latter. Although there was a zone of overlap, each species excluded the other from its dominant region by becoming better adapted to its habitat over time. In some such cases, each species gets displaced into an exclusive segment of the original habitat. Because each species suffers from competition, natural selection favors the avoidance of competition in such a way.

Niche differentiation is a process by which competitive exclusion leads to differences in resource use. In some cases, niche differentiation results in spatial displacement,