Tetrapods evolved from lobe-finned fish and developed legs from muscular lower fins to navigate algae-choked swamps. There are three main groups of tetrapods: amphibians, synapsids, and sauropsids. Synapsids and sauropsids are amniotes and evolved from amphibians around 320 million years ago. Tetrapods are a monophyletic (descended from a common ancestor) group of land animals that […]