Ultimately, the source of energy for all life originates from the sun. Plants utilize the sun's energy, animals eat plants and utilize the plants' energy, and some animals eat other animals and utilize their energy. The food chain is a cycle of predation, and although it is necessary for life to exist, it has to have limits. Prey develop defenses against their predators, and predators strive to overcome such obstacles. The balance between survival of prey and predator is part of the reason that our ecosystem is so diverse.
