adaptedness and diversity, rather than a change in gene frequencies, as suggested by the reductionists.

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Ernst Mary (2001) What Evolution Is, Basic Books, New York p.189

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Consistency is not one of the hallmarks of Ernst Mayr's writings. That's why he can propose two conflicting definitions in the same book; even a book that's devoted to the topic of defining biological evolution! Nevertheless, Mayr does highlight two different objections to the minimal definition that I am defending.

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I suggest you read the whole article.That Mayr can give - and use - two different definitions does not mean that one or the other is more correct. In the second case he is talking about adaptive evolution -- the 'fixing' of changes in the genotype, a necessary step (imho) on the way to speciation. See Message 147 and related discussion with Hoot Mon. This doesn't happen without change in alleles and their frequency in populations.Enjoy.

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You mean the part where I posted:

quote:

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Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species.

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Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.157

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That is the quote and the reference citation. Are you saying he was not one of the principal architects of the modern synthesis? DO a google on it and see what names you come up with.http://bioinfo.med.utoronto.ca/...dent/Modern_Synthesis.html

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One of the goals of the Modern Synthesis was to reach consensus on the place of macroevolution. The founders of the Modern Synthesis insisted that macroevolution could be explained by microevolution and no additional mechanisms, such as the bogeyman of saltation, were required. Ernst Mary, one of the original founders, sums it up this way ...

The term "evolutionary synthesis" was introduced by Julian Huxley in Evolution: The Modern Synthesis (1942) to designate the general acceptance of two conclusions: gradual evolution can be explained in terms of small genetic changes ("mutations") and recombination, and the ordering of the genetic variation by natural selection; and the observed evolutionary phenomena, particularly macroevolutonary processes and speciation, can be explained in a manner that is consistent with the known genetic mechanisms.

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Ernst Mayr (1980) "Some Thoughts on the History
of the Evolutionary Synthesis" in The Evolutionary Synthesis,
E. Mayr & W.B. Provine eds. Harvard University Press.

The origanl version of the Modern Synthesis included mechanisms other than natural selection, especially random genetic drift.

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(FYI the indented portion is the direct quote from Mayr)Criticizing the use of wikipedia is useless if the same information is generally available and it is correct. Now you're just being confused. Note that "the blog writer" is a professor of molecular biology. No, actually it is shown by quoting Mayr from two different parts of the same book where he gives (or appears to give) two different definitions for "evolution" -- both are quoted so you can compare them yourself. That Mayr said that is not disputed. That he ALSO said the other definition is the point being made -- which it seems you are unable to refute and are attempting to ignore. If you don't believe this then check the book out at the library and read page 157. But if you are going to argue that the quote from page 157 is not correct then you have to demonstrate it, and to do that you do need to go to the original source. You are the one claiming this is "quote mined" (ie quoted out of context) so it is incumbent on you to demonstrate that fact. He also says that it is. See page 157. You are just choosing the definition you prefer based on your opinion. Your cite is also from the preface rather than the actual body of the book, and so context is more difficult to evaluate. Looking in the body of the book for context you need to look at p 189 and this quote where he gives an alternate definition for evolution:

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... At first sight, there seems to be no method available to explain macroevolutionary phenomena by microevolutionary theories. But should it nevertheless be possible to expand the microevolutionary processes into macroevolutionary ones? And furthermore, can it be shown that macroevolutionary theories and laws are fully consistent with microevolutionary ones?

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The possibility of such an explanation was shown by a number of authors during the evolutionary synthesis, particularly by Rensch and Simpson. They successfully developed Darwinian generalizations about macroevolution without having to analyze any correlated changes in gene frequencies. This approach was consistent with the modern definition of evolution as a change in adaptedness and diversity, rather than a change in gene frequencies, as suggested by the reductionists. To put it in a nutshell, in order to prove that there is an unbroken continuity between macro- and microevolution, the Darwinians have to demonstrate that seemingly very different "types" are nothing but the end points in a continuous series of evolving populations.

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Same book, but here he is talking specifically about macroevolutionary effects -- ie the evolution that leads to speciation -- rather than evolution in general.Finally, Mayr is not the only biologist that defines evolution, nor is he considered an ultimate authority, though his opinion is respected. One of the problems with the arguments from authority eh?For instance, another well recognized authority says:

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Biological (or organic) evolution is change in the properties of populations of organisms or groups of such populations, over the course of generations. The development, or ontogeny, of an individual organism is not considered evolution: individual organisms do not evolve. The changes in populations that are considered evolutionary are those that are ”heritable' via the genetic material from one generation to the next. Biological evolution may be slight or substantial; it embraces everything from slight changes in the proportions of different forms of a gene within a population, such as the alleles that determine the different human blood types, to the alterations that led from the earliest organisms to dinosaurs, bees, snapdragons, and humans.

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Douglas J. Futuyma (1998) Evolutionary Biology 3rd ed., Sinauer Associates Inc. Sunderland MA p.4

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(quote is from the book referenced -- a common textbook used to teach evolution) But the point being discussed here is that it is a valid definition of evolution, one that is also supported by Mayr (as well as other authorities).Enjoy.Edited by RAZD, : corrected page reference from 168 to 189 and expanded quoted material from that page.

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You could just admit that you were wrong, Ray. Notice I said "one of the principal architects" not chief architect -- that is your conflation to avoid the reality. And in this case got it 100% correct. Gosh. Wonder why? I have absolutely no idea where you get this bizarre concept from Ray. Moran wrote the article and quoted Mayr in it -- so how could the book quoted in the article be written as a response to the article that quotes the book? One can conclude that reading for comprehension is not your strong suit if you make assertions like this. Notice that you claimed I had "quote mined" the definition on page 157 -- that means misrepresenting what was said out of context. For reference here is all of page 157:

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Conclusions

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Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species. Numerous processes, particularly mutation, contribute to these genetic changes to supply the phenotypic variation needed by selection. The most important factor is recombination, which is largely responsible for the virtually inexhaustible supply supply of new genotypes in every generation. Selection, then, is responsible for the elimination of all but on average two of the offspring of two parents. Those individuals that are best adapted to the abiotic and biotic environment have the greatest chance to be among the survivors. This process favors the development of new adaptations and the acquisition of evolutionary novelties, thus leading to evolutionary advance, as stated in the language of evolutionary biology. Evolution, being on the whole a population turnover, is ordinarily a gradual process, except for certain chromosomal processes that may lead to the production of a new species-individual in a single step.

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Genetic material (nucleic acids) is constant and impervious to any influence from the environment. No genetic information can be transmitted from proteins to nucleic acids, and so the inheritance of acquired characteristics is therefore impossible. This provides an absolute refutation of all Lamarkian theories of evolution. The Darwinian model of evolution, based on random variation and natural selection, explains satisfactorily all phenomena of evolutionary change at the species level, and in particular all adaptation.

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-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.157

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Note: when I use a quote box like this I do not need to use quote marks -- they would be redundant.Now, please point out where he contradicts evolution as "genetic change from generation to generation in populations" anywhere in that quoted material, for that is your claim when you say I quote-mined.Show me where in that material he says this is not evolution, Ray, or acknowledge that this is an accurate and correct quote of the material and there is not misrepresentations of what Mayr said on that page.Note that this is his conclusion to "Section II: How Are Evolutionary Changes and Adaptedness Explained" and are not just off the cuff remarks. No you haven't -- you have not demonstrated that I misrepresented what he said on page 157 or taken it out of context at all: you haven't even discussed what he said on page 157 because you are avoiding it Ray. Or you don't understand what "quote mining" means. It says what evolution is. It is not qualified in stating what evolution is. You can call it something other than a definition if you want to Ray, but you are only fooling yourself. No Ray, what I have said is that Mayr say two contradictory things about what evolution is, and that to claim that only one or the otehr of them applies is false and misrepresents the reality: that is what you are doing. And on page 157 he says

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Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species.

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He says both, as I have pointed out, and ignoring either is to misrepresent what he says.Get it? Getting all huffy and posting one in big colored letters does not negate that he also said the other.Now I also give you this quote from near the end of the book, where he is wrapping up all the issues covered:

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End

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Evolution is often considered as something unexpected. Wouldn't it be more natural, some antievolutionists ask, if everything would always stay the same? Perhaps this was a valid question before we understood genetics, but it is no longer. In fact, the way organisms are structured, evolution is inevitable. Each organism, even the simplest bacterium, has a genome, consisting of thousands to many millions of base pairs. Observation has established that each base pair is subject to occasional mutation. Different populations have different mutations, and if they are isolated from each other, these populations inevitably become more different from each other from generation to generation. Even this simplest of all possible scenarios represents evolution. If one adds further biological processes, such as recombination and selection, the rate of evolution accelerates exponentially. Therefore, the mere fact of the existence of genetic programs makes the assumption of a stationary world impossible. Evolution is thus a plain fact, not a conjecture or assumption.

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It is very questionable whether the term "evolutionary theory" should be used any longer. That evolution has occurred and takes place all the time is a fact so overwhelmingly established that it has become irrational to call it a theory. To be sure, there are particular evolutionary theories such as those of common descent, origin of life, gradualism, speciation, and natural selection, but scientific arguments about conflicting theories concerning these topics do not in any way affect the basic conclusion that evolution as such is a fact. It has taken place ever since the origin of life.

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-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.264

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Can you tell me where in that page he says evolution is not "genetic change from generation to generation in populations" Ray?Enjoy.Edited by RAZD, : spleling in end quote

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Yet on Message 165 you said: And on Message 171 you said: Conclusion: yes you did accuse me of quote mining, and now that it has been shown that you cannot support this claim you are equivocating? My simple interpretation is that (a) "the subject of this little essay" is the definition of what evolution is, that (b) "this little essay" is the one with those words in it, and that (c) he notes that Mayr wrote a whole book on the subject (defining what evolution is) from which he proceeds to quote. If you think this is whack, then I suggest you go to the horses mouth and ask Dr. Moran -- he has his email addy on the essay. It's not something I'm going to lose sleep over, and it's irrelevant to the thread. From the words used, Ray: "Evolution ... consists of ... " -- with no qualification of the statement anywhere in the rest of the paragraph.Gravity between two objects consists of the the attraction between the two objects based on their mass and the distance between them (squared).Notice, Ray, that your pet quote does not mention the word definition at all, so you are guilty of conflating this word into that quote.Where do you get the idea that he says that quote involves a definition? Really Ray, your logic is faulty: if I ignore the preface there is no contradiction. You are really making a mountain out of a molehill by this ridiculous argument. The reality is that Mayr made two statements in the book that are contradictions:

1. "Evolution deals with phenotypes of individuals, with populations, with species; it is not 'a change in gene frequencies.'"
   -- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.XIV).
2. "Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species."
   -- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.157

Do you dispute that these two statements are contradictory?Enjoy.Edited by RAZD, : mary\mayr tpoyEdited by RAZD, : subtitle

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Welcome to the fray Q. Such changes are not necessarily hereditary, they can be acquired traits (muscles), so I would add hereditary.I would also use genome or genotype instead of blue-print, as that is not strictly accurate as a description of the function of DNA.And finally there is no mention of the time scale of these changes -- do they occur in individuals (no) or are they realized in descendant populations (yes)?Enjoy.

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We can just simplify the language to: Or is there something missing there from your definition?

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oops looks like your content was deleted ... that's what happens when you insult instead of deal with the issue.For clarity Ray, "quote mining" is taking something OUT OF CONTEXT in a manner that MISREPRESENTS its original meaning. I have not done that. You have totally FAILED to show that to be the case, so all you do now is rail, insult, dance and equivocate on your original argument.That is the truth.Mayr said two things that are contradictory. That has been shown, that is the truth.There are other places where he gives other "definitions" -- one example is:

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Evolution is best understood as the genetic turnover of the individuals of every population from generation to generation.
-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.76

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That too shows "inconsistency" in his writing.Perhaps you could document some other place where he says it is not the change in frequency of alleles? You know, back up your position with additional information? For it certainly seems that the main body of the book keeps referring to evolution as hereditary change in populations from generation to generation in one form or another.This would also be on topic for this thread - the definition of evolution.Given the topic of the book you should be able to substantiate your position by providing a quote of "what Evolution is" where it does not involve hereditary change in populations from generation to generation -- if that is really Mayr's position in the body of the book.Consider that it is possible that Mayr was saying that "evolution is not a change in gene frequencies", but that it is still "consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species", because that is more than just change in gene frequencies (which is true).Enjoy.ps -- This is what a quote mine looks like when exposed:(1) your quote in Message 172(2) The actual text with your quoted sections in pink:

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The existing volumes intended to fill these needs have some of the following shortcomings. All of them are rather poorly organized and fail to present a concise, reader-friendly account. Most of them are not as didactic as they should be, because a difficult subject such as evolution should be presented as answers to a series of questions. Nearly all of them devote too much space to specialized aspects of evolution, such as the genetic basis of variation and the role of sex ratios. Virtually all of them are too technical and use too much jargon. About one-quarter of the content of all recent major evolutionary texts is devoted to genetics. I agree that the principles of genetics must be thoroughly explained, but there is no need for so much Mendelian arithmetic. Nor should space be wasted on arguing for or against obsolete claims, such as that the gene is the object of selection, or to a refutation of extreme recapitulationism (the idea that ontogeny recapitulates or repeats phylogeny). On the other hand, several of these texts do not give adequate space to an analysis of the different kinds of natural selection for reproductive success.

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Most existing volumes on evolution have two other weaknesses. First, they fail to point out that almost all evolutionary phenomena can be assigned to one or the other of two major evolutionary processes: the acquisition and maintenance of adaptedness, and the origin and role of organic diversity. Although both take place simultaneously, they must be analyzed separately for a full understanding of their respective roles in evolution.

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Second, most treatments of evolution are written in a reductionist manner in which all evolutionary phenomena are reduced to the level of the gene. An attempt is then made to explain the higher-level evolutionary process by "upward" reasoning. This approach invariably fails. Evolution deals with phenotypes of individuals, with populations, with species; it is not "a change in gene frequencies." The two most important units in evolution are the individual, the principal object of selection, and the population, the stage of diversifying evolution. These will be the major objects of my analysis.

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-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.XIV).

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You have misrepresented what he was talking about when you say There is no "however" involved.What he says is that evolution is not just "a change in gene frequencies" as it involves other components, but he also consistently throughout the book says that evolution does not occur without a hereditary (ie genetic) component. To say otherwise is to misrepresent what he says, and to use your quotation to justify that position is to be guilty of quote-mining.Edited by RAZD, : downEdited by RAZD, : subtitleEdited by RAZD, : added ps

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So we have this quote from the beginning of the book, where he is talking about evolution in general (Part I - What is Evolution)

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What Evolves?

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Almost everything in the inanimate universe is also evolving, that is, it is changing in a distinctly directional sequence. But what is it that evolves in the living world? Species surely evolve, and so do all combinations of species in the Linnaean hierarchy - genera, families, orders, and all higher taxa up to the totality of the living world. But what about the lower levels? Do individuals evolve? Certainly not in any genetic sense. To be sure, our phenotype changes in the course of our life, but our genotype remains essentially the same from birth to death. Then what is the lowest level of living organization to evolve? It is the population. And the population turns out to be the most important site of evolution. Evolution is best understood as the genetic turnover of the individuals of every population from generation to generation.

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To be complete the precise characterization of evolution in sexually reproducing species, it is necessary to define the evolutionary population. A local population (deme) consists of the community of potentially interbreeding individuals of a species at a given locality (see Chapter 5). Curiously, the concept of population, as here described, was unknown before 1859; even Darwin was inconsistent in its application. Everybody else tended to think in terms of types.

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-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.76

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Italics in the original. So what can he mean when he says "Evolution deals with phenotypes of individuals, with populations, with species; it is not 'a change in gene frequencies.'" (p. xiv, preface)? He could be saying that just change in gene frequencies is not enough to be evolution, but can we substantiate that from the book?

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Neutral Evolution

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Molecular genetics has found that mutations frequently occur in which the new allele produces no change in the fitness of the phenotype. Kimura (1983) has called the occurrences of such mutations neutral evolution, and other authors have referred to it as non-Darwinian evolution. Both terms are misleading. Evolution involves the fitness of individuals and populations, not of genes. When a genotype, favored by selection, carries along as hitchhikers a few newly arisen and strictly neutral alleles, it has no influence on evolution. This may be called evolutionary "noise," but it is not evolution. However, Kimura is correct in pointing out that much of the molecular variation of the genotype is due to neutral mutations. Having no effect on the phenotype, they are immune to selection.

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-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.199

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Here we have an explicit statement of where he explains why "a change in gene frequencies" is not evolution, because it involves genes that are not subject to selection.It is clear from the rest of the book (and the numerous quotes I've provided from it) that Mayr considers genetic change to be an important element of evolution, and that it must be linked with phenotype selection - the "turnover of the individuals of every population from generation to generation."This is why I also prefer "hereditary traits" to "genetic traits" in the definition we have been discussing on this thread: Or we could specify hereditary phenotypic traits ... if we need to.Enjoy.Edited by RAZD, : finished.Edited by RAZD, : completed

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westernjoe in Message 8 states: I would compare this with the university definitions presented in Message 107 here and with the subsequent discussion above.

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The real crux of the matter is that you need to be discussing evolution with the definition used in the science, or you are not discussing the science of evolution but something else. In this regard there are a couple of definitions that come directly from scientific sources -- universities teaching evolution:

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An introduction to evolution - Understanding Evolution

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The Definition:
Biological evolution, simply put, is descent with modification. This definition encompasses small-scale evolution (changes in gene frequency in a population from one generation to the next) and large-scale evolution (the descent of different species from a common ancestor over many generations). Evolution helps us to understand the history of life.

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The Process of Speciation

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Definitions of Biological Evolution
We begin with two working definitions of biological evolution, which capture these two facets of genetics and differences among life forms. Then we will ask what is a species, and how does a species arise?

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Definition 1:
Changes in the genetic composition of a population with the passage of each generation

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Definition 2:
The gradual change of living things from one form into another over the course of time, the origin of species and lineages by descent of living forms from ancestral forms, and the generation of diversity

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Note that the first definition emphasizes genetic change. It commonly is referred to as microevolution. The second definition emphasizes the appearance of new, physically distinct life forms that can be grouped with similar appearing life forms in a taxonomic hierarchy. It commonly is referred to as macroevolution.

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These can be summarized as you have with "Change in a population's genetic traits across generations" -- noting that this tends to emphasis the microevolutionary aspect over the macroevolutionary one.

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You will note that both of these discuss the "change in frequency of alleles within a population over generations" type of definition, but also discuss hereditary traits at a wider focus.You will also note that they teach degree courses in biological evolution, and thus we can be confident that they know what they are talking about.In Message 14 westernjoe replies Curiously, that this is similar to the "change in hereditary traits in populations from generation to generation," which you originally claimed was wrong. Now can you tell me how to measure the frequency of alleles for a fossil?Note, you may want to read Message 192 above that discusses Mayr's explanation of why he thinks "a change in gene frequencies" alone is not evolution, because it involves genes that are not subject to selection.In Message 16 westernjoe adds No, it is really specific by referring to hereditary traits, because this does not confuse the issue with non-effective mutations that can be counted as genetic changes while not affecting in any way the growth, development, behavior, survival or breeding of the organism. Such mutations do not affect the phenotype and thus are not subject to selection. Without selection it is not evolution.Saying that evolution is the process of change in hereditary traits in populations from generation to generation is actually more precise as it is telling you what is subject to selection. LOL. Seeing as they did not even know what a "genome" was when Darwin formulated his theory of evolution, your comment is patently false.The theory of evolution was developed to explain the diversity of life at the time Darwin formulated it. Since then it has been used to explain the complete and full diversity of life that we now know, from the world around us, from history, from prehistory and the archeological record, from geology, physics, paleontology and the fossil record, and from chemistry and the genetic record. There is more to explain, yet the theory is still the same, it is still descent with modification. We now know that the modification is to hereditary traits via genetics, but this has only refined the original concept. Nor does the theory of evolution or the process of evolution or the SCIENCE of evolution need to explain where genomes come from.All evolution needs to explain is what exists: the diversity of life we can see around us, as well as what is known from history, archeology, the fossil record and the genetic record, etc.The theory of evolution does this by descent with modification. Curiously you have now fully confused yourself between the process of evolution and the theory of evolution. All the theory needs to do is explain the evidence we have for the diversity of life. You may want to refer to the The Definition for the Theory of Evolution (if you have learned how to follow links to other threads where the different topics are already covered).In a simple form the theory of evolution can be defined as follows: the theory of evolution is that the process of evolution - the change in hereditary traits in populations from generation to generation - coupled with the process of speciation - the division of parent populations into reproductively isolated daughter populations - is sufficient to explain the diversity of life. To answer that, YOU are going to have to define what YOU mean by "micro" and "macro" ... and, curiously we have a thread dedicated to that: MACROevolution vs MICROevolution - what is it?.Enjoy.Edited by RAZD, : added later joe commentEdited by RAZD, : added end.Edited by RAZD, : added further responseEdited by RAZD, : ...

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westernjoe in Message 19 states: I note two things about this:(1) this is now the third definition you have offered, and(2) the gene pool consists of the total hereditary traits for the population - so there is no real difference between these definitions.What you are saying is that my definition - that evolution is the change in hereditary traits in populations from generation to generation - is wrong, because the "real" definition is that evolution is the change in hereditary traits in populations from generation to generation.Color me underwhelmed. You still confuse me with coyote, Message 3: It speaks volumes of your ability to read and comprehend things, when you (a) can't see that the definitions of evolution are the same, and (b) confuse the people you are replying to. So providing one example will satisfy you that I am right?Several examples have already been presented, denial of them does not make them go away.We have ring species:
Greenish warblers Here we see a small difference in hereditary traits - slight difference in plumage coloration and slight difference in mating songs that leave the two varieties reproductively isolated. These differences can be tracked around the far side of the ring, and they show gradual change from one to the other, and gene flow (reproduction mixing hereditary traits in hybrid zones) between adjacent varieties.We have pelycodus:
A Smooth Fossil Transition: Pelycodus Here we see the variety of hereditary traits in the "gene pool" as bands at each level, we see a general trend in their change from level to level (= time = passage of many generations), and we see a division of the parent population into two reproductively isolated daughter populations.we have foraminifera
article 8 The latter example shows "An intact fossil record with no missing links" and "a virtually complete evolutionary record" with "hundreds of speciation events" where "The record reveals a robust, highly branched evolutionary tree, complete with Darwin's predicted "dead ends"--varieties that lead nowhere--and a profusion of variability in sizes and body shapes. Transitional forms between species are readily apparent, making it relatively easy to track ancestor species to their descendents." The continuous fossil record extends back past the K-T boundary, 65 million years ago.Based on your argument (I won't call it logic) you will now concede that evolution does indeed consist of the change in hereditary traits in populations from generation to generation.Now you MAY be able to argue that the "genetic definition" (which is what evolutionary biologists usually call the "change in frequency of alleles in populations over generations" definition) is the better definition, but to do that, you will need to show how you have measured this change in the three examples of evolution in action shown above.I'll await your reply ... It is your assertion that evolution does not exist, and you have yet to establish this as a credible statement in any way. This small detail means that the straw man is your argument.Curiously, you are claiming that the life work of millions of scientists is all smoke and mirrors, while you somehow posses an insight nobody else has. All this based on your personal assertion ... and you ask us for evidence. Interestingly, saying that something does not happen does not prevent it from happening: you can claim that the earth does not spin on it's axis, but that won't make is so.Amazingly, life will continue to live, eat, sleep, reproduce and evolve, whether you think so or not: nature is completely undeterred in any way by your opinion.Enjoy.

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Rebel American Zen Deist
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Welcome to the fray pix1 Yes, but ... you can have evolution without resulting in new species, natural selection operates on the phenotype rather than the genotype, genetic composition is not always expressed in the phenotype and ... so I would have said:

quote:

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3. Biology
a. Change in the composition of hereditary traits in a population during successive generations, often as a result of natural selection acting on the variety of phenotypes in the population,
b. such evolution resulting in the development of new species, through the division of parent populations into reproductively isolated daughter populations, living in different ecologies, and
c. the formation of nested hierarchies that result in the pattern of historical development of a related group of organisms; phylogeny.

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Not quite so succinct ...Enjoy.

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Welcome to the fray -Sky- The problem is that "evolution" is a term used for several processes, one of which is biological. The "definition" by Ihategod is missing the aspect of heredity, and without heredity biological evolution would not work. It also is missing where evolution occurs. The definition I prefer isEvolution is the change in hereditary traits in populations from generation to generation.I prefer generations to "over time" as this is a more appropriate measure for the time involved for any species.Enjoy.

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This is a bit unsatisfactory to me, because it can just be an oscillation back and forth between existing traits, while the hereditary traits (alleles, etc) are unchanged.While technically true, to me evolution (the process) occurs when the hereditary trait changes to a new variant of existing alleles\traits\genes\whatever. This is similar to Mayr's objection to neutral traits not being evolution because they are not selected.My personal criteria for a definition of the process of evolution is that it must be applicable in the field without genetic analysis, and it must be applicable to fossils (for which genetic information is poor to non-existing), and thus I tend to a larger, more directly observable change.This process, as Straggler notes, is also the basis for the Theory of Evolution, often conflated with the process, and it is also the basis for the science of evolution, so we do have to be careful which term we mean.Darwin did not like the term because it was already used in embryology for the development of embryos evolving through different stages.Creationists also like to bring in stellar evolution and other ways the term is meant, so it is usually good measure to qualify the use with "biological evolution" when appropriate.Enjoy.

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we are limited in our ability to understand
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Rebel American Zen Deist
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