NCERT Solutions For Class 7 Geography Social Science Chapter 1 Environment

Question 1.
Answer the following questions briefly.

1. What is an ecosystem?
2. What do you mean by the natural environment?
3. Which are the major components of the environment?
4. Give four examples of a human-made environment.
5. What is the lithosphere?
6. Which are the two major components of the biotic environment?
7. What is the biosphere?

Answer:

1. All plants, animals and human beings depend on their immediate surroundings. They are also interdependent on each other. This relation between the living organisms as well as the relation between the organism and their surroundings form an ecosystem.
2. The natural environment consists of land, water, air, plants and animals. Thus, the natural environment refers to both biotic (plants and animals) and abiotic (land) conditions that exist on the earth.
3. The major components of the environment are—natural (land, air, water, living things), human-made (buildings, parks, bridges, roads, industries, monuments, etc.), and humans (individual, family, community, religion, educational, economic, etc).
4. Four examples of human-made environments—buildings, parks, bridges, and roads.
5. The lithosphere is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals and covered by a thin layer of soil. It is an irregular surface with various landforms such as mountains, plateaus, plains, valleys, etc.
6. Plants and animals are the two major components of a biotic environment,
7. The biosphere is a narrow zone of the earth where land, water, and air interact with each other to support life. Thus, plant and animal kingdom together make biosphere, ie., the living world.

Question 2.
Tick the correct answer.

1. Which is not a natural ecosystem?
   (a) Desert
   (b) Aquarium
   (c) Forest.
2. Which is not a component of the human environment?
   (a) Land
   (b) Religion
   (c) Community.
3. Which is a human-made environment?
   (a) Mountain
   (b) Sea
   (c) Road.
4. Which is a threat to the environment?
   (a) Growing plant              (b) Growing population
   (c) Growing crops.

Answer:
(i)—(b), (ii)—(a), (iii)—(c), (iv)—(b).

Question 3. Match the following:

1. Biosphere              (a)    blanket of air which surrounds the earth
2. Atmosphere          (b)   domain of water
3. Hydrosphere       (c)    gravitational force of the earth
4. Environment      (d)    our surroundings
   (e) the narrow zone where land, water, and air interact

Answer: 

1. —(e)
2. —(a)
3. —(b)
4. —(d)

Question 4.
Give reasons:

1. Man modifies his environment
2. Plants and animals depend on each other.

Answer:

1. Man modifies his environment in the following ways:
   • He cuts forests and clears land for agriculture, industries, and habitation.
   • He tills land for agriculture.
   • He uses the land to build buildings, roads, and railways.
   • He uses water.
   • He uses air for his survival.
   • He sets up industries, factories, etc.
   • He does numerous other activities for his life, making it comfortable.
2. Plants and animals depend on each other in the following ways:
   • Plants provide food to animals.
   • They, in the form of forests, provide shelter to wildlife.
   • Wildlife adds beauty to the forests.
   • Animals provide manure to plants for growth.
   • Animals also provide beauty to forests.
   • Dead animals also provide humus content.

Question 5. Activity
Imagine an ideal environment where you would love to live. Draw the picture of your ideal environment.
Answer: Students are expected to do this activity themselves. However, a sample is given below:

Very Short Answer Type Questions

Question 1.
What is the environment? [Imp.]
Answer:
Everything that we see in our surroundings forms environment. It is our basic life support system. It provides us air, water, food, and land—the basic needs of our life.

Question 2.
Why is our environment changing?[V. Imp.]
Answer:
Our environment is changing because our needs are increasing day by day. To fulfill these needs we often don’t think about the environment and start modifying it.

Question 3.
What are the basic components of the natural environment?
Answer:
The basic components of the natural environment are—land, water, air, plants and animals.

Question 4.
What does the lithosphere provide us? [Imp.]
Answer:
Lithosphere provides us forests, grasslands for grazing land for agriculture and human settlements. It is a rich source of minerals.

Question 5.
Name different types of water bodies.
Answer:
Rivers, lakes, seas, oceans, etc.

Question 6.
How is the atmosphere important for us? [Imp.]
Answer:
The atmosphere protects us from the harmful rays and scorching heat of the sun.

Question 7.
What do you see in the deserts? Name some animals.
Answer:
We see camels, snakes, lizards, and insects.

Question 8.
What is the barter system?
Answer:
The barter system is a method of trade in which goods are exchanged without the use of money.

Question 9.
Distinguish between the biotic and abiotic environments with examples.
Answer:
The world of living organisms is known as a biotic environment. Example: plants and animals.
The world of the non-living element is known as the abiotic environment. Example: land.

Question 10.
How is the environment important for us?
Answer:
It is important for us because it is the provider of air, water, food, and land— the basic necessities of life.

Short Answer Type Questions

Question 1.
Write a note on the lithosphere. [Imp.]
Answer:
The lithosphere is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals. It is covered by a thin layer of soil. It is an irregular surface with various landforms such as mountains, plateaus, deserts, plains, valleys, etc. The lithosphere plays an important role in our life. It provides us forests, grassland for grazing, land for agriculture, and human settlements. It is also a treasure of various minerals.

Question 2.
Give an account of the atmosphere.
Answer:
Atmosphere is the thin layer of air that surrounds the earth. It is made up of various gases such as oxygen, nitrogen, carbon dioxide, dust particles and water vapor. The gravitational force of the earth holds the atmosphere around it. It protects us from harmful rays and scorching heat of the sun. The changes in the atmosphere produce changes in the weather and climate.

Question 3.
How do human beings modify the natural environment? [V. Imp.].
Answer:
The needs of human beings are increasing day and day. Hence, they modify the natural environment to fulfill these needs. Sometimes they even destroy their environment Human beings have made cars for their convenience. These cars release fumes which pollute the air. They have established factories on land. These factories manufacture various items such as containers. This is how they modify natural environment.

Long Answer Type Questions

Question 1.
Give an account of various domains of the environment.
Answer:
Various domains of the environment are:

1. Lithosphere
2. Atmosphere
3. Hydrosphere
4. Biosphere
5. It is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals and covered by a thin layer of soil. It provides us forests, grasslands, and land. It is a source of mineral wealth.
6. It is the thin layer of air that surrounds the earth. The gravitational force of the earth holds the atmosphere around it. It protects us from harmful rays and scorching heat of the sun. It consists of various gases, dust, and water vapour.
7. It refers to various water bodies such as rivers, lakes, seas, oceans, etc. that exist on the earth.
8. The biosphere or the living world is comprised of plant and animal kingdom. It is a narrow zone of the earth where land, water, and air interact with each other to support life.

Question 2.
How have human beings adapted to the environment to fulfill their needs?
Answer:
Human beings from the early times have been interacting with the environment and modifying it according to their needs. Early humans adapted themselves to their natural surroundings. They led a simple life and fulfilled their requirements from the nature around them. But their needs kept on increasing. They became varied also. To fulfill these varied needs, humans learned to grow crops, tamed animals, and began a settled life.

The wheel was invented, surplus food was produced, the barter system emerged, trade started and commerce developed. The industrial revolution made possible large scale production. By and by transportation became faster. The information revolution made communication easier and speedy across the world. In this way, human beings adapted to the environment in order to fulfill their needs.