Narrator: This is Science Today. What if 75 percent of all animal species on Earth disappeared? It could be a reality sooner than you think. Scientists at the University of California, Berkeley, are predicting that, due to human activities, such an extinction could occur in as little as 300 years.
Barnosky: That's dramatically very much faster than we can say most of these past mass extinctions took place in.
Narrator: Paleobiologist Anthony Barnosky says that a mass extinction would have grave effects on humans, as well as other animals.
Barnosky: We do get certain things back from other species. For example, our very important medicine. Some of our most needed heart medications come from wild species.
Narrator: According to Barnosky, there's still hope. Since people have created this crisis, we also have the power to reverse it.
Barnosky: But we still have a long way to go in order to get public awareness up to the level where these grassroots movement that our policy leaders will start listening to actually solve the problem.
Narrator: For Science Today, I'm Larissa Branin.