Tata DAV Class 7 Science Chapter 1: Components of Environment – Solutions
Introduction
The environment includes everything that surrounds us and affects our life. It consists of both living (biotic) and non-living (abiotic) components. The four major spheres of the environment are:
Biosphere – The narrow zone where land, water, and air interact and support life.
Lithosphere – Solid land or rocky part of the Earth.
Atmosphere – Blanket of air surrounding the Earth.
Hydrosphere – All forms of water present on the Earth.
A. Tick (✓) the Correct Option
1. Which one is not a part of the biological environment?
Answer: (d) Human beings
2. Volcanoes erupt due to—
Answer: (a) Internal disturbance of the earth
3. Which one brings a sudden change in the environment?
Answer: (d) Formation of a mountain
4. Identify the term that stands for the topmost layer of the earth comprising loose materials.
Answer: (a) Mineral
5. In which year was the Wildlife Protection Act passed in India?
Answer: (b) 1972
B. Give a Single Term for Each of the Following Statements
- A situation or condition in which an organism lives.
Answer: Environment - The only planet in our solar system where life exists.
Answer: Earth - The uppermost part of the lithosphere rich in silica and aluminium.
Answer: Sial - The sphere of air that envelops the Earth.
Answer: Atmosphere - Mass of water on the Earth’s surface.
Answer: Hydrosphere
C. Match the Following
| Column A | Column B |
|---|---|
| Physical environment includes | Atmosphere |
| It is the most dynamic in nature | Atmosphere |
| A narrow zone supporting life | Biosphere |
| They are capable of modifying the environment | Human beings |
| Rocks rich in silica and magnesium | Sima |
D. Answer the Following Questions in Brief (Detailed and Humanistic Answers)
Tata DAV Class 7 Science Chapter 1 – Components of Environment
1. Name the major components of the environment.
Answer:
The environment has two major components:
- Physical Environment (Abiotic Environment): It includes all the non-living things around us, such as land, water, air, soil, mountains, rivers, and climate. These components provide the basic conditions necessary for life on Earth.
- Biological Environment (Biotic Environment): It includes all the living organisms, such as plants, animals, and microorganisms. These living beings interact with one another and depend on the physical environment for survival.
Both components are closely related and work together to maintain the balance of nature. If one component is disturbed, the entire environment gets affected.
2. What is meant by Sima and Sial?
Answer:
The Earth’s crust is made up of different layers based on their composition.
- Sial: It is the upper layer of the Earth’s crust, mainly composed of silica and aluminium. It forms the continents and is lighter in nature.
- Sima: It is the lower layer of the Earth’s crust, mainly composed of silica and magnesium. It is denser and forms the ocean floors.
These layers together make up the lithosphere and provide the land on which we live, grow crops, build houses, and carry out various activities.
3. Mention the distribution of water in the Northern and Southern Hemispheres.
Answer:
Water is not equally distributed on the Earth’s surface.
- About 43% of the Earth’s water is found in the Northern Hemisphere.
- About 57% of the Earth’s water is found in the Southern Hemisphere.
This unequal distribution explains why the Southern Hemisphere has larger oceans and is often called the “Water Hemisphere.” Water plays a vital role in supporting life, regulating climate, and maintaining ecological balance on our planet.
4. Give the literal meaning of four spheres of environment.
Answer:
The environment consists of four major spheres, each having a specific meaning:
- Lithosphere: Sphere of rocks or land
- Atmosphere: Sphere of air
- Hydrosphere: Sphere of water
- Biosphere: Sphere of life
These four spheres are interconnected and depend on one another. Together, they create suitable conditions for life on Earth. Any change in one sphere directly or indirectly affects the other spheres and the living organisms that depend on them.
5. What is the atmosphere composed of?
Answer:
The atmosphere is the blanket of gases surrounding the Earth. It is mainly composed of:
- Nitrogen – 78%
- Oxygen – 21%
- Other gases – about 1%, including carbon dioxide, argon, water vapour, and traces of other gases.
The atmosphere is extremely important because it provides the oxygen needed for breathing, carbon dioxide for photosynthesis, and protects the Earth from harmful solar radiation and extreme temperatures. Without the atmosphere, life on Earth would not be possible.
E. Answer the Following Questions
1. Differentiate between the physical and biological environment.
| Physical Environment | Biological Environment |
|---|---|
| Consists of non-living things. | Consists of living organisms. |
| Includes land, water, air, soil, and climate. | Includes plants, animals, and microorganisms. |
| Cannot grow or reproduce. | Can grow, reproduce, and respond to surroundings. |
| Provides conditions necessary for life. | Depends on the physical environment for survival. |
. Answer the Following Questions (Detailed and Humanistic Answers)
Tata DAV Class 7 Science Chapter 1 – Components of Environment
1. Differentiate between the physical and biological environment.
Answer:
The environment around us consists of both living and non-living things. These are classified into the physical environment and the biological environment.
| Physical Environment | Biological Environment |
|---|---|
| It consists of all non-living components of nature. | It consists of all living organisms. |
| It includes land, air, water, soil, mountains, and climate. | It includes plants, animals, and microorganisms. |
| It cannot grow, reproduce, or respond to stimuli. | Living organisms can grow, reproduce, and respond to their surroundings. |
| It provides the basic conditions necessary for life on Earth. | It depends on the physical environment for food, water, air, and shelter. |
Humanistic Note:
Both environments are closely connected and depend upon each other. Living organisms cannot survive without air, water, and land, while the physical environment remains balanced because of the activities of living organisms. Therefore, both components must be protected to maintain harmony in nature.
2. Why is the Earth called the Blue Planet?
Answer:
The Earth is called the Blue Planet because about 71% of its surface is covered with water in the form of oceans, seas, rivers, lakes, glaciers, and groundwater.
When astronauts look at the Earth from space, the large amount of water reflects sunlight and makes our planet appear blue. This gives Earth its beautiful blue colour and distinguishes it from other planets in the solar system.
Humanistic Note:
Water is essential for all forms of life. It is used for drinking, agriculture, industries, and maintaining ecological balance. Since water is one of our most precious resources, every individual should use it wisely and avoid wasting or polluting it.
3. Define biosphere. Why is it important for us?
Answer:
The biosphere is the narrow zone of the Earth where the lithosphere (land), hydrosphere (water), and atmosphere (air) interact and support life. It includes all living organisms, such as plants, animals, and microorganisms.
Importance of the Biosphere:
- It provides a habitat for all living organisms.
- It supplies food, water, and oxygen necessary for life.
- It maintains ecological balance.
- It supports biodiversity and enables the survival of different species.
- It helps in the cycling of nutrients and energy.
Humanistic Note:
The biosphere is like a giant home that shelters all forms of life on Earth. Human beings are also a part of the biosphere and depend on it for their survival. Therefore, it is our responsibility to protect forests, conserve wildlife, and prevent pollution so that future generations can also enjoy a healthy environment.
4. Explain with the help of an example how physical and biological components of the environment are interdependent.
Answer:
The physical and biological components of the environment are closely related and depend on one another for survival.
Example:
Plants need sunlight, air, water, and soil (physical components) to prepare their food and grow. Animals and human beings depend on plants for food and oxygen. In return, animals and humans release carbon dioxide, which plants use for photosynthesis.
Similarly, trees help in maintaining soil fertility and regulating rainfall, while rivers and rainfall support the growth of forests and crops.
Humanistic Note:
Nature functions like a well-connected family where every component supports another. If forests are cut down or water resources are polluted, the balance of nature gets disturbed, affecting all living organisms. Therefore, we should respect and protect every part of our environment.
5. Explain how human beings are changing the environment.
Answer:
Human beings are an important part of the environment and continuously modify it to fulfil their needs and improve their standard of living.
Activities such as:
- Cutting down forests for agriculture and industries,
- Building roads, dams, and cities,
- Mining and excessive extraction of natural resources,
- Burning fuels and releasing harmful gases,
- Polluting air, water, and soil,
have brought significant changes to the environment.
These activities often disturb ecological balance, reduce biodiversity, and lead to problems such as global warming, water scarcity, and environmental pollution.
Humanistic Note:
Although human beings have the intelligence to use nature’s resources, they also have the responsibility to protect them. We should plant more trees, conserve water, reduce pollution, and use natural resources wisely. By caring for the environment today, we can ensure a cleaner, greener, and healthier Earth for future generations.
Keywords
- Biodiversity
- Environment
- Biosphere
- Hydrosphere
- Lithosphere
- Atmosphere
- Conservation
Conclusion
The environment is a precious gift of nature. The four spheres—lithosphere, atmosphere, hydrosphere, and biosphere—work together to support life on Earth. Understanding their importance helps us protect our environment and conserve natural resources for future generations.
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