Is professor supposed to be capitalized?

... only if it precedes a person's name

Explanation:

My professor told me to stop cheating.

Professor Smith is an army veteran.

one of the central themes of edward abbey's work has been his staunch opposition to the glen canyon dam on the colorado river that created lake powell, destroying stunning scenery and wildlife habitat, endangering many rare species of fish and animals, and also irreparably destroying many important archaeological sites which provided information about the early inhabitants of the united states.