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Difference Between Grazing and Detritus Food Chain

What is the Food Chain?

A Food chain is the sequence of transfers of matter and energy in the form of food from one organism to another organism. Food chains are connected locally into a food web because most organisms consume more than one type of animal or plant. Plants that convert solar energy to food by photosynthesis are the primary food source. In a predator food chain, a plant-eating animal is usually eaten by a flesh-eating animal. In a parasite food chain, a smaller organism consumes part of a larger host and may be consumed by even smaller organisms. And in a saprophytic food chain, microorganisms live on the dead organic matter.


A food chain always starts with the producers and ends with the apex predator.


For example, grass   →   insects   →   lizard   →   snake.


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A food chain is of two types, grazing food chain and detritus food chain. There is a lot of difference between the grazing food chain and the detritus food chain, and here we will discuss it in detail. 


Grazing Food Chain

As we know, the primary source of energy is the Sun. The plants convert the Sun’s energy into food by the process of photosynthesis. This is the start of the grazing food chain. A food chain where the energy is gained by the organisms is from photosynthesis; it is termed as the grazing food chain. 


The grazing food chain starts with the green plants as they are the producers and can perform photosynthesis. Then, the energy is transferred from the green plants to the herbivores. In a grazing food chain, the Sun is the ultimate or primary source from which energy transfer takes place.


The grazing food chain can be further subdivided into two types:

  • Predator food chain – Here, the autotrophs or producers are directly consumed by the herbivores.

  • Parasitic food chain – Here, the Herbivores that eat the producers are infected by parasites.


The grazing food chain is a type of food chain where the energy transfer is between the lowest trophic levels. 


Examples of grazing food chain are:


Phytoplankton  → small fish → Large Fish


The above food chain is an example of an aquatic grazing food chain. Here, we can see that the phytoplanktons which are the aquatic plants are consumed by small fishes which are eaten by large fishes.


Grass → Deer → Lion/Tiger.


Here is another example of a grazing food chain that represents the terrestrial animal food chain. 


Detritus Food Chain

In a detritus food chain, the main source of nutrition is dead plants or animals. The detritus food chain does not depend on solar energy. The organisms that gain their energy from the dead remains of the plants or animals are known as detrivores or decomposers. 


In a detritus food chain, the energy is first transferred from the dead remains of plants and animals to the decomposers and then it is transferred to the predators feeding on the decomposers.


Examples of detritus food chain are:

Dead organic matter → microorganisms → decomposers.


Here, the food chain starts with the dead remains of plants and animals, which is consumed by microorganisms such as bacteria or fungi. These microorganisms are eaten by decomposers such as snails, and earthworms, and the decomposers are finally consumed by other large animals.


Difference Between Grazing and Detritus Food Chain

Grazing food chain and detritus food chain have certain differences which we have listed down here.


Basis of Difference

Grazing Food Chain

Detritus Food Chain

Definition

A grazing food chain is a food chain that starts with green plants as the main source of energy.

A detritus food chain is a food chain that starts with the dead remains of organisms as a main source of energy.

Energy Source

The primary source of energy in a grazing food chain is solar energy.

The dead remains of plants and animals act as the primary source of energy for the detritus food chain.

Organisms Involved

The grazing food chain involves all the macroscopic or sub-soil organisms.

The detritus food chain mainly involves microscopic organisms.

Importance

The grazing food chain releases energy into the ecosystem.

The detritus food chain uses a large amount of energy from the environment.

First Trophic Level

In the grazing food chain, green plants form the first trophic level.

In the detritus food chain, the first trophic level is occupied by the decomposers. 


Implications of Grazing Food Chain

Implications of the grazing food chain are as follows:

  • Grazing food chain is directly dependent on the flow of solar energy and thus, the gross production of plants might be oxidized during respiration or can be eaten by herbivores or they may die and decay.

  • In the grazing food chain, sunlight energy serves as the primary source of energy.

  • This food chain always adds energy to the ecosystem.

  • The grazing Food Chain helps in the fixation of inorganic nutrients.

  • The grazing Food Chain involves every macroscopic organism.


Implications of Detritus Food Chain

Implications of the detritus food chain are listed below:

  • Energy for the detritus food chain is from the dead and decomposed matter known as detritus.

  • Detritus food chain acquires energy from detritus, utilizing the detritus to its fullest, with minimum wastage.

  • This food chain helps in solving inorganic nutrients.

  • This food chain includes subsoil species that can be macroscopic or microscopic.

  • In comparison with other kinds of food chains, this food chain has a much larger energy flow in a terrestrial ecosystem.

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FAQs on Difference Between Grazing and Detritus Food Chain

1. What do you mean by autotrophs?

Autotroph refers to those organisms that can produce food on their own. They produce food by the process of photosynthesis. They use sunlight, water, and carbon dioxide and produce food in the presence of chlorophyll. Green plants are mostly considered as autotrophs. They are also called producers and hence form the first trophic level in a food chain. There are certain bacteria and algae that are considered as autotrophs as they can produce their own food. Autotrophs are considered as the most important part of a food chain as, without them, no food chain can be created. They provide food to various other animals.

2. What are the types of grazing food chains?

There are two types of grazing food chains:

  • Predator chain: In the predator chain, one animal consumes another animal. The animal that got eaten is known as the prey and the animal that eats the prey is known as the predator.

  • Parasitic chain: In the parasitic chain, the plants and animals in a grazing food chain are infected by parasites.

3. What are the examples of detritus food chains?

An example of the detritus food chain is the leaves of a mangrove tree. Whenever the leaves of a red mangrove tree fall into a shallow water body, only about five per cent of the leaves are eaten by phytophagous insects before they fall.


These parts of the leaves are usually eaten by smaller organisms like insect larvae, crabs, copepods, etc. Then, these organisms are consumed by fishes that are carnivores. And finally, these fishes are eaten by larger fishes or fish-eating birds.

4. What are the features of the grazing food chain?

Features of the grazing food chain are as follows:

The grazing food chain depends on the Sun that is a primary source of energy in this food chain.


Various factors are affecting the grazing food chain including oxidation of plants, virus attack, and plant decay due to increased water flow.


The grazing food chain helps in adding energy to the environment and it is also helpful in fixing inorganic nitrogen in the soil.


The grazing Food chain involves every macroscopic organism which means all the organisms that are visible to the naked eye are involved in this food chain.

5. What is the detritus food chain?

Detritus food chain begins from organic matter of dead and decaying animals and plant bodies from the grazing food chain. These dead organic matter or detritus feeding organisms are called detritivores or decomposers and the detritivores are then eaten by predators. And in an aquatic ecosystem, the grazing food chain is the major conduit for energy flow.


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