A heterotroph is any organism, including carnivores, omnivores and herbivores, that cannot produce its own food through solar energy and must feed off another life form. In the food chain, heterotrophs represent the consumers. The autotrophs, such as plants and algae, are called the producers of the food chain because of their ability to produce their food with no need to consume another organism.
All animals, including humans, are classified as heterotrophs because they consume other animals, plants or both in order to obtain the organic substances needed to sustain life. Fungi and some species of bacteria are also heterotrophs. Herbivores are considered the primary consumers in the food chain because they obtain their food directly from the autotrophs of the plant world. Heterotrophs represent about 95 percent of all living organisms.