ALTRUISM AND ORGANISM - DISENTANGLING THE THEMES OF MULTILEVEL SELECTION THEORY

The evolution of groups into adaptive units, similar to single organis ms in the coordination of their parts, is one major theme of multileve l selection theory. Another major theme is the evolution of altruistic behaviors that benefit others at the expense of self. These themes ar e often assumed to be strongly linked, such that altruism is required for group-level adaptation. multilevel selection theory reveals a more complex relationship between the themes of altruism and organism. Ada ptation at every level of the biological hierarchy requires a correspo nding process of natural selection, which includes the fundamental ing redients of phenotypic variation, heritability, and fitness consequenc es, These ingredients can exist for many kinds of groups and do not re quire the extreme genetic variation among groups that is usually assoc iated with the evolution of altruism, Thus, it is reasonable to expect higher-level units to evolve into adaptive units with respect to spec ific trails, even when their members are not genealogically related an d do not behave in ways that are obviously altruistic. As one example, the concept of a group mind, which has been well documented in the so cial insects, may be applicable to other species.