dinosaurs

dinosaurs are a diverse group of animals that were the dominant terrestrial vertebrates for over 160 million years from the late  triassic period (about 230 million years ago) until the end of the  cretaceous (about 65 million years ago) when the cretaceous -paleogene extinction  event led to the extinction of the most dinosaur species at the close of the mesozoic era the fossil record indicates that bird evolved within theropod dinosaurs some of them survived the cretaceous-paleogene extinction event including the ancestors of all modern birds