As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.

It strikes me that all our knowledge about the structure of our Earth is very much like what an old hen would know of the hundred-acre field in a corner of which she is scratching.

The formation of different languages and of distinct species and the proofs that both have been developed through a gradual process, are curiously parallel.

It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed.

When primeval man first used flint stones for any purpose, he would have accidentally splintered them, and would then have used the sharp fragments. From this step it would be a small one to break the flints on purpose and not a very wide step to fashion them rudely.

With mammals the male appears to win the female much more through the law of battle than through the display of his charms.

It's not the strongest, but the most adaptable that survive.