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7th Class (CBSE) Social Science: Our Environment

7th Class (CBSE) Social Science: Our Environment

Question: Explain the following terms:

  • Environment: It refers to all external conditions in which an organism lives. It comes from the French word ‘environer’ which means to surround. It is used to describe everything, such as places, things, people, nature etc. It also includes thing created by human beings.
  • Lithosphere: The rocky outermost layer of the earth is called the lithosphere. The term lithosphere means rocky crust. It includes the crust and upper part of the mantle. The average thickness of the lithosphere is about 100 km. It is made up of rocks and minerals. The uppermost part of the lithosphere forms a thin layer of soil.
  • Biosphere: The narrow zone where the lithosphere, hydrosphere, and atmosphere meet and interact is called the biosphere. The word biosphere comes from the Greek word ‘BIOS’ meaning life and Latin word ‘sphaera’ which means the total range. This sphere supports life and is thus called the ‘living world’. The biosphere consists of the plant and animal kingdom.
  • Ecosystem: The complex system of interactions between the organisms and their physical environment in a particular area is referred to as an ecosystem the size of the ecosystem varies greatly. It can be as large as rain-forests, grasslands, desserts, lakes, rivers or as small as a pond.
  • Pollution: The disturbances caused to the environment due to excessive exploitation of nature, unplanned and unwise use of technology, overpopulation, and Industrialization is called pollution.
  • Urbanization: Number of People living in urban areas as compares to the total population of the country is called urbanization.

Question: Why did the Chipko movement take place?

Answer: In 1973 the villagers in the Alaknada river valley of Uttarakhand protested against the indiscriminate cutting down of trees. They did so by hugging the trees in order to save them from being cut down. This movement became famous as the Chipko movement.

Question: What are the reasons for environment pollution?

Answer: The reasons for environmental pollution are unplanned and unwise use of technology by human beings.

Question: How can natural environment be managed properly?

Answer: A perfect balance is needed between the natural and human environment. A number of organization with the help of scientists, technologists and planners are working to solve the environmental problems facing the world.

Question: Explain the relationship between geography and environment?

Answer: Environment refers to the external conditions in which an organism lives. Geography studies the interrelationship between human beings and their environment. The relationship between geography and environment is very close.

Question: How have human needs undergone changes with the passage of time and technological development?

Answer: Early humans adjusted themselves with the surroundings in which they lived. Most of their needs were fulfilled from the environmental resources. Thus with time, the quality and quantity of human needs changed and they started developing techniques and new ways to use the environment. Humans settled in the fertile plains of the river valleys to cultivate land. They domesticated animals and learnt to use fire and invented wheel and it let to surplus food production and exchange of surplus goods.

Question: What is the importance of ecosystem?

Answer: The importance of an ecosystem is that it provides space to plants and animals to interact with each other as well as their physical environment. Through interactions they are interdependent on each other for their environment.

Question: The earth would have been a barren planet without the atmosphere do you agree? Why?

Answer: Yes, I agree because the atmosphere prevents the sun’s harmful rays from reaching the earth’s surface. It controls the extremes of temperatures during day and night. The change in weather and climate are also due to the presence of the atmosphere. Without atmosphere our earth would have been barren like other planets.

Question: Why do planet and animals depend on each other?

Answer: Planet and animals depend on each other because plants need which is given by animals and animals need food and oxygen which is given by planets.

Question: Describe the main features of natural and human made environment.

Answer: The natural elements, such as mountains, rivers, vegetation, animals, etc. are created by nature. This is called natural environment. It includes the biotic and abiotic components. The human-made elements, such as agriculture, industries, settlements, means of transport, etc. are created by human beings. Therefore, it is called human-made environment. Human being develop these features to live comfortably in their environment.

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