[Biology Class Notes] on Grazing Food Chain Pdf for EXAM

The Grazing Food Chain is a type of Food Chain in which energy at the lowest trophic level is acquired via photosynthesis. The Grazing Food Chain begins with producers like green plants, who create their own Food through the process of photosynthesis and later move from herbivores to carnivores. In the Grazing Food Chain, energy is acquired from the sun. In an aquatic ecosystem setting, the Grazing Food Chain is the primary source of energy flow. However, in terrestrial ecosystem settings, a large amount of energy flows through the detritus Food Chain. 

The Grazing Food Chain is highly important to maintain the equilibrium of energy flow as it releases back energy into the ecosystem.

While the detritus Food Chain consumes a huge amount of energy from the environment.

Implications of Grazing Food Chain

• This type of Food Chain is directly dependent on the flow of solar energy. i.e. the sunlight. Therefore, the gross production of plants might meet the following consequences; they may be oxidised during respiration, they can be eaten by herbivores or they may die and decay. 

• Sunlight energy serves as the primary source of energy in the Grazing Food Chain. 

• The Grazing Food Chain always adds energy to the ecosystem. 

• This Food Chain fixes inorganic nutrients. 

• The Grazing Food Chain involves every macroscopic organism.

More than 100,000 diverse types of decomposer organisms are part of the Food Chain.

The natural nutrients are subsided to the land and plants can use them furthermore. It restarts the energy Chain and the whole process starts all over again.

It’s not only beneficial for the environment but also simplifies the natural process of recycling and reuse. Nature indeed heals itself.

Fun Fact: Humans are known as the end of the Food Chain. As they eat plants as well as animals that have absorbed other kinds of energies too.

Types of Grazing Food Chain

Moving forward to the types of the Grazing Food Chain.

There are mainly two types of Grazing Food Chains and they are as follows:

Predator Chain – Here, one animal consumes another animal. The animal that is being eaten is known as the prey and the animal that is eating the prey is known as the predator.

Plants initiate the energy cycle, as they create their Food by using sunlight and soil. On the other hand, Animals are consumers of these energies, because they eat other plants and animals.

Parasitic Chain – Here, the plants and animals in a Grazing Food Chain are infected by parasites.

Grazing vs. Detrital Food Webs

The main difference between the Detrital and Grazing Food Chains is that the Detrital Food Chain is a Food Chain that starts with deceased organic substances as the source of energy.

Contrary to this, The Grazing Food Chain is a Food Chain that starts with green plants as the key source of energy.

Food webs don’t usually show decomposers—you may have noticed that the Lake Ontario Food cycle above doesn’t. Yet, all ecosystems follow different methods to recycle dead material and wastes. That means decomposers are indeed present, albeit they do not get much air time.

The ecosystem generally has two different types of Food webs:

For example, the meadow ecosystem includes a Grazing Food cycle of plants and animals that gives inputs for a detrimental Food cycle of bacteria, fungi, and detritivores. The detrital web is shown in simplified form within the brown band across the rock bottom of the diagram. In reality, it might contain various species linked by specific feeding interactions—that is, connected by arrows, as within the Grazing Food cycle aboveground. Detrital Food webs can come up with energy to graze Food webs, as when a robin eats an earthworm.

The Grazing Food Chain starts with a photosynthetic plant.

The detrital Food Chain is the Food Chain that forms by using the deceased or dead organisms. 

Energy Transfer Efficiency Limits

Food Chain Lengths When one organism eats another and gets the energy-rich molecules from its prey’s body, wherein the energy is transferred between trophic levels.

However, limits the length of Food Chains due to inefficiency, and also transfers are inefficient. When energy enters a trophic level, a number of it’s stored as biomass, as a part of organisms’ bodies. This is the energy that’s available to subsequent trophic levels since only energy stored as biomass can get eaten. It is a rule to be followed, only about 10% of the energy that’s stored as biomass in one trophic level-per unit time ends up stored as biomass within the next trophic level-per the same unit time. This 10% rule of energy transfer may be a good thing to plan for memory.

There is a huge energy loss during 

Energy transfer between trophic levels. The net productivity of one level is only 10% of the net productivity of the preceding level.

It means 90% energy loss happens during energy transfer.

Examples of Grazing Food Chain

• This kind of Food Chain depends on energy captured by autotrophic plants and the flow of this captured energy to herbivores. The phytoplankton is eaten by zooplankton, the zooplankton is eaten by fishes or grasses, then these grasses are eaten by rabbits, and finally, the rabbit is eaten by a fox.

•  The small plants or grass are eaten by a deer, and the deer is later eaten by a lion.

Simplifying the example here:

Microorganisms→Small organisms→ Fishes or grass

Grass→ Rabbit →Fox

Grass→Deer → Lion

Other examples can be included such as:

Leaf → Caterpillar→ Chameleon → Mongoose →Snake

Examples of Detrital Food Chain

The Food Chain depends upon the composers, mostly microorganisms.

Its Chain begins as follow:

Sun + Soil + Air + Water = Plants & Grass 

Plants & Grass → Herbivore animals (Deer, Rabbit, etc) → Omnivore → Carnivore → Detritivores → Soil 

That’s how the cycle continues from soil to back to the soil. It’s good for the environment and mother earth. As it helps in the natural process of reuse, recycle and re-extraction of the energy from one phase to another.

Let’s Understand the difference between Detrital Food Chain and Grazing Food Chain by using the following table.

Fun Facts About Grazing Food Chain

1. In the 10th century, an Arab scientist and philosopher Al-Jahiz became the first person to introduce the concept of the Food Chain.

2. Later Charles Elton’s book “Animal Ecology” was published in 1927 and became the reason for popularizing the concepts.

Along with the concept of Food cycles, Food Chains, and Food size.  

The term ‘Food cycle’ was later renewed by ‘Food web’.

3.  The Food webs have a keystone lineage or species.  

It means that a keystone species is a species that has a huge influence on the enclosing environment. It can immediately influence the Food Chain. 

The demolition of the keystone species can disturb the equilibrium of the entire Food Chain.

Keystone species keep herbivores from consuming or utilizing all the greenery available in their environment and preventing mass demise.