Blute, Marion;
Bell, Graham;
Dickins, David W.;
Ghiselin, Michael T.;
Hartung, John;
Leibowitz, Lila;
Smith, John Maynard;
Reynolds, V.;
Rogers, Alan R.;
Taylor, Peter D.;
Griffin, Malcolm P.;
Tooby, John;
Van Den Berghe, Pierre L.;
Yokoyama, Shozo
The Sociobiology of Sex and Sexes Today [and Comments and Reply]
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Medientyp:
E-Artikel
Titel:
The Sociobiology of Sex and Sexes Today [and Comments and Reply]
Beteiligte:
Blute, Marion;
Bell, Graham;
Dickins, David W.;
Ghiselin, Michael T.;
Hartung, John;
Leibowitz, Lila;
Smith, John Maynard;
Reynolds, V.;
Rogers, Alan R.;
Taylor, Peter D.;
Griffin, Malcolm P.;
Tooby, John;
Van Den Berghe, Pierre L.;
Yokoyama, Shozo
Erschienen:
University of Chicago Press, 1984
Erschienen in:Current Anthropology
Sprache:
Englisch
ISSN:
0011-3204;
1537-5382
Entstehung:
Anmerkungen:
Beschreibung:
<p>Three problems pertaining to sex and sexes-why sex exists at all, why there should normally be two mating types in a sexual species, and why the two should so often be dimorphic (take the form of male and female)-have created a crisis in evolutionary theory. This paper contains a sketch of these puzzles and some opinions about the direction in which solutions are likely to be found, including a new theory of sex chromosome morphology and activity and of sexual selection. The advantage of sex is probably diversity, but opinion varies on why diversity is advantageous. Bipolarity appears to reduce the probability of finding a mate by half. When dimorphism is present and the female contributes more resources to each offspring than the male, a mutant parthenogenic female should have up to a twofold advantage over sexually reproducing females; this raises the question why females permit their parental investment to be parasitized by males. Sex is here viewed as a mode of gene dispersal in adaptation to a spatially heterogeneous environment. It is pointed out that different levels of investment in each offspring by parents of opposite sex imply parasitism among sex chromosomes but not among autosomes, which assort at random relative to sex. Autosomal mutations increasing the frequency of parthenogenesis are unlikely to prevail, and autosomes may be viewed as being engaged in a form of generalized exchange. With simple forms of matingtype or sex determination, greater heterogeneity among offspring in a family is achieved with bipolarity. Constraints on mutation may make sex with an odd number of mating types less likely than sex with no or with paired mating types. Consideration of the evolution of gamete or egg-and-sperm dimorphism suggests that instead of differential investment's givin rise to sexual selection, sexual selection may have created differential investment. It is suggested that in male-heterogametic groups such as mammals and where the female is the high-investing sex, because the Y chromosome is parasitizing the X chromosome females should prefer as mates males with missing, small, or silent Y chromosomes and males should further silence their Y chromosomes to prevent their direction. This would account for Y-chromosome morphology and activity and for the existence in males of sexually selected traits with no obvious functional significance.</p>