The Latitudinal Gradient in Recent Speci
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Weir, J. T.; Schluter, D.
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Article
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2007
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American Association for the Advancement of Scienc
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English
β 239 KB
Although the tropics harbor greater numbers of species than do temperate zones, it is not known whether the rates of speciation and extinction also follow a latitudinal gradient. By sampling birds and mammals, we found that the distribution of the evolutionary ages of sister speciesβpairs of species