A food chain in Class 10 science is defined as a straight sequence of organisms where energy and nutrients are transferred from one organism to another by the process of eating and being eaten (who eats whom).

Simple definition (Class 10 level)

  • A food chain is a sequence of organisms in which each organism feeds on the one before it and is eaten by the one after it.
  • It shows the flow of energy from producers → consumers → top consumers in an ecosystem.

Example (terrestrial chain):
Grass → Grasshopper → Frog → Snake → Hawk (each arrow shows “is eaten by”).

Key terms you should write in exams

  • Producer (1st trophic level): Green plants that make food using sunlight.
  • Primary consumer (2nd trophic level): Herbivores that eat plants (e.g., grasshopper, deer).
  • Secondary consumer (3rd trophic level): Carnivores that eat herbivores (e.g., frog).
  • Tertiary / top consumer: Higher carnivores at the end of the chain (e.g., hawk, lion).
  • Trophic level: Each step/level in a food chain is called a trophic level.

Most natural food chains have only 3–4 (max 5) trophic levels because energy decreases at every step.

Characteristics of a food chain (Class 10 points)

You can remember these as ready-made answer points:

  1. It is always straight (linear), not branched.
  1. It shows unidirectional flow of energy : from sun → producers → consumers.
  1. At each step, a large part of energy is lost as heat, so only a small part (about 10%) goes to the next level.
  1. Usually there are 3–4 trophic levels , rarely 5.

Types of food chain (for Class 10 answers)

  • Terrestrial food chain (on land):
    Example: Grass → Insect → Lizard → Snake → Hawk.
  • Aquatic food chain (in water):
    Example: Phytoplankton → Zooplankton → Small fish → Big fish → Shark.

Both types show the same idea: energy flows step by step as organisms eat one another.

One-line exam-ready answer

A food chain is the sequence of organisms in an ecosystem where one organism eats another and energy flows from producers to various levels of consumers in a straight line.

TL;DR:
Food chain (Class 10) = who eats whom in nature, shown in a straight line from plants to herbivores to carnivores, with energy flowing in one direction and decreasing at each step.

Information gathered from public forums or data available on the internet and portrayed here.