Food Chain and Food Web

A simple food chain basically consists of producers, herbivores and carnivores. For example, small fish feeds on phytoplanktons which in turn is being eaten by a bigger fish. This constitutes the food chain.

A simple food chain consists of producers, herbivores and carnivores. A simple food chain in a terrestrial ecosystem links the trees and shrubs (producers), the giraffes (herbivores that eat trees and shrubs) and the lions (carnivores that eat the herbivores). Each link in this chain is food for the next level and is said to be at a particular trophic level. In the example, trees and shrubs are the producers and occupy trophic level I, giraffe comes at trophic level II, while lion occupies the third trophic level.

As food provides energy, food chain may be defined as succession of organisms in an ecological community that constitutes a passing on of food energy from one organism to another as each consumes a lower member and in turn is preyed upon by a higher member of the food chain.

Different types of food chain can exist in an ecosystem.

Grazing food chain

Grazing food chain is found both in aquatic as well as grassland ecosystem. It is the most common food chain found in the terrestrial ecosystem.

Food chain in a terrestrial ecosystem:

• Grass → Rabbit → Wolf → Tiger
• Grass → Grasshopper → Frog → Snake → Hawk

Food chain in an aquatic ecosystem:

• Phytoplankton → Amoeba → octopus → Seal → Whale
• Phytoplankton → Zoplankton → Prawn → Mosquito → Small Fish → Big Fish → Crocodile

Detritus food chain

This type of food chain starts from dead organic matter. The dead organic matter is broken down into simple nutrients by micro-organisms like fungi and bacteria. These simple nutrients and decomposers are then consumed by smaller carnivores which in turn become food for larger carnivores.

• Micro-organism → Earthworm → Frog → Snake → Peacock

Food Web

Most animals form a part of more than one food chain and eat more than one kind of food in order to meet their food and energy requirements. These interconnected food chains form a food web.

Significance of food chain and food web

• They help to maintain ecological balance.
• They help in understanding the feeding relations among organisms.
• Energy flow and nutrient cycle takes place through them.