Page "Natural selection" Paragraph 7

If the traits that give these individuals a reproductive advantage are also heritable, that is, passed from parent to child, then there will be a slightly higher proportion of fast rabbits or efficient algae in the next generation.

This is known as differential reproduction.

Even if the reproductive advantage is very slight, over many generations any heritable advantage will become dominant in the population.

In this way the natural environment of an organism " selects " for traits that confer a reproductive advantage, causing gradual changes or evolution of life.

This effect was first described and named by Charles Darwin.