| adaptive radiation (ə-dāp'tĭv) The evolutionary diversification of a species or single ancestral lineage into various forms that are each adaptively specialized to a specific environmental niche. Adaptive radiation generally proceeds most rapidly in environments where there are numerous unoccupied niches or where competition for resources is minimal. See Note at adaptation. |
evolution of an animal or plant group into a wide variety of types adapted to specialized modes of life. A striking example is the radiation, beginning in the Tertiary period (beginning 66.4 million years ago), of basal mammalian stock into forms adapted to running, leaping, climbing, swimming, and flying.