Environment - Solutions

 CBSE Class –VII Social Science

NCERT Solutions
Geography Chapter 1
Environment

Q1. Answer the following questions.

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

Ans:

  1. Plants, animals, and human beings depend on their immediate surroundings. They are often interdependent for many reasons. These relations of dependence and interdependence together constitute an ecosystem.
    In other words, an ecosystem is a system formed as a result of the interactions of all living organisms with each other, and with the physical and chemical factors of the environment in which they live.
  2. The environment is our basic life supporting system. Any environment which is found naturally is known as a natural environment. Natural environment refers to both biotic and abiotic conditions existing on the earth. The environment that consists of all objects created by nature is called natural environment. The natural environment comprises land, water, air, plants and animals. In other words, they are known as lithosphere, hydrosphere, atmosphere and biosphere.
  3. There are three major components of the environment, namely natural environment (consists of all objects created by nature), human environment(consists of human beings) and human-made environment (consists of objects created by human beings). Natural environment comprises land, water, air, plants and animals. The human environment comprises human beings. The human-made environment comprises bridges, roads, monuments etc.
  4. Parks, buildings, roads, and industries are some examples of the human-made environment. These are created by human beings and not found naturally.
  5. Lithosphere(or the domain of land) is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals and is covered by a thin layer of soil. It is an irregular surface with various landforms such as mountains, plateaus, plains and valleys. It has varied landforms and are found over continents and also on ocean floors. It is the domain that provides us forests, grasslands for grazing, land for agriculture and human settlements. It is also a source of mineral wealth.
  6. The two major components of the biotic environment are plants and animals. They support each other. They cannot survive without each other.
  7. The biosphere is the narrow zone of the Earth in which land, water, and air interact with each other to support life. It comprises all organisms which have a life. For example, human beings, plants and animals.

Q2. Tick the correct answer:
(i) Which is not a natural ecosystem?
(a) Desert
(b) Aquarium
(c) Forest
(d) Lake
Ans: (b) Aquarium

(ii) Which is not a component of the human environment?
(a) Land
(b) Religion
(c) Community
(d) School
Ans:(a) Land

(iii) Which is a human-made environment?
(a) Mountain
(b) Sea
(c) Road
(d) River
Ans: (c) Road

(iv) Which is a threat to the environment?
(a) Growing plant
(b) Growing population
(c) Growing crops
(d) Growing intelligence
Ans: (b) Growing population

Q3. Match the following.

(i) Biosphere(a) blanket of air which surrounds the earth
(ii) Atmosphere(b) domain of water
(iii) Hydrosphere(c) gravitational force of the earth
(iv) Environment(d) our surroundings
 (e) narrow zone where land, water and air interact
 (f) a relation between the organisms and their surroundings

Ans:

(i) Biosphere(e) narrow zone where land, water and air interact.
(ii) Atmosphere(a) blanket of air which surrounds the earth
(iii) Hydrosphere(b) domain of water
(iv) Environment(d) our surroundings

Q4. Give reasons:
(i) Man modifies his environment.
(ii) Plants and animals depend on each other.

Ans: (i) The environment is our basic life support system. Early humans adapted themselves to the natural surroundings. They led a simple life. With time, needs grew and became varied. To fulfill his needs, man built homes and factories and modified the environment and its mineral wealth. For food, shelter and agriculture, he cut forests and utilized water. The car fumes pollute the air, water is collected in a pot and food is served in vessels. Due to industrial revolution and technological innovations, man has used fossil fuels such as coal and petroleum and has invaded animal habitat for his own development. Human beings made cars, mills, factories and manufactured containers. This is how a man not only modified the environment but also destroyed it.
(ii) Plants and animals are interdependent. They cannot survive without each other. Plants consume carbon dioxide and give oxygen to air and prepare food, thus are producers. Animals consume plants and plant products. They also absorb oxygen and release carbon dioxide for plants. The dead and decaying animals act as nutrition to plants. Forests are the natural habitat for wildlife. Plants also serve as medicinal herbs for animals.