Natural selection and adaptation can occur on a variety of levels. Group selection is the natural selection of group characteristics on the level of the group. It happens through the interaction of two distinct evolutionary processes on two different scales: the level of the gene, and the level of group (or meme). It is a special case of multilevel selection, where two processes of natural selection interact with each other. In group selection, different forms of replicators support each other: genes increase the fitness of the memes in the groups of the individuals, and memes increase in turn the fitness of genes in their groups.
As David Sloan Wilson has observed, "what is adpative at one level may be maladaptive at another" (Keller and Lloyd, 1992). What is good for the group can be bad for the individual and vice versa.
- Wikipedia Entry for Group Selection
- Nicholas S. Thompson, Shifting the Natural Selection Metaphor to the Group Level, Behavior and Philosophy, 28, 83-101 (2000)
- David S. Wilson & Elliott Sober, Reintroducing group selection to the human behavioral sciences, Behavioral and Brain Sciences 17 (4) (1994) 585-654
- Evelyn Fox Keller and Elisabeth A. Lloyd, "Keywords in Evolutionary Biology", Harvard University Press, 1992