Alfred Wallace

Alfred Russel Wallace was born in 1823.

 Wallace in 1848, aged 25

He was an English naturalist whose theory of natural selection was almost identical to Darwin's, (although Darwin got most of the credit for this as he had more evidence and had started working on the theory earlier).  Unlike Darwin, he could not accept that the human mind was the product of evolutionary processes.

Wallace in 1878, aged 55

On a visit to the Malay archipelago (1854-1862) he discovered that some islands had oriental fauna and other islands had  Australian fauna. He imagined a boundary between the two, known as Wallace's line, and published his findings in The Geographical Distribution of Animals in 1876. He also wrote a study of the distribution of living organisms, which is now called biogeography. 

Wallace in 1902, aged 80

He died in 1913.