Quick Revision Notes: Class 7 Social Science (Geography)

Chapter: Environment

Definition: The 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.
Hindi Meaning: पर्यावरण (हमारे चारों ओर का आवरण - वायु, जल, भूमि आदि)।
Etymology: The word 'Environment' is derived from the French word "Environner", which means "neighborhood" (पड़ोस).

The environment is broadly divided into three main components:

Natural Environment (प्राकृतिक पर्यावरण):
- Created by nature.
- Includes land, water, air, plants, and animals.
- Domains: Lithosphere, Hydrosphere, Atmosphere, Biosphere.
Human Environment (मानवीय पर्यावरण):
- Created by human beings.
- Includes individuals, families, communities, religion, educational systems, economic and political situations.
Human-Made / Modified Environment (मानव-निर्मित पर्यावरण):
- Created by humans to suit their needs.
- Examples: Buildings, parks, bridges, roads, industries, and monuments.

Lithosphere (स्थलमंडल):
- The solid crust or the hard top layer of the earth.
- Made up of rocks and minerals and covered by a thin layer of soil.
- Importance: Provides forests, grasslands for grazing, land for agriculture, and human settlements.
Hydrosphere (जलमंडल):
- The domain of water.
- Includes various sources of water and different types of water bodies like rivers, lakes, seas, oceans, etc.
- Importance: Essential for all living organisms.
Atmosphere (वायुमंडल):
- The thin layer of air that surrounds the earth.
- Importance: Protects us from the harmful rays and scorching heat of the sun. Contains gases, dust, and water vapor. Changes in the atmosphere produce changes in weather and climate.
Biosphere (जीवमंडल):
- A narrow zone of the earth where land, water, and air interact with each other to support life.
- Importance: Contains all plant and animal life.

Ecosystem (पारिस्थितिकी तंत्र):
- A system formed by the interaction of all living organisms with each other and with the physical and chemical factors of the environment in which they live, linked by transfer of energy and material.
- Hindi: पारिस्थितिकी तंत्र (जीवों और उनके परिवेश के बीच का संबंध)।
Biotic (जैविक):
- The world of living organisms (e.g., plants and animals).
Abiotic (अजैविक):
- The world of non-living elements (e.g., land, water, air).
Barter System (वस्तु-विनिमय पद्धति):
- A trade in which goods are exchanged without the use of money (e.g., exchanging corn for wheat).

Early humans adapted themselves to the natural surroundings.
With time, needs grew, and humans learned to use new ways to modify the environment:
- Growing crops, domesticating animals, and settling down to a permanent life.
- Discovery of fire, invention of the wheel, emergence of the barter system, and development of trade.
- Industrial Revolution and mass production.
- Information technology (IT) revolution making communication easier and faster across the world.

World Environment Day (विश्व पर्यावरण दिवस): Celebrated worldwide on 5th June every year to raise global awareness about taking positive action to protect the environment.