68K views · 542 reactions | What happens when you lose a keystone species, like sea otters or kelp? Find out in "Extinction: The Facts,” now streaming on the PBS Video app. | PBS | Facebook

7.9K views · 176 reactions | Wolves are considered a “keystone species,” which means they have an invaluable impact on the overall health of an ecosystem. Wolves control prey species populations to such an extent that they create both floral and faunal biodiversity ranging from the largest of predators to the smallest of plant species.  Kelsey Lotz | Lincoln Park Zoo | Facebook