During the 1980s, wolves were reintroduced to Yellowstone National Park after decades of absence due to attempted extermination in the early part of the twentieth century. Within 20 years, not only had the wolf population increased, but there was also a dramatic increase in other species, such as aspen, cottonwood, and willow trees, beavers, warblers, insects, and fish. These changes in Yellowstone Park are examples of how important a(n) ________ can be to an ecosystem.
A) keystone species
B) competitor
C) herbivore
D) parasite

Question

Quizplus · Accepted Answer

A keystone species is a species that has a disproportionately large effect on its environment relative to its abundance. In the case of Yellowstone National Park, the wolves were a keystone species because their reintroduction led to a cascade of ecological impacts that affected multiple other species in the ecosystem. The wolves helped to control the populations of herbivores like elk, which in turn allowed vegetation to recover and support more diverse communities of plants and animals. This is a classic example of how a keystone species can be crucial to maintaining the functioning and biodiversity of an ecosystem.

During the 1980s, Wolves Were Reintroduced to Yellowstone National Park