Abstract: | To condense the evolution of life on Earth . . . suppose the whole history of the planet is contained within a single year. The conditions suitable for life do not develop until late June. The oldest known fossils are living creatures around mid-October, and life is abundant . . . by the end of that month. In mid-December, dinosaurs and other reptiles dominate the scene. Mammals . . . appear in large numbers only a little before Christmas. On New Year's Eve, at about five minutes to midnight, man emerges. . . . The period since 1600 A.D., when man-induced extinction began to increase rapidly, amounts to three seconds, and the quarter century just begun, when the disappearance of species may be on the scale of all the mass extinctions of the past put together, will take another sixth of a second-a twinkling of an eye in evolutionary time. |