Trophic Levels A food chain follows one path of energy and materials between species. A food web is more complex and is a whole system of connected food chains. In a food web, organisms are placed into different trophic levels. Trophic levels include different categories of organisms such as producers, consumers, and decomposers. Producers are the basic trophic level while top predators are the peak level. Producers are autotrophs, meaning they produce their own food through photosynthesis or chemosynthesis. Consumers are animals that eat producers and are split into many different categories: primary consumers, secondary consumers, tertiary consumers, and more. Primary consumers are plant-eating herbivores; secondary consumers eat the herbivores; tertiary consumers can consume both the primary and secondary consumers. There may be more levels of consumers until eventually the top predator is reached. The relationship between trophic levels (e.g. primary producers, herbivores, primary predators, and top predators) is shown in Figure 1. It is important to note that consumers can be carnivores, animals that eat other animals, and also omnivores, animals that consume many types of food. Decomposers are also part of the food web and include organisms that feed on all varieties of dead plants and animals which are responsible for returning nutrients to the environment.