This shouldn't be a surprise to anyone since Wilson has become a supporter of group selection and—even more egregious—a critic of kin selection. Dawkins is a big fan of gene centric adaptation so group selection is heresy. Dawkins thinks that Hamilton's discovery of kin selection ranks right up there with Newton and Darwin, so anyone who casts doubt on kin selection is also a heretic.
I'm not an expert on the details of this debate although my instinct is to think that kin selection is vastly overblown1 and there's nothing obviously wrong with the concepts of group selection or species sorting. However, Dawkins mentions something that raises some important questions about evolution and I wonder what people think.
Nobody doubts that some groups survive better than others. What is controversial is the idea that differential group survival drives evolution, as differential individual survival does. The American grey squirrel is driving our native red squirrel to extinction, no doubt because it happens to have certain advantages. That’s differential group survival. But you’d never say of any part of a squirrel that it evolved to promote the welfare of the grey squirrel over the red. Wilson wouldn’t say anything so silly about squirrels. He doesn’t realise that what he does say, if you examine it carefully, is as implausible and as unsupported by evidence.The fact that gray squirrels are displacing red squirrels in Great Britain surely has something to do with evolution. The question is, what? It can't be an examples of population-level natural selection acting on individuals through their genes. It seems more like species sorting as advocated by Stephen Jay Gould in The Structure of Evolutionary Theory.
Evolution, then, results from the differential survival of genes in gene pools. “Good” genes become numerous at the expense of “bad.” But what is a gene “good” at? Here’s where the organism enters the stage. Genes flourish or fail in gene pools, but they don’t float freely in the pool like molecules of water. They are locked up in the bodies of individual organisms. The pool is stirred by the process of sexual reproduction, which changes a gene’s partners in every generation. A gene’s success depends on the survival and reproduction of the bodies in which it sits, and which it influences via “phenotypic” effects. This is why I have called the organism a “survival machine” or “vehicle” for the genes that ride inside it. Genes that happen to cause slight improvements in squirrel eyes or tails or behaviour patterns are passed on because individual squirrels bearing those improving genes survive at the expense of individuals lacking them. To say that genes improve the survival of groups of squirrels is a mighty stretch.
Maybe it's not group selection but surely it's evolution acting at a level higher than individuals in populations? There are currently 30 species of squirrels in the genus Sciurus. Some of these will survive and some will go extinct, especially in areas where the species overlap. What part of evolutionary theory explains this? Don't we look for an evolutionary explanation for why Neanderthals went extinct?
Ryan Gregory is also confused by Dawkin's example [Does Dawkins understand group selection?]. He says ...
That’s not group selection among conspecifics, that’s interspecific competition. And I can easily imagine traits evolving in response to competitive pressure. However, if grey and red squirrels have only recently come into sympatry then this wouldn’t apply and this would be an irrelevant example. It’s curious to see Dawkins make such a silly argument.Go over to Genomicron is you want to discuss whether this is an example of group selection and whether Dawkins got it wrong.
Stay here if you want to discuss whether the squirrel example is any kind of evolution that can't be fully explained by populations genetics.
UPDATE: Jerry Coyne really liked the Dawkins review [Richard Dawkins reviews Ed Wilson’s new book. He defends inclusinve fitness (kin selection) as; "one of the most productive concepts in modern evolutionary biology." I'm still not clear on why a concept that mostly applies to animals with substantial brains is so important to all of evolutionary biology.
1. For example, it's hard to see how it applies to maple trees, mushrooms, diatoms, and E. coli whereas Darwin's discoveries apply to all living things and Newton's discoveries apply to the entire universe.