Details: This poster shows drawings of several different dinosaurs. At the top it says Dinosaurs . At the bottom it shows a timeline of when these species existed, and in which period (triassic, jurassic, creaceous).
Dinosaurs were the dominant vertebrate animals of terrestrial ecosystems for over 160 million years, from the late Triassic period (about 230 million years ago) until the end of the Cretaceous period (65 million years ago), when most of them became extinct in the Cretaceous-Tertiary extinction event. The 10000 living species of birds may be classified as dinosaurs. The term dinosaur was coined in 1842 by Sir Richard Owen and derives from Greek deinos terrible, powerful, wondrous sauros lizard . Since the first dinosaur fossils were recognized in the early nineteenth century, mounted dinosaur skeletons have become major attractions at museums around the world.