animal vs organism

animal and organism both are nouns.

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

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

animal: a living organism characterized by voluntary movement
organism: a living thing that has (or can develop) the ability to act or function independently

Other hypernyms of animal include being.

animal (noun)	organism (noun)
a living organism characterized by voluntary movement	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

animal (adjective)	organism (adjective)
marked by the appetites and passions of the body