The eras of dinosaurs consists of three different periods; the Triassic, Cretaceous and Jurassic periods. The Triassic era was the first instance of dinosaurs beginning to rule the planet. It was about 240 million years ago, long after life on land truly started.

Back during this time, early sauropods, which were large herbivores, and theropods, two legged carnivores, began to exist. These dinosaurs would pave the way to future, more famous dinosaurs like the T-Rex and brontosaurus.

This was the point where pterosaurs became the first reptiles to take to the sky in flight, becoming the first vertebrates in general to actually do so. These creatures continued thriving throughout the Cretaceous and Jurassic periods.

Towards the end of the triassic period, life was expanding in ways completely new to the time. Oceans became populated with many reptilian animals, including the plesiosaur, an ruthless predator with a very long neck, and the ichthyosaurus, which resembled dolphins despite not being related to them. 

The Triassic period ended via drastic changes in climate and devastating volcanic eruptions. Despite this, some species like the plesiosaurs and the pterosaurs survived and continued living into the other two periods, while others evolved into different dinosaur species that would become far more well known and wouldn’t die out for a long time after this event.