naturalist

Short definition from Wiktionary

Noun

1. 1
   A natural philosopher; a scientist.
2. 2
   A person who believes in or advocates the tenets of philosophical or methodological naturalism.
3. 3
   An expert in natural history or the study of plants and animals.
4. 4
   A creative artist who attempts to faithfully represent nature; an adherent of artistic naturalism.

Adjective

1. 1
   Synonym of naturalistic.