|
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly 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.〔(''Parallel Adaptive Radiations - Caribbean Anoline Lizards.'' ) Tood Jackman. Villanova University. Retrieved 10 September 2013.〕 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.〔Gavrilets, S., & Losos, J. B. (2009). Adaptive radiation: contrasting theory with data. Science, 323(5915), 732-737. 〕 == Identification == Four features can be used to identify an adaptive radiation:〔 # A common ancestry of component species: specifically a ''recent'' ancestry. Note that this is not the same as a monophyly in which ''all'' descendants of a common ancestor are included. # A phenotype-environment correlation: a ''significant'' association between environments and the morphological and physiological traits used to exploit those environments. # Trait utility: the performance or fitness advantages of trait values in their corresponding environments. # Rapid speciation: presence of one or more ''bursts'' in the emergence of new species around the time that ecological and phenotypic divergence is underway. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「adaptive radiation」の詳細全文を読む スポンサード リンク
|