All interesting issues in natural history are questions of relative frequency, not single examples. Everything happens once amidst the richness of nature. But when an unanticipated phenomenon occurs again and again—finally turning into an expectation—then theories are overturned.

Asian Homo erectus died without issue and does not enter our immediate ancestry (for we evolved from African populations); Neanderthal people were collateral cousins, perhaps already living in Europe while we emerged in Africa... In other words, we are an improbable and fragile entity, fortunately successful after precarious beginnings as a small population in Africa, not the predictable end result of a global tendency. We are a thing, an item of history, not an embodiment of general principles.

You put three facts together - that all organisms produce more offspring that can survive, that there's variation among organisms, and that at least some of that variation is inherited - and the syllogistic inference is natural selection.

A lot of scientists hate writing. Most scientists love being in the lab and doing the work and when the work is done, they are finished.

I am glad that the life of pandas is so dull by human standards, for our efforts at conservation have little moral value if we preserve creatures only as human ornaments; I shall be impressed when we show solicitude for warty toads and slithering worms.

Can I pay any higher tribute to a man [George Gaylord Simpson] than to state that his work both established a profession and sowed the seeds for its own revision? If Simpson had reached final truth, he either would have been a priest or would have chosen a dull profession. The history of life cannot be a dull profession.

The basic formulation, or bare-bones mechanics, of natural selection is a disarmingly simple argument, based on three undeniable facts (overproduction of offspring, variation, and heritability) and one syllogistic inference (natural selection, or the claim that organisms enjoying differential reproductive success will, on average, be those variants that are fortuitously better adapted to changing local environments, and that these variants will then pass their favored traits to offspring by inheritance).