While he's most famous for his contributions to evolutionary biology, Darwin's work encompassed a broader range of scientific interests. He was also:

* A geologist: He studied the geological formations of the Galapagos Islands and South America, which helped shape his thinking about evolution.

* A biologist: He studied the diversity of life, particularly the variations he observed in plants and animals across different environments.

* An anthropologist: He was interested in the origins and evolution of humans.

In essence, Darwin was a polymath, a person who has expertise in many different areas of study. His broad interests allowed him to synthesize information from different fields and develop his groundbreaking theory of evolution by natural selection.