The phenomenon I chose was the Mono Lake ecosystem. The agents are algae, brine shrimp, brine flies, and migrating birds. The environment is Mono Lake, which is a large, shallow saline soda lake. In Mono Lake, the growth of algae is dependent on the salinity of the lake and the weather. The growth of algae affects the populations of brine shrimp and brine flies. The population sizes of the shrimp and flies determines whether the migrating birds will have enough to eat and reproduce. If there are too many migrating birds, they will deplete the populations of shrimp and flies, and the algae will overtake the lake. On the other hand, if there are not enough migrating birds, the shrimp and flies will overpopulate and wipe out the algae.