These DAV Class 7 SST Book Solutions Pdf and DAV Class 7 SST Chapter 1 Question Answer – Components of Environment are thoughtfully prepared by experienced teachers.
DAV Class 7 SST Ch 1 Question Answer – Components of Environment
DAV Class 7 SST Ch 1 Solutions – Components of Environment
Something To Know
A. Tick (✓) the correct option.
Question 1.
Which one is not a part of biological environment?
(a) plants
(b) water
(c) animals
(d) human beings
Answer:
(b) water
Question 2.
Volcanoes erupt due to
(a) internal disturbance of the earth.
(b) external disturbance of the earth.
(c) climate change.
(d) man-made changes on the earth.
Answer:
(a) internal disturbance of the earth.
Question 3.
Which one brings a sudden change in the environment?
(a) formation of a river
(b) rainfall
(c) growth of a plant
(d) formation of a mountain
Answer:
(b) rainfall
Question 4.
Identify by the term that stands for the topmost layer of the earth comprising of loose material
(a) minerals
(b) soil
(c) sial
(d) sima
Answer:
(c) sial
Question 5.
In which year was the Wildlife Protection Act passed in India?
(a) 1971
(b) 1972
(c) 1973
(d) 1974
Answer:
(b) 1972
B. Give a single term for each of the following statements.
Question 1.
A situation or condition in which an organism lives.
Answer:
Environment.
Question 2.
The only planet in our solar system where life exists.
Answer:
Earth.
Question 3.
The uppermost part of the lithosphere which is rich in silica and aluminium.
Answer:
Soil.
Question 4.
The sphere of air that envelopes the earth.
Answer:
Atmosphere.
Question 5.
Mass of water on the earth’s surface.
Answer:
Hydrosphere.
C. Match the following:
| Physical environment includes | (a) Atmosphere |
| It is the most dynamic in nature | (b) Human beings |
| A narrow zone supporting life | (c) Non-living things |
| They are capable of modifying environment | (d) Biosphere |
| Rocks rich in silica and magnesium | (e) Sima |
Answer:
| Physical environment includes | (c) Non-living things |
| It is the most dynamic in nature | (a) Atmosphere |
| A narrow zone supporting life | (d) Biosphere |
| They are capable of modifying environment | (b) Human beings |
| Rocks rich in silica and magnesium | (e) Sima |
D. Answer the following questions in brief.
Question 1.
Name the major components of the environment.
Answer:
The major components of the environment are—natural (land, air, water, living things), human-made (buildings, bridges, industries, roads, parks, monuments, etc.), and human (individual, family, community, religion, educational, economic, etc.).
Question 2.
What do you mean by Sima and Sial?
Answer:
The uppermost part of the lithosphere is composed of rocks rich in silica and aluminium called sial. Below the sial layer, the rocks are mainly rich in silica and magnesium and are called sima. It is generally found below the bottom of the ocean basins.
Question 3.
Mention the distribution of water in the Northern and Southern hemispheres.
Answer:
It is estimated that 43% of the total area covered by water lies in the Northern hemisphere; whereas the remaining 57% lies in the Southern hemisphere.
Question 4.
Give the literal meanings of fou spheres of environment.
Answer:
(i) Lithosphere – the ‘sphere of rocks’.
(ii) Atmosphere – the ‘sphere of air’.
(iii) Hydrosphere – the ‘sphere of water’.
(iv) Biosphere – the ‘sphere of life’.
Question 5.
What is the atmosphere composed of?
Answer:
The atmosphere is composed of a mixture of gases like oxygen, nitrogen, carbondioxide, hydrogen, ozone, etc.
E. Answer the following questions.
Question 1.
Differentiate between the physical and the biological environment.
Answer:
The physical environment includes the non-living elements of the environment such as the land, water and air. The biological environment, on the other hand, includes all living things such as, plants, animals and other living organisms.
Question 2.
Why is the earth also called the ‘Blue Planet’?
Answer:
71% of the earth’s surface is covered by waterbodies that include rivers, lakes, seas and oceans. The earth is called the ‘Blue Planet’ because of this abundance of water on its surface.
Question 3.
Define biosphere. Why is it important for us?
Answer:
The word biosphere literally means the ‘sphere of life’. It is the narrow zone where we find land, water and air together. All kinds of life exist in this zone. Therefore, it is important for us.
Question 4.
Explain with the help of an example how physical and biological components of the environment are interdependent.
Answer:
The physical and biological com¬ponents of the environment are interdependent. It means they cannot be separated. Any major change in the physical environment is bound to bring a change in the accompanying biological environment.
Example:
The development of soil takes years together and cannot be noticed through our senses. On the other hand, some changes are very sudden. The occurrence of an earthquake or volcano can bring sudden changes.
Question 5.
Explain two ways in which human beings are disturbing the natural environment.
Answer:
Human beings use the environment for their selfish motives and many times disturb the natural balance of the environment. The two ways in which they are disturbing the natural
environment are –
(i) Technological and scientific development have posed danger.
(ii) Forests are being cut on a large scale. This has reduced the green cover on the earth.
Value-Based Question
1. On 25 April 2015, a massive earthquake of 7.8 magnitude struck 77 km northwest of Nepal’s capital, Kathmandu. It was the most powerful earthquake to have hit Nepal since 1934. It led to heavy loss of life and property. During this earthquake, four men were trapped under the 10 feet rubble. They were rescued by NASA technology, FINDER (Finding Individuals for Disaster and Emergency Response) which sensed their heartbeats. This was the first time when this technology was used in a real-life situation. This is indeed a big step towards disaster management. But this is no way, reduces our responsibilities as human beings.
- Under the circumstances, what best can we do after the disaster?
- Suggest any five ways in which we can help the victims of a disaster.
Answer:
Do it yourself with the help of Internet.
Map Skill
Question 1.
On an outline map of the world, show the given National Parks.
(a) Gir National Park – India
(b) Jim Corbett National Park – India
(c) Yellowstone National Park – USA
(d) Serengeti National Park – Tanzania
(e) Fiord land National Park – New Zealand
Answer:
Something To Do
Question 1.
Hold a class discussion on good and bad environment.
Answer:
Do yourself.
Question 2.
Prepare a diagram showing different spheres of the environment
Answer:
Question 3.
Prepare 20 flash cards showing the wildlife species of India (flora and fauna both), based on this, hold a quiz in the class showing one flash card at a time. For every card, ask the questions like –
(a) Who has seen it live and where?
(b) If not, where can we see it live?
Answer:
Do it yourself.
DAV Class 7 Social Science Chapter 1 Question Answer – Components of Environment
A. Tick (✓) the correct option.
Question 1.
The sphere of the environment where life exists is called
(a) biosphere
(b) hydrosphere
(c) lithosphere
(d) atmosphere
Answer:
(a) biosphere
Question 2.
The sphere of the environment which provides for us land is called
(a) hydrosphere
(b) atmosphere
(c) lithosphere
(d) biosphere
Answer:
(c) lithosphere
Question 3.
The sphere which is the most dynamic in nature is
(a) biosphere
(b) lithosphere
(c) hydrosphere
(d) atmosphere
Answer:
(d) atmosphere
Question 4.
The number of National Parks in India is
(a) 489
(b) 301
(c) 103
(d) 89
Answer:
(c) 103
Question 5.
The uppermost part of the lithosphere is composed of
(a) rocks
(b) minerals
(c) soil
(d) magnesium
Answer:
(a) rocks
Question 6.
The most important component of the biological environment is
(a) plant
(b) man
(c) water
(d) land
Answer:
(b) man
B. Fill in the blanks.
1. The lithosphere is about …………… km in thickness.
2. ………….. and ………….. are the living components in the environment.
3. ………….. The Act 1972 was passed in India to protect the species of plants and animals.
4. …………. is the process which brings out emergence of new species of plants and animals in the environment.
5. ………….. form the major part of water on earth.
Answer:
1. 100
2. Plants; animals,
3. Wildlife Protection,
4. Biodiversity
5. Oceans.
C. Very Short Answer Type Questions
Question 1.
What is the atmosphere?
Answer:
It is a gaseous envelope extending about 1600 km above the earth’s surface.
Question 2.
What do you know about the distribution of water in the Northern and Southern hemispheres?
Answer:
The distribution of water is not uniform in the Northern and Southern hemispheres. About 43% of the total area covered by water lies in the Northern hemisphere and 57% lies in the Southern hemisphere.
Question 3.
Where is Sima found?
Answer:
Sima is generally found below the bottom of the ocean basins.
Question 4.
What percentage of the Earth’s surface is covered by water?
Answer:
71 per cent.
Question 5.
How can you say that the ocean is the largest reservoir of water?
Answer:
90 per cent part of water is covered by four oceans, namely, Pacific, Atlantic, Indian and Arctic.
Question 6.
Name two groups of environment.
Answer:
1. Physical environment
2. Biological environment.
D. Short Answer Type Questions
Question 1.
How can you say that environment has both natural and man-made elements?
Answer:
The environment provides us the air we breathe, the water we drink, the food we eat and the land where we live. It also includes plants, animals and a large variety of man-made things which are necessary for our being. Thus, we can say that environment has both natural and man-made elements.
Question 2.
Among the four major elements of the environment, atmosphere is the most dynamic in nature. Explain.
Answer:
It is an atmosphere where changes occur not only from one season to another but also within a short period of time (a few hours). These sudden changes produce changes in weather conditions which affect our life both directly and indirectly.
Question 3.
What do you mean by the term biodiversity? What has the Government of India done to protect and conserve it?
Answer:
Our earth is full of diversities. There is diversities in land, soil, plants and animals. This process of diversification has occurred over a long period of time. As a result of this, new species of plants and animals have emerged. These changes together are known as biodiversity. To protect and conserve this biodiversity, the Government of India has passed the Wildlife Protection Act 1972 under which 103 National Parks and 535 Wildlife Sanctuaries have been established in the country.
Question 4.
What is expected from the human beings?
Answer:
It is expected from the human beings that they live in harmony with their surroundings. This will allow the earth to sustain all forms of life on it. If they exploit various resources available on the earth, they must do it carefully and responsibly.
E. Long Answer Type Questions
Question 1.
What is lithosphere? Give a brief description of it.
Answer:
The lithosphere refers to the solid portion of the earth where we live. It is about 100 km in thickness. The uppermost part of the lithosphere is composed of rocks rich in silica and aluminium called sial. Below this layer, the rocks are mainly rich in silica and magnesium, which together are called sima. It is generally found below the bottom of the ocean basins. This sphere provides for us land which we live on. It provides soil for the plants. It is also a source of different minerals.
Question 2.
Define atomosphere, hydrosphere and biosphere.
Answer:
Atmosphere. The atmosphere is composed of a mixture of gases which forms an envelope around the earth. It is a gaseous envelope extending about 1,600 km above the earth’s surface. Of the total mass of the atmosphere, 99 per cent exits within 32 km of height from the earth’s surface. Hydrosphere. The planet earth is often called the Water Planet or the Blue Planet because of abundance of water on its surface. The water bodies that include rivers, lakes, seas and oceans cover 71 per cent of the earth’s surface.
The distribution of water is not uniform in both the Northern and the Southern Hemispheres. It is estimated that 43 per cent of the total area covered by water lies in the Northern Hemisphere whereas the remaining 53 per cent lies in the Southern Hemisphere. Oceans hold 96.5 per cent water on the earth.
Rest of the water is available in the form of ice, water vapours, underground water, rivers and lakes. Biosphere. It is the narrow zone of contact between all the three spheres of environment where all kinds of life exist. Most of the living organisms like plants, animals and microbes present on the earth are found on or near the earth’s surface of the land, water and air. Human beings are an important part of the biosphere. They are capable of changing it.
Question 3.
Suggest ways in which we can live in harmony with our surroundings and stop the exploitation of the environment.
Answer:
The exploitation of the environment can be stopped through the following measures.
- Hunting and poaching of wild animals should be stopped. We should refuse buying things made from parts of the bodies of animals; such as, their bones, horns, fur, skins and feathers.
- Afforestation should be encouraged
- Population growth should be checked.
- Awareness about environment should be spread.