The dinosaurs disappeared because they could not adapt to their changing environment. We shall disappear if we cannot adapt to an environment that now contains spaceships, computers - and thermonuclear weapons.
Arthur C. Clarke. . . Moon-Watcher felt the first faint twinges of a new and potent emotion. It was a vague and diffuse sense of envy--of dissatisfaction with his life. He had no idea of its cause, still less of its cure; but discontent had come into his soul, and he had taken one small step toward humanity.
Arthur C. Clarke