Many animals regulate their population density by patterns of behavior
that would be easy to explain if the forces of natural selection acted
to optimize group properties. But Darwinian selection acts on
individuals, not groups, and most simple theories have shown group
selection to be too slow ever to oppose individual selection
successfully.
In this book Michael Gilpin presents a model, based on predator-prey
dynamics, wherein nonlinear effects are important, so that small
advantages to the selfish individual are nonlinearly amplified into
disaster for his group. The result is that group selection can be rapid
and powerful. Of course many instances of apparent group selection can
be explained by kin selection; in other cases, close examination reveals
that seemingly altruistic behavior directly benefits the individual
genotype as well as the group. The value of the monograph is that it
provides a robust model in which group selection, pure and
unadulterated, can be seen to work.