In this episode we discuss the framework of multilevel selection. The gene is the fundamental unit of heredity, but it is not the fundamental unit of selection. Rather, there are different levels of aggregated biological material which result in differential reproductive success. These levels are:
Genes (genetic selection — selection between genes on the same genome)
Cells (cellular selection — selection between cells)
Organisms (individual selection — selection between individual organisms)
Groups (group selection — selection between groups of organisms)
When one invokes the ultimate purpose for why an adaptation exists, multilevel selection requires that one specify at what level of biological organization the trait was selected for.
For example, aggression is a adaptation for competition between individuals, but the ability to cooperate violently with members of one’s own tribe against an opposing group (warfare) is an adaptation furnished by group selection.
