A consumer in a

food chain A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...

is a living creature that eats organisms from a different population. A consumer is a

heterotroph A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

and a producer is an

autotroph An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Works", ...

. Like sea angels, they take in organic moles by consuming other organisms, so they are commonly called consumers. Heterotrophs can be classified by what they usually eat as herbivores, carnivores, omnivores, or decomposers. On the other hand, autotrophs are organisms that use energy directly from the sun or from chemical bonds. Autotrophs are vital to all

ecosystem An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...

s because all organisms need organic molecules, and only autotrophs can produce them from inorganic compounds. Autotrophs are classified as either photoautotrophs (which get energy from the sun, like plants) or chemoautotrophs (which get energy from chemical bonds, like certain bacteria). Consumers are typically viewed as predatory animals such as meat-eaters. However, herbivorous animals and parasitic fungi are also consumers. To be a consumer, an organism does not necessarily need to be carnivorous; it could only eat plants (producers), in which case it would be located in the first level of the food chain above the producers. Some carnivorous plants, like the

Venus flytrap The Venus flytrap (''Dionaea muscipula'') is a carnivorous plant native to subtropical wetlands on the East Coast of the United States in North Carolina and South Carolina. It catches its prey—chiefly insects and arachnids—with a trapping ...

, are classified as both a producer and a consumer. Consumers are therefore anything that eats; hence the word ''consume'' which means to eat.

Levels of the food chain

Within an ecological food chain, consumers are categorized into primary consumers, secondary consumers, and tertiary consumers. * Primary consumers are

herbivores A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

, feeding on plants. Caterpillars, insects, grasshoppers, termites and hummingbirds are all examples of primary consumers because they only eat autotrophs (plants). There are certain primary consumers that are called specialists because they only eat one type of producers. An example is the koala, because it feeds only on eucalyptus leaves. Primary consumers that feed on many kinds of plants are called generalists. * Secondary consumers are

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

s that prey on herbivorous animals.

Omnivores An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...

, which feed on both plants and animals, can be considered as being both primary and secondary consumers. * Tertiary consumers, which are sometimes also known as

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...

s, are

hypercarnivorous A hypercarnivore is an animal which has a diet that is more than 70% meat, either via active predation or by scavenging. The remaining non-meat diet may consist of non-animal foods such as fungi, fruits or other plant material. Some extant exampl ...

or omnivorous animals usually at the top of food chains, capable of feeding on both secondary consumers and primary consumers. Tertiary consumers are usually the largest, strongest and most aggressive animal in the local environment. Both secondary and tertiary consumers must

hunt Hunting is the human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/ hide, bone/tusks, horn/antler, et ...

for their food, so they are collectively referred to as predators.

Human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

s are an example of a tertiary consumer.

Importance to the ecosystem

In an ecosystem, energy is transferred from level to another as food. A balance in these transfers is vital to the health and stability of an ecosystem. Consumers balance the food chain in an ecosystem by keeping plant populations at a reasonable number. Without proper balance, an ecosystem can collapse and cause the decline of all affected species. This will lead to a severely disrupted ecosystem and a nonfunctional consumer web. In addition, there will be a change in climate, which can further worsen the ecosystem and affect the air quality and water.

References

{{modelling ecosystems Trophic ecology

Levels of the food chain

Importance to the ecosystem

See also

References