We’re taught about the food chain but not taught there must be a balance. A symbiosis. My sister has a cat living on her property hunting mice. And I think “he must be a good hunter to catch the mice.” There is a symbiosis. If it were too easy for a cat to catch the mice, the mice would go extinct. Too hard, the cat would starve. Instead there’s a middle ground. Nature balances itself out naturally. The strong survive. But they don’t win every time. I don’t know where I’m going with this there are tons of scenarios. Maybe if a cat was particularly good at hunting he would get too fat and have to burn the pounds before he hunts again. So that’s another type of symbiosis. Poor mice though. They probably don’t ever die of old age. Even the sneakiest mouse slows down as he gets older and eventually gets caught by the cat. Hmm ya that’s all I got.
I too have thought about this…!
But also, not all mice are preys, not all cats can catch mouses, as not all humans know how to hunt to survive, but most humans know how to go to the supermarket. Is it natural, though? It sure is 
There are animal populations that follow a boom and bust cycle, sometimes due to predation. It’s a harsh way that nature preserves its balance. If the balance wasn’t preserved by predation it would be likely to be preserved by starvation and/or disease.
The next question is whether humans are to be considered part of this environment (if they die it’s not a symbiosis FYI). If humans are, we don’t need to care about the mass extinction our lifestyles cause. If we are something new and are making a conscious choice not to consume everything in our path… You should all be vegetarians like I am. Hahaha! 