Name the naturalist who travelled on HMS Beagle from 1831 to 1836.

The naturalist who traveled on HMS Beagle from 1831 to 1836 was Charles Darwin. During this voyage, he made extensive observations and collected a significant amount of data from various locations, including the Galápagos Islands. His findings on the diversity of species and their adaptations to different environments significantly contributed to his formulation of the theory of evolution by natural selection. The Beagle's journey allowed him to gather evidence that would later challenge prevailing scientific views of his time and lay the groundwork for modern evolutionary biology.

While Alfred Russel Wallace was also a key figure in the development of evolutionary theory, his major contributions occurred after Darwin's voyage and were based on his own explorations. Joseph Banks was an earlier explorer and naturalist who traveled with Captain Cook, and Edward Blyth was a naturalist known for his work in zoology but did not partake in the Beagle expedition. These individuals made important contributions to science, but they were not involved in the specific voyage that defined Darwin’s career and the theory of evolution.