environment vs ecology

environment and ecology both are nouns.

Word	Noun	Adjective	Verb	Adverb
environment	Yes	No	No	No
ecology	Yes	No	No	No

As nouns, ecology is a hyponym of environment; that is, ecology is a word with a more specific, narrower meaning than environment:

environment (noun)	ecology (noun)
the area in which something exists or lives	the branch of biology concerned with the relations between organisms and their environment
the totality of surrounding conditions	the environment as it relates to living organisms