Summary
Heterotrophs that obtain energy by eating other organisms: primary, secondary and tertiary consumers.
In depth
Herbivores eat plants, carnivores eat animals, omnivores both, and detritivores eat dead organic matter. Primary consumers are herbivores; secondary consumers eat them; tertiary eat secondary.
Feeding mode influences gut length, teeth and behaviour. Omnivores link food chains. Parasites, though small, can account for large biomass in some webs.
Example: the grazing herbivore guild of the Serengeti.
Consumers are classified by diet, and organisms may shift between categories. Primary consumers have gut adaptations: ruminants have multi-chambered stomachs with microbes digesting cellulose, while carnivores have sharp teeth and short guts. Apex predators have few natural enemies and regulate food webs. Filter feeders like baleen whales and bivalves consume plankton.
Parasites and parasitoids are also consumers. In biomass terms, consumers are far smaller than producers, which reflects energy loss between levels. Selective feeding by herbivores influences plant community composition.
Remember: a tertiary consumer is not necessarily a top predator, and the same species can be a secondary consumer in one chain and a tertiary in another.
Frequently asked questions
What is Consumers?
Heterotrophs that obtain energy by eating other organisms: primary, secondary and tertiary consumers.
Which area of biology covers Consumers, and how advanced is it?
Consumers is one of the 54 topics in Ecology. It is rated Beginner, so it suits learners who are starting out in biology. Related topics in this area include Trophic Levels, Food Chain, Energy Pyramid.
Can you give an example of Consumers?
A vulture is a scavenger while an earthworm is a detritivore.
What should I learn before Consumers?
Consumers is a Beginner topic, so no earlier topic is required. Other Beginner topics in Ecology that pair well with it include Ecology, Ecosystem, Biotic and Abiotic Factors.
What topics are related to Consumers?
The closest topics to Consumers are Trophic Levels, Food Chain, Energy Pyramid, Primary Productivity. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Consumers?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Consumers. To practise the whole of Ecology, use the Ecology quiz.
How is Consumers different from Trophic Levels?
Consumers: Heterotrophs that obtain energy by eating other organisms: primary, secondary and tertiary consumers. Trophic Levels: The feeding position of an organism in a food chain, from producers upward. Read both side by side and note what each one explains.
How should I study Consumers step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Trophic Levels and explain the difference aloud. Finally, take the Ecology quiz and come back to this page for any question you miss.