[Biology Class Notes] on Difference Between Grazing and Detritus Food Chain Pdf

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:

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.

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.

• 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.