Adaptation and Natural Selection

Models of Group Selection

---

Williams presents a simple of model of biotic adaptation, and a more complicated model by Wright which makes use of "drift". First, biotic adaptation is theoretically possible, as the following figure shows.

Sewall Wright is known for the notion of "drift". If a group is small and relatively isolated, a peculiar gene may become dominant within the group by genetic drift. The holder of such a gene may be disadvantageous but beneficial to the group (e.g., by altruistic behavior), and the group may become larger (the group is successful vis-a-vis other groups). And if the group becomes large enough, some of the holders of this gene may move into other groups, and a similar process can begin within these new groups.

 

---

webmaster