Question

Approximately how long ago did the first dinosaur appear on earth?

Answer 1

Dinosaurs appeared around 243 and 233 million years ago. On the basis of taxonomy and morphology, it is observed that dinosaurs are extremely diverse. Dinosaurs form an integral part of clade Dinosauria.

Complete answer:
The dinosaurs were primarily dominant in the Jurassic and Cretaceous periods. Dinosaurs evolved around 243 and 233.23 million years ago (during the Triassic period). From the fossil evidence it is concluded that the birds are modern feathered dinosaurs. It can also be concluded from the fossil fuels that birds evolved during the Late Jurassic epoch. On the basis of fossil evidence dinosaurs can be categorized into two types:

1)Avian Dinosaurs – These dinosaurs were capable of flying.
2)Non-Avian Dinosaurs- These dinosaurs were not capable of flying.

Around 1000 species of non-avian dinosaurs have been identified from the fossil remains.
Every continent has the remains of dinosaurs in the form of extant species (birds) and fossil remains. Earlier (in the early 1990s), it was believed that the dinosaurs were sluggish and cold-blooded. At the late 1990s, it was proved that dinosaurs were active and had elevated metabolisms and some of them were herbivorous and others were carnivorous. From the fossil evidence it was found that all the dinosaurs were oviparous (egg-laying). The characteristic of nest-building was also shown by both avian and non-avian dinosaurs.

Note: From the fossil evidence it was observed that some dinosaurs had feathers (or feather- like body covering). It was also found that many of the dinosaurs didn’t fly and didn’t even glide. The characteristic of nest-building was also shown by both avian and non-avian dinosaurs.