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Group Selection, Sex, and Fossils
Leigh Van Valen
Vol. 29, No. 1 (Mar., 1975), pp. 87-94
Published by: Society for the Study of Evolution
Stable URL: http://www.jstor.org/stable/2407143
Page Count: 8
You can always find the topics here!Topics: Mammals, Genera, Evolution, Species, Group selection, Extinct species, Species extinction, Biological taxonomies, Body size, Fossils
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The loss of sex and other recurrent unidirectional evolutionary trends can be treated as a simple equilibrium balanced by group selection. Genera of large mammals and large foraminiferans have a selective disadvantage of 0.02 to 0.05 per million years. The components of this selection act in opposite directions and in each case are much larger than the total selection, suggesting that most interspecific competition is with organisms of rather similar size. A related conjecture is disproved. Group selection is an important cause of evolution, including that of man.
Evolution © 1975 Society for the Study of Evolution