Rice S H
Department of Biology and Ecosystems Analysis and Management Group, University of Warwick, Coventry, U.K.
J Theor Biol. 1995 Dec 7;177(3):237-45. doi: 10.1006/jtbi.1995.0241.
Species selection, differential rates of speciation or extinction resulting from species level characters, is often invoked as the main mechanism of macroevolution that is not simply an extension of microevolutionary processes. So long as we are careful in defining "species", the logic of species selection is sound. This does not mean, however, that this process can influence evolutionary dynamics under realistic conditions. The principal challenge to the efficacy of species selection as an evolutionary mechanism is the idea that selection between individuals within species will be so much more efficient as to swamp out any effects of selection between species. To assess this, a genetic model is constructed that includes simultaneous selection within and between species, and this is used to ask: under what conditions could species selection influence evolutionary dynamics, even in the face of opposing selection between individuals? The model shows that the efficacy of species selection is strongly determined by the time between speciation events (measured in individual generations), the mutation rate of the character under consideration, and the initial size of a newly formed reproductively isolated population. Data indicate that a few studied lineages have shown sufficiently high speciation rates to make species selection an important mechanism in the evolution of characters with mutation rates on the order of 10(-6) per generation. Quantitative characters, such as body size, generally change too readily for species selection to be relevant to their evolution. Complex characters, however, may be good candidates to be influenced by species selection. The interaction of selection within and between species can be subtle, with individual selection looking, from the standpoint of a species, very much like development of an individual. Furthermore, selection between individuals may be the main process assembling complex adaptations, while species selection allows them to persist over long periods of time.
物种选择，即由物种层面特征导致的不同物种形成或灭绝速率，常被视为宏观进化的主要机制，而不仅仅是微观进化过程的延伸。只要我们在定义“物种”时足够谨慎，物种选择的逻辑就是合理的。然而，这并不意味着在现实条件下这个过程能够影响进化动态。物种选择作为一种进化机制有效性的主要挑战在于，物种内个体间的选择效率要高得多，以至于会掩盖物种间选择的任何影响。为了评估这一点，构建了一个遗传模型，该模型包括物种内和物种间的同时选择，并用于探讨：即使面对个体间的反向选择，在何种条件下物种选择能够影响进化动态？该模型表明，物种选择的有效性在很大程度上取决于物种形成事件之间的时间间隔（以个体世代衡量）、所考虑特征的突变率以及新形成的生殖隔离种群的初始大小。数据表明，一些已研究的谱系显示出足够高的物种形成速率，使得物种选择成为每代突变率约为10^(-6)的特征进化中的一个重要机制。像体型这样的数量性状通常变化太快，以至于物种选择与其进化无关。然而，复杂性状可能是受物种选择影响的良好候选对象。物种内和物种间选择的相互作用可能很微妙，从一个物种的角度来看，个体选择很像个体的发育。此外，个体间的选择可能是形成复杂适应性的主要过程，而物种选择则使它们能够长期持续存在。
