Skip to content
Know.itKnow.it
Create an animated lesson
On request

Read the answer free. Creating a lesson uses your daily or stored credits; review the language and settings before starting.

What is a food chain, and what are trophic levels?

Class 10 ScienceNCERT chapter: Our Environmentइसे हिंदी में पढ़ें

Exam-ready answer

A food chain is a series of organisms through which food and energy pass as one organism eats another. Each step in the chain is called a trophic level. Producers (green plants) form the first trophic level, herbivores the second, and carnivores the third or fourth. Energy flows from producers to consumers.

Explanation

A food chain shows how food and energy move from one organism to another in an ecosystem. It always starts with producers—green plants that make food by photosynthesis. For example, grass is eaten by a grasshopper, which is eaten by a frog, which is eaten by a snake. This forms a simple food chain: grass → grasshopper → frog → snake.

Each level in a food chain is called a trophic level. The first trophic level is occupied by producers (green plants). The second trophic level has herbivores (plant-eaters) like grasshoppers. The third trophic level has small carnivores like frogs, and the fourth has larger carnivores like snakes. Decomposers like bacteria and fungi break down dead matter and return nutrients to the soil, but they are not given a trophic level.

Energy flows from one trophic level to the next. Only about 10% of the energy is transferred from one level to the next; the rest is lost as heat and used in life processes. This is why food chains usually have only 3 or 4 trophic levels. The length and complexity of food chains vary in different ecosystems.

Points to remember

  1. Food chain: a sequence of organisms through which energy and nutrients pass as one organism eats another.
  2. Trophic level: each step or level in a food chain.
  3. Producers (green plants) = first trophic level; herbivores = second; carnivores = third or fourth.
  4. Energy transfer is only about 10% from one trophic level to the next; energy is lost as heat.
  5. Decomposers break down dead organisms but are not assigned a trophic level.

Exam tip

Always draw a labelled diagram of a food chain (e.g., grass → grasshopper → frog → snake) and label the trophic levels. Mention the 10% law of energy transfer to score full marks.

Questions students also ask

What is the difference between a food chain and a food web?
A food chain is a single linear path of energy transfer, while a food web is a network of many interconnected food chains. Food webs show the real feeding relationships in an ecosystem more accurately.
Why are food chains usually short?
Because only about 10% of energy is transferred from one trophic level to the next. After 3–4 levels, too little energy remains to support more organisms, so food chains are short.
What are producers and consumers?
Producers are green plants that make their own food by photosynthesis. Consumers are organisms that depend on others for food: herbivores eat plants, carnivores eat animals, and omnivores eat both.

Chapter labels help you find the topic in your textbook. Check your own edition: chapter names and order can change. These are Know.it explanations, not official NCERT solutions.