Engels words on the difference between humans and animals:

"In short, the animal merely uses external nature, and brings about changes in it simply by his presence; man by his changes makes it serve his ends, masters it. This is the final, essential distinction between man and other animals, and once again it is labour that brings about this distinction."
Apart from the use of man/men instead of people/humanity which was the convention of the time this can be read as humanity domineering over nature. But Engels subsequently makes clear that unsustainable exploitation of nature will bring a "revenge":
"Thus at every step we are reminded that we by no means rule over nature like a conqueror over a foreign people, like someone standing outside nature - but that we, with flesh, blood, and brain, belong to nature, and exist in its midst, and that all our mastery of it consists in the fact that we have the advantage over all other beings of being able to know and correctly apply its laws." (Role Played by Labour in the Transition from Ape to Man, Engels 1883).
Engels' key insight is that it was the evolution of a mode of production out of the mode of being of animals that demarcated humanity from animals. Fire was probably instrumental in this but it was probably accompanied by other changes like adoption of permanent bases for sleeping, food storage, cooking and butchery (a "home" ), pair bonding instead of a primate mating system of dominant males and "harems", and an extended cho=ildhood supported by a co-operative community that constituted a "human revolution" rather than any gradual incremental transition of separate changes that took our species from the world of animals to that of humanity.