What is a heterotroph? – Definition & Examples
Heterotroph definition
A heterotroph is a living organism that eats other organisms for their energy source. Heterotrophic organisms are consumers in the ecosystem because they cannot manufacture their own food. Examples of heterotrophic organisms are humans, dung beetles, and hyenas.
The word “heterotroph” is a combination of two Greek words:
hetero, meaning “other.”
troph, meaning “nourishment” or “feeding.”
Types of heterotrophs
Most biologists name three types of heterotrophs: herbivores (plant eaters), carnivores and omnivores (meat-eaters and eaters of meat and plants), and detritivores (debris eaters).
Herbivores – Plant-eating heterotrophic organisms occupy the second tier of food chains; they feed on organic matter like living plants such as sedges, trees, grasses, flowering plants, and bushes
Carnivores and Omnivores – Carnivores eat meat, meaning they eat other heterotrophs; omnivores eat both plants and meat, and both types of heterotrophs occupy the third level of food chains.
Detritivores – Like herbivores, detritivores occupy the second level of food chains because they feed on decaying organic material such as dead plants and animal matter, and animal feces. You can think of these as the decomposers of an ecosystem.
The trophic level of an organism is determined by where it is positioned in a food web.
Heterotroph examples
You are surrounded by examples of heterotrophic organisms, which consume other organisms as their food source. If you examine any landscape or cityscape, anything living that is not a plant is probably a heterotroph. Here are just a few examples for each of the three types:
Herbivores – Cows, elk, goats, buffalo, zebras, parrots, elephants, sheep, squirrels, deer, mice, moose, chipmunks, manatees, yak, kangaroos, swans, and honeybees
Carnivores – Lions, tigers, seals, great white sharks, penguins, polar bears, hawks, eagles, walruses, spiders, toothed whales, octopuses, snakes, frogs, herons, vultures, and coyotes
Omnivores – Aardvarks, humans, emus, piranhas, hedgehogs, brown bears, flies, black bears, pigs, raccoons, wasps, galagos, toucans, all great apes (gorillas, orangutans, chimpanzees, and bonobos), box turtles, and jerboas
Detritivores – Millipedes, fungi, earthworms, springtails, bacteria, woodlice, dung flies, slugs, sea stars, sea cucumbers, fiddler crabs, and polychaeta worms
Herbivores are known as primary consumers.
Two of the simplest heterotrophs are also among the most numerous living organisms on the planet:
Bacteria – Bacteria (except blue-green bacteria, which are autotrophs) are microscopic heterotrophs that make up around 13 percent of the earth’s biomass
Fungi – Fungi (mushrooms and toadstools), yeasts, and molds are heterotrophs that make up around two percent of the earth’s biomass and are their own kingdom of life
By contrast, heterotrophic humans make up only about one ten-thousandth of one percent of earth’s biomass.
Autotrophs and heterotrophs
Heterotrophs contrast with autotrophs. Autotrophic organisms are living organisms that can manufacture their own nourishment from their environment.
A leafy grass plant takes in sunlight, carbon dioxide, trace minerals from the soil, and water to produce plant sugars it uses for energy. The plant consumes sunlight and, through photosynthesis, creates its own food. A leafy grass plant is an autotroph.
If a field mouse eats the leafy grass blade, it consumes the stored chemical energy in the grass blade and uses it to sustain its life. The mouse is a heterotroph.
Heterotrophs quiz
See if you have a solid understanding of heterotrophs by answering these questions.
What does the word “heterotroph” mean?
If a living organism is not a heterotroph, what must it be?
Please name the three types of heterotrophs.
Which levels of a food chain do heterotrophs occupy?
Please give three examples of heterotrophs that are not mammals.
Regarding intake of nourishment, how would you classify humans and great apes?
Please give an example of a heterotroph that has no arms, legs, or brain.
See how your answers stack up against our answers below.
The word “heterotroph” means “other nourishment,” as in a living organism that must get its nourishment by consuming other living organisms.
If a living thing is not a heterotroph, it must be an autotroph or self-nourishing organism (like a tree, flowering plant, grass, sedge, or bush).
The three types of heterotrophs are herbivores, omnivores and carnivores, and detritivores.
Heterotrophs occupy the second and third levels of food chains, feeding on autotrophs (second level) or feeding on autotrophs and other heterotrophs (third level).
Three examples of heterotrophs that are not mammals are the great white shark, a red hawk, and a millipede.
Regarding intake of nourishment, humans and great apes are heterotrophs in the omnivore category.
A heterotroph with no arms, legs, or brain could be a mushroom, toadstool, or bacterium.