Climate and Geography During the Triassic period, all of the earth's continents were joined together into a vast landmass called Pangaea (which was itself surrounded by an enormous ocean called Panthalassa). There were as yet no polar ice caps, and the climate was hot and dry, punctuated by violent monsoons.
Terrestrial Life The start of the Triassic period followed the Permian Extinction, an event of unknown cause that wiped out over two-thirds of land-dwelling vertebrates and 95 percent of ocean-dwelling species. Taking their place were the therapsids (mammal-like reptiles), archosaurs (from which the first dinosaurs like Herrerasaurus and Eoraptor evolved, as well as the first prehistoric crocodiles and pterosaurs), and primitive reptiles called pelycosaurs (the most famous of which was Dimetrodon). It was during the late Triassic period that the mammal-like reptiles evolved into the first mammals.
Marine Life Because the Permian Extinction depopulated the world's oceans, the Triassic period was ripe for the rise of early marine reptiles like Placodus and Nothosaurus. The vast Panthalassan Ocean was soon restocked with new species of prehistoric fish, as well as simple animals like corals and cephalopods.
Avian Life Except for insects, the skies of the early Triassic period were relatively quiet. It was only toward the end of the Triassic that the earliest pterosaurs, such as Eudimorphodon, appeared on the scene, and they probably weren't the most accomplished fliers.
Plant Life The Triassic period wasn't nearly as lush and green as the later Jurassic and Cretaceous periods, but it did see an explosion of various land-dwelling plants, including cycads, ferns, and Gingko-like trees. Part of the reason there were no enormous dinosaurs during the Triassic (along the lines of Brachiosaurus) is that there simply wasn’t enough vegetation to nourish them!
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