An organism that cannot make its own food is called a heterotroph. All animals and species of fungi, along with some types of bacteria, are heterotrophs.
Decomposers, consumers and detritivores are all examples of heterotrophs. Decomposers get needed nutrients by breaking down decaying animals and plants or the waste products of other organisms. Some types of fungi and bacteria are classified as decomposers.
Consumers survive by eating other living things. Humans are consumers because they eat plants and animals. Detritivores feed on dead organisms and decaying matter, and what they leave behind is eaten by decomposers. Vultures feed on dead animals, so they are classified as detritivores. All three types of heterotrophs are important to their ecosystems.
Heterotrophs also rely on autotrophs for their survival. Autotrophs are organisms that have the ability to produce their own food. Some autotrophs use the energy generated by chemical reactions to produce food, while others use energy from the sun to convert carbon dioxide and water into sugar and oxygen.
If there were no autotrophs, many organisms would cease to exist. Herbivores, which are plant-eating organisms, would not have any food. Omnivores eat plants as well as animals, so there would be less available to them. Some decomposers feed on decaying plant matter. Without plants, there would not be as much food available to these organisms.