Grizzly bears are top carnivores in some North American ecosystems. What do you think might happen to a community of organisms if grizzly bears suddenly became extinct?

There would be an increase of the population of the prey that the Grizzly bears eat

This is true, but more specifically, the grizzly bear is probably the keystone species of this ecosystem. It's prey would not only increase in number, but probably takeover the environment without any natural predators. Food sources would disappear, and opposing organisms would die out