Charles Darwin was only 22 years old in 1831 when he sailed as ship's naturalist on the H.M.S. Beagle on what would turn out to be a five-year voyage circumnavigating the globe. A hunter and specimen collector (he especially liked rocks and minerals—and beetles), Darwin was an all-around outdoorsman. He had not especially liked school, though by the time he left England on the Beagle he had taken the botany course taught by Prof. John Stevens Henslow at Cambridge University three times. He had also profited from a short excursion to learn the rudiments of field geology from Prof. Adam Sedgwick only a few months earlier. But Darwin was far from a highly trained or seasoned scientist.

In those early days of professional science in England, many believed that the idea of "transmutation" was false and anti-religious. Transmutation was the contemporary term for what we now call "evolution," or the idea that all species now and formerly alive are descended from a single common ancestor that lived in the remote geological past. The concept was more widely accepted on the continent by scientists such as the well-known biologist Jean-Baptiste Lamarck and by Etienne Geoffroy, who worked at the natural history museum in Paris. In England, the tendency was still to reconcile the findings of natural history—primarily geology, paleontology, botany, and zoology—with a literal reading of the biblical account of creation. Thus, most people in England—scientists, clergy, and the public at large—were creationists. They believed that God had created each species separately, in more or less its present form, no more than 10,000 years ago.

But there were a few exceptions. Darwin's own grandfather, the successful physician Erasmus Darwin, wrote 

, a book on physiology and medicine that included evolutionary ideas. And when Darwin's father (also a physician) sent Darwin to Edinburgh to study medicine at the tender age of 16, Charles met the young zoologist Robert Grant, a devotee of Lamarck's evolutionary ideas and also a fan of Darwin's own grandfather. Years later, in his 

, Darwin wrote that he did not think that either his grandfather's or Grant's pro-evolutionary views had much "effect on my mind," though he conceded that the ideas of such important figures in his life must have meant something to him!

When Darwin set sail, then, as a Cambridge graduate and also a cautious and conservative young gentleman, he was a creationist, but one who had already heard arguments in favor of transmutation. It is difficult to tell precisely when he decided in favor of evolution, though it is certain that by the time he reached home in the fall of 1836, he was a convert. Several factors—what Darwin saw on the trip, how he reconciled his experiences with his onboard reading, and the intelligence and ambition of a young man anxious to make his mark in the scientific world—combined to lead him to the conclusion that the origin of new species could be explained by natural law.

Charles Darwin on October 26, 1831 10:21 PM

Yesterday I went on board the Beagle, found her moored to the Active hulk & in a state of bustle & confusion. -- The men were chiefly employed in painting the fore part & fitting up the Cabins. -- The last time I saw her on the 12th of October Sept. she was in the Dock yard & without her masts or bulkheads & looked more like a wreck than a vessel commissioned to go round the world. 

My own private corner looks so small that I cannot help fearing that many of my things must be left behind.

The first location on your tour will provide some background information on Darwin and his voyage that you will summarize from the article, “Young Naturalist”.

The Young Naturalist