Figure 7.14

GEO-GRAPHIC: The gray wolf as a keystone species in Yellowstone National Park.

(Clockwise from top left: © Jim Kruger/E+/Getty Images; © Tania Thomson/Shutterstock.com; Ken M Johns/Photo Researchers/Getty Images; National Park Service, Yellostone National Park; © William H. Mullins/Photo Researchers/Getty Images)