McQuade A B
Q Rev Biol. 1977 Sep;52(3):249-62. doi: 10.1086/409994.
A theory regarding the early evolution of the eukaryotes is presented. It is proposed that the eukaryotes evolved through the successive stages: amoeba, flagellate, sexual flagellate. It postulated that sexuality emerged only once. A scheme relating evolution of the whiplash and tinsel forms of the flagellum to the evolution of sexuality is presented. It is suggested that sexuality first appeared in organisms capable of producing both forms of the flagellum. The phylogeny supports the hypotheses that the flagellum developed from the spindle system, and that the nucleate algae evolved from protozao through symbiosis with photosynthetic organisms related to the blue-green bacteria. It is consistent with the hypothesis that the mitochondrion was acquired by symbiosis. The phylogeny provides clearer definitions for kingdoms, and indicates the separation into seven kingdoms, as follows: Monera, Protozoa, Algae, Fungi, Porifera, Plantae, Animalia.
本文提出了一种关于真核生物早期进化的理论。该理论认为，真核生物是通过以下连续阶段进化而来的：变形虫、鞭毛虫、有性鞭毛虫。它假定有性生殖只出现过一次。本文还给出了一个将鞭毛的尾鞭型和茸鞭型的进化与有性生殖的进化联系起来的示意图。有人认为，有性生殖最初出现在能够产生两种鞭毛形式的生物体中。系统发育学支持以下假说：鞭毛由纺锤体系统进化而来，有核藻类通过与与蓝细菌相关的光合生物共生，从原生动物进化而来。这与线粒体是通过共生获得的假说相一致。系统发育学为各生物界提供了更清晰的定义，并表明可分为七个生物界，如下：原核生物界、原生动物界、藻类、真菌界、多孔动物门、植物界、动物界。
