University of Liverpool, Liverpool, UK.
University of Manchester, Manchester, UK.
J Math Biol. 2021 Apr 1;82(5):43. doi: 10.1007/s00285-021-01597-z.
As ecosystems evolve, species can become extinct due to fluctuations in the environment. This leads to the evolutionary adaption known as bet-hedging, where species hedge against these fluctuations to reduce their likelihood of extinction. Environmental variation can be either within or between generations. Previous work has shown that selection for bet-hedging against within-generational variation should not occur in large populations. However, this work has been limited by assumptions of well-mixed populations, whereas real populations usually have some degree of structure. Using the framework of evolutionary graph theory, we show that through adding competition structure to the population, within-generational variation can have a significant impact on the evolutionary process for any population size. This complements research using subdivided populations, which suggests that within-generational variation is important when local population sizes are small. Together, these conclusions provide evidence to support observations by some ecologists that are contrary to the widely held view that only between-generational environmental variation has an impact on natural selection. This provides theoretical justification for further empirical study into this largely unexplored area.
随着生态系统的演变，物种可能会因环境波动而灭绝。这导致了一种被称为“风险分散”的进化适应，物种通过这种适应来分散风险，降低灭绝的可能性。环境变化既可以发生在代内，也可以发生在代际之间。以前的研究表明，针对代内变化的风险分散选择不应在大种群中发生。然而，这项工作受到了种群混合良好的假设的限制，而实际上的种群通常具有一定程度的结构。利用进化图论的框架，我们表明，通过向种群中添加竞争结构，代内变化可以对任何种群大小的进化过程产生重大影响。这补充了使用细分种群的研究，该研究表明，当地种群规模较小时，代内变化很重要。总之，这些结论为一些生态学家的观察结果提供了证据，这些观察结果与普遍认为只有代际环境变化对自然选择有影响的观点相悖。这为进一步研究这一尚未充分探索的领域提供了理论依据。
