Evolution of developmental morphology and life history.

进化分支，即种群中从单一性状发展出两个或两个以上不同性状的共同进化现象，是适应动力学的最新研究课题。在以往的研究中，性状变异是进化分支的最低要求，对分支的进化模式没有重要影响。本文论证了性状进化从相同的初始性状到不同的进化终点性状，只要改变性状变异的假设，就会出现多种进化分支路径。这一现象的关键性质是保护二态流形中平衡点的拓扑构型和二态分支在其中发展的起始点。这表明种群中现存的单态或多态集合并不是由相同的初始表型产生的独特的必然结果。我在反映同类相食现象的最小因果本质的框架内分析了进化同类相食游戏的可实现状态。在我分析同类相食的可能性时，没有形态专门化和大小优先性被假设为保守的情况。在保守条件下，如果最初野生种群的同类相食率没有充分低于阈值，则可能发生同类相食。由于对饥饿的恐惧，拥挤和/或替代猎物的低可用性促进了同类相食的进化。从同种猎物获得的能量会被同种受害者的反击成本和自身的挑战成本所削弱。在同类相食挑战的军备竞赛中，忽略净摄入能量会导致高同类相食率的相对劣势，并形成低同类相食率的进化平衡，即使在同种猎物的潜在盈利能力很高的情况下也是如此。

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.