Homoplasy

Abstract

The analysis and interpretation of evolutionary trends in the nervous system, as in other organ systems of the body, depends in large measure upon similarities between equivalent parts in different organisms. The analysis is often complex because similarity can arise from several different sources. One source of similarity is homology, which is similarity that results from a common phyletic history. In other words, two closely related animals are more likely to have similarities in their neural morphology than two remotely related animals. Although common ancestry does not always result in similarity, it does often enough that similarity, along with other evidence about the history of the various species under consideration, can be used to reconstruct the evolutionary history of a neuronal population or system.