1962 Group selection

1962 Group selection

CHAPTER NINETEEN 1962 Group selection The concept Vero Wynne-Edwards proposed a novel mechanism for the evolution of altruistic traits. He suggested ...

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CHAPTER NINETEEN

1962 Group selection The concept Vero Wynne-Edwards proposed a novel mechanism for the evolution of altruistic traits. He suggested that traits that would not be favored by individual selection, but which may be beneficial to the entire group could nevertheless increase in frequency by the differential extinction of whole groups.

The explanation Wynne-Edwards (1962, 1963) was concerned with population regulation and the mechanisms animals use to prevent overexploitation of their resources. He suggested that many social behaviors of animals were primarily adaptations to prevent overexploitation of resources. Among these behaviors are holding territories and social status. But Wynne-Edwards argued that these traits would be opposed by individual selection. After all individual selection ought to favor the consumption of as much of the available resources as possible and the production of as many offspring as possible. How then would any trait that is not favored by individual selection become established in a population? Wynne-Edwards argued that populations without traits that prevent overexploitation would go extinct due these behaviors leaving behind populations with the favorable traits. This process has become known as group selection. Wynne-Edwards (1963) would also assert that group selection might also be responsible for the sociality seen in the insect groups of the Hymenoptera (but see Chapter 21). Wynne-Edwards also suggested his theory could be thought of as an extension of Wright’s shifting balance theory. However, Wright’s theory did not involve the differential extinction of whole populations and has at its core individual selection. Using an experimental system of flour beetles, Michael Wade (1977) showed that if individual selection and group selection acted in the Conceptual Breakthroughs in Evolutionary Ecology ISBN: 978-0-12-816013-8 https://doi.org/10.1016/B978-0-12-816013-8.00019-3

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opposite directions then sufficient levels of population extinction could overcome individual selection. However, most of the debate over group selection has revolved around how often the conditions allow for sustained differential extinction of whole populations. In addition, the development of kin selection helped explain the evolution of many altruistic behaviors (Chapter 21).

Impact: 5 Wynne-Edward’s ideas were thought provoking and stimulated research on the evolution of social behavior and altruism via individual selection.

References Wade, M.J., 1977. An experimental study of group selection. Evolution 31, 134e153. Wynne-Edwards, V.C., 1962. Animal Dispersion in Relation to Social Behavior. Hafner, New York. Wynne-Edwards, V.C., 1963. Intergroup selection in the evolution of social systems. Nature 200, 623e626.