Illustration showing survival of the fittest concept

How Darwin changed the world

Charles Darwin put forward a theory of evolution by natural selection – but he was not the only person to come up with such an idea

In the mid-19th century, two natural historians independently developed almost identical theories. One, Charles Darwin, is remembered as the father of evolutionary thinking. The other, Alfred Russel Wallace, is much less well known.

Their shared insight was that living species were not fixed but were the product of a gradual process of change driven by natural selection: the survival and reproduction of organisms suited to their environment, at the expense of those less well suited. Natural variation in a population provided the raw material on which natural selection could act.

Darwin laid out his ideas in ‘On the Origin of Species by Means of Natural Selection’, possibly the most important scientific book ever published. Biology would never be the same again.

What is natural selection?

  • Organisms produce more offspring than survive to reproduce.
  • Their offspring vary slightly.
  • Characteristics can be passed on from generation to generation.
  • Those most suited to their environment survive at the expense of those less ‘fit’.

Lead image:

Illustration © Glen McBeth

Questions for discussion

  • How did Alfred Russel Wallace’s ideas differ from Darwin’s?
  • Why is Darwin so much better known than Wallace?

About this resource

This resource was first published in ‘Evolution’ in January 2007 and reviewed and updated in December 2014.

Ecology and environment, Genetics and genomics, History
Education levels:
16–19, Continuing professional development