His Big Idea is that natural selection has not only been overemphasized in evolution, but appears to play very little role at all. Even though he’s spreading nonsense in a widely-read place, I don’t go after him very often, for he just uses my criticisms as the basis of yet another abstruse and incoherent post. Like the creationists whose ideas he appropriates, he resembles those toy rubber clowns that are impossible to knock down. But once again, and for the last time, I wade into the fray. . .
In his post of August 12, “Does natural selection really explain what makes evolution succeed?” (the answer, of course, is “no”), Shapiro simply recycles some discredited arguments used by creationists against evolution. The upshot, which we’ve heard for decades, is the discredited idea that natural selection is not a creative process. I quote:
“Darwin modeled natural selection on artificial selection by humans. He ignored the inconvenient fact that human selection for altered traits has never generated a truly new organismal feature (e.g., a limb or an organ) or formed a new species. Selection only modifies existing characters. When humans wish to create new species, they use other means.”
This is the old canard that artificial selection doesn’t create “new features.” His definition of a “new organismal feature” is, of course, one that hasn’t been generated by artificial selection, so it’s all tautological. Of course we haven’t seen whole new organs or limbs arise in the short term, for people have been doing serious selection for only a few thousand years, and have not even tried to create new organs or limbs. But we can create a strain of flies with four wings, breeds of dogs that would be regarded as new genera if they were found in the fossil record, and whole new biochemical systems in bacteria. Both Barry Hall and Rich Lenski, for example, have demonstrated the evolution of brand new biochemical pathways that have evolved to deal with new metabolic challenges. Now that is a “new organismal feature”!
Often new species are created by hybridization, but Shapiro forgets that that hybridization is often followed by either natural or artificial selection for increased interfertility of the new hybrid form, so it truly becomes an interbreeding population that characterizes a species. And that, of course, gives a crucial role to selection, as it did in the experiments of Loren Rieseberg and his colleagues on hybrid sunflowers.