On Dec. 27, 1831, naturalist Charles Darwin departed England on the British science expedition voyage of the “Beagle” around the world. For the next five years, Darwin served as the expedition’s naturalist, studied plants and animals, and collected specimens for further study.

Out of Darwin’s study grew his theory of evolutionary selection which holds that variation within species occurs randomly and that the survival or extinction of each organism is determined by that organism’s ability to adapt to its environment. Darwin’s theory of evolution remains the foundation of modern biology.