Convergence (or convergent evolution)
The situation where two unrelated species or groups have developed in the course of evolution a similar adaptation to their environment, because they live in the same habitat and have evolved a similar life style. Swifts (family Apodidae) and swallows (family Hirundinidae) are good examples, while webbed feet have been developed by several groups of aquatic birds.From Peter Weaver's Birdwatcher's Dictionary
Copyright © 1981 by Peter Weaver