ancestral 专八GRE

The branching points of the cladogram may be regarded either as an ancestral species (as in an evolutionary tree) or solely as representing shared characteristics.

在这个形象化的进化，两个物种间的距离都是由它们共有的特性来决定的。

The special body plan of Yunnanozoon is almost identical to that of the living enteropneust hemichordate Balanoglossus,which suggests that the earlyCambrian creature is ancestral to the hemichordates.

这种独特的身体造型与现生肠鳃类半索动物几无二致，从而表明这个早寒武世动物是地球半索动物门中已知最古老的祖先类型。