What was the original purpose of Charles Darwin's voyage on the H.M.S beagle

what was the original purpose of Charles Darwin's voyage on the H.M.S beagle and what was the ultimate significance of the voyage?

If you do the research, you will find a very large amount of historical material about how Darwin came to be on the Beagle. Capt. Fitzroy who commanded the Beagle wanted someone along to disprove current thoughts about species evolving. In addition, he wanted someone who could provide fresh meat for the crew, and Darwin was a very good shooter. Darwin was not his first choice but a relative backed out. Fitzroy's mission was to chart the coast of South America. . In addition, there was a high suicide rate among English Captains since they were a social class above the sailors and isolated from them during the voyage, so Fitzroy wanted someone of his own class to accompany him. Darwin paid to go on the voyage and brought his man servant. He shared quarters with Fitzroy.

In the end, Darwin's eyes were opened on the voyage as to the age of the earth, physical processes (he saw the effects of a huge earthquake that raised the level of the land), variation among organisms, isolation of species on islands, marine fossils on top of mountains, etc. and thought long and hard after the voyage on a possible mechanism for such observed changes....eventually coming up with his natural selection theory. He first published his findings on what he saw on the voyage and that established him as a leading naturalist of the time.