Four of the 13 finch species found on the Galápagos Archipelago, are thought to have evolved by an adaptive radiation that diversified their beak shapes to adapt them to different food sources. Darwin's finches (also known as the Galápagos Finches) are 13 or 14 different closely related Species of Finches that Charles Darwin collected Anatomy Stegosaurus --> Beaks can vary significantly in size and shape from species to species

An adaptive radiation is a rapid evolutionary radiation characterized by an increase in the morphological and ecological diversity of a single, rapidly diversifying lineage. An evolutionary radiation is an increase in taxonomic diversity or morphological disparity due to adaptive change or the opening of ecospace Phenotypes adapt in response to the environment, with new and useful traits arising. ^[1] This is an evolutionary process driven by natural selection. eVolution is the third Album by eLDee, it was due to be released in 2008 Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of

Causes of adaptive radiation

Innovation

The evolution of a novel feature may permit a clade to diversify by making new areas of morphospace accessible. A classic example is the evolution of a fourth cusp in the mammalian tooth. This trait permits a vast increase in the range of foodstuffs which can be utilized, with species able to specialize on feeding on a range of foodstuffs. The trait arose a number of times in different groups during the Cenozoic, and in each instance was immediately followed by an adaptive radiation. ^[2] Birds find other ways to provide for each other, ie. the evolution of flight opened new avenues for evolution to explore, initiating an adaptive radiation. ^[3]

Opportunity

Adaptive radiations often occur as a result of an organism arising in an environment with unoccupied niches, such as a newly formed lake or isolated island chain. The colonizing population may diversify rapidly to take advantage of all possible niches.

In Lake Victoria, an isolated lake which formed recently in the African rift valley, over 300 species of cichlid fish adaptively radiated from one parent species in just 15,000 years. Lake Victoria or Victoria Nyanza (also known as Ukerewe and Nalubaale) is one of the Great Lakes of Africa. Cichlids (ˈsɪklɪd are Fish from the family Cichlidae in the order Perciformes.

Adaptive radiations commonly follow mass extinctions: following an extinction, many niches are left vacant. An extinction event (also known as mass extinction; extinction-level event, ELE is a sharp decrease in the number of Species in a relatively short period A classic example of this is the replacement of the non-avian dinosaurs with mammals at the end of the Cretaceous, and of brachiopods by bivalves at the Permo-Triassic boundary. The Cretaceous–Tertiary extinction event, which occurred approximately ( Ma) was a large-scale mass extinction of animal and plant species in a geologically The Permian–Triassic (P–Tr extinction event, informally known as the Great Dying, was an Extinction event that occurred, and 70 percent of terrestrial .

See also

• Evolutionary radiation - a more general term to describe any radiation
• Cambrian explosion - the most famous evolutionary radiation

Further reading

• Wilson, E. An evolutionary radiation is an increase in taxonomic diversity or morphological disparity due to adaptive change or the opening of ecospace The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the et al. Life on Earth, by Wilson,E. ; Eisner,T. ; Briggs,W. ; Dickerson,R. ; Metzenberg,R. ; O'brien,R. ; Susman,M. ; Boggs,W. ; (Sinauer Associates, Inc. , Publishers, Stamford, Connecticut), c 1974. Chapters: The Multiplication of Species; Biogeography, pp 824-877. 40 Graphs, w species pictures, also Tables, Photos, etc. Includes Galápagos Islands, Hawaii, and Australia subcontinent, (plus St. Helena Island, etc. The State of Hawaii ( or həˈwaɪʔiː Hawaiian: Mokuāina o Hawaii) is a state in the United States located on an Archipelago in the Saint Helena (pronounced saint he-LEE-na) named after St Helena of Constantinople, is an island of volcanic origin and a British overseas territory ).
• Leakey,Richard. The Origin of Humankind - on adaptive radiation in biology and human evolution, pp. 28-32, 1994, Orion Publishing.
• Grant, P. R. 1999. The ecology and evolution of Darwin's Finches. Princeton University Press, Princeton, NJ.
• Mayer, Ernst. 2001. What evolution is. Basic Books, New York, NY.
• Kemp, A. C. 1978. A review of the hornbills: biology and radiation. The Living Bird 17: 105-136.

References