mascot vs organism

mascot and organism both are nouns.

Word	Noun	Adjective	Verb	Adverb
mascot	Yes	No	No	No
organism	Yes	No	No	No

As nouns, organism is a hypernym of mascot; that is, organism is a word with a broader meaning than mascot:

mascot: a character, animal or object that is adopted by a team or group as a symbolic figure
organism: a living thing that has (or can develop) the ability to act or function independently

Other hypernyms of mascot include being.

mascot (noun)	organism (noun)
a character, animal or object that is adopted by a team or group as a symbolic figure	a living thing that has (or can develop) the ability to act or function independently
	a system considered analogous in structure or function to a living body