Environment - Revision Notes

 CBSE Class 07 Social Science

Revision Notes
Geography Chapter – 1

  • Environment is the basic life support system that helps us live.
  • The nature, place, people, things, etc. that surround the living organisms make the environment.
  • It has three components: Natural, human and human-made.
  • It is a combination of both natural as well as man-made phenomena.
  • Natural environment comprises biotic and abiotic conditions, whereas the man-made phenomena comprises the activities and interactions among human beings.
  • Biotic conditions refer to the living organisms and abiotic conditions refer to the non-living elements.

• Natural Environment:

(i) Lang, water, air, plants and animals comprise the natural environment.

(ii) Lithosphere, atmosphere, hydrosphere and biosphere are the four domains of the natural environment.

(iii) Lithosphere is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals and has a thin layer of soil on top. It contains landforms like mountains, plateaus, plains and valleys.

(iv) Hydrosphere is the domain of water. It comprises water bodies like rivers, lakes, seas, oceans, etc. It is essential for life.

(v) The atmosphere is the thin layer of earth that surrounds the earth. It protects us from the harmful rays and scorching heat of the sun. The gravitational force of the earth holds the atmosphere around it. The changes in the atmosphere create the weather and climate.

(vi) Biosphere is a narrow zone of the earth where land, water and air interact with each other to support life. Both the Plant and Animal Kingdoms make up the biosphere.

• What is Ecosystem?

(i) The relation between the living organisms and the relation between the organisms and their surroundings form the ecosystem. The ecosystem is the biological community of interacting organisms and their physical environment.

(ii) There could be an ecosystem of a large rain-forest, grassland, desert, mountains, lake, river, ocean and even a small pond.

• Human Environment:

(i) Human beings interact with the environment and modify it according to their needs.

(ii) Early humans adapted themselves to their natural surroundings. They learned to invent the wheel, grow crops, domesticate animals, hunt and gather food.

(iii) With time, trade and commerce flourished and the barter system emerged.

(iv) Industrial revolution, transportation and information revolution and information made communication easier and speedy across the world.

(v) Humans need to maintain a perfect balance between natural environment and themselves. Humans must learn to live and use their environment in a harmonious way.