First there was bacterium (microscopic fluid satchets made up of sugar, fat, protein, and DNA shielded by a cell membrane), then there were fish that got lungs and fins resembling limbs, then there were amphibians (creatures that inhabit damp areas and breed in the water), then there were reptiles, and then there were dinosaurs.
This was what came after the Paleozoic Era which caused 70% of organisms to face extinction. It took 10 million years for the Earth to face complete recovery and when it did, the surviving reptiles evolved. Therapsids were in this group. They were mammal-like reptiles and they marked the introduction of the first authentic mammals. Marine reptiles, flying pterosaurs, and the first dinosaurs were in this group too. The world looked very different because the supercontinents Pangea, Gondwana, and Laurasia did not split yet.
The Triassic was devoid of grass and flowers. Instead, it had ferns and horsetails which were consumed by herbivores. The forests had cycads, conifers, and ginkgoes, which are still alive today. Modern ginkgoes have not changed much.
Some of the dinosaurs that lived during this time were:
- Placerias, which was a large, herbivorous mammal-like reptile that faced extinction after the Triassic.
- Lariosaurus, which inhabited the more shallow areas of the sea.
- Eudimorphodon, a small dinosaur who had a long tail and leather-like wings.
- Eoraraptor, which had a long tail, a thin jaw which held minuscule spear-like teeth and probably ate lizards.
- Coelophysis, who had a thin, flexible long neck and was a quick predator.
- Thecodontosaurus, a 7 foot (2.1 meter) dinosaur who ate plants.