CBSE Class 11 Fundamental of Physical Geography: Chapter 15 NCERT Solutions

Reviewed by NCERT Help Editorial Team · Updated on 29 Jul 2026

NCERT Solutions PDF Class 11 PDF

This chapter, 'Life on the Earth,' delves into the fundamental concepts of physical geography related to living organisms and their environment. The NCERT Solutions provide clear explanations and answers to questions covering the biosphere, the definition and types of ecosystems, and the structure of food chains. It also touches upon the process of photosynthesis and the chemical reactions involved in the Earth's processes, such as oxidation. These solutions are designed to help students grasp the interrelationships between living and non-living components of the Earth, understand ecological principles, and prepare effectively for their examinations by offering detailed, step-by-step explanations.

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Quick info

Board	CBSE
Class	Class 11
Subject	Fundamental of Physical Geography
Session	2026
Language	English
Type	NCERT Solutions
Chapter	Chapter 15

Chapter summary

Chapter 15, 'Life on the Earth,' focuses on introducing students to the basic principles of ecology and the biosphere. The NCERT Solutions cover multiple-choice questions on the components of the biosphere and types of grasslands, short-answer questions defining ecology and ecological systems, and a question on food chains with an example. The solutions aim to clarify concepts like photosynthesis and chemical reactions in rocks, providing a foundational understanding of life's interactions on our planet.

Learning outcomes

Understand the components and definition of the biosphere.
Identify different types of ecosystems and their characteristics.
Define and explain the concept of a food chain with examples.
Explain the process of photosynthesis and its inputs and outputs.
Recognize the chemical reactions involved in geological processes like oxidation.

Topics covered

Paper topics

Biosphere
Ecology
Ecological System
Terrestrial Ecosystems
Aquatic Ecosystems
Food Chain
Photosynthesis
Oxidation of Rocks
Living Organisms
Biotic Components
Abiotic Components
Trophic Levels

Important topics

Definition and components of the Biosphere
Understanding Ecology and Ecosystems
Structure and examples of Food Chains
The process of Photosynthesis
Types of Ecosystems (Terrestrial and Aquatic)

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Questions and Solutions

Multiple choice question

(i) Which one of the following is included in biosphere?

(a) only plants

(b) all living and non-living organisms

(d) all living organisms

Solution: The biosphere refers to the sum total of all living organisms on Earth, along with their interactions with the physical environment. Therefore, it includes all living organisms.

Answer: (d) all living organisms

(ii) Tropical grasslands are also known as:

(a) the prairies

(b) the savannas

(d) none of the above

Solution: Tropical grasslands, which are characterized by grasses and scattered trees, are widely known by the name savannas. Prairies are temperate grasslands, and steppes are also temperate grasslands, often found in Eurasia.

Answer: (b) the savannas

(iii) Oxygen combines with iron found in the rocks to form:

(a) iron carbonate

(b) iron nitrites

(d) iron sulphate

Solution: When oxygen reacts with minerals containing iron in rocks, a chemical process called oxidation occurs. This process results in the formation of iron oxides, which is commonly observed as rust.

Answer: (c) iron oxides

Question 1

During photosynthesis, carbon dioxide combines with water in the presence of sunlight to form:

1. proteins

2. amino acids

3. carbohydrates

4. vitamins

Solution: Photosynthesis is the process by which green plants use sunlight, water, and carbon dioxide to create their own food. In this process, carbon dioxide and water are converted into carbohydrates (like glucose) and oxygen. Sunlight provides the energy for this reaction.

Answer: (c) carbohydrates

Question 2

What do you understand by the term 'ecology'?

Solution: Ecology is the scientific study of the relationships between living organisms, including humans, and their physical environment. It examines how these interactions influence the distribution and abundance of organisms, essentially viewing the Earth as an interconnected 'household' of plants, animals, microorganisms, and their surroundings.

Question 3

What is an ecological system? Identify the major types of ecosystems in the world.

Solution: An ecological system, or ecosystem, is a community of living organisms (biotic components) interacting with each other and with their non-living physical environment (abiotic components) as a functional unit. The major types of ecosystems found globally are broadly categorized into two main groups: terrestrial ecosystems, which are land-based (like forests, grasslands, deserts), and aquatic ecosystems, which are water-based (like oceans, lakes, rivers, and wetlands).

Question 4

What is a food-chain? Give one example of a grazing food-chain identifying the various levels.

Solution: A food chain illustrates the flow of energy through an ecosystem by showing a linear sequence of organisms where each organism is eaten by the next organism in the chain. It typically starts with producers and moves up through different levels of consumers.

An example of a grazing food-chain is:

Producer level: Paddy stalk (a plant that produces its own food through photosynthesis).
Primary Consumer level: A plant-eating beetle that feeds on the paddy stalk.
Secondary Consumer level: A frog that eats the beetle.
Tertiary Consumer level: A snake that consumes the frog.
Quaternary Consumer/Apex Predator level: A hawk that preys on the snake.

This sequence demonstrates how energy is transferred from one trophic level to the next.

Common mistakes

Confusing the biosphere with only living organisms.
Incorrectly identifying types of grasslands or ecosystems.
Not clearly defining ecological terms like 'ecology' or 'ecosystem'.
Failing to identify all trophic levels in a food chain.

Revision tips

Review the definitions of key terms like biosphere, ecology, and ecosystem.
Memorize the example of a food chain and its different levels.
Understand the inputs and outputs of photosynthesis.
Practice identifying the components of an ecosystem (biotic and abiotic).

Practice MCQs

Q1. Which of the following is considered part of the biosphere?

Q2. What is the alternative name for tropical grasslands like the prairies?

Q3. When oxygen reacts with iron in rocks, it forms:

Q4. During photosynthesis, the primary products formed from carbon dioxide and water are:

Frequently asked questions

What is the biosphere according to NCERT Class 11 Geography?

The biosphere is understood as the realm of life on Earth, encompassing all living organisms and their interactions with the non-living components of the planet.

What are the main types of ecosystems mentioned in the solutions?

The solutions identify two main types of ecosystems: terrestrial (land-based) and aquatic (water-based).

Can you explain what a food chain is based on the provided solutions?

A food chain is a sequence showing the transfer of energy from producers to consumers and decomposers. An example given is a plant being eaten by a beetle, which is eaten by a frog, then a snake, and finally a hawk.

What is the role of ecology in understanding life on Earth?

Ecology is the study of how living organisms interact with each other and their environment, helping us understand the Earth as a 'household' of life.

How do these NCERT solutions help with exam preparation?

These solutions provide clear, rewritten answers to chapter questions, helping students understand key concepts like the biosphere, ecosystems, and food chains, which are crucial for exams.

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