Chapter 1. Environment

• place, people, things & nature that surround any living organism is known as environment. This is a combination of natural and human made phenomena. natural environment refers to both biotic and abiotic conditions existing on Earth.
• Tropic of Cancer [23°30’N] divides India into two almost equal parts.

Natural Environment
• Natural environment comprises land, water, air, plants & animals.
• Lithosphere: Lithosphere is solid crust or hard top layer of Earth. Landforms are found over continents and on ocean floors.
• Environment provides:
(1) Basic life support system
(2) air
(3) water
(4) food
(5) land

• Lithosphere is solid crust or hard top layer of earth. This is made up of rocks and minerals and covered by a thin layer of soil. This is an irregular surface with various landforms such as mountains, plateaus, plains, valleys.
• Landforms are found over continents and on ocean floors such as mountains, plateaus, plains, valleys.
• Lithosphere is domain that provides us with forests, grasslands for grazing, land for agriculture and human settlements. This is a source of mineral wealth.

• domain of water is referred to as hydrosphere. It comprises various sources of water and different types of water bodies like rivers, lakes, seas, oceans. This is essential for all living organisms.

• atmosphere is thin layer of air that surrounds Earth.
• gravitational force of earth holds atmosphere around it. It protects us from harmful rays and scorching heat of Sun. It consists of a number of gases, dust & water vapour.
• changes in atmosphere produce changes in weather and climate.

• Plant and animal kingdoms together make biosphere or living world. This is a narrow zone of Earth where land, water & air interact with each other to support life.

• This is a system formed by interaction of all living organisms with each other It includes physical and chemical factors of environment in which all living beings live and all are linked by transfer of energy and material.
• All plants, animals & human beings depend on their immediate surroundings.
• These relations between living organisms, as well as relation between organisms and their surroundings, form an ecosystem.
• There could be an ecosystem of any large rain forest, grassland, desert, mountain, lake, river, ocean & even a small pond.

Human Environment
• Human beings interact with environment and modify it according to their needs.
• Early humans adapted themselves to their natural surroundings.
• Humans learn new ways to use and change environment. They learn to grow crops, domesticate animals and lead a settled life.
• wheel was invented, surplus food was produced, barter system emerged, trade started and commerce developed.
• industrial revolution enabled large scale production.
• Transportation became faster. Information revolution made communication easier and speedy across world.

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