Evolutionary implications of fluctuating natural selection

有人说，自然环境唯一可靠的特征是它们在不断变化。 虽然众所周知，这种变化可以是任何规模，并可能发生在任何时间尺度上，仍然有很多关于生物如何科普这种变异性的了解。 这项由NSERC发现补助金支持的研究将导致对环境变化反应的基本理解的进展。 除了灭绝，已知的环境变化的结果包括直接的反应，如范围转移和个人层面的塑料调整在一生中，或可能包括长期进化的反应，如“适应性跟踪”或风险规避（“赌注对冲”）策略的演变几代人。 关于单个物种如何孤立地对环境变化作出反应，人们已经了解了很多，但它们的反应将部分取决于它们作为物种集合的一部分时的反应。 这项研究的目标之一是设计一个实验系统，观察物种的混合物，或组合，在一个“微观”组成的热梯度，然后迫使组合，以适应这种热梯度的变化。 这也将使研究人员能够评估不同的进化和生态过程对结果的相对重要性。 环境变化下生殖进化的其他研究将提供生物体对变化条件的反应的基本知识。 例如，所谓的“赌注对冲”是对不可预测变化本身的一种适应。 在不可预测的世界中，人类会有意识地做出牺牲眼前利益的决定，通过“对冲赌注”来抵御风险（购买保险就是一个例子）。 由于自然环境也是不可预测的，因此预计赌注对冲特征将通过自然选择进化，因为它们降低了失败的风险。 因此，这一专题对那些关心环境变化的任何方面的人都有意义。尽管理论文献中已经承认赌注对冲是对变化的一般反应，但其与未来气候变化反应的相关性尚属首次。

It has been said that the only reliable characteristic of natural environments is that they are constantly changing. Although it is well known that such changes can be of any magnitude and may occur over any time scale, much remains to be learned about how organisms cope with this variability. The research supported by this NSERC Discovery Grant will lead to progress in the basic understanding of response to environmental change. Aside from extinction, known outcomes of environmental change include direct responses such as range shifts and individual-level plastic adjustments within a lifetime, or may include long-term evolved responses such as "adaptive tracking" or the evolution of risk aversion ("bet-hedging") strategies over generations. Much is being learned about how individual species may respond to environmental change in isolation, but their response will partly be determined by how they respond when part of a species assemblage. One of the goals of this proposed research is to devise an experimental system to observe species mixtures, or assemblages, in a "microcosm" consisting of a thermal gradient, and then forcing the assemblage to adjust to a change in this thermal gradient. This will also allow the researchers to assess the relative importance of different evolutionary and ecological processes to the outcome. Other studies of the evolution of reproduction under environmental variance will provide fundamental knowledge of organismal response to changing conditions. For example, so-called "bet hedging" is an adaptation to unpredictable change itself. Humans make conscious decisions to sacrifice immediate gain by "hedging their bets" against risk in an unpredictable world (the purchase of insurance is an example). Because natural environments are also unpredictable, bet-hedging traits are expected to evolve through natural selection because they reduce the risk of failure. This topic is thus of interest to those concerned with any aspect of environmental change. Although bet hedging has been acknowledged in the theoretical literature as a general response to change, its relevance to response to future climate change is being studied for the first time.