Dinosaurs are a diverse staff of animals of the clade Dinosauria. They first appeared throughout the Triassic length, 231.4 million years in the past, and have been the dominant terrestrial vertebrates for 135 million years, from the beginning of the Jurassic (about 201 million years ago) until the end of the Cretaceous (66 million years in the past), when the Cretaceous–Paleogene extinction experience led to the extinction of most dinosaur groups on the close of the Mesozoic technology.
The fossil file signifies that birds advanced from theropod dinosaurs during the Jurassic length and, in consequence, they are considered a subgroup of dinosaurs via many paleontologists. Some birds survived the extinction adventure that came about 66 million years in the past, and their descendants continue the dinosaur lineage to the current day. Dinosaurs are a varied group of animals from taxonomic, morphological and ecological standpoints. Birds, at over 10,000 dwelling species, are probably the most various workforce of vertebrates along with perciform fish. the usage of fossil evidence, paleontologists have recognized over 500 distinctive genera and greater than 1,000 totally different species of non-avian dinosaurs. Dinosaurs are represented on every continent by each extant species and fossil is still. Some are herbivorous, others carnivorous. while dinosaurs were ancestrally bipedal, many extinct groups incorporated quadrupedal species, and a few have been able to shift between these stances. tricky show structures reminiscent of horns or crests are in style to all dinosaur teams, and a few extinct groups developed skeletal changes equivalent to bony armor and spines.