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Food chain

Food chain definition and example

Food chain
n., plural: food chains
[fud ˈt͡ʃeɪn]
Definition: Feeding relationships beween species

Everything is a cycle in life. The way organisms consume their food also follows a cycle. This is usually described as the food web, which can be broken down into food chains. In the wild, the food chain consists of who eats whom. Every living thing, from single-celled algae to massive blue whales, requires food to thrive. Each food chain represents a potential path for energy and nutrients to travel through the environment.

What Is A Food Chain?

The food chain is a series of creatures that begins with producer organisms, having consumers at various levels in between, and ends with decomposer species. A food web connects numerous food chains. The food chain takes a single path, whereas the food web takes several paths. The food chain teaches us about the relationships between creatures. The food chain and food web are essential components of this ecosystem.

diagram of a food chain
Figure 1: Annotated diagram of a food chain. Image Credit: Sylvia Freeman.

The majority of ecosystems rely on sunlight for energy. Photosynthesis converts light energy to chemical energy in carbon molecules. Chemical energy in carbon compounds is transferred across food chains by feeding.

The energy released by respiration from carbon molecules is consumed by living organisms and transformed into heat. Heat cannot be converted into other types of energy by living beings. Heat escapes from ecosystems. Food chain length and biomass at higher trophic levels are constrained by energy losses between trophic levels.

Since energy is produced in the form of heat at each step or trophic level, chains are typically limited to four or five trophic levels. People can boost the overall food supply by eliminating one stage in the food chain: instead of consuming animals that eat cereal grains, people consume the grains themselves. The total amount of energy accessible to final consumers increases as the food chain is shortened.

Watch this vid about the food chain, food webs, and energy pyramids:

Biology definition:
A food chain is a group of organisms that are consumed in a linear order, passing nutrients and energy along the way. Each organism in a food chain is at a particular trophic level, which is determined by how many energy transfers distance it from the chain’s primary energy source. A feeding hierarchy in which organisms in an ecosystem are grouped into trophic (nutritional) levels and are shown in succession to represent the flow of food energy and the feeding relationships between them.

The directional flow of materials and energy from one organism to another is graphically represented by arrows. For example:

trees and shrubs (producer) → giraffe (herbivore) → lion (carnivore)

Most food chains have only about four to five links since too many links in a food chain will result in high demand, and less supply of food (and therefore energy).


The length of a food chain depends on a continuous variable that provides a measure of energy flow and an index of ecological complexity that grows through linkages from the lowest to the highest trophic levels (feeding levels).

Food chains (for example, a three-species food chain) are frequently employed in ecological modeling. They are simplified representations of genuine food webs, but their dynamics and mathematical implications are complicated.

Ecologists have developed and tested ideas on the nature of ecological patterns related to food chain length, such as length growing with ecosystem volume, being limited by energy decrease at each succeeding level, or reflecting habitat type.

The food chain is divided into four major components:

  1. The sun
    • A portion of the tremendous quantity of energy coming from the sun powers the light and heat that keep Earth habitable for life.
  2. Producers
    • Autotrophs or primary producers are the organisms that the food chain begins with this. As the first level of the food chain, these organisms create their own form of nourishment. Some of these include algae, green plants, and other forms of cyanobacteria and phytoplankton.
    • Producers are often referred to as autotrophs because they produce their own food and they use the sun’s energy to do so. This is known as photosynthesis and any organism that photosynthesizes is considered to be a producer.
  3. Consumers
    • All species that rely on organisms – especially plants – for nourishment are considered consumers. This is the most extensive section of a food web since it comprises nearly all living organisms. It contains herbivores (animals that eat plants), carnivores (animals that eat other animals), parasites (which live on other creatures by hurting them), and scavengers (who devour deceased animals’ carcasses).
    • There are various levels of consumers. For instance, primary consumers pertain to any organism that eats plants. Any organism that eats plants and animals is called an omnivore. Organisms that eat solely animals are carnivores. They will be known as secondary consumers. Tertiary consumers eat both primary and secondary consumers.
  4. Decomposers
    • Decomposers are microbes that obtain energy by decomposing organic matter. These conclude the food chain as the final step. Decomposers are essential components of the food chain because they convert organic waste into inorganic elements, which feed the soil or land with nutrients.

Decomposers finish their life cycle. They aid in nutrient recycling by supplying nutrients to soil or seawater that can be used by autotrophs or producers. When this occurs, it completes the cycle, and a new one is created by other organisms.

food chain example
Figure 2: Showing a full-length food chain. Image Credit: Media Wiki.
  • Trophic Levels

Trophic levels are classifications of organisms in food chains. These levels are typically consistent with producers, consumers, and decomposers. The producers and decomposers make up the first and fifth trophic levels respectively and the other trophic levels are made up of consumers.

An organism’s trophic level is the number of steps it has taken since the beginning of the chain. A food web typically begins at trophic level 1 with primary producers such as plants, progresses through herbivores at level 2, carnivores at level 3 or higher, and concludes with apex predators which are at the 4th and 5th trophic level.

The sun is the beginning point for the trophic level in the ecosystem, which autotrophs use. The other trophic level below is known as heterotrophs, which cannot produce their own food and must rely on autotrophs to meet their nutritional demands.

  1. Autotroph – Trophic level one (1)
    • Green algae and plants (the producers), often known as autotrophs, make up the first stage. They rely on solar energy for photosynthesis and do not rely on other animals to meet their dietary needs. Heterotrophic organisms devour autotrophs.
  2. Primary Consumers – Trophic level two (2)
    • This trophic level of the food chain is occupied by herbivores. They rely on autotrophs to meet their dietary needs and include species such as insects, cows, and pigs.
  3. Secondary Consumers – Trophic level three (3)
    • Secondary consumers, sometimes known as carnivores, usually eat other animals but are smaller in stature. Rats, spiders, and fish are some examples of this group of organisms.
  4. Tertiary Consumers – Trophic level four (4)
    • Tertiary consumers eat primary and secondary consumers to meet their nutritional demands. They get their energy from meat, making them generally carnivores. This typically includes the smaller but dangerous land animals like hyenas as well as animals like dolphins, and sharks which live in the sea.
  5. Quaternary Consumers – Trophic level five (5)
    • Apex predators, also known as quaternary consumers, are at the top of the food chain. Humans fall into this category as well as land mammals like wolves, lions, and marine organisms such as orcas are all examples.
trophic levels - ecological pyramid
Figure 3: Depicts the trophic levels in food chains. Image Credit: CK-12.

Types Of Food Chain

The grazing food chain, which starts with autotrophs, and the detrital food chain, which starts with dead organic materials (or dead organisms), are the two different kinds of food chains.

  1. The grazing food chain
    • Energy and nutrients travel from plants to herbivores that consume them, and then to carnivores or omnivores that prey on the herbivores.
    • In a grazing food chain, photosynthesis gives energy to the lowest trophic level. In this form of the food chain, the first energy transfer occurs from plants to herbivores. Because autotrophs are the foundation of all ecosystems on Earth, the majority of ecosystems in the environment follow this type of food chain.
    • As a result, autotrophic energy capture and transfer to herbivores is required in this type of cycle. This type of food chain can be found in almost all natural ecosystems.
  2. The detrital food chain – this is also known as the decomposer food chain
    • Decomposers, such as bacteria and fungus, break down dead organic matter or dead organic compounds from plants and animals in a detrital food chain, which then transfers to detritivores and finally predators.
    • The detritus food chain includes algae (like blue-green algae ), bacteria, fungi, protozoa, mites, insects, worms, and other organisms and plants. The dietary energy is used by decomposers and detritivores, which is then devoured by smaller organisms such as predators.
    • Carnivores like maggots are eaten by larger carnivores like frogs, snakes, and other predators.
    • Primary consumers that feed on detritus include fungi, bacteria, protozoans, and other creatures.
grazing food chain
Figure 4: A grazing Food chain. Image Credit: PMF IAS.
  • Examples of Organisms and Food Chains

Single-celled organisms known as phytoplankton supply food for small shrimp known as krill in one marine food chain. The blue whale, which is on the third trophic level, feeds primarily on krill.

Food chain example in marine water
Figure 5: Food chain example 1 mentioned above. Image Credit: Cool Antartic.

A cricket may consume grass, a producer, in a grassland ecosystem. The cricket may be eaten by a bird, which is then eaten by a small mountain lion cub. Finally, an apex predator, a hawk, swoops down and grabs up the cub.

The autotroph in a pond could be green algae. A fly larva consumes the algae, and subsequently, a frog larva consumes the immature fly. The frog larva gets eaten by a fish, which then becomes a delectable meal for a black bear.

Frequently Asked Questions

The following are questions that are often asked about food chains and the best possible answers to those questions:

  • What are the first organisms in a food chain?

The first organisms in the food chain are producers. Autotrophs, or producers, create their own form of nourishment. They are the foundation of every food chain. Plants and single-celled creatures are examples of autotrophs. Photosynthesis is used by nearly all autotrophs to produce glucose – their source of nourishment – from sunlight, carbon dioxide, and water.

  • What is the difference between the food chain and the food web?

A food chain shows who eats who. A food web is the collection of all the food chains within an ecosystem. Every organism in an ecosystem has a certain trophic level, position, or web in the food chain. The bottom of the trophic pyramid is made up of producers who manufacture their own food through photosynthesis or chemosynthesis.

  • What role do humans play in a food chain?

Humans are thought to be “the king” of the food chain because they eat various sorts of plants and animals but are not consistently devoured by any creatures. This is because of the way humans have advanced themselves as a species so that they are able to defend themselves again predators.

They are often considered to be at the fifth trophic level as quaternary consumers. This is because plants are the foundation of the human food chain as well as humans consume plants known as fruits and vegetables, and they are the principal eaters of these plants.

  • What are animals called in a food chain?

In general, animals are known as the consumers of the food chain since they consume plants and other animals. However, as explained before, they can either be a primary consumer, a secondary consumer, or a tertiary consumer based on their diets (herbivore, carnivore, or omnivore).

  • What do food chains end with?

Food chains are completed by detritivores and decomposers. Detritivores are creatures that consume dead plants and animals. Scavengers, such as vultures, devour dead animals.


Decomposers are a crucial part of the food chain

Most people think that food chains end at the ‘consumers’ because they often forget that decomposers exist. Decomposers are a crucial part of the food chain as the cycle would not be able to recommence without them. Producers depend on decomposers to break down nutrients so they can absorb them.

decomposer definition
Definition ol decomposers

Take the Food Chain – Biology Quiz!


Choose the best answer. 

1. What is a food chain?

2. Autotrophs are members of which group in a food chain?

3. Their primary role is to break down dead organic matter

4. Herbivores are _______ consumers of the food chain

5. Example of quaternary consumers

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