What is a Food Chain (with Examples)

The food chain is the sequence by which living things obtain food from each other in the ecosystem. It is also known as a food chain or food pyramid.

The function of the food chain is to transfer energy from one living being to another through food. For example, grass gets energy from sunlight and nutrients from the soil. Antelopes eat grass and lions eat antelopes. Finally, the bacteria decompose the remains of all living things, providing nutrients to the grass. Thus the energy transfer cycle that we call the food chain is completed.

The importance of the food chain lies in the fact that it guarantees the survival of the species and perpetuates the balance in nature. Unfortunately, practices such as the indiscriminate hunting of animals, the contamination of water, air and soil are factors that put the food chain and the survival of certain species at risk.

The word trophic comes from the Greek trophos (τροφός), which means ‘food’.

Elements of the food chain

The elements of the food chain are: producers, consumers and decomposers.

Producers. They are living beings capable of producing their own food.

Consumers. They are the ones that feed on other living beings. They can be herbivorous (eating plant products), carnivorous (meat-eating) or omnivorous (meat and vegetable-eating) individuals. They usually feed by predation, parasitism, commensalism, and mutualism.

  • Predation: It consists of consuming living beings directly. Includes hunting or feeding from vegetables. For example, a fox hunting a rabbit.
  • Parasitism: It consists of benefiting from another living being causing harm, but without killing it. For example, mosquitoes that bite people or animals.
  • Commensalism: It consists of obtaining food and transport from another living being without benefiting or harming it. For example, herons prey on insects attracted to hoofed animals.
  • Mutualism: It consists of reciprocity between two organisms. For example, the boqui toad lives in the burrows of certain types of tarantulas, who protect it in exchange for eating the parasites that kill their eggs.
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Decomposers. They are the living beings that are in charge of degrading and decomposing the residues of organic matter into chemical compounds.

food chain

trophic pyramid

There are five levels in the trophic pyramid. Each of the elements of the chain (producers, consumers and decomposers) are located at a different level, depending on the order in the feeding sequence. Level one is occupied by producers, intermediate levels are occupied by consumers, and the last level is occupied by decomposers.

Level 1: Producers

food chain

Primary producers are the first link in the chain. These are living beings that generate their own food, that is, they are living beings autotrophssuch as plants and prokaryotes. These living beings do not depend on others for energy.

Plants get their food from sunlight in a process called photosynthesis. Prokaryotic organisms obtain their food from mineral chemical reactions, called chemosynthesis.

Level 2: Primary consumers

food chain

Primary consumers represent the second level or link in the chain. They are the living beings that feed on the producers. Therefore, primary consumers are herbivores, since they feed on plants, vegetables and fruits.

For example, cows, rabbits, goats, elephants, horses, llamas, deer, or koalas. We can also count certain types of insects, such as bees, grasshoppers, and caterpillars.

Level 3: Secondary consumers

food chain

Secondary consumers are the third level of the chain. It brings together living beings that feed on primary consumers (hervivores) and that are exposed to being consumed by others. Secondary consumers are usually carnivorous. For example, snakes, spiders, eagles, mongooses, penguins, and seals.

However, there are omnivorous living beings (that eat plants and animals) that participate at the level of primary and secondary consumers at the same time. For example, pigs, chickens, mice, possums, and humans.

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Level 4: Tertiary consumers

food chain

Third-party consumers represent the fourth level of the chain. They are living things that feed on secondary consumers.

They are usually the final consumers and therefore at the top of the food chain. In other words, nobody eats them. Consequently, the control of its population depends on the available food.

For example, sharks, whales, dolphins, lions, tigers, bears, boas, birds of prey, herons, etc.

Level 5: Decomposers

food chain

Decomposers are the fifth and last level or link in the food chain. They are defined as those living beings that decompose the dead residues of plants and animals and transform them back into organic matter. At this level are bacteria and fungi. Decomposing living beings play a very important role, thanks to the fact that the organic matter produced will then be absorbed by plants through the earth, perpetuating the cycle of life.

types of food chain

Food chains can be of two fundamental types or groups according to their habitat: terrestrial food chain and aquatic food chain.

We must remember that all the remains left by living beings on levels 1, 2, 3 and 4 are degraded, decomposed and converted into organic matter by bacteria.

terrestrial food chain

They are the feeding sequences of living beings that occur on the continental shelf. This also includes what happens below the earth’s surface. The trophic or food chains are different in each type of habitat, such as the jungle, the forest, the desert, the mountain peaks, the savannah, etc.

For exampleCarrots – Rabbits – Foxes – Coyotes.

food chain

Let’s see the explanation of the example. At level 1 (producing living beings), we have carrots, which feed on sunlight, water, and nutrients from the soil. At level 2, we have the rabbit (herbivore, primary consumer), which feeds on carrot leaves. At level 3 we have the fox (carnivore and secondary consumer), which consumes the animals of the second level. Finally, at level 4 we see the coyote (carnivore and tertiary consumer), predator of the fox.

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aquatic food chain

They are the feeding sequences of living beings that occur in the different environments where water is present as a habitat, whether we are talking about seas, oceans, lakes or rivers. There, different species adapted to these particular living conditions meet. Depending on the specificity of the aquatic habitat, there may be coastal, river, and lake food chains, etc.

For exampleseaweed – anchovy – tuna – shark.

food chain

Explanation of the example. At the producer level (level 1), we have marine algae, which feed on inorganic matter present in the sea. These are consumed by anchovies (primary consumers of level 2). The anchovies are preyed on by tuna, which belongs to the secondary consumers. Finally, the tuna is consumed by the shark, which is the tertiary consumer and the last link in the chain, that is, at the top. This means that no one eats the shark.

Delve into:

  • Terrestrial food chain.
  • Aquatic food chain.

food chain examples

  1. Dry vegetation – Earthworms – Chicken – Human being. Earthworms feed on dry vegetation. These are part of the hen’s diet, in addition to plant products. Human beings eat chickens and, like them, eat vegetables. Remember that both the chicken and the human being are omnivores. For this reason, they are positioned at the same time as primary and secondary consumers.
  2. Grass – Zebras – Hyenas – Lions. The grass is fed by photosynthesis. Zebras eat grass. Hyenas hunt zebras, and lions hunt both hyenas and zebras. The lions are the final consumers of this chain.
  3. Fresh leaves – Snails – Beetles – Frog – Owl. Snails feed on fresh leaves. Beetles include snails in their diet. Similarly, beetles serve as food for frogs. Finally, the barn owl can feed on frogs.
  4. Seaweed – Common Carp Fish – Heron. Marine algae feed on inorganic matter. These provide food for common small fish. Small fish are the main food for herons.

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