Abstract: This paper argues that the Cambrian explosion did not only signify a rapid phylogenetic radiation of many kinds of multicellular metazoans on the Earth, but also created the first Animal Consumer-Driven Marine Ecosystem on the Earth. Since then, the Earth’s ecosystem has transformed from the Precambrian Bacteria-algae (producers and decomposers) supported Preliminary Evolutionary Ecosystem to the first Animal Consumer-driven Primary Evolutionary Ecosystem with complex trophic webs (producers, decomposers and consumers) on the Earth. On the basis of earlier studies, this paper emphasizes that the macro evolution of early life on the Earth can be divided into three stages: molecular level evolution, cellular level evolution and tissue level evolution based on the organismal hierarchical level of living organisms and its geological background. The three evolutionary stages led respectively to the origin of prokaryotes, protists and multicellular Metazoa (animal kingdom). Based on this framework, the Cambrian explosion is viewed as the inevitable outcome of the organization of protozoan cell clusters and reinterprets the new Lego Blocks of Tissues Hypothesis of the Cambrian explosion. At the end of Ediacaran, the weakening of the Earth’s magnetic field, increased radiation and the oxidation of seawater provided the environmental background for the evolution of animal tissues. At the same time, the origin of animal tissues provided the material basis for the differentiation of animal organ systems and the evolution of body configuration, and accelerated the explosive emergence and rapid radiation of multi-phyla and higher-order animal phyla.

Key words:  , Cambrian, Brachiopod, Lophotrochozoan, Metazoan, tissue and organ, Cambrian Explosion hypothesis