One of the most influential scientists of the nineteenth century, Darwin is best known for establishing the theory of organic evolution by natural selection.

Darwin was born in Shrewsbury, England, the son of a respected physician. He was the grandson of the poet-physician Erasmus Darwin (1731-1802) and the porcelain manufacturer Josiah Wedgwood (1730-1795). At age 16, Darwin entered the University of Edinburgh in Scotland with the expectation of becoming a physician. While attending medical classes, however, he was unable to watch actual surgical procedures (often done without anesthesia), and so he was pressured by his family to consider the ministry. Darwin transferred to Christ's College at Cambridge three years later to study theology, but he discovered that he had no religious aspirations, either.

One positive outcome for Darwin during his years at Cambridge was having the opportunity to meet Adam Sedgwick (1785-1873), a professor who interested him in geology...