Genes, individuals, and kin selection.
The altruistic-gene theory of kin selection requires conditions so improbable that its reality is doubtful. The gene-quantity theory, including the theory of inclusive fitness, assumes that selection acts on sums of kins' genes, but no effective mechanism is apparent. Insect and human societies may have evolved by individual selection, in two steps: first something made staying together advantageous to individuals, and then altruistic behaviors evolved in net-gain lotteries, also (statistically) advantageous to individuals. Kin selection is not required in these or any other unequivocal cases; the theory should be reexamined and probably abandoned. The probability of kin selection is further reduced by the cost of evolution by selection. Much current evolutionary mathematics and determinist sociobiology, which ignore how the cost of selection limits the precision of adaptations, including adaptive behaviors, may be dangerously unrealistic.
Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138.
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Darlington