population scientist vs demographer

population scientist and demographer both are nouns.

Word	Noun	Adjective	Verb	Adverb
population scientist	Yes	No	No	No
demographer	Yes	No	No	No

As nouns, population scientist and demographer are synonyms defined as:

population scientist and demographer: a scientist who studies the growth and density of populations and their vital statistics

Other synonyms of population scientist include demographist.

population scientist (noun)	demographer (noun)
a scientist who studies the growth and density of populations and their vital statistics	a scientist who studies the growth and density of populations and their vital statistics