At Cambridge University, Darwin formed a friendship with J. S. Henslow, a professor of botany, and that association, along with his enthusiasm for collecting beetles, led to “a burning zeal,” as he wrote in his Autobiography, for the natural sciences. When Henslow obtained for him the post of naturalist on H.M.S. Beagle, the course of his life was fixed. The five-year-long voyage to the Southern Hemisphere between 1831 and 1836 would lay the foundation for his ideas about evolution and natural selection. Upon his return Darwin lived in London before retiring to his residence at Down, a secluded village…