All About: Evolution by Natural Selection

The Basics

Charles Darwin came up with an assumption to explain evolution by natural selection. The theory of its action was first fully expounded by Charles Darwin and is now believed to be the main process that brings about evolution. The four postulates of Darwin explain how species are able to survive and adapt.


1. In all species there is heritable variation.

2. In every generation, more progeny (offspring) are produced than can survive.

3. Survival and reproduction of individuals is not random. Within given conditions, individuals with some phenotypes produce more offspring, find more mates and survive better. (Those individuals better suited to their environment survive long enough to reproduce.)

4. Some phenotypic variants are passed on to offspring. Thus, more fit phenotypes are better represented in the next generation. (Over time the species changes to reflect those traits better suited for survival.)

The Four Postulates

"It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change"

-Charles Darwin


"Introduction to Ecological Genetics." Darwin’s Four Postulates. Berkley. Web. 08 Apr. 2016.

Pujari, Saritha. "4 Main Theories of Evolution (explained with Diagram and Tables) | Biology." YourArticleLibrarycom The Next Generation Library. YourArticleLibrary, 2014. Web. 08 Apr. 2016.