At his blog, evolutionary biologist Jerry Coyne recently took after his University of Chicago colleague, James Shapiro, complaining about him in the following manner:
Virtually all of the non-creationist opposition to the modern theory of evolution, and all of the minimal approbation of Shapiro’s views, come from molecular biologists. I’m not sure whether there’s something about that discipline (the complexity of molecular mechanisms?) that makes people doubt the efficacy of natural selection, or whether it’s simply that many molecular biologists don’t get a good grounding in evolutionary biology.
Is it just me, or might this argument be turned on Jerry Coyne himself? Maybe it’s Jerry Coyne who is insufficiently trained in molecular biology and this leads him to an excess of confidence in natural selection. When I read Coyne’s book (I reviewed it here), his chapter on natural selection’s power struck me as its weakest. I can’t help but wonder if the news from contemporary molecular biology is being downplayed by other biologists insufficiently trained in it, and that this makes for an excess of (unwarranted) confidence in natural selection as the primary driver of evolution.
Below, for example, is Jerry Coyne, at the end of the fifth chapter of his book on evolution, summing up his defense of natural selection without any specific appeals to findings within molecular biology. If you’ll forgive me, his writing here comes across as, well, special pleading:
So where are we? We know that a process very like natural selection—animal and plant breeding—has taken the genetic variation present in wild species and from it created huge ‘evolutionary’ transformations. We know that these transformations can be much larger, and faster, than real evolutionary change that took place in the past. We’ve seen that selection operates in the laboratory, in microorganisms that cause disease, and in the wild. We know of no adaptations that absolutely could not have been molded by natural selection, and in many cases we can plausibly infer how selection did mold them. And mathematical models show that natural selection can produce complex features easily and quickly. The obvious conclusion: we can provisionally assume that natural selection is the cause of all adaptive evolution—though not of every feature of evolution, since genetic drift can also play a role.
True, breeders haven’t turned a cat into a dog, and laboratory studies haven’t turned a bacterium into an amoeba (although, as we’ve seen, new bacterial species have arisen in the lab). But it is foolish to think that these are serious objections to natural selection. Big transformations take time—huge spans of it. To really see the power of selection, we must extrapolate the small changes that selection creates in our lifetime over the millions of years that it has really had to work in nature. We can’t see the Grand Canyon getting deeper, either, but gazing into that great abyss, with the Colorado River carving away insensibly below, you learn the most important lesson of Darwinism: weak forces operating over long periods of time create large and dramatic change.
No doubt this is true, and a good story. But is it the whole story? The clash between Jerry Coyne and James Shapiro makes me wonder.