Charles Darwin, English naturalist, c 1860s.

Engraving by C H Jeens of Charles Darwin (1809-1882), a British naturalist and the originator of evolutionary theory, was employed as a naturalist on HMS Beagle from 1831 to 1836. He first made his name as a geologist, but is remembered for his momentous contributions to biology. His most famous work, 'The Origin of Species by Means of Natural Selection', was published in 1859.