Food Web

For a very long period, nature has been a matter of fascination and wonder to everyone curious to know more about it. With an immense amount of research and studies, it is finally found that everything and everyone who exists on earth is related to each other, either this way or that way. Starting from the microscopic particles to the tonnes size living beings, everyone is dependent on one another for survival.

The natural interconnection between different organisms to sustain life on this planet is known as the "food chain".

On the other hand, a graphical representation of different food chains occurring in the environment, collaboratively known as the "food web".

In simple terms, the food web is simply based on who feeds on whom in an ecological community. Food webs are also known as "consumer-resource systems". These are mainly based on different trophic levels. The trophic levels are broadly classified into two types:

● Autotrophs

● Heterotrophs

Autotrophs

The living beings who make their food on their own, come in these categories. These living beings mainly use the sun and essential gases like carbon dioxide and go through a process known as photosynthesis, to form organic matter. This further helps them to grow, sustain and reproduce. These categories mainly contain plants.

Heterotrophs

The living beings which are unable to produce their food and rather obtain it from other organisms are known as heterotrophs. These living beings sustain life by feeding on autotrophs or other heterotrophs. These categories mainly contain animals or human beings.

Pyramids

Food webs are quite complicated than food chains. This is because they are a combination of a huge number of food chains. To understand the food web, there are pyramids. This helps to understand the food web in a better form.

The different types of pyramids are:

● Pyramid of numbers

● Pyramids of biomass

● Pyramids of energy

Pyramids of Number

In these types of pyramids, the number of consumers at each level decreases. This is because the top consumers will have more separate producers. The top consumers mostly include the human beings themselves.

Pyramids of Biomass

The dry weight of an organism or the size of different levels of the pyramids represents biomass. Autotrophs take the upper level of these types of pyramids. Sometimes, the microbes can also be placed under the top level of this type of pyramid. The biomass pyramids are sometimes inverted also.

Pyramids of Energy

This type of pyramid is generally based on the second law of thermodynamics. This type of pyramid is always upright.

More about the Food Webs

Energy can be stated as the power to do things. This power can be derived in many ways and multiple forms, but all of them can be easily linked to the sun. The Sun is the source of all the energy and no energy can be produced without it. 

The living organisms present in the ecosystem can either make their food or depend on others to make food for them. Plant, for example, capture solar energy and through the process of photosynthesis, prepare their food. Due to this reason the plants are called producers or autotrophs. Other organisms consume these green plants to obtain energy and are termed heterotrophs.

What is a Food Web?

Various components of the ecosystem with the help of the sun produce energy. The energy, when produced and stored is continuously distributed among the various living organisms. This process of transfer of energy is referred to as the food web. The Food web demonstrates the flow of energy through different organisms in the ecosystem. The Food web can depict the multiple food chains that are linked together to illustrate the feeding relationships among the organisms in the ecosystem. Another name for the food web is the Consumer-Resource system. 

The Food web can be described as the natural interconnection of several food chains. It can also be stated as the graphical representation of which what is eaten by the members of the ecological community. The connections between the food webs depict the feeding pathways such as where the heterotrophs obtain organic matter by feeding on the autotrophs. The food web presents a picture of the various ways of feeding which connect the ecosystem into a single unified system.

What is a Food Chain?

A food chain can be described as a linear sequence of organisms, where the cycle starts with the producers and ends with the decomposers. The food chain allows us to understand how various organisms of the ecosystem are connected. The food chain is the chronological order that demonstrates the flow of energy from organism to organism. Our ecosystem comprises producers, consumers, and decomposers and thus, the pathway for the flow of energy is very specific. The energy once created is never destroyed rather; it is transferred from one organism to another. The food chain shows the single path that passes through the producers to the consumers and the flow of the energy in this way. 

When more than one food chain occurs in the ecosystem, it is termed the food web. The food chain depicts the direct transfer of energy from organism to organism. But as each organism feeds upon multiple things, the food web is considered a more realistic and simple method for the transfer of energy. Food chains and the food web are similar but they are not the same. The common feature that is shared by both the food chain and the food web is the type of organisms. There are three types of organisms present in the food chain – producers, consumers, and decomposers. 

Producers 

Producers, as we have discussed earlier are those organisms who are capable of synthesizing their food with the help of solar energy. Plants, algae and some bacteria fall into this category. These organisms produce their food by converting sunlight into chemical energy and this process is termed photosynthesis. Plants use the energy from sunlight to convert CO2 into simple glucose which easily breaks down to produce energy. This energy is stored in the form of sugar to be used later. 

Consumers

Consumers are the organisms that derive energy by eating other organisms. The consumers can feed on both plants and/or animals. In a food chain, the producers are always on the lowest step and the first step after them is occupied by primary consumers. The primary consumers are the ones that feed on the producers and are known as herbivores. Some examples of herbivores are insects, deer, cow elephants, etc.

After the primary consumers, comes the secondary consumers who survive by eating the primary consumers. They generally eat meat and are known as predators. Animals like lions, tigers, wolves, spiders, etc. are some of the secondary consumers. 

There exists a third category of consumers known as tertiary consumers. These are known to be feeding on the secondary consumers and are termed the apex predators. The tertiary consumers can be both carnivores and omnivores. For example, a hawk can feed on another bird or on a snake which is a secondary consumer. 

Why are Humans not at the Top of the Food Chain?

One can easily assume that humans are sat at the top of the food chain but the fact is that it is not true. Ecologists have a statistical method for calculating the Trophic Level of a species in the food chain. Trophic Level represents the position of an organism in the food chain concerning the lowest level of the same. The predators in a community generally apply top-down control over the organisms. But humans are not considered apex predators owing to their different forms of diet. However, the human trophic levels keep rising with the consumption of meat. 

The producers or the plants are placed at the trophic level 1 by the ecologists. The apex producers rank higher and are placed at level 4 or level 5. As per the calculations of the scientists the humans are placed at a trophic level of 2.21.

Summary

Energy is essential for all processes and the sun is the main source of all the energy.

The process through which energy is transferred from one organism to another is termed a food web.

A food chain can be described as a linear sequence of organisms, where the cycle starts with the producers and ends with the decomposers.

The apex predators are ranked at level 4 or 5.

Humans are not apex predators and are placed at the trophic level 2.21.