What is the link between dinosaurs birds and reptiles?
Reptiles first evolved about 300 million years ago, and dinosaurs didn’t appear for another 50 million years. There are many types of reptiles. “Dinosaur” is actually a grouping which includes many types of only distantly-related reptile. The two major groups of dinosaur were the Ornithischia and the Saurischia. Within the Saurischia, there were other subdivisions: one of these was the Sauropod, which included most of the four-legged dinosaurs (like the diplodocus). Another group were the Theropods (most two-legged, carnivorous dinosaurs, like the T. rex) Archaeopteryx was an example of the theropod dinosaurs, and it evolved around 150 million years ago (100 million years *after* the age of the dinosaurs started). Though it is not thought to be a direct ancestor of the modern birds, it is an example of the kind of theropod dinosaur which is thought to have evolved into birds after the dinosaurs became extinct 65 million years ago. So reptiles evolved before dinosaurs did; dinosaurs of
