25 Keystone predators function as biological linchpins—without them, ecosystems will plunge into chaos. (A) Without the major function of predators, ecosystems will malfunction gradually. (B) Powerful predators function properly with the hope of maintaining the stability of ecosystems. (C) Ecosystems will be properly maintained if major predators no longer function. (D) Major predators are key players in maintaining the order of ecosystems.