The Earliest fish appeared in the course of the Cambrian as smaller filter feeders; they ongoing to evolve in the Paleozoic, diversifying into numerous varieties. The earliest fish with committed respiratory gills and paired fins, the ostracoderms, had hefty bony plates that served as protective exoskeletons from invertebrate predators. 欢迎关注@B计划老妈，孩子成长路漫漫，在这不可逆的... https://maps.app.goo.gl/kTisAZCbSjAw6nkX8