Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene extinction event, 66 million years ago, was a sudden mass extinction of three-quarters of the plant and animal species on Earth. With the exception of some ectothermic species such as the sea turtles and crocodilians, no tetrapods weighing more than 25 kilograms survived. The surviving group of dinosaurs were avians, ground and water fowl who radiated into all...