Class 7 Science

Chapter 17: Forests – Our Lifeline

STAGE 0: Foundation / Basics

A forest is a large area covered mainly with trees and plants.

Forests are very important for plants, animals, and human beings.

Components of a Forest

A forest is made up of:

• Plants (trees, shrubs, herbs)
• Animals
• Microorganisms
• Soil
• Air and water

Layers of a Forest

• Canopy – Top layer formed by tall trees
• Understory – Small trees and shrubs
• Forest floor – Dead leaves and organisms

Interdependence in Forest

Plants and animals depend on each other for food, shelter, and oxygen.

This relationship is called interdependence.

Food Chain

A food chain shows how energy flows from plants to animals.

Example:

Grass → Deer → Lion

Decomposers

Decomposers are organisms that break down dead plants and animals.

Examples: Bacteria and fungi

They help return nutrients to the soil.

Importance of Forests

• Provide oxygen
• Maintain balance of gases
• Prevent soil erosion
• Provide shelter to animals
• Control climate

Conservation of Forests

• Plant more trees
• Stop deforestation
• Use forest products carefully
• Protect wildlife

STAGE 2: NCERT Textbook Questions & Answers

Q1. Why are forests called our lifeline?

Forests provide oxygen, food, shelter, and maintain ecological balance.

Q2. What are decomposers?

Organisms that break down dead plants and animals are called decomposers.

Q3. What is a food chain?

A sequence showing how food energy passes from one organism to another.

STAGE 3: Exam-Oriented Questions

Fill in the blanks:

• The top layer of a forest is called __________.
• Bacteria and fungi are called __________.

Very Short Answer:

Name one function of forests.
Answer: Provide oxygen

Quick Revision Points

• Forests support life on Earth
• Plants and animals are interdependent
• Decomposers recycle nutrients
• Forests must be conserved