Solow Andrew R, Wang Steve C
Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA.
Evolution. 2008 Aug;62(8):2092-6. doi: 10.1111/j.1558-5646.2008.00410.x. Epub 2008 Apr 29.
Cope's Rule states that the size of species tends to increase along an evolutionary lineage. A basic statistical framework is elucidated for testing Cope's Rule and some surprising complications are pointed out. If Cope's Rule is formulated in terms of mean size, then it is not invariant to the way in which size is measured. If Cope's Rule is formulated in terms of median size, then it is not invariant to the degree of separation between ancestral and descendant species. Some practical problems in assessing Cope's Rule are also described. These results have implications for the empirical assessment of Cope's Rule.
柯普法则指出，物种的体型往往会沿着进化谱系增大。阐明了一个用于检验柯普法则的基本统计框架，并指出了一些惊人的复杂情况。如果柯普法则是根据平均体型来表述的，那么它对于体型测量的方式并不具有不变性。如果柯普法则是根据中位数体型来表述的，那么它对于祖先物种和后代物种之间的分离程度并不具有不变性。还描述了评估柯普法则时的一些实际问题。这些结果对柯普法则的实证评估具有启示意义。
