Evolutionary radiation: Difference between revisions

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An '''evolutionary radiation''' is an increase in [[taxonomy|taxonomic]] diversity or [[morphology (biology)|morphological]] disparity, due to [[adaptation|adaptive]] change or the opening of [[ecospace]].<ref name=Wesley-Hunt2005>{{cite doi|10.1666/0094-8373(2005)031<0035:TMDOCI>2.0.CO;2}}</ref> Radiations may affect one [[clade]] or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment, they are termed [[adaptive radiationsradiation]]s.<ref name=Schluter2000>{{cite book
| author = Schluter, D.
| year = 2000
==Examples of evolutionary radiation==
Perhaps the most familiar example of an evolutionary radiation is that of [[Eutheria|placental mammalsmammal]]s immediately after the [[extinction]] of the [[dinosaur]]s at the end of the [[Cretaceous]], about 65 million years ago. At that time, the placental mammals were mostly small, insect-eating animals similar in size and shape to modern [[shrew]]s. By the [[Eocene]] (58-37 million years ago), they had evolved into such diverse forms as [[bat]]s, [[whale]]s, and [[horse]]s. <ref>This topic is covered in a very accessible manner in Chapter 11 of Richard Fortey's ''Life: An Unauthorised Biography'' (1997)</ref>
Other familiar radiations include the [[Cambrian explosion]], the radiation of land plants after their [[Evolutionary history of plants#land|colonisation of land]], the Cretaceous [[Evolutionary history of plants#flowers|radiation of angiosperms]], and the diversification of insects, a radiation that has continued almost unabated since the [[Devonian]], {{Ma|400}}.<ref>The radiation only suffered one hiccup, when the [[Permo-Triassic extinction event]] wiped out many species.</ref>
==Recent evolutionary radiations==
A number of groups have undergone evolutionary radiation in relatively recent times. The [[cichlidae|cichlids]] in particular have been much studied by [[biology|biologists]]. In places such as [[Lake Malawi]] they have evolved into a very wide variety of forms, including species that are filter feeders, snail eaters, brood parasites, algal grazers, and fish-eaters.<ref>The Cichlid Fishes: Nature's Grand Experiment in Evolution by George Barlow (2002)</ref> [[Grass]]es have been another success, evolving in parallel with [[grazing]] [[herbivore]]s such as [[horseshorse]]s and [[antelope]].<ref>[http://www.palaeos.com/Cenozoic/Cenozoic.htm Palaeos Cenozoic: The Cenozoic Era<!-- Bot generated title -->]</ref>