adaptive radiation
1. A burst of evolution, with rapid divergence from a single ancestral form, that results from the exploitation of an array of habitats. The term is applied at many taxonomic levels (e.g. the radiation of the mammals at the base of the Cenozoic is of ordinal status, whereas the radiation of ‘Darwin's finches’ in the Galápagos Islands resulted in a proliferation of species).

2. A term used synonymously with cladogenesis by some authors. (Such a use is misleading, because cladogenesis involves the division of one species into two and adaptive radiation imposes no such constraint.)

adaptive radiation
1. A burst of evolution, with rapid divergence from a single ancestral form, that results from the exploitation of an array of habitats. The term is applied at many taxonomic levels (e.g. the radiation of the mammals at the base of the Cenozoic is of ordinal status, whereas the radiation of Darwin's finches in the Galápagos Islands resulted in a proliferation of species).

2. Term used synonymously with cladogenesis by some authors.

adaptive radiation
1. A burst of evolution, with rapid divergence from a single ancestral form, resulting in the exploitation of an array of habitats. The term is applied at many taxonomic levels, e.g. the radiation of the mammals at the base of the Cenozoic refers to orders, whereas the radiation of ‘Darwin's finches’ in the Galápagos Islands resulted in a proliferation of species.

2. Term used synonymously with ‘cladogenesis’ by some authors
.

adaptive radiation In biology, the evolution of different forms of living organisms from a common ancestral stock, as different populations adapt to different environmental conditions or modes of life. Eventually, the populations may become so different that they constitute separate species. Examples are the many different kinds of finches found on the Galápagos Islands, which diversified to specialize in different kinds of food, feeding methods, and habitats. See also adaptation

adaptive radiation (divergent evolution) The evolution from one species of animals or plants of a number of different forms. As the original population increases in size it spreads out from its centre of origin to exploit new habitats and food sources. In time this results in a number of populations each adapted to its particular habitat: eventually these populations will differ from each other sufficiently to become new species. A good example of this process is the evolution of the Australian marsupials into species adapted as carnivores, herbivores, burrowers, fliers, etc. On a smaller scale, the adaptive radiation of the Galapagos finches provided Darwin with crucial evidence for his theory of evolution (see Darwin's finches).