The Collaborative International Dictionary
adaptive radiation \adaptive radiation\ n. 1. (Palaeontology) the evolutionary generation of multiple specialized life forms from one ancestral form, evidenced in the fossil record. The inverse of extinction.
Wiktionary
n. (context biology English) The diversification of species into separate forms that each adapt to occupy a specific environmental niche.
WordNet
n. the development of many different forms from an originally homogeneous group of organisms as they fill different ecological niches
Wikipedia
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. Starting with a recent single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits with which they can exploit a range of divergent environments.
Adaptive radiation, a characteristic example of cladogenesis, can be graphically illustrated as a "bush", or clade, of coexisting species (on the tree of life). Caribbean anoline lizards are a particularly interesting example of an adaptive radiation. The Hawaiian islands are very isolated and contribute numerous examples of adaptive radiation. An exceptional example of adaptive radiation would be the avian species of the Hawaiian honeycreepers. Via natural selection, these birds adapted rapidly and converged based on the different environments of the Hawaiian islands.
Much research has been done on adaptive radiation due to its dramatic effects on the diversity of a population. However, more research is needed, especially to fully understand the many factors affecting adaptive radiation. Both empirical and theoretical approaches are helpful, though each has its disadvantages. In order to procure the largest amount of data, empirical and theoretical approaches must be united.
Usage examples of "adaptive radiation".
With the rate of mutation and adaptive radiation on this planet, it was easy to imagine the appearance of life forms able to prey upon even the huge submarine netters which supplied the keeps with fish.
It reminded him that ecological control needed to be reestablished here before a random pattern of adaptive radiation took holdone in which the planned human and Do'utian components might not fit so well.