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formation and evolution of regional organizations: the case study of the economic cooperation organization (eco)
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15 صفحه اولMating behavior and the evolution of sperm design.
Sperm are the most diverse of all animal cell types, and much of the diversity in sperm design is thought to reflect adaptations to the highly variable conditions under which sperm function and compete to achieve fertilization. Recent work has shown that these conditions often evolve rapidly as a consequence of multiple mating, suggesting a role for sexual selection and sexual conflict in the e...
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Evolutionary theory predicts that senescence, a decline in survival rates with age, is the consequence of stronger selection on alleles that affect fertility or mortality earlier rather than later in life. Hamilton quantified this argument by showing that a rare mutation reducing survival is opposed by a selective force that declines with age over reproductive life. He used a female-only demogr...
متن کاملThe evolution of multiple mating
Polyandry is a paradox: why do females mate multiple times when a single ejaculate often provides enough sperm for lifetime egg production? Gowaty et al. addressed explanations for polyandry in Drosophila pseudoobscura from the perspective of hypotheses based on sex differences in costs of reproduction (CoR). Contrary to CoR, Gowaty et al. showed that (1) a single ejaculate was inadequate for l...
متن کاملHominoid seminal protein evolution and ancestral mating behavior.
Hominoid mating systems show extensive variation among species. The degree of sexual dimorphism in body size and canine size varies among primates in accordance with their mating system, as does the testes size and the consistency of ejaculated semen, in response to differing levels of sperm competition. To investigate patterns of evolution at hominoid seminal proteins and to make inferences re...
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ژورنال
عنوان ژورنال: Evolution
سال: 1953
ISSN: 0014-3820
DOI: 10.1111/j.1558-5646.1953.tb00102.x