Polyphyletic Origin of Metazoa from Plants

Abstract

BOTANISTS show us an aspect of evolution-in-progress, so far as that can be shown, of which zoologists tell us nothing—because there is possibly nothing to tell. The evolution of plants is often indicated in terms of the appearance of the sexual differentiation in unicellular organisms, of the appearance of multicellularity, of the total life-cycle of one plant as an alternation of two generations, asexual and sexual, the individuals being sometimes morphologically distinct and independent, and of the various fate of these phases of the total life-cycle in, say, the moss, the fern and the angiosperm, when they are not distinct and independent individuals, “but the one remains permanently connected to the other like a parasite on its host plant” in Strasburger's-words.