Final answer:
Charles Darwin joined the HMS Beagle as a naturalist for a five-year voyage that significantly contributed to his theory of evolution by means of natural selection, with key observations made on the Galápagos Islands.
Step-by-step explanation:
The Naval Ship of Charles Darwin's Voyage
The naval ship that Charles Darwin was invited to join on its long voyage around the world was the HMS Beagle. In 1831, Darwin embarked on this historic, five-year scientific expedition as the ship's naturalist. During this voyage, Darwin collected an immense amount of data and biological specimens, and made keen observations, particularly on the Galápagos Islands. These observations of flora and fauna would eventually contribute significantly to his development of the theory of evolution by means of natural selection. Given the meticulous research and data he gathered, Darwin's journey on the HMS Beagle is considered pivotal to the study of biology and natural history.