William D. Hamilton; Biologist Helped to Advance Darwinism

William D. Hamilton, whose seminal theories on the evolution of animal behavior--particularly altruism and sex--made him one of the greatest evolutionary biologists since Darwin, has died at 63.

A research professor in the zoology department of Oxford University, Hamilton died Tuesday in a London hospital. He had been in intensive care for six weeks after contracting malaria on a research expedition in Congo, where he was testing a controversial theory that the AIDS virus originated in polio vaccine trials conducted in Africa in the 1950s, according to the Guardian newspaper of London.

Hamilton was a leader of what has been called “the second Darwinian revolution,” a group that includes evolutionary theorists Richard Dawkins and John Maynard Smith.

“He offered some explanations for some persistent problems that remained after Darwin formulated his theory--the problem of altruism and the problem of sex,” said Vassiliki Betty Smocovitis, historian of science at the University of Florida.

Hamilton was best known for his theory of kin selection, which addressed a baffling conundrum in Darwinian thinking: Namely, if natural selection favors the survival of the fittest, why do some individuals sacrifice themselves for the good of the group or others? Evolution should produce selfish, not altruistic, individuals.

As Darwin had observed, the extreme cooperation seen in colonies of bees and ants made no sense from an evolutionary standpoint. A sterile worker bee, for instance, will direct an equally sterile sister to a source of food. Whole castes of bees exist to fight and die for the hive.

The answer, according to Hamilton, was genetic relatedness. The bees were all so closely related to one another that, although it seemed as though they were sacrificing themselves for the hive, their chief interest was to preserve the gene pool. What appeared altruistic was, in fact, selfish. Thus a mother would protect her child before she would her sibling’s child, and her sibling’s child before a cousin’s child, and a cousin’s child before a stranger. Hamilton devised a formula to calculate the likelihood of self-sacrificing acts, which came to be known as Hamilton’s Rule.

His gene’s-eye view influenced other major evolutionists, such as Oxford biologist Dawkins, who considered Hamilton one of the most important Darwinians of the 20th century and who went on to write the bestseller “The Selfish Gene.” Hamilton’s ideas also inspired the field of sociobiology, which attempts to reduce social science to a branch of biology.

His work, which became known as kin selection or inclusive fitness, was published in two papers in the Journal of Theoretical Biology in 1963 and 1964. It was a benchmark in the history of evolution and is cited today.

The focus of Hamilton’s later work focused on another puzzle of evolution: why sex exists. From an evolution standpoint, sexual reproduction, which takes two individuals and much time and energy, is a wasteful activity compared to the more efficient asexual propagation of species.

Hamilton’s theory was that sexual reproduction evolved as a means of combating parasites. He suggested that sex evolved because it generated more variation, which in turn could thwart parasites and accelerate evolution.

“The problem of why sex exists, and in particular why the vast inefficiency of maleness exists, seems to me biology’s greatest, most exciting problem,” Hamilton once said of his theory, which continues to spark debate among evolutionists.

Hamilton was an eccentric figure, who once drew a curious crowd at a Berlin zoo when he performed a turkey mating dance, complete with “gobble” noises, in front of a cage full of turkeys. He dressed up as a baker so that he could obtain a colony of rare ants from a biscuit factory. He was notably lacking in charisma as a teacher, once stopping in mid-lecture and staring into space for a few long minutes while trying to fathom an answer to a question he had just raised.

Born in Cairo, he grew up in England, earning his bachelor’s degree at Cambridge University and his PhD at London University. He was a lecturer in genetics at Imperial College, London, from 1964 to 1977, moving to the University of Michigan for several years beginning in 1978. He had been a research professor in zoology at Oxford since 1984.