EXPERIMENTAL STUDIES OF GROUP SELECTION - WHAT DO THEY TELL US ABOUT GROUP SELECTION IN NATURE

The study of group selection has developed along two autonomous lines. One approach, which we refer to as the adaptationist school, seeks to understand the evolution of existing traits by examining plausible me chanisms for their evolution and persistence. The other approach, whic h we refer to as the genetic school, seeks to examine how currently ac ting artificial or natural selection changes traits within populations and focuses on current evolutionary change. The levels of selection d ebate lies mainly within the adaptationist school, whereas the experim ental studies of group selection lie within the genetic school. Becaus e of the very different traditions and goals of these two schools, the experimental studies of group selection have not had a major impact o n the group selection debate. We review the experimental results of th e genetic school in the context of the group selection controversy and address the following questions: Under what conditions is group selec tion effective? What is the genetic basis of a response to group selec tion? How common is group selection in nature?