Chapter 1 – Environment
Important Notes
The place, people, things and nature that surround the living organisms, is called Environment.
The term 'environment' is derived from French word, 'environner' which means 'surroundings' or 'neighbourhood'.
Environment is a combination of natural and man-made phenomena. For example, air, water, land, place, things, etc.
Pictorial representation of the different components of environment:
Environment is a basic life support system that provides
air to breathe
water to drink
food to eat
land to live
Natural Environment
The natural environment comprises of land, water, air, plant and animal.
There are two factors of natural environment-Biotic and Abiotic.
• Biotic is the world of living organisms. For example, plants and animals.
• Abiotic is the world of non-living elements. For example, lands.
Domains of Natural Environment
There are four domains of natural environment i.e., lithosphere, hydrosphere, atmosphere and biosphere.
Lithosphere
It is the outermost solid surface (e.g., solid crust) or the hard top layer of the Earth. It is an irregular surface made up of rocks and minerals and covered by a thin layer of soil. Mountains, plateaus, plains, valleys, etc are various landforms of lithosphere.
Landforms of lithosphere are found over the continents and on the ocean floors. The lithosphere is the domain that provides forests, grasslands for grazing, land for agriculture and human settlements. It is also a source of mineral wealth.
Hydrosphere
It is a domain of water that comprises various sources of water and water bodies like-rivers, lakes, seas, oceans, etc. This domain is essential for all living organisms for survival.
Atmosphere
It is the blanket of air that surrounds the Earth which is firmly held by the gravitational force of the Earth. Atmosphere plays an essential role in the sustenance of life by protecting us from harmful rays and scorching heat of the Sun. It is basically an envelope of gases like N2, O2, CO2, etc. dust and water vapour. The atmospheric changes influence the weather and climate on the Earth.
Biosphere
It is constituted by all living organisms (means plant and animal kingdoms together). It is also called living world. It is narrow zone of Earth where land, water and air interact for supporting of lives.
Ecosystem
The relation between the living organisms as well as the relation between organisms and their surroundings, form an ecosystem.
In other words, it is a system which is formed by the physical and chemical interaction of living and non-living organisms.
They are connected by the transfer of energy and materials.
Ecosystem can be as huge as a large rainforest, grassland, desert, ocean, mountain and can be as small as a lake or pond.
(A pond Ecosystem)
Human Environment
Human beings interact with environment and modify it for their adaptation and need. This modified environment is called 'human environment'.
Modification in the environment does got take place instantly. Early humans were adapted to natural surroundings leading a simple life. With the passage of time their needs grew. Humans learnt new ways to use and change environment. Growing crops and domestication of animals are some such ways.
Humans learnt to lead a settled life. Wheel was invented, surplus food was produced. Barter system also emerged, trade started and commerce developed.
Industrial revolution enabled large scale production. Transportation became faster.
Information revolution made communication easier and speedy across the world.
Conclusion
All living beings and environment are interrelated. Hence, human beings should learn to live and use their environment in sustainable, amicable and harmonious ways. A perfect balance is necessary between the natural and human environments.
Some Important Terms
Weather It reflects short term condition of atmosphere.
Continent It is a huge landmass surrounded by water.
Grasslands They are areas where the vegetation is dominated by grasses.
Man-made When humans change natural environment for their survival and their need is called man-made.
Climate It is the variation of weather at a given place for a specified interval of time.
Barter system It is a trade in which goods are exchanged without the use of money.
Gravitational force It is the force of attraction between all masses in the universe.
Solid crust It is the top layer of the Earth.
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