Can an American please explain to me, what the difference is between the noun {Segh} and the noun {mut}?

According to Ca'Non:

Segh (n) "race (type, sort, class)"

mut (n) "species"

In science fiction movies/series I've heard both "the survival of the human race" and "the survival of the human species", so I can't understand what's the difference between these two.

Does an American "feel" any difference between these two words? And I ask for the opinion of Americans, because 'oqranD is an American too, so I'm trying to understand what he means by each of these two words.