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What is a food web, and how is it different from a food chain?

Class 8 ScienceNCERT chapter: How Nature Works in Harmonyइसे हिंदी में पढ़ें

Exam-ready answer

A food chain is a single, straight sequence showing who eats whom, starting from a producer, such as grass → grasshopper → frog → snake → eagle. In nature, most animals eat more than one kind of food and are eaten by more than one animal. So many food chains link together to form a network, called a food web.

Explanation

Every food chain begins with producers, the green plants that make their own food using sunlight. Herbivores, such as grasshoppers, rabbits and deer, eat plants. Carnivores, such as frogs, snakes and eagles, eat other animals, and omnivores eat both. In a food chain, the arrow points from the food to the organism that eats it, showing the direction in which food and energy pass.

A food chain shows only one path, but real feeding links are more varied. A frog eats grasshoppers and also other insects. A snake may eat frogs as well as rats, and an eagle may hunt snakes, rats and rabbits. When all these chains in a forest or pond are drawn together, the arrows cross and connect, forming a food web. Decomposers such as bacteria and fungi break down dead remains and return nutrients to the soil.

The main difference is that a food chain is a single straight line, while a food web is a network of many interconnected chains. A food web makes an ecosystem more stable. If one kind of organism becomes scarce, animals that eat it can switch to another food source. In a single food chain, removing one link would directly affect every organism above it.

Points to remember

  1. Food chain: a single sequence of organisms showing who eats whom, starting from a producer.
  2. Food web: a network of many interconnected food chains in an ecosystem.
  3. Producers (green plants) → herbivores → carnivores; omnivores eat both plants and animals.
  4. Arrows point from the food to the eater, showing the flow of food and energy.
  5. A food web gives animals alternative food sources, so the ecosystem stays more stable than with a single chain.

Exam tip

Draw one food chain and one small food web with correct arrow directions, from food to eater. Label producer, herbivore and carnivore, and end with a one-line difference: chain is a single path, web is a network.

Questions students also ask

Why does every food chain start with a green plant?
Green plants are producers; they make their own food from sunlight, water and carbon dioxide by photosynthesis. All other organisms depend on them directly or indirectly for food, so the energy in every food chain starts with plants.
What happens to a food web if one species disappears?
The animals that ate it lose a food source and may decline or switch to other food, while the organisms it ate may increase in number. Because the chains are linked, the change spreads and can upset the balance of the whole ecosystem.
What role do decomposers play in a food web?
Decomposers, such as bacteria and fungi, break down dead plants, dead animals and their wastes. This returns nutrients to the soil, which plants use again to grow. Without them, nutrients would stay locked in dead matter.

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