KEY POINTS:
A war of words has broken out between two of the world's leading evolutionists.
Edward Wilson of Harvard and Richard Dawkins of Oxford University have gone head to head over the evolution of altruism in the animal kingdom and whether it can arise from something called group selection.
The subject matter of their dispute is social insects, particularly ants, which display a supreme form of altruism in that sterile workers lay down their lives for the benefit of their fertile colleagues in the colony.
Conventional Darwinian theory could not really explain why one individual should sacrifice its life, and its precious genes, for the benefit of another individual, unless it could be viewed in terms of group selection, when individuals do it for the benefit of the colony or the species.
But nearly 50 years ago, ago, scientists punched intellectual holes in the theory of group selection and pointed instead to something called kin selection, in which altruism in social communities evolves as a result of one individual being closely related to a member of the same colony.
Social insects such as ants display unusual degrees of relatedness within the colony, with sister workers being more closely related to one another than to the offspring they may have. It was therefore seen as beneficial for individual sisters to sacrifice their fertility for their sister queen because of the genes they had in common.
Mathematical models supported kin selection which rose to prominence because it appeared to explain the evolution of altruism in ants and many other species.
Group selection was dead in the water. But Professor Wilson has brought it back to life in a book on ants to be published this year, and in an interview this week with New Scientist magazine.
"If you look at the literature of the theory, there are a lot of impressive-looking mathematical models but they scarcely ever come up with a real measure of anything that can be applied to nature," he says.
This has not pleased Professor Dawkins who, while he has respect for Wilson, spent much of his early career exploding the myth of group selection, which is anathema to the "selfish gene" theory behind kin selection.
In a separate article in New Scientist, Professor Dawkins acknowledges Professor Wilson's "characteristically fascinating account" of the evolution of social insects, but says: "His 'group selection' terminology is misleading, and his distinction between 'kin selection' and 'individual direct selection' is empty."
What matters, he says, is natural selection at the level of the gene, not the group.
"All we need ask of a purportedly adaptive trait is, 'what makes a gene for that trait increase in frequency?'
"Wilson wrongly implies that explanations should resort to kin selection only when 'direct' selection fails," says Professor Dawkins.
"Here he falls for the first of my '12 misunderstandings of kin selection'; he thinks it is a special, complex kind of natural selection, which it is not."
Professor Dawkins says Professor Wilson relegates kin selection to a chapter on group selection in his book Sociobiology, published in the mid-seventies.
Professor Wilson is convinced he will be proved right and says: "I am used to taking the heat."
- Independent