Levels within the food chain characterized by similar energy consumption. A trophic level is a step in a food chain of an ecosystem. The organisms of a chain are classified based on their feeding behavior: 1) the producers, green plants; 2) the herbivores, or plant eaters; 3) primary carnivores, or meat eaters, which eat the herbivores; and 4) secondary carnivores which eat the primary carnivores.