After the Permian period, the epic saga of evolution and extinction on Earth produced the world's first dinosaurs, plesiosaurs and pterosaurs. They dominated land, sea and air until another period of extreme volcanism generated vast waves of lava and toxic gas and killed roughly 75% of all species. After the Permian period, the epic saga of evolution and extinction on Earth produced the world's first dinosaurs, plesiosaurs and pterosaurs. They dominated land, sea and air until another period of extreme volcanism generated vast waves of lava and toxic gas and killed roughly 75% of all species.