The Roles of Individual, Kin, and Group Selection in the Evolution of Sociality

Abstract

The main intent of this chapter is to develop a general framework in which to answer the question: What are the roles of individual, kin, and group selection in the evolution of social behavior? Evolution occurs when the gene frequencies in a population or species change. Natural selection in response to environmental conditions is the primary source of genetic change in most populations. But what is the unit of selection? Classically, the differential survival and reproduction of individuals, or individual selection, are regarded as the major cause of genie evolution. More recently, units larger than the individual have been proposed. The feasibility of the differential survival and reproduction of groups such as families, demes, trait groups, populations, and species has been examined qualitatively and quantitatively in theory, but few field data exist yet that prove the occurrence of these selection processes in nature.