we are the cause of most species going extinct in the modern era.
natural extinction is longer drawn out process. even the extinction of the dinosaurs took a few thousand years.
and in that process they are frequently replaced, or the beginings of a replacement, by a new critter on the rise, or other critters filling in, or whatever equilibrium ends up being reached.
but therein lies the problem. not only are WE the cause, we are doing it far faster than nature can cope and adapt.
and we're not really an apex predator either. in nature if lions or wolves eat too many critters, they face starvation the next year, and their numbers drop. in the following cycle, now the prey multiplies. now with a surplus of food the predator numbers once again rebound. the cycle swings like this naturally every so often.
we, humans, no longer see or partake in that natual predator and pry boom/bust cycle.
if we wipe out all the fish in the sea, oh well, there's plenty of other stuff we can eat. in fact that's WHY we're not apex predators. we're omnivores, with very adaptable diets. but that omnivorous diet coupled with our ability to adapt and grow as a species (such that we're now the only sentient one here, and the single most numourous outside of insects and some fish) is even vastly different than other adaptable species. if we eat all the fish in the sea or some "local" area, for nearly concept or size of local, we barely feel it because we can ship in rice from asia, or corn from nebraska, or beef from australia.
we are so disconnected from the natural cycles that the comparison to apex predators is completely unjustified.