Examples of predation?

Cats preying on Stephen's Island Wren.  Led to extinction of the poor bird.

The relationship of predator and prey causes evolution between both types of organisms. The prey adapts over time to better escape the predator. The predator adapts over time to better catch potential prey. So, no natural predation would cause a large drop in the amount of prey. If it did its prey would become extinct over time. The only type of predation I can think of that would cause a large drop in prey, would be the type that introduces an exotic (foreign) species to an area. The exotic animal would be able to cause a large drop in potential prey because it could have several adaptations that would enable to catch its prey.

there are tons of examples. Just google the phrase exotic species, or invasive species, or introduced species.

some examples off the top of my head are toads introduced to Australia andd pythons introduced to Florida