Olive P J
Symp Soc Exp Biol. 1985;39:267-300.
The dominant 'demographic' theory of life history evolution supposes that different lifetime patterns of reproduction are the result of selection of alternative optimal solutions for the allocation of limited resources between somatic and reproductive functions. A number of trade-off possibilities have been recognized--those between current reproductive output and residual reproductive value and between fecundity and initial offspring size being considered especially important. Many theoretical studies assume that natural selection will favour the adoption of optimal solutions, but it has been pointed out that such solutions may not be obtainable due to design constraints and the development of physiological adaptations to specific reproductive traits which limit subsequent evolutionary potential. The validity of this idea is examined in this paper through a review of the major reproductive strategies available to marine invertebrates and the physiological adaptations associated with them. The ecologically important distinction between planktotrophic and lecithotrophic development is not necessarily associated with major physiological adaptations in the adults, but the distinction between strictly semelparous and iteroparous life histories is. This is demonstrated in a survey of the endocrinological and environmental control of reproductive processes in related organisms with contrasting modes or reproduction. Particular reference is made to the Polychaeta, in which the contrast between semelparous and iteroparous life histories is particularly marked. A similar contrast is found between cephalopoda and other mollusca, and the discussion of physiological adaptations is extended to include these groups and the Echinodermata.
生命史进化的主流“人口统计学”理论认为，不同的终生繁殖模式是在体细胞功能和生殖功能之间分配有限资源时选择替代最优解决方案的结果。人们已经认识到许多权衡的可能性——当前生殖产出与剩余生殖价值之间以及繁殖力与初始后代大小之间的权衡被认为尤为重要。许多理论研究假设自然选择会倾向于采用最优解决方案，但有人指出，由于设计限制以及对特定生殖特征的生理适应的发展限制了后续的进化潜力，这些解决方案可能无法实现。本文通过回顾海洋无脊椎动物可用的主要生殖策略以及与之相关的生理适应，来检验这一观点的有效性。浮游生物营养型发育和卵黄营养型发育在生态上的重要区别不一定与成体的主要生理适应相关，但严格的单次生殖和多次生殖生命史之间的区别则与之相关。这一点在对具有不同繁殖模式的相关生物的生殖过程的内分泌和环境控制的调查中得到了证明。特别提到了多毛纲动物，其中单次生殖和多次生殖生命史之间的对比尤为明显。在头足类动物和其他软体动物之间也发现了类似的对比，并且对生理适应的讨论扩展到包括这些类群和棘皮动物。
