the first group of animals to live on land was the
Evolutionary history of life Ediacara biota appear during the Ediacaran period,[37] while vertebrates, along with most other modern phyla originated about 525 Ma during the Cambrian explosion.[38] During the Permian period, synapsids, including the ancestors of mammals, dominated the land,[39] but most of this group became extinct in the Permian–Triassic extinction event 252 Ma.[40] During the recovery from this catastrophe, archosaurs became the most abundant land vertebrates;[41] one archosaur group, the dinosaurs, dominated the Jurassic and Cretaceous periods.[42] After the Cretaceous–Paleogene extinction event 66 Ma killed off the non-avian dinosaurs,[43] mammals increased rapidly in size and diversity.[44] Such mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.[45]