Adaptation by group selection: elimination acts on all levels

Abstract

Due to criticisms of early na?Ève group selection arguments, most evolutionary biologists hesitate to invoke selection at any level higher than the individual. Subsequent group selection arguments, while attempting to address conflicts between individual and group interests, have remained focused on individuals as units and have consequently been limited in scope. By focusing on groups as evolutionary units while avoiding the errors of earlier arguments, a simple, yet informative view emerges in which selection for groups capable of persisting favors those that are both superior in terms of group formation/extinction rates and stable with respect to individual selection. Hence, apparent adaptations of groups are the result of not just selection at the individual or lower level, but selection at all levels, and are therefore true higher-level adaptations. This framework is applied to a variety of theoretical evolutionary scenarios to demonstrate its usefulness, generality, and logical consistency.