共查询到20条相似文献,搜索用时 15 毫秒
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Our view of sperm competition is largely shaped by game-theoretic models based on external fertilizers. External fertilization is of particular interest as it is the ancestral mode of reproduction and as such, relevant to the evolution and maintenance of anisogamy (i.e., large eggs and tiny, numerous sperm). Current game-theoretic models have been invaluable in generating predictions of male responses to sperm competition in a range of internal fertilizers but these models are less relevant to marine broadcast spawners, the most common and archetypal external fertilizers. Broadcast spawners typically have incomplete fertilization due to sperm limitation and/or polyspermy (too many sperm), but the effects of incomplete (<100% fertilization rates) fertilization on game-theoretic predictions are unclear particular with regards to polyspermy. We show that incorporating the effects of sperm concentration on fertilization success changes the predictions of a classic game-theoretic model, dramatically reversing the relationship between sperm competition and the evolutionarily stable sperm release strategy. Furthermore, our results suggest that male and female broadcast spawners are likely to be in conflict at both ends of the sperm environment continuum rather than only in conditions of excess sperm as previously thought. Across the majority of the parameter space we explored, males release either too little to too much sperm for females to achieve complete fertilization. This conflict could result in a coevolutionary race that may have led to the evolution of internal fertilization in marine organisms. 相似文献
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E. M. Cowell 《BMJ (Clinical research ed.)》1939,2(4109):736-738
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A great deal of folklore, superstition and emotional reaction is attached to the common cold, but established objective information is quite limited. The evidence concerning etiology, epidemiology, physiology, prevention and treatment of the common cold is briefly summarized and critically evaluated. There is disappointing lack of real progress in any of these aspects of the common cold problem. 相似文献
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E. M. Cowell 《BMJ (Clinical research ed.)》1939,2(4110):778-781
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C. Thurstan Holland 《BMJ (Clinical research ed.)》1908,2(2502):1781-1782
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Charles J. Whitby 《BMJ (Clinical research ed.)》1912,2(2705):1249-1250
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《动物学研究》1981,(1)
By examining the type specimens, it is certain that the upper tooth band of Euchiloglanis davidi (Sauvage) is produced backwards on each side instead of being misconceived hitherto as not produced backwardly. Of course this character must be the attribute of the genus Euchiloglanis at the same time.Because CoragIanis shares the same diagnostic character with Euchiloglanis, it is evident that Coraglanis is, in fact, a synonym of Euchiloglanis. So far as 相似文献
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Norman C. Lake 《BMJ (Clinical research ed.)》1938,2(4056):715-718