1831: HMS Beagle, a 10-gun, Cherokee-class brig sloop of the Royal Navy's survey service, sets sail from Plymouth, England on its second voyage as a survey vessel.

On board, at the invitation of the Beagle’s captain, Robert FitzRoy, is a young biologist called Charles Darwin. Darwin’s account of The Voyage of the Beagle, published in 1839, establishes him as one of the foremost naturalists of his time.

Darwin accepted the invitation over the objections of his father, who saw the proposed two-year voyage as a chance for his son to continue idling, something he had become pretty good at since graduating from Cambridge.

What became a five-year voyage was intended primarily to continue exploring the coastline of South America, many parts of which remained uncharted. Coasting in this fashion enabled Darwin to spend long periods of time ashore as the Beagle meandered around South America and the Galapagos Islands, taking depth soundings and charting coastlines. The ship also visited numerous islands in the South Pacific and Indian oceans before setting sail for home.

The young naturalist was fascinated by the seemingly endless variety of plant and animal life he encountered. His ruminations on the source of that variation resulted in his theory of evolution by natural selection, published in an 1858 paper and a year later in his paradigm-shaping The Origin of Species.

Darwin’s observations of other societies, particularly the natives of Tierra del Fuego, would also provide the basis for The Descent of Man, in which Darwin further elaborates on natural selection. It was published in 1871, four decades after the start of the voyage.

The Beagle finally returned to England, reaching Falmouth on Oct. 2, 1836. She would undertake a third survey voyage to Australia, then see duty as a coast-guard watch vessel before being laid up. The Beagle was broken up in 1870.

(Source: AboutDarwin.com)