Mauve Dog, and Ben:
I confess I was knocking off the type of finding that would be counter evidence against evolution, IMO. (Once again, I don’t expect such a finding to occur). I really didn’t think the idea would get such close scrutiny. According to Watson’s “Molecular Biology of the Gene” and Lewin’s “Genes V”, the rates of mutation are known for E.coli but only very unreliably so for eukaryotes. So I was wrong about that, and I can’t defend the experiment as doable.
As to changes in the fossil record being proportional to changes in the genome, how could they not be? (Remember, I was careful to exclude silent and lethal mutations). Even changes in gene regulation have to be coded somehow, ultimately, in the genome if the change is to be heritable, right? In another sense, though, I think you guys are right and this is just a semantic error on my part: when I think of “great change” in phenotype, I mean that changes are occuring rapidly, not that the change is a radical one. If our metric for phenotypic change somehow included a detailed consideration of what the specific change was, then I agree a “small” genotype change could result in a “large” phenotype change and the two would not be proportional in a definable way. But how could you define a generally applicable metric of phenotypic change? Is a longer humerus a bigger or a smaller change than a larger eyesocket? But this is my fault; I should have been more specific and said “rate of change”. So what I want to assert is that rates of phenotypic change should be reflected in rates of genetic change.
On another note, I do have to object to the idea that evolution is unassailable. We observe many different closely related forms in the fossil record that form a rough continuum (for some things more rough than others). We observe great sequence homologies that correlate strongly with the fossil record. We observe the principles of genetics and especially the genetics of poulations. We observe changes taking place in rapidly-reproducing organisms in the laboratory. We observe that organisms are adapted to their environments. THOSE are the facts.
Add it all up and evolution emerges as the most reasonable explanation for those facts (indeed, the only reasonable explanation yet proposed). I will go farther and say that reasoning from the observations dictates that it almost certainly MUST be true. This explanation is so powerful and so consistent with all the facts that it is established as well as any interpretive explanation in science, from Maxwell’s equations to continental drift. But it is not a fact in the same sense as the things in the last paragraph. It is an interpretation of all the evidence, it is not evidence in and of itself.
This makes it necessary that evolution be a falsifiable theory. There has to be some experiment we could do that could, in principle, prove evolution wrong. I tried to construct such an experiment that may not have been done already, which is what I thought the OP was asking for, but apparently I didn’t do a very good job. Oh well, the theory is so well established I don’t think it’s important at this point, anyway.
[On reading this over before posting I realize I may need to define my terms to avoid confusion again. If you define “evolution” as any change in gene frequency occuring in a population, then it IS a simple fact, as mentioned above when I said we observe changes in rapidly-reproducing organisms in the lab. But I am thinking of “evolution” here as the more interesting phenomenon of the accumulation of traits to produce new species, which as far as I know has not been observed directly.]
