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Evolution of developmental morphology and life history.

发育形态和生活史的进化。

基本信息

批准号：
13640621
负责人：
NISHIMURA Kinya
金额：
$ 2.24万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Evolutionary branching, that is coevolutionary phenomenon of development of two or more distinctive traits from a single trait in a population, is the issue of recent study of adaptive dynamics. In the previous studies, trait variance is a minimum requirement for evolutionary branching, and it did not play important role for the evolutionary pattern of branching. Here I demonstrate that trait evolution exhibits variety of evolutionary branching paths starting from an identical initial trait to different evolutional terminus traits only changing assumption of trait variance. The key property for this phenomenon is the topological configuration of equilibria and initial point in the manifold of protected dimorphism in which the dimorphism branches developing. This suggests that the existing monomorphic or polymorphic set in a population not a unique inevitable consequence from an identical initial phenotype.I analyzed the attainable state of an evolutionary cannibalism game within a framework that reflects the minimum essence of cause-effect in the cannibalism phenomenon. No morphological specialization and no size priority of cannibalism individuals are assumed as conservative situations in which I analyze the possibility of cannibalism. Cannibalism would be possible under the conservative condition, if initially the wild population's cannibalism rate is not sufficiently lower than a threshold value. Crowding and/or low availability of alternative prey with the fear of starvation facilitates cannibalism evolution. Energy gain from conspecific prey would be attenuated by costs of counterattacks by conspecific victims and by challenge cost of its own. Discounting net intake energy required in the arms race for cannibalism challenge result in a relative disadvantage of having a high cannibalism rate and makes an evolutionary equilibrium of low cannibalism rate, even when potential profitability of conspecific prey is high.

进化分枝，即群体中两个或两个以上不同性状由单一性状发育而成的共同进化现象，是近年来适应性动力学研究的热点。在以往的研究中，性状变异是进化分枝的最低要求，对分枝的进化模式并没有起到重要作用。在这里，我证明了性状进化表现出从相同的初始性状到不同的进化终点性状的各种进化分支路径，只是改变了对性状变异的假设。这一现象的关键性质是受保护二态流形中平衡点和初始点的拓扑结构，二态分支在其中发展。这表明种群中存在的单态或多态集合不是唯一的必然结果，因为相同的初始表型。我在一个框架内分析了进化同类博弈的可达到状态，该框架反映了同类相食现象中因果关系的最小本质。没有形态特化和没有吃人个体的大小优先被假设为保守的情况，在这种情况下我分析了吃人的可能性。在保守的条件下，如果最初野生种群的食人率不足以低于阈值，吃人是可能的。由于害怕饥饿，替代猎物拥挤和/或可获得性低，促进了同类相食的进化。来自同种猎物的能量收益将因同种受害者的反击成本和自身的挑战成本而减弱。即使在同类猎物的潜在利润率很高的情况下，扣除军备竞赛中为自相残杀挑战所需的净摄入量，也会导致高自相残食率的相对劣势，并形成低自相残食率的进化平衡。