Wells' Icons of Evolution - Peppered Moths

I think this issue keeps coming up because of the posed peppered moth photographs in biology textbooks, and I think it has more to do with unrealistic expectations than with anything else. Photographs in textbooks are for illustration purposes. A section on predator and prey may show a leopard prepared to pounce when the reality is that the leopard was at the San Diego zoo and was just preparing to get up. That is not misrepresentation but illustration. The biology textbook's purpose is not to present firsthand evidence, but to convey information in the best way possible, and picture's do that very effectively.A section on camouflage might describe how a chameleon protects itself along side pictures of a chameleon first gray on a leaf and then green on the same leaf. It makes no difference that the chameleon was actually placed on the leaf by an attendant at the reptile barn of a local zoo. The purpose is to illustrate camouflage, not to present evidence for a research paper.It turns out that peppered moth predation is too complex to properly analyze in the wild (see my book review at Book Review: Of Moths and Men), so we may never know what really happens, but there is no doubt in anyone's mind, Creationist or evolutionist, that camouflage provides a survival advantage and thereby contributes to natural selection, and this is all the textbook is trying to communicate with peppered moth photographs. The photographs aren't supposed to be from actual researchers or journal papers - they're for illustration and pedagogical purposes.While the specifics of peppered moth predation remain elusive, and so we cannot even be sure that predation is the cause of the color changes, that the populations tend toward light and dark in response to environmental factors is very well established.--Percy

I agree that insufficient evidence exists to establish natural selection as the causative force behind the color changes, but I'm uncertain why you think this a significant point within the Creation/Evolution debate. Are you also arguing that there is insufficient evidence generally for natural selection as a force for change within nature?--Percy

I'm curious about the degree to which we've really established natural selection as the causative factor. For example, has the possibility that something in the pollutants is interacting with moth metabolism been eliminated? Or have the affected alleles been identified? If the anwers to such possibilities is no, then I don't think we can say with any certainty that natural selection was responsible.--Percy

If natural selection is responsible for the color change, then it is likely due to selection for existing alleles that control coloration, not through production of new alleles by mutation. I don't think anyone on this thread is arguing that random mutations are responsible (according to the results of a search I just did, you're the first to use the term "mutation" in this thread), so it makes no sense to raise this issue. The discussion isn't about speciation, but about whether the peppered moth is a legitimate example of natural selection in nature.--Percy

Actually, I believe the Creationists on this thread are arguing precisely that, that the peppered moth has *not* been shown to be an example of natural selection in nature. And until someone presents evidence demonstrating otherwise, I agree with them.You raise some other interesting issues, such as that NS can't account for change, or that Ed Blythe conceived of NS before Darwin, or that speciation doesn't happen, and those seem like good issues for other threads.--Percy

You quoted me enumerating JP's assertions. Having been involved in discussions with JP previously, I'm pretty sure I know what he means. I don't think anyone is misconstruing the nature of NS.--Percy

You might also take a look at Message 6 where Cromwell makes a lengthy argument and concludes that whatever the cause, it isn't NS. Cromwell draws upon arguments from Wells, but having not read Wells myself I don't know if Cromwell's conclusion agrees with him.--Percy

Hi, JonF!Can I assume that your mentions of mutation did not mean to imply that repeated and relatively contemporary mutations were the source of the color changes. A recent mutation would surprise me as a source of the changes, since I would have thought it far more likely that NS was operating on preexisting alleles already in the peppered moth genome, even though of course they originally arose, who knows when, by mutation.You mention that the changes were found to follow "classic Mendelian genetic rules", and this would seem fairly conclusive for NS to me. Actually finding the gene on a chromosome doesn't seem necessary, though it would provide an additional level of confirmation.--Percy

I guess I'd be surprised to learn that's the case. If you happen to run across more info let us know.--Percy