Loss of biodiversity (i.e. individual species dying out) makes the entire system less stable, since remaining species are less adapted to the environment. In the extreme, even if the individuals of a species, e.g. a particular breed of ant are displaced by another species, the system moves closer to a monoculture, which is prone to population shocks and other chaotic behavior.
Ultimately, all of Earth's ecosystems are connected through a vastly complicated food web. Even us. We've been blowing holes in that food web, roasting it, setting it fire, chopping off limbs, eradicating the places where it grows, etc.
This is actually very, very bad.
Asking questions is fine! It's great. It's how we learn. But cavalier comments like the OP are downvoted not because they are asking serious questions, but for stinking of militant ignorance.