Captain Robert FitzRoy had been ordered to chart the coasts of South America and wanted an educated companion who could study geology and natural history. Darwin, who had trained for the Church, joined as an unpaid gentleman naturalist. The voyage, planned for two years, lasted almost five. He collected fossils, plants and animals, and his observations in the Galápagos Islands in 1835 helped shape his later ideas. He published On the Origin of Species in 1859.
The Beagle's departure was delayed for weeks by storms and, on Christmas Day, by a crew that was too drunk to sail. It finally left its anchorage in Plymouth Sound on the morning of December 27, 1831. Darwin was seasick for much of the voyage and spent as much time as he could on land, riding across the Argentine pampas and climbing in the Andes, while the ship surveyed the coast.
He was struck by the fossils of giant extinct mammals he found in Argentina, which resembled living species, and by an earthquake in Chile that raised the land by several feet, supporting the geologist Charles Lyell's view that Earth had been shaped by slow, continuing processes. In the Galápagos, he noted differences between the mockingbirds of different islands, and was told that the local tortoises could be identified by island.
The Beagle returned to Falmouth on October 2, 1836. Darwin's journal of the voyage made his name as a writer. In 1837 he opened his first notebook on the "transmutation" of species, and in 1838 he formulated the idea of natural selection, although he did not publish it for two decades.
Key people: Charles Darwin, Robert FitzRoy