Sexual Selection

sexual selection: see selection.

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sexual selection [¦seksh·ə·wəl si′lek·shən]

(evolution)

A special form of natural selection responsible for the evolution of traits that promote success in competition for mates.

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Sexual Selection 

the particular form of natural selection distinguished by the evolutionary development of secondary sex characteristics. These characteristics include the bright nuptial plumage of many birds, including ducks and grouse, the dances of insects, the mating calls of birds, the fighting of male birds and mammals, the varied sound signals of males used to attract females, and the odoriferous glands of insects and mammals used for attracting the opposite sex. Prominent characteristics, such as coloration, develop chiefly in males. Females, especially during the reproductive period, are usually protected by appropriate behavior, coloration, and form.

The primary basis for sexual selection was the divergence in the identifying characteristics of males and females, which probably facilitated inbreeding of the same species and prevented crossbreeding with other species. Subsequently, individuals with more pronounced sexual characteristics attracted the opposite sex more easily and had the advantage in reproduction.

The ethological or behavioral mechanisms of isolation are partially affected by sexual selection. The course of sexual selection sometimes conflicts with other trends of natural selection. Genotypes that are preserved make reproduction more successful but do not increase the viability of the species as a whole. However, this does not justify contrasting sexual selection with natural selection or considering it an independent factor in evolution. Sexual selection was first suggested by C. Darwin in 1859 and later substantiated in 1871.

REFERENCES

Darwin, C. Proiskhozhdenie vidov putem estestvennogo otbora. In Soch, vol. 3. Moscow-Leningrad, 1939. (Translated from English.)
Darwin, C. Proiskhozhdenie cheloveka i polovoi otbor. In Soch., vol. 5. Moscow, 1953. (Translated from English.)
Shmal’gauzen, I. I. Problemy darvinizma, 2nd ed. Leningrad, 1969.

A. V. IABLOKOV