About over 230 million years ago, dinosaurs began to evolve after the period the Permian extinction. dinosaurs began to develop and grow throughout the Triassic period, and were seen as a great threat to other living creatures around them. However, about 66 million years ago, dinosaurs became extinct near the end of the Cretaceous period due to a huge comet or asteroid that struck the face of the earth. This area, at the time, was under water but is today known as modern day Mexico. Dinosaurs had first began to evolve from a species known as the archosaurs. Archosaurs were Triassic reptiles and were much smaller than the later species of dinosaurs. These Triassic reptiles carried certain features that were much different from the species that they had evolved into. They had a much different posture, almost as if they were “locked in” …show more content…
These creatures were all over Pangea for as long as 20 million years. The archosaurs began to spread throughout the whole supercontinent. The archosaurs, crocodiles, and pterosaurs were very distinct in size and shape that they were so hard to tell apart. Archosaurs are thought to be descended from either the therapsids, which evolved around the Permian period, or if they were living around that time period and maintained their species for thousands of years. However, it is unsure whether they appeared during the triassic period because of the great extinction event that occured, which wiped out millions of species. Once these major dinosaur families were established, around the start of the Jurassic period, evolution continued to take its natural course. However, the pace of the dinosaur adaptation slowed down by a huge amount during the Cretaceous period. Dinosaurs started to develop more clearly, specific species would be more primitive and would start to develop various amounts of dinosaurs during the