英和和英

出典:『Wikipedia』 (2011/02/11 17:30 UTC 版)

英語による解説

引用

In cladistics, a symplesiomorphy or symplesiomorphic character is a trait which is shared (a symmorphy) between two or more taxa, but which is also shared with other taxa which have an earlier last common ancestor with the taxa under consideration. They are therefore not an indication that the taxa be considered more closely related to each other than to the more distant taxa, as all share the more primitive trait. A close phylogenetic relationship, that the taxa form a certain clade to the exclusion of certain other taxa, can only be shown by the discovery of synapomorphies: shared traits that have originated with the last common ancestor of the taxa considered, or at least in the branch, not including the taxa to be excluded, leading to it.