“I think it inevitably follows, that as new species in the course of time are formed through natural selection, others will become rarer and rarer, and finally extinct. The forms which stand in closest competition with those undergoing modification and improvement will naturally suffer most.”

“Natural Selection almost inevitably causes much Extinction of the less improved forms of life and induces what I have called Divergence of Character.”

“I am fully convinced that species are not immutable; but that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that natural selection has been the most important, but not the exclusive, means of modification.”

“When faced with a radical crisis, when the old way of being in the world, of interacting with each other and with the realm of nature doesn't work anymore, when survival is threatened by seemingly insurmountable problems, an individual life-form -- or a species -- will either die or become extinct or rise above the limitations of its condition through an evolutionary leap.”

“Of the four billion life forms which have existed on this planet, three billion, nine hundred and sixty million are now extinct. We don't know why. Some by wanton extinction, some through natural catastrophe, some destroyed by meteorites and asteroids. In the light of these mass extinctions it really does seem unreasonable to suppose that Homo sapiens should be exempt. Our species will have been one of the shortest-lived of all, a mere blink, you may say, in the eye of time.”

“Wickedness is too common in the world for us to think much of why and wherefore.It is more natural to ask about the rarer thingand wonder why people sometimes do good.”