Dinosaurs
Dinosaurs are a diverse group of reptile species in the dinosaur genus. Although the exact origin and timing of the evolution of dinosaurs is the subject of active research, they first appeared between 243 and 233.23 million years during the Triassic. After the Triassic-Jurassic extinction 201.3 million years ago, they became powerful terrestrial vertebrates; Their dominance lasted throughout the Jurassic and Cretaceous eras. The fossil record shows that birds are the only surviving dinosaurs on Earth that evolved from feathered dinosaurs. During the last Jurassic period, birds evolved from earlier theropods, the only generation of dinosaurs to survive the extinction of Cretaceous-Paleogene about 66 million years ago. Therefore, dinosaurs can be divided into bird dinosaurs or birds. And extinct non-bird dinosaurs, which are all dinosaurs except birds. Because birds are dinosaurs and dinosaurs are reptiles, this makes birds reptiles, even though they are highly evolved and specialized.