Twenty-two-year-old Charles Darwin boarded the Beagle, a sloop captained by one Robert Fitzroy, an amateur naturalist and a prospective parson. The expedition was to last two years, though it ended up lasting five, taking the Beagle and its crew across the Atlantic, around the coasts of South America, and eventually around the Earth. The main objective of the voyage was to conduct hydrographic surveys, but it was the ship’s young “gentleman naturalist”, hired almost as an afterthought, who cemented the trip’s place in history.
The Beagle set sail from Plymouth on December 27, 1831. Darwin was ill-suited for life at sea, commenting that “the misery I endured from seasickness is far beyond what I ever guessed”; luckily, he spent much of his time exploring and theorizing on land rather than sailing at sea. In Punta Alta, Argentina, Darwin discovered giant fossils of extinct mammals. On an island near Chile, he witnessed a volcano and earthquake that levelled cities and altered the coastline. In 1835 he arrived at the Galápagos Islands where he briefly observed his famous finches without bothering to label and categorize them properly. On the islands he noted that “by far the most remarkable feature in the natural history of this archipelago” was “that the different islands to a considerable extent are inhabited by a different set of beings”.
By the time he returned to England, Darwin had established his reputation as a respected up-and-coming geologist among the country’s elite scientific circles. In the years following his return, Darwin wrote extensively on his five-year journey. Between 1838 and 1843 The Zoology of the Voyage of H.M.S. Beagle, a book Darwin edited, was published in five different parts, and in 1839 he published The Voyage of the Beagle. Neither work directly addressed evolution or natural selection, although Darwin was most certainly formulating his theories by that time, and in fact he may have been pondering the idea during the voyage. Although it would take years of further research, when he finally published his 1859 work On the Origin of Species, which presented his theory of evolution by natural selection, Darwin conceded in the introduction that his travels with the Beagle played a key role in formulating the theory:
WHEN on board H.M.S. ‘Beagle,’ as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries, as it has been called by one of our greatest philosophers.