摘要
The distribution of species body size within taxonomic groups exhibits a heavy right tail extending over many orders of magnitude, where most species are much larger than the smallest species. We provide a simple model of cladogenetic diffusion over evolutionary time that omits explicit mechanisms for interspecific competition and other microevolutionary processes, yet fully explains the shape of this distribution. We estimate the model's parameters from fossil data and find that it robustly reproduces the distribution of 4002 mammal species from the late Quaternary. The observed fit suggests that the asymmetric distribution arises from a fundamental trade-off between the short-term selective advantages (Cope's rule) and long- term selective risks of increased species body size in the presence of a taxon-specific lower limit on body size.
摘要译文
种身体大小分类群内的分布显示出重右尾许多量级，在那里大多数物种是比最小的品种大得多上延伸。我们提供cladogenetic扩散的一个简单的模型在进化的时间，省略了种间竞争等微进化过程中明确的机制，还没有完全解释这种分布的形状。我们估计模型的参数，从化石数据，并发现它再现了强劲的4002种哺乳动物的晚第四纪的分布。所观察到的拟合表明非对称分布从短期选择性优势（科普的规则），并增加了物种的车身尺寸的长期选择性风险之间存在根本的折衷产生的一个类群特异下限上的车身尺寸的存在。
Clauset, Aaron; Erwin, Douglas H. The Evolution and Distribution of Species Body Size[J]. Science, 2008,321(5887): 399-401