For those collecting the various Charles Darwin issues in this (2009) the bicentenary of his birth, it is interesting to note this early issue commemorating the famous scientist. This 20c. stamp was issued by Ecuador in 1936.

Charles R. Darwin (1809-1882) was born in Shrewsbury, grandson of Erasmus Darwin, student of Divinity and then of Medicine in Edinburgh. Darwin travelled widely and it was on the hundredth anniversary of his visit to the Galapagos Islands that Ecuador issued the stamp bearing his portrait.
stamp-ecuador-1936-darwin
Universally known for his theory of Evolution and many scientific works including The Voyage of the Beagle, The Origin of the Species, and The Descent of Man.

Charles Darwin

Charles Darwin c. 1854