UGC NTA NET Exam Preperation : Structure of Environment |Unit-9| Part-1|

 UGC NTA NET Exam Preparation : Structure of Environment |Unit-9| Part-1|

Environment: Everything that surrounds or affects an organism during its life time, is collectively known as its environment. Environment is derived from the French word 'Environ' which means 'our surrounding'.

Environment makes up our surrounding and affects our quality to live on the earth. The air we breath, the water that covers most of the earth surface, the plants and animals around us and so on come in our environment.

Structure of Environment: Our environment can be divided into following 4 segments

1. Lithosphere: It is the solid crust or the hard top layer of the earth. It is made up of rocks and minerals and covered by a thin layer of soil. It constitutes about 29% part of the Earth, which is mainly composed of plants and animals or living organism. Lithosphere is an irregular surface with various landforms such as mountains, plateaus, plains, valleys etc. it is the domain that provides us forests,grasslands, land for agriculture and human settlement.

2. Hydrosphere: The domain of water is referred to as hydrosphere. it comprises various sources of water and different types of water bodies like rivers, lake, seas, oceans, etc. it is essential for all living organism. Only less than 1% of water resources are available for human exploitation.

3. Atmosphere: The atmosphere is the thin layer of air that surrounds the earth. The gravitational force of the earth holds the atmosphere around it. it protects us from the harmful rays and scorching heat of the sun.

Atmosphere consists of a no. of gases, dust and water vapour. The changes in the atmosphere produce changes in the weather and climate. it consists of different layers like troposphere, stratosphere, mesosphere and thermosphere. ozone gas is present in stratosphere layer.

4. Biosphere: Plant and animal kingdom together make biosphere or the living world. it is a narrow zone of the earth where land, water and air interact with each other to support life.

Life in the biosphere is abundant b/w 200 metres below the surface of the ocean and about 6000 metres above sea level.

The sun provides energy required for life within the biosphere and the nutrients necessary for living organisms come from air, water and soil. 

Distribution of organism is not uniform throughout the biosphere. only few organisms live in the polar regions, while the tropical rainforests have an exceedingly rich species of animals.

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