NCERT Class 7 Social Science Chapter 21 Environment Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 7 Social Science Chapter 21 Environment and select need one. NCERT Class 7 Social Science Chapter 21 Environment and After Question Answers Download PDF. NCERT SST Class 7 Solutions.
NCERT Class 7 Social Science Chapter 21 Environment
Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 7 Social Science Solutions are part of All Subject Solutions. Here we have given NCERT Class 7 Social Science Chapter 21 Environment and After, NCERT Class 7 Social Science Textbook of Our Pasts – II: History, Social and Political Life – II: Civics, Our Environment: Geography. for All Chapters, You can practice these here.
Environment
Chapter: 21
Our Environment [Geography]
QUESTIONS WITH ANSWERS
I. Answer the following questions:
(i) What is an ecosystem?
Ans: A community of living things and their environment that works together as a unit is called an ecosystem. An ecosystem is formed by the interaction of all living organisms with each other and with their physical and chemical factors of the environment in which they live.
(ii) What do you mean by Natural environment?
Ans: Everything we see around us which is not made by human is a part of natural environment. Land, water, plants, animals and air comprise the natural environment. Natural environment is untouched by human interference.
(iii) Which are the major components of the environment?
Ans: The major components of the environment are classified under following leadings:
1. Natural Environment.
2. Human Environment and Human Made Environment.
Natural Environment consists of both physical and the biological environment. While human and human made environment is created by human beings interacting with the natural environment.
(iv) Give four examples of human made environment.
Ans: Building, Park, Bridges and Roads are the four examples of human made environment.
(v) What is Lithosphere?
Ans: Lithosphere is the outermost solid layer of the earth. It consists of rock materials and soil.
(vi) What are the two major components of biotic environment?
Ans: (a) Plants.
(b) Animals.
(vii) What is Biosphere?
Ans: Biosphere is the narrow zone of the contact between lithosphere, hydrosphere and atmosphere. It is also referred to as biological environment. Everything in the biosphere is interconnected and interdependent.
II. Tick the correct answer:
(i) Which is not a natural ecosystem?
(a) Desert.
(b) Aquarium.
(c) Forest.
Ans: (b) Aquarium.
(ii) Which is not a component of human environment?
(a) Land.
(b) Religion.
(c) Community.
Ans: (a) Land.
(iii) What is a human made environment?
(a) Mountain.
(b) Sea.
(c) Road.
Ans: (c) Road.
(iv) Which is a threat to environment?
(a) Growing plant.
(b) Growing population.
(c) Growing crops.
Ans: (b) Growing population.
III. Match the following:
Ans:
IV. Give reasons:
1. Man modifies his environment.
Ans: Man modifies his environment to satisfies his needs and to make his life comfortable. He also modifies his environment to adapt himself to the natural surrounding. For his comfort he made buildings, parks and roads. To make his travel comfortable he made cars, buses and develops other modes of transport but at the cost of environment. All his activities put pressures on the natural surrounding by causing noise, water and air pollution.
2. Plants and animals depend on each other.
Ans: Plants and animals depend on each other. Plants release oxygen which is essential for survival of animals. On the other hand animals release carbon dioxide which absorbed by plants to make their food.
V. Activity:
Imagine an ideal environment where you would have to live. Draw the picture of your ideal environment.
Ans: An ideal environment where I would like to live consists of:
(i) Green parks.
(ii) Clean road.
(iii) Pollution free environment.
(iv) Availability of drinking water.
(v) Proper arrangement for drainage.
Student will themselve draw the picture of their ideal environment on the given space.
SOME OTHER IMPORTANT QUESTIONS FOR EXAMINATION
Very Short Answer Type Questions
Q.1. What is environment?
Ans: Anything that surrounds us is called our environment.
Q.2. What are the two components of our environment?
Ans: The two main components of our environment are – Natural and human environment.
Q.3. What consist of human environment?
Ans: Human environment consists of human society, culture, economy, political life, religion, etc.
Q.4. What does natural environment consist of?
Ans: Natural environment consist of all living things (biotic) and non-living things (abiotic) that occur or have occurred naturally on the earth’s surface.
Q.5. What is biodiversity?
Ans: The great variety of living organisms in our environment is called biodiversity.
Q.6. What gives rise to human environment?
Ans: The relationship between natural environment including its physical natural components and the people in a given area gives rise to human environment.
Q.7. What does natural environment comprise?
Ans: Land, water, air, plants and animals comprise the natural environment.
Q.8. What is Lithosphere?
Ans: Lithosphere is the solid crust or the hard top layer of the earth.
Q.9. What is referred to as hydrosphere?
Ans: The domain of water is referred to as hydrosphere.
Q.10. What is atmosphere?
Ans: The atmosphere is the thin layer of air that surrounds the earth.
Q.11. When do we celebrated World Environment Day?
Ans: We celebrated the World Environment Day on 5th June every year.
Q.12. Where are landforms found?
Ans: Landforms are found over continents and on ocean floor also.
Q.13. Give examples of different types of water bodies.
Ans: Different types of water bodies are oceans, rivers, lakes, seas etc.
Q.14. Define Barter System.
Ans: It is a trade in which goods are exchanged without the use of money.
Q.15. What is our basic life support system?
Ans: Environment is our basic life support system.
Q.16. Distinguish between physical and biological environment.
Ans: Both physical and biological environ-ment are part of environment. Physical environment consists of atmosphere, lithosphere and hydrosphere while biological environment consists of biosphere. Biosphere is the zone of the contact of all components of physical environment.
Q.17. How does burning of leaves affect people?
Ans: The burning of leaves leads to air pollution which is the major cause of asthma and other human diseases.
Q.18. Name and explain two categories of living beings of the biosphere.
Ans: (i) Autotrophs: These are those organisms of biosphere which produces their own food.
(ii) Heterotrophs: These are those organisms that depend on plants and animals for their food.
Q.19. What is the importance of hydrosphere for living beings?
Ans: Hydrosphere refers to water on the earth. Our earth is called blue planet because its 71% of surface is covered with water bodies. It (water) fulfils all the essential requirements of all the living beings, therefore this sphere is very important.
Q.20. How does cutting of forests affect the environment?
Ans: Cutting of forests adversely affect our environment. If forests are cut down to make building, the environment will loose the major producer of the oxygen. Slowly it would affect the human beings as well.
Q.21. What are the different constituents of our natural environment?
Ans: Major constituents of our natural environment are land, water, air and living organisms.
Short Answer Type Questions
Q.1. Differentiate between Biotic and Abiotic components.
Ans:
Q.2. What is the meaning of Lithosphere? Write about its composition.
Ans: ‘Lithos’ is a Greek word, which means rocks. Rocks are the main materials of the earth’s crust. They are made up of minerals, which are found in the interior as well as on the earth’s surface. Many landforms are formed on the earth’s surface as well as on the ocean floor, through decomposition and disintegration of rocks. These are caused by both internal as well as external processes.
Q.3. Describe in brief the importance of Biodiversity.
Ans: Importance of Biodiversity: The great variety of living organisms in our environment is called biodiversity. It is one of the essential requirements for the balance between natural and human environment. It is the variety and difference among living organisms from all sources including terrestrial, marine and other ecosystems and ecological complexes of which they are a part. Biodiversity is also an integral key to develop sectors like agriculture, livestock, forestry, fishing and tourism.
Q.4. Write a short note on hydrosphere.
Ans: 1. It is the domain of water, which comprises of nearly three-fourths of the earth’s surface.
2. This includes oceans, rivers, lakes, seas and other water bodies.
3. Various types of landforms on ocean floor are seamounts, trenches, continental slopes, ridges and abyssal plains.
4. The ocean water is also saline as compared to the freshwater found on land.
Q.5. Describe the evolution of life and landforms.
Ans: Evolution of Life: Evolution means the gradual change and development of lifeforms-plants, animals and microorganisms. It also takes into account the environmental conditions in which they survive.
Evolution of Landforms: This interaction and interdependence also leads to the gradual change and development of landforms.
Q.6. Discuss the relationship between Ecosystem and Environment.
Ans: Ecosystem is a complex set of relationship that exists between the biotic and the abiotic components and with their environment. Both environment and ecosystem have similar components-Living and Non-living. However, in the case of the environment, they may exist independently, whereas, in the case of ecosystem, they form a system of interaction and interdependence.
Q.7. Define natural and human environment.
Ans: The environment which includes both the physical and the biological environment containing biotic and abiotic components is called natural environment. Land, water, air, plants and animals comprise the natural environment.
The environment which consists of human society, culture, economy, political life, religion, etc., besides man-made structures like canals, dams, roads, buildings, etc. is called Human environment.
Long Answer Type Questions
Q.1. Describe the main features of interaction and interdependence and how it takes place.
Ans: It is made possible through the cyclic movement of nutrients and energy among all these realms.
(i) Lithosphere: The rock cycle transports rocks of the earth’s crust to its interior and again back to the surface. Through this movement, soil on the earth’s crust and many other features are formed.
(ii) Atmosphere: In atmosphere, the cyclic movement of nutrients and energy takes place through the Bio-geo chemical cycle. Water cycle is one example of these cyclic motions.
(iii) Hydrosphere: The horizontal and vertical movement of water in oceans takes place through the great conveyor belt. It transports heat energy between the tropics, the poles and ocean bottoms and back.
Q.2. Write a descriptive note on ecosystem and environment with their two common components-biotic and abiotic.
Ans: Natural environment includes both the physical and the biological environment containing biotic and abiotic components.
Biotic components of environment has following features:
1. They are living things.
2. They perform functions of birth, growth and death.
3. They are found in a particular environment.
Examples: Plants and animals.
Abiotic components of environment has following features:
1. They are non-living things.
2. They supply energy to the living things.
3. They make the environment of living things.
Examples: Fire, water and soil.
Q.3. ‘Human beings interact with the environment and modify it according to their need’. Explain, how?
Ans: Human beings interact with the environment and modify it according to their need as humans adapted themselves to the natural surroundings. They led a simple life and fulfilled their requirements from the nature around them. With time, needs grew and become more varied. Humans learned new ways to use and change environment. They learned to grow crops, domesticate animals and lead a settled life. The wheel was invented, surplus food was produced, barter system emerged, trade started and commerce developed. Industrial revolution enabled large scale production. Transportation became faster. Information revolution made communication easier and speedy across the world.
Q.4. Describe the steps taken to protect our environment and ecosystem.
Ans: One of the most critical need at present is the protection of our environment and ecosystem, the basic unit of our life systems. Some of the steps towards the protection and preservation of lifeforms are as follows:
1. Waste Disposal: Waste, either from household garbage or from industries, are always harmful and need proper management.
2. Maintenance of Balance in the System: We must correct our actions to maintain the delicate balance between nature and man, like, to check pollution by using eco-friendly materials.
3. Afforestation and Check on Poaching: Proper emphasis should be given to trees and animals as both are vital sources of life, providing us clean water, air, as well as food to eat. Afforestation and reforestation should be put into practice. Poaching of animals should be checked and prohibited to maintain the proper ecological balance on the earth.
4. Saving Resources and Energy: Excessive dependence on fossil fuels and mineral resources of the earth has not only caused harm beyond the critical limit but is also holding threat of their exhaustion in the next 2-3 decades. We must think of our future generation and should maintain a balance between the human and natural components of the environment.
Q.5. Everything in the biosphere i interconnected and interdependent. How?
Ans: Everything in the biosphere is interconnected and interdependent as,
(i) Forests provide products like timber, fruits, nuts, resins, etc., and medicinal herbs.
(ii) It also provides a natural habitat for various plants and animals.
(iii) Forest helps to moderate atmospheric temperature by absorbing carbon dioxide and adding moisture to air through transpiration.
(iv) Many animals depend on forests and grassland for their food.
Q.6. How did human interaction in various form effects the environment? Explain by giving example.
Ans: Human interaction in various forms effects the environment as:
(i) Industrialisation causes smoke and other chemical pollutants which go into the air and water around them which cause contamination both in air and water and affect the life of the people.
(ii) Burning of dry leaves, plastic and cracker cause air pollution which is the main reason of asthma and many other problems.
(iii) The drainage of waste from towns and cities cause water pollution. The excessive use of chemical fertilizers and pesticides in agriculture is also a major cause of water pollution.
Higher Order Thinking Skill
Q.1. “Everything in the biosphere is interconnected and interdependent”. Explain, how?
Ans: Everything in the biosphere is interconnected and interdependent as:
(i) Forests provide products like timber, fruits, nuts and medicinal herbs.
(ii) They also provide natural habitat for various plants and animals.
(iii) Forest helps to moderate atmospheric temperature.
(iv) Many animals depend on forests and grassland for their food.
(v) Humans, in turn depend on animals as a source of food and use some animals to transport and carry heavy loads.
Q.2. “The lithosphere is that realm of the earth through which most of the human needs are met.” Explain.
Ans: Lithosphere is the outermost layer of the earth. It is that realm of the earth through which most of the human needs are met as:
(i) Land is required for human settlement.
(ii) Soil is an essential requirement for agriculture.
(iii) Industries get vital minerals and other raw materials from Lithosphere.
Value Based Questions
Q.1. How atmosphere is useful to humans beings?
Ans: Atmosphere is useful to human beings as:
(i) It provides the life-giving gas-oxygen.
(ii) It acts as a blanket and keeps the earth warm by trapping the heat that radiates from the earth.
(iii) It protects the life from harmful rays and the scorching heat of the sun.
Q.2. Environment is essential for our survival. Why should we protect it?
Ans: Environment is essential for our survival and we must protect it, as:
(i) It is our basic life support system and provides us fresh air to breath, water to drink and the food we eat.
(ii) It provides us natural resources such as fuel, wood and minerals.
Q.3. Why water is an essential component for life?
Ans: Hydrosphere refers to the water on earth. It is essential for all kinds of living beings to maintain biological water balance. It is important for the survival of humans and is helpful to them in many ways. It is used in both domestic and industrial use. We must not waste water and prevent it from getting polluted and wasted.
OBJECTIVE TYPE QUESTIONS
1. Fill in the blanks:
1. ______is our basic life support system.
Ans: Environment.
2. The _______ refers to both biotic and abiotic environment.
Ans: Natural environment.
3. _______, _______, air, plants and ______comprise the natural environment.
Ans: Land, water, animals.
4. ______ is the domain that provides us forests and grasslands for grazing.
Ans: Lithosphere.
5. The _______ is the thin layer of air that surrounds the earth.
Ans: Atmosphere.
II. Tick the (✓) correct and cross (x) the wrong statement:
1. The domain of water is referred to as biosphere.
Ans: (×).
2. Lithosphere is the solid crust or the hard top layer of the earth.
Ans: (✓).
3. French word Environer/Environner meaning “neighbourhood”.
Ans: (✓).
4. Plant and animal kingdom together make hydrosphere.
Ans: (×).
5. Early humans adapted themselves to the natural surroundings.
Ans: (✓).
III. Multiple Choice Questions (MCQs): Choose the right option:
1. Which of these is not a natural ecosystem?
(a) Desert.
(b) Aquarium.
(c) Forest.
(d) Mountains.
Ans: (b) Aquarium.
2. Which of these is a threat to environment?
(a) Growing plant.
(b) Growing population.
(c) Growing crops.
(d) Growing flowers.
Ans: (b) Growing population.
3. Which of these is not a component of human environment?
(a) Land.
(b) Religion.
(c) Community.
(d) Education.
Ans: (a) Land.
4. The interactive zone between land, air and water is called-
(a) Aquarium.
(b) Lithosphere.
(c) Biosphere.
(d) Atmosphere.
Ans: (c) Biosphere.
5. Which of these is a human made environment?
(a) Mountain.
(b) Sea.
(c) Road.
(d) Beach.
Ans: (c) Road.
6. The language from which the word ‘environment’ is derived:
(a) Spanish.
(b) French.
(c) German.
(d) Greek.
Ans: (b) French.
7. World Environment Day is celebrated on:
(a) 2nd June.
(b) 5th June.
(c) 11th June.
(d) 9th July.
Ans: (b) 5th June.
8. One of these is not a heterotrophs:
(a) Cacti.
(b) Snake.
(c) Elephant.
(d) Tiger.
Ans: (b) Snake.
IV. Match the column:
| Column A | Column B |
| (A) Lithosphere | (a) Lakes |
| (B) Hydrosphere | (b) Nitrogen |
| (C) Biosphere | (c) Continents |
| (D) Atmosphere | (d) Ecosystem |
Ans:
| Column A | Column B |
| (A) Lithosphere | (c) Continents |
| (B) Hydrosphere | (a) Lakes |
| (C) Biosphere | (d) Ecosystem |
| (D) Atmosphere | (b) Nitrogen |
