Dinosaurs evolved from archosaurs, the dominant reptiles that appeared during the late Perian period. The archosaurs split into two groups, with one leading to crocodiles and the other leading to dinosaurs. Over time, dinosaurs evolved into thousands of different species, with one of their main traits being their bipedal abilities.

During the Triassic period, one of the earliest dinosaurs to emerge from archosaurs was the Eoraptor, which was about the size of a dog. The climate during this time was generally hot and dry, with no polar ice caps, and the vegetation was different from modern-day Earth. The Triassic period would experience a great extinction event, which would lead to the extinction of numerous species.

The Jurassic period was where dinosaurs thrived, with different species evolving and becoming rulers of the earth. Some of the largest creatures ever to walk the earth, such as the stegosaurus, brachiosaurus, and Allosaurus, occupied the earth during this time. The Cretaceous period was the final era for dinosaurs, and during this time, numerous species went extinct.