Wolves were reintroduced to Yellowstone National Park in 1995. They began to hunt the abundant elk population, so elk numbers decreased. The elk carcasses provided food for other predators, like foxes, coyotes, and bears, so all of their populations increased. Elk used to overgraze on willow plants; now that willows are growing back, beaver numbers are increasing, because they prefer the slow-moving water that willows cause.

Question

Which of these species is a keystone species?

(1 point)
Responses

elk
elk

willows
willows

bears
bears

wolves
wolves
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Answer 1

The correct response is:

wolves

Wolves are considered a keystone species because their predation on elk helps to regulate the elk population, which in turn affects the entire ecosystem, including plant life and other animal species. The removal of wolves from an ecosystem can lead to overpopulation of herbivores like elk, resulting in negative impacts on vegetation and other species.