Coddington Jonathan A
Department of Entomology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, U.S.A.
Cladistics. 1988 Mar;4(1):3-22. doi: 10.1111/j.1096-0031.1988.tb00465.x.
Abstract- A cladistic viewpoint provides an historical definition of adaptation and an operational ecological test for evolutionary adaptations. Adaptation is apomorphic function promoted by natural selection, as compared with plesiomorphic function. Adaptation is thus a conditional, hierarchical, comparative term, like homology. Hypotheses of adaptation that do not specify levels of apomorphy are weak; they should refer to and explain the function at the level at which it is apomorphic with respect to the plesiomorphic (outgroup) condition. The adaptational hypothesis serves as a prior prediction in the comparison of the apomorphic function of the derived trait with the plesiomorphic function of the plesiomorphic trait serving as the null hypothesis. It is useful to distinguish whether hypotheses about characters identify selection as facilitating: 1) the origin of a character; 2) its maintenance; 3) neither; or 4) both. The latter two are uniformitarian and testable in a strong sense. The former two possibilities use ancillary arguments to protect the hypothesis of the role of natural selection in one way or another, but might still be tested by the weak criterion of plausibility. Given an hypothesis of both origin and maintenance due to selection, the test of adaptation may still be thwarted because only certain kinds of cladistic structure allow feasible tests. Few of the really classic and common examples of supraspecific adaptation survive this kind of cladistic test.
摘要——分支系统学观点为适应提供了一种历史定义，并为进化适应提供了一种可操作的生态学检验方法。与近裔共性功能相比，适应是由自然选择推动的近裔特性功能。因此，适应是一个有条件的、分层的、比较性的术语，类似于同源性。未明确近裔特性水平的适应假说较为薄弱；它们应该提及并解释相对于近裔共性（外类群）条件而言呈现近裔特性的那个水平上的功能。在将衍生性状的近裔特性功能与作为零假设的近裔共性性状的近裔共性功能进行比较时，适应假说可作为一种先验预测。区分关于性状的假说是将选择认定为促进了：1）一个性状的起源；2）其维持；3）两者皆非；还是4）两者皆是，这很有用。后两种情况在很强的意义上是均变论的且可检验。前两种可能性以某种方式使用辅助论据来保护自然选择作用的假说，但仍可能通过合理性这一较弱标准进行检验。鉴于存在因选择而导致起源和维持的假说，适应的检验仍可能受阻，因为只有某些类型的分支结构允许进行可行的检验。很少有真正经典且常见的超种适应例子能通过这种分支检验。
