Homo erectus vs homo

Homo erectus and homo both are nouns.

Word	Noun	Adjective	Verb	Adverb
Homo erectus	Yes	No	No	No
homo	Yes	No	No	No

As nouns, homo is a hypernym of Homo erectus; that is, homo is a word with a broader meaning than Homo erectus:

Homo erectus: extinct species of primitive hominid with upright stature but small brain
homo: any living or extinct member of the family Hominidae characterized by superior intelligence, articulate speech, and erect carriage

Other hypernyms of Homo erectus include human, human being, man.

Homo erectus (noun)	homo (noun)
extinct species of primitive hominid with upright stature but small brain	any living or extinct member of the family Hominidae characterized by superior intelligence, articulate speech, and erect carriage
	someone who is sexually attracted to persons of the same sex