The Earliest fish appeared through the Cambrian as modest filter feeders; they continued to evolve with the Paleozoic, diversifying into quite a few varieties. The earliest fish with committed respiratory gills and paired fins, the ostracoderms, had weighty bony plates that served as protecting exoskeletons versus invertebrate predators. Together with https://maps.app.goo.gl/kTisAZCbSjAw6nkX8