A Short History of Nearly Everything: 2.0

by Bill Bryson

Earth has seen five major extinction episodes in its time—the Ordovician, Devonian, Permian, Triassic, and Cretaceous, in that order—and many smaller ones. The Ordovician (440 million years ago) and Devonian (365 million) each wiped out about 80 to 85 percent of species. The Triassic (210 million years ago) and Cretaceous (65 million years) each wiped out 70 to 75 percent of species. But the real whopper was the Permian extinction of about 245 million years ago, which raised the curtain on the long age of the dinosaurs. In the Permian, at least 95 percent of animals known from the fossil record check out, never to return. Even about a third of insect species went—the only occasion on which they were lost en masse. It is as close as we have ever come to total obliteration.