Abstract Why is life paced so differently across as well as within organisms? Can one expect across-species patterns to be repeated within a species too, among individuals? The answer to these questions requires understanding conditions under which reaction norms evolve. We provide an overview of what we believe to be understudied areas of life-history theory, to foster theoretical work and to help deriving predictions for the evolution of human reaction norms. We discuss both why one might expect reaction norms to be aligned with patterns across species, and why that expectation might sometimes fail. It is not impossible for environmental cues to shape life histories in the current generation, but compared with cue-independent genetic adaptation, the adaptive task is now more complex; cues may be unreliable or change in value with time; and parental strategies may differ between situations where offspring have the possibility to disperse to new habitats and situations where environmental conditions remain the same across generations. In that regard, we comment on the value of source-sink theory and on the importance of being specific about the way density regulation affects individual vital rates. We also remind the reader that adaptation does not necessarily optimize population growth rates when conflict between entities (e.g. between the two sexes) is a feature of the adaptive process. All these factors likely play an important role on the evolution of reaction norms, and we argue in favour of their more systematic inclusion in human life-history research.

中文翻译：

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生命史理论中的适应性和可塑性：如何得出预测。

摘要 为什么生物体之间和生物体内的生活节奏如此不同？是否可以期望跨物种模式也会在一个物种内在个体之间重复？这些问题的答案需要了解反应规范发展的条件。我们概述了我们认为是生命史理论研究不足的领域，以促进理论工作并帮助推导出人类反应规范演变的预测。我们讨论了为什么人们可能期望反应规范与跨物种的模式保持一致，以及为什么这种期望有时可能会失败。环境线索塑造当代人的生活史并非不可能，但与独立于线索的遗传适应相比，现在的适应任务更加复杂；线索可能不可靠或随时间变化；在后代有可能分散到新栖息地的情况和环境条件在几代人之间保持不变的情况下，父母的策略可能会有所不同。在这方面，我们评论了源汇理论的价值以及具体说明密度调节影响个体生命率的方式的重要性。我们还提醒读者，当实体之间的冲突（例如两性之间）是适应过程的一个特征时，适应不一定会优化人口增长率。所有这些因素都可能在反应规范的演变中发挥重要作用，我们主张将它们更系统地纳入人类生活史研究。