Whitlock Michael C
Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada.
Evolution. 1997 Aug;51(4):1044-1048. doi: 10.1111/j.1558-5646.1997.tb03951.x.
Two similar evolutionary theories, the shifting balance theory and founder-flush models, invoke random genetic drift to allow evolution on complex adaptive landscapes. These models, in their usual incarnations, deal with fitness as a static entity, and the probability of transition from one form to another is predicted to be quite small by analysis of these models. Fitness itself can change, however, and the amount of change in the parameters of the fitness functions required to allow deterministic evolution to new adaptive peaks is very small. The probability of environmental changes sufficient to allow substantial morphological evolution or reproductive isolation is large relative to the probability that similar changes could occur by processes requiring genetic drift, even with very small population sizes. The rapid evolution or speciation following a population founding event is more closely linked with environmental changes than genetic drift.
两种相似的进化理论，即动态平衡理论和奠基者-扩张模型，借助随机遗传漂变来实现复杂适应景观上的进化。在其通常的形式中，这些模型将适合度视为一个静态实体，并且通过对这些模型的分析预测，从一种形式转变为另一种形式的概率相当小。然而，适合度本身可以改变，并且允许确定性进化到新的适应峰所需的适合度函数参数的变化量非常小。相对于通过需要遗传漂变的过程（即使种群规模非常小）可能发生类似变化的概率而言，足以允许实质性形态进化或生殖隔离的环境变化的概率很大。种群奠基事件后的快速进化或物种形成与环境变化的联系比与遗传漂变的联系更为紧密。
