PSEB Solutions for Class 7 Social Science Geography Chapter 1 Environment
SST Guide for Class 7 PSEB Environment Textbook Questions and Answers
I. Give answers to the following questions approximately in 1-15 words.
What do you understand by environment?
The environment is the surroundings of an organism. It is not the same everywhere. It changes according to the physical factors of some area, i.e. temperature and rainfall which are not same everywhere.
Which are the main spheres of the environment?
How man affects the environment?
Man affects the environment in the following ways :
- Deforestation’for procuring agricultural land.
- Making dams on rivers and changing the direction of- water towards deserts.
- Mining to get minerals from the earth.
Write down the names of layers of the earth.
The earth has three crusts
- Mantel (Sima)
II. Fill in the Blanks :
Environment has been divided in __________ spheres.
The SIAL layer of the earth is made up of the material which is rich in and __________
Silicon and Aluminium
NiFe is made up of the material which is rich in __________ and __________ elements.
Nickel and Ferrous
The different types of species of animals is known as __________
__________ portion of earth has been covered by hydrosphere.
Make a list of factors which has effect over the environment.
- Degradation Processes
- Human factors.
PSEB 7th Class Social Science Guide Environment Important Questions and Answers
Multiple Choice Questions :
Which is not a natural ecosystem?
(d) None of the above.
Choose the correct answer out of the three alternatives given :
Hard top layer of the earth is called :
Which is a large ecosystem?
Which is a human made environment?
Fill in the Blanks :
Environment has been divided in __________ sphere.
__________ portion of earth has been covered by hydrosphere.
__________ is a human made environment,
On __________ june every year world environment day is celebrated.
__________ environment is the world of nonliving things.
True / False :
The combination of Biosphere and physical environment is called ecology.
The different types of species of animals is known as Biodiversity.
Domain of water is called Biosphere.
The world of living things are called biotic environment.
Physical environment includes non-living elements.
Very Short Answer Type Questions
Name the three realms of the earth.
The environment on the earth consists of three major elements-land, water and air. All these elements are very important and lithosphere, hydrosphere and atmosphere are three realms of the earth.
When is the world environment day celebrated?
On 5 June.
What do you mean by Habitat?
On the basis, of lithosphere, hydrosphere and atmosphere, a different type of biosphere is created for flora and fauna. Like humans, these also depend upon their environment which is called Habitat.
What do you mean by Ecology?
The combination of Bio-sphere and physical environment is called Ecology.
How did the different spheres of the earth come into existence?
The earth was a gaseous formation. The gases melt, become cold and solidified. The gaseous elements became atmosphere, watery elements became hydrosphere and solid particles became lithosphere.
What is atmosphere?
Around the earth, there is a roundabout of earth which is several hundred kms wide. This is called Atmesphere. This roundabout is about 1600 km in radius but 99% of inhalable air (oxygen) is in the 32 km radius only.
What are the main elements of atmosphere?
Temperature, humidity, air pressure, etc.
Describe the distribution of land and wq£er on earth.
What is lithosphere? Write two features.
The outer solid part of earth’s surface is called lithosphere.
- Its thickness is 80-100 km.
- Its thickness is more on land and less in water.
What is the utility of lithosphere?
- It provides us forests.
- It provides grasslands for grazing.
- It provides land for Agriculture.
- It provides land for settlement.
- It is a source of mineral wealth.
Name four types of water bodies included in Hydrosphere.
Rivers, lakes, seas, oceans.
State two functions of Atmosphere.
- It provides life-support gases.
- It keeps the earth’s temperature moderate.
- It protects us from hot-ultraviolet rays of the sun.
Give four examples of ecosystems.
- A large rain forest
- A grassland
- A desert
- A mountain.
Differentiate between Natural and Human Environment.
|Natural environment||Human environment|
|1. Land, water, air, plants and animals comprise the natural environment.||1. Individual, family, community, education religion,comprise the human environment.|
|2. It is essential for the existence of plant and human life.||2. It provides knowledge and technology to utilise the natural environment.|
Distinguish between Physical and Biological environment.
|Physical Environment||Biological Environment|
|1. Land, water, air and inorganic elements form the physical environment.||1. Plants, animals (including man) and organisms form biological environments.|
|2. It is essential for the existence of plants and human life.||2. It provides food and other materials for human beings.|
|3. It includes non-living elements.||3. It includes all living elements.|
|4. The physical environment influences human activities.||4. The physical and human environment interact with each other.|
What is Biosphere? Write its two components.
Plants and animals together form biospljere or the living world. It is narrow zone on the earth where land, water and air comes in contact with each other to support life.
By which name we call the sphere, that is product of interaction of three spheres? Write in brief. ‘ ‘
The sphere made up by the combination of three spheres is called biosphere. It is made up of atmosphere, lithosphere and hydrosphere. Biosphere is the most important sphere on the earth because here the effect of natural factors is quite visible.
What do you mean by changing environment?
On the surface, environment is ever changing because all its elements undergo a change. These elements are interdependent. The changes in natural environment brings about changes in Biological environment.
Short Answer Type Questions
Name the uses of Environment.
- It provides the air we breath.
- It provides water and drink.
- It provides food we eat.
- It provides land where we live.
From the earth’s surface till the deep inside, in how many parts has the earth been divided? Write each in brief.
- Earth’s surface: It is the upper most part of earth. It is called Sial. It has mainly Silicon (Si) and Aluminium (Al).
- Mantle: It is the middle part of earth called Sima. Its main components are Silicon (Si) and Magnesium (Mg).
- Central part/Core: It is the deep inside of earth called Nife. It has more of Nickle (Ni) and Iron (Ferrous Fe).
What is the importance of oceans?
The hydrosphere is the part of the earth’s surface, covered by water. Rivers, lakes, seas and oceans form this sphere. More than 70 per cent of the earth’s surface is covered with water. Continents are like vast islands floating in the oceans. On the other hand, oceans are the major links between landmasses. Water supports all forms of life on the earth and is very crucial for our survival.
‘Man modifies his environments’. Discuss.
Human life is closely related to the environment, Man modifies environment according to his needs. He learnt to cultivate crops, domesticate animals and lead a settled life. He used raw materials to make finished goods.
Why is it necessary to study natural environment?
The study of natural environment is necessary because it, provides us conditions for living like land, air, water and food. It affects our economic activities and basic needs of food, shelter and clothing. It is the basic life supporting system on the earth.
‘Most of the environmental problems are man-made.’ Explain.
Man is using water, land, soil and other resources at such an alarming rate that there will be serious shortage of these resources in the near future. Careless use may destroy them to such an extent that they may not be available to mankind. Man will have to live in harmony with the environment so that ecological balance is not disturbed.
‘Man has disturbed the environment.’ Discuss.
Man has tried to exploit the resources of Biosphere. But he has disturbed the eco-system in this attempt. Human interference with the natural environment has modified or altered the ecosystem in many areas.
- Deforestation for cultivation has changed the habitat of the organisms living in the forests.
- It has resulted in soil erosion.
- Excessive cultivation, over-grazing, and shifting agriculture have increased the rate of soil erosion.
- Irrigation projects in dry areas have resulted into salinization of soil and spread of water borne diseases.
- Land, air and water have got polluted and have become unsuitable for human consumption.
- In recent years, environmental pollution and presence of chemicals in air, water and food has damaged human health.
‘The earth is a unique planet.’ Give reasons.
The earth is a unique planet of the Solar System because its environment favours the evolution and survival of life to make it a life bearing layer or biosphere.
- It is the only planet supporting plant and human life.
- On the earth moderate temperatures (Mean temp. 15°C) are found. It is neither too hot like Mercury, nor too cold like Jupiter due to optimum distance of the earth from the sun.
- The presence of oxygen nad nitrogen in the atmosphere around the earth favours the existence of life on the Earth. The atmosphere protects the earth from high temperatures.
- The earth is a ‘watery planet’. Water cycle on the earth provides water for growth of all living beings. The earth is the home of man.
Why should we protect our environment?
- Environment is our basic life support system. It provides the air we breathe, the water we drink, the food we eat and the land where we live.
- It provides us natural resources such as wood, fuel, energy and minerals.
- Most of the human activities affect the environment in one way or the other.
- Many parts of the environment have already been badly damaged by over use or irrational use of resources like forest, pastures and farms.
- If we continue to do so, the damage will be irreparable and the consequences will be very serious.
What are the biotic and abiotic components of the natural environment?
- Biotic component is the world of living organisms for example – plants and animals.
- Abiotic components are non-living elements for example land and minerals etc.
How many types of environment are there? Give brief account.
The environment is of three types-Physical, Cultural and Biological.
- The physical environment is the prevailing natural conditions comprising the land, water and air.
- The environment of lifeforms plants, animals including humans and other organisms is called biological environment.
- Cultural environment includes man-made features like settlements, roads, industries etc.
Long Answer Type Question
Describe the four spheres of environment.
Broadly we can divide the environment into four spheres atmosphere, lithosphere, hydrosphere and biosphere.
1. Atmosphere: The atmosphere is the thin layer of air that envelops our earth. It is very dynamic in nature, changes can take place every hour. These changes in the atmosphere produce weather and climate. The atmosphere is not uniform all through its width. There are several layers of the atmosphere. The atmosphere provides a setting in which all forms of life are created and sustained. The force of gravity exerted by the earth holds the atmosphere around it. The atmosphere protects us from scorching heat and harmful ultraviolet radiation.
2. Lithosphere: The lithosphere is the layer of the earth consisting of rock materials, extending both over the continents and ocean basins. The overage thickness of the lithosphere is about 100 km.
- The lithosphere is composed of oceans and continents. It has two parts—Sial and Sima.
- The lithosphere is the sphere which provides us land to settle, soils for plants and is a source of mineral wealth.
Four Spheres of The Earth
3. Hydrosphere: The hydrosphere is the part of the earth’s surface, covered by water. Rivers, lakes, seas and ocean form this sphere. More than 70 per cent of the earth’s surface is covered with water. Continents are like vast islands floating in the oceans. On the other hand, oceans are the major links between landmasses. Water supports all forms of life on the earth and is very crucial for our survival. Oceans provide us with food and minerals. Even in the sea-bed, deposits of mineral, oil and gas are found.
4. Biosphere: The biosphere is a very narrow sphere of the earth which contains life. This sphere includes parts of the atmosphere, hydrosphere and lithosphere. Most of the living organisms be it plants or animals on the earth are found on or near the surface of land or water surrounded by air. Thus the biosphere is a very narrow zone where life on this planet exists.
Environment PSEB 7th Class SST Notes
- Earth: The earth is called a blue planet-71% is water and 29% island.
- Environment: Environment means surroundings. Its components are the Physical, Biological and Cultural environment.
- Physical Environment: The prevailing natural conditions comprising the land, water and air.
- Biological Environment: It consists of all life forms – animals including humans, plants and other organisms.
- Earth’s Spheres. The above four components form spheres called lithosphere, hydrosphere, atmosphere and biosphere.
- Lithosphere: The outermost layer of the crust is called lithosphere (Rock-sphere). The rocky layer under continents is called Sial and under oceans is called Sima.
- Hydrosphere: Rivers, lakes, seas and oceans comprise this sphere and provide support to all life-forms.
- Atmosphere: The thin layer of air around earth.
- Biosphere: Biosphere is a narrow zone of contact between land, water and air. It is life giving sphere.
- Biotic environment: The world of living things.
- Abiotic environment: The world of non- living things.
- Components of environment: Land, Water, Air.
- Crust: Hard top layer of the earth.
- Landforms: Mountains, Plateaus, Plains.
- Ecosystem: A community of plants and animals within a particular physical environment.
- Human Environment: Human life is closely related to the environment of the earth.
Punjab State Board PSEB 7th Class Social Science Book Solutions Geography Chapter 1 Environment Textbook Exercise Questions and Answers.