Adaptive Radiation Definition

ə-dăptĭv
noun
Diversification of a species or single ancestral type into several forms that are each adaptively specialized to a specific environmental niche.
American Heritage
The dispersal of, and adaptation to new environments by, a line of animals or plants, resulting in the evolution of divergent forms, often new species, specialized for surviving in the new habitats.
Webster's New World

(biology) The diversification of species into separate forms that each adapt to occupy a specific environmental niche.

Wiktionary