In fact, Alfred Russel Wallace, another British naturalist, was a co-discoverer of the theory — though Darwin has gotten most of the credit. Wallace died 100 years ago this year.

Wallace developed some of his most important ideas about natural selection during an eight-year expedition to what was then the Dutch East Indies — modern-day Indonesia — to observe wildlife and collect specimens. Few places on earth can rival this vast archipelago's tremendous diversity of plant and animal life.

Wallace collected more than 100,000 insect, bird and animal specimens, which he gave to British museums.

By 1855, Wallace had come to the conclusion that living things evolve. But he didn't figure out how until one night three years later. He was on the island of Halmahera, ill with a fever, when it came to him: Animals evolve by adapting to their environment.