Animals have genes for altruism, and those genes have been selected in the evolution of many creatures because of the advantage they confer for the continuing survival of the species.

I was aware of Darwin's views fourteen years before I adopted them and I have done so solely and entirely from an independent study of the plants themselves.[Letter to W.H. Harvey]

It is not always the magnitude of the differences observed between species that must determine specific distinctions, but the constant preservation of those differences in reproduction.

Science, as long as it limits itself to the descriptive study of the laws of nature, has no moral or ethical quality and this applies to the physical as well as the biological sciences.

To the question of whether sharing 96% of our genetic make-up with chimps makes us 96 percent chimp; we also share about 50% of our DNA with bananas - that does not make us half bananas!

Perhaps eggs are like neurons, which also are not replenished in adulthood: they know too much. Eggs must plan the party. Sperm need only to show up- wearing top hat and tails, of course.

Those who have dissected or inspected many [bodies] have at least learnt to doubt; while others who are ignorant of anatomy and do not take the trouble to attend it are in no doubt at all.

A grain in the balance will determine which individual shall live and which shall die - which variety or species shall increase in number, and which shall decrease, or finally become extinct.

Today, the theory of evolution is an accepted fact for everyone but a fundamentalist minority, whose objections are based not on reasoning but on doctrinaire adherence to religious principles.

Indeed, not all attacks—especially the bitter and ridiculing kind leveled at Darwin—are offered in good faith, but for practical purposes it is good policy to assume that they are.

The secrets of evolution are death and time—the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations.

The science of genetics is in a transition period, becoming an exact science just as the chemistry in the times of Lavoisier, who made the balance an indispensable implement in chemical research.

If you happen to be one of the people who has a split zygomaticus major muscle, where the lower part of it is tethered to the overlying skin, this will create a dimple in your cheek when you smile.

I am quite sure that our views on evolution would be very different had biologists studied genetics and natural selection before and not after most of them were convinced that evolution had occurred.

The embryological record is almost always abbreviated in accordance with the tendency of nature (to be explained on the principle of survival of the fittest) to attain her needs by the easiest means.