Competition evolutionary history sperm

It exposes the competition not only between males but between males and females for control over reproduction, particularly after coitus occurs. Beyond these exemplars of bizarre, though, this book contains cogent arguments for the place of sperm competition. We decided not to include these data to avoid further errors in the analyses. The results replicate and extend the findings of a previous study that was based on a sample of college students. Sperm competition risk also influences males' choice of female partners.
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Promiscuity: An Evolutionary History of Sperm Competition

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Human sperm competition

Why Jealousy is as Necessary as Love and Sex By viewing males and females as each having their own agenda, the choices underlying reproduction become far more complex than previously thought. This pattern is broadly consistent with the idea that males who lose out in social competition strategically compensate by investing preferentially in competitive ejaculates. It sounds simple enough. A Comment on Theory Testing. Harris, Metapsychology A century after Darwin originated the concept of sexual selection, an explosion of research began on the topic. Tim Birkhead guides us through the unseen side of the battle of the sexes. New pairs were then formed by placing two dominant males with each other, and two subordinate males with each other:
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Sperm competition: The need for speed | eLife

For example, because plant pollen is immobile, some plant species have evolved pollen spines for better dispersal and for sticking to fertile flower parts Figure 1, middle row on far left. The prize is fertilizing the egg, and many species have evolves ways of controlling when and by whom that happens. Polytomies in comparative analyses of continuous characters. Here, we manipulate male social status in an externally fertilising fish, chinook salmon Oncorhynchus tshawytscha , and find that in less than 48 hr, males can upregulate sperm velocity when faced with an increased risk of sperm competition. Because female bats store sperm during hibernation, the need for sperm to survive inside the female reproductive tract for up to several months could imply that in bats sperm competition favours sperm traits which enhance their longevity, rather than their swimming speed.
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National Human Genome Research Institute. If so, this study identifies a mechanistic pathway through which genetic variance can be maintained in the face of intense sexual selection in polyandrous populations. The American Naturalist. Therefore, rather there being directional selection for a single phenotype, this trade-off can foster disruptive selection and the evolution and maintenance of alternative mating tactics. And he shows how much human behavior--from the wife-sharing habits of Inuit hunters to Charlie Chaplin's paternity case--is influenced by sperm competition. Robin; Bellis, Mark A.
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