Food Web – Geography – UGC NET – Notes

Introduction

The word ‘web’ means network. Food web can be defined as ‘a network of interconnected food chains so as to form a number of feeding relationships amongst different organism of a biotic community.

A food web is an illustration that depicts the feeding links within a community. It also refers to the movement of dietary energy from plants to herbivores and then to predators. Normally, food webs are made up of a number of interconnected food chains. Each food chain is a descriptive graphic with a succession of arrows pointing from one species to the next, illustrating the transfer of food energy from one feeding group to the next. 

A food chain cannot stand isolated in an ecosystem. The same food resource may be a part of more than one chain. This is possible when the resource is at the lower tropic level.

A food web comprises all the food chains in a single ecosystem. It is essential to know that each living thing in an ecosystem is a part of multiple food chains.

• A food web is a thorough representation of the species in a community and their relationships with one another.
• It demonstrates how energy is moved up interconnected food chains.
• A food web differs from a food chain in that the latter is a linear structure depicting a succession of animals in which each species is eaten in turn by another species, but a food web is a more intricate network of who eats who in a given environment.
• If any link in the intermediate food chain is removed, the chain’s subsequent links will be severely impacted.
• Most species in an ecosystem have more than one food source due to the food web, which boosts their chances of survival.
• For instance, grasses can provide food for rabbits, grasshoppers, goats, and cows.
• A herbivore, on the other hand, maybe a food source for a variety of carnivorous species.
• A food web is depicted in the diagram below. Arrows in food webs point from a devoured organism to the organism that eats it.

Background

A single food chain is the single possible path that energy and nutrients may make while passing through the ecosystem. All the interconnected and overlapping food chains in an ecosystem make up a food web.

Food webs are significant tools in understanding that plants are the foundation of all ecosystem and food chains, sustaining life by providing nourishment and oxygen needed for survival and reproduction. The food web provides stability to the ecosystem.

The tertiary consumers are eaten by quaternary consumers. For example, a hawk that eats owls. Each food chain ends with a top predator and animal with no natural enemies (such as an alligator, hawk, or polar bear).

A food web is a detailed interconnecting diagram that shows the overall food relationships between organisms in a particular environment. It can be described as a “who eats whom” diagram that shows the complex feeding relationships for a particular ecosystem.

The study of food webs is important, as such webs can show how energy flows through an ecosystem. It also helps us understand how toxins and pollutants become concentrated within a particular ecosystem. Examples include mercury bioaccumulation in the Florida Everglades and mercury accumulation in the San Francisco Bay. Food webs can also help us study and explain how the diversity of species is related to how they fit within the overall food dynamic. They may also reveal critical information about the relationships between invasive species and those native to a particular ecosystem.

Key Points:

• A food web can be described as a “who eats whom” diagram that shows the complex feeding relationships in an ecosystem.
• The concept of a food web is credited to Charles Elton, who introduced it in his 1927 book, Animal Ecology.
• The interconnectedness of how organisms are involved in energy transfer within an ecosystem is vital to understanding food webs and how they apply to real-world science.
• The increase in toxic substances, like man-made persistent organic pollutants (POPs), can have a profound impact on species within an ecosystem.
• By analyzing food webs, scientists are able to study and predict how substances move through the ecosystem to help prevent the bioaccumulation and biomagnification of harmful substances.

Food Web