Futuyma Douglas J
Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY, USA.
Interface Focus. 2017 Oct 6;7(5):20160145. doi: 10.1098/rsfs.2016.0145. Epub 2017 Aug 18.
Evolutionary theory has been extended almost continually since the evolutionary synthesis (ES), but except for the much greater importance afforded genetic drift, the principal tenets of the ES have been strongly supported. Adaptations are attributable to the sorting of genetic variation by natural selection, which remains the only known cause of increase in fitness. Mutations are not adaptively directed, but as principal authors of the ES recognized, the material (structural) bases of biochemistry and development affect the variety of phenotypic variations that arise by mutation and recombination. Against this historical background, I analyse major propositions in the movement for an 'extended evolutionary synthesis'. 'Niche construction' is a new label for a wide variety of well-known phenomena, many of which have been extensively studied, but (as with every topic in evolutionary biology) some aspects may have been understudied. There is no reason to consider it a neglected 'process' of evolution. The proposition that phenotypic plasticity may engender new adaptive phenotypes that are later genetically assimilated or accommodated is theoretically plausible; it may be most likely when the new phenotype is not truly novel, but is instead a slight extension of a reaction norm already shaped by natural selection in similar environments. However, evolution in new environments often compensates for maladaptive plastic phenotypic responses. The union of population genetic theory with mechanistic understanding of developmental processes enables more complete understanding by joining ultimate and proximate causation; but the latter does not replace or invalidate the former. Newly discovered molecular phenomena have been easily accommodated in the past by elaborating orthodox evolutionary theory, and it appears that the same holds today for phenomena such as epigenetic inheritance. In several of these areas, empirical evidence is needed to evaluate enthusiastic speculation. Evolutionary theory will continue to be extended, but there is no sign that it requires emendation.
自进化综合论（ES）以来，进化理论几乎一直在不断扩展，但除了基因漂变被赋予了更大的重要性之外，进化综合论的主要宗旨得到了有力支持。适应性归因于自然选择对遗传变异的筛选，而自然选择仍然是已知的唯一导致适应性增加的原因。突变并非适应性定向的，但正如进化综合论的主要创始人所认识到的，生物化学和发育的物质（结构）基础会影响通过突变和重组产生的表型变异的多样性。在这一历史背景下，我分析了“扩展进化综合论”运动中的主要命题。“生态位构建”是对各种众所周知的现象的一个新标签，其中许多现象已经得到了广泛研究，但（与进化生物学中的每个主题一样）某些方面可能研究不足。没有理由将其视为被忽视的进化“过程”。表型可塑性可能产生新的适应性表型，这些表型随后会在遗传上被同化或顺应，这一命题在理论上是合理的；当新表型并非真正新颖，而是在类似环境中已经由自然选择塑造的反应规范的轻微扩展时，这种情况可能最有可能发生。然而，在新环境中的进化往往会补偿适应不良的可塑性表型反应。将群体遗传理论与对发育过程的机制理解相结合，通过将终极因果关系和近因因果关系结合起来，能够实现更全面的理解；但后者并不会取代前者或使其无效。过去，通过阐述正统进化理论，新发现的分子现象很容易被纳入其中，如今表观遗传等现象似乎也是如此。在这些领域中的几个方面，需要实证证据来评估那些热情的推测。进化理论将继续扩展，但没有迹象表明它需要修正。
