Charles Darwin (02/12/1809 - 04/19/1882)

Common Descent

1844

Charles Darwin was well known for his contribution to science in evolution, and his theory was that all species of life have come over time from common ancestors.

Gradualism

1849

Evolution is a much slower process, the rate at which it takes place is slow in small steps, but consistent over time, it suggests the world to be a lot older than the age geological theories claimed. the species that we see in present-day gradually evolved over millions of years and many generations.

Population Speciation

1856

This part of Darwin's theory states that in a population, changes in a species result from hereditary characteristics shift across that population.

Natural Selection

1858

The difference in genes is responsible for this variation.
Species that are more likely to survive, avoid predators, find food and resist diseases in an environment have characteristics best suited for that environment. They have higher chances to reproduce and pass their genes to their offspring. As a result, those species survive and with time they gradually evolve.

Citation

1859

Darwin, Charles, 1809-1882. On The Origin of Species by Means of Natural Selection, or Preservation of Favoured Races in the Struggle for Life. London: John Murray, 1859.