Book review of William-Donald Hamilton

William-Donald Hamilton:
NARROW ROADS OF GENE LAND (W.H. Freeman, 1996)

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The collected papers of William Hamilton on kin selection and the evolution of social behaviour.
In the Sixties, with a few seminal papers, the British biologist William Donald Hamilton showed that, in reality, even altruism evolved by natural selection for a utilitarian reason: altruism helps genes as a global pool, even if at the expense of the survival of a specific individual. Altruism is just another step, beyond personal survival and reproduction, in the program to proliferate maximally the genes of an organism. Traditionally, selection (and therefore evolution) had been viewed as driven by "reproductive success"; but Hamilton, armed with sophisticated mathematical tools, extended that concept to the reproductive success of close relatives (or "kins"). Every individual has an investment in its own genetic pool. The investment peaks in its own body, but it is not limited to the body, it extends, albeit in lesser amount, to all of its kins, and it is proportional to how closely they share the same genes. Hamilton's theory managed to explain why parents care for their offspring and why females are more choosy than males about their mates. Cooperation is but one odd side-effect of competition
Hamilton thinks that evolution is accelerated even by parasites. Organisms adopted sexual reproduction in order to cope with invasions of parasites (parasites have a harder time adapting to the diversity generated by sexual reproduction, whereas they would have devastating effects if all individuals of a species were identical). Furthermore, life can be viewed as a symbiotic process which necessitates of competitors. In a sense, co-evolving parasites help improve evolution.