Planet earth differ from other planet because of existence of life here. Life is possible only on earth due to its specific environment. The conditions surrounding an organism form its environment. Thus each and everything which surrounds and affected the living organisms constitute its environment. It includes two essential components. Components and abiotic components. The biotic components of the environment are plants, animals, including human beings and microorganism (e.g., viruses, bacteria, single called) (microscopic) plants, fungi and animals). The abioitc components of the environment are air, water soil, light and temperature.
Our external environment is made up of by various non-living or abiotic thing like air, water, soil light and temperature, which all exists around us. These abiotic components of our environment tend to affect us and all the living organisms of earth surface every aspect, they play vital role in the growth, development and in survival of these living organisms e.g. Animals need food, water and air (O2) for their survival for photo synthesis green plants need light, water and carbon dioxide (CO2).
Types of Abiotic Components
Abiotic components of the environment are classified as follows :
A. Climatic factors
B. Topographic factors
2. Directions of mountain chains and volleys
3. Steepness and exposure to slopes.
C. Endaphic factor or soil
But in this particular chapter we will study only abut climatic factors. Such as Air, water, Soil, Light & Temperature.
The various gaseous layer which surrounding the planet earth is called atmosphere. Atmosphere filters sunlight reaching the earth, it affect climate and reserve these element which are essential for survival of life.
It is divided into fine different layers or zones : troposphere, stratosphere, mesosphere and exosphere. Troposphere is the lowest region of atmosphere which contain air. Air is a mixture of gases such as nitrogen, oxygen and carbon dioxide. It also contains water vapours and supreded dust particles. The composition of gases sin air as follows :
1. Nitrogen (N2) 78.09%
2. Oxygen (O2) 20.93%
3. Argon (A) 0.93%
4. Carbon dioxide (CO2) 0.032%
5. Miscellaneous (moisture, dust, etc (N2) 0.02%
The role of atmosphere is climatic control
Atmosphere cover our earth like a blanket by which it maintain the temperature of earth surface because Air is a bad conductor of heat. The atmosphere prevents the sudden increase in temperature during the daylight houses and during the night atmosphere shows down the escape of heat into outer space. If we consider the case of the moon, which is about the same distance from the sun the earth is, consequence, on the surface of the moon, the temperature ranges from – 1900C to 1100C.
The movement of Air : wind
A cool evening breeze after a hot day or rain after a few days of hot weather bring us considerable relief. So in our mind the question strike what causes the movement of air?
When the solar radiations fall on the earth, some are absorbed and majority of these are reflected back or re-radiated by the sand and water bodies. These reflected solar radiations heat the atmosphere from below. As a result convention currents are set up in the air. But since the land gets heated faster than the water, the air over land also gets heated faster than the air over water bodies. Now let us understand what happen in the coastal regions during the day and at night. During the day, the air above the land gets heated faster and starts rising creating a region of low pressure. The movement of air from one region to the other creates winds. Thus, during the day the direction of the wind is from the sea to the land. During night both the land and the sea starts to cool. Since, water cools down slower than the land, the air above land. Thus during the night, the direction of wind is from land to the sea. At a much larger scale temperature differences across the earth generate the development of the major wind belts. Such wind belts, to some degree, define the climate zone of the world.
We can demonstrate that air current are caused by the uneven heating of air by doing small activity.
Place a candle in a beaker or wide mouthed bottle and lit it. Now, lit an incense stick (Agar bati) and bring it to the edge of the mouth of the beaker or bottle observe the direction of flow of smoke. In next step keep the lighted incense stick a little above the candle and note the direction of how of smoke.
The smoke will flow towards the candle and then above. When the incense stick is placed at different regions above the beaker or bottle, the direction of flow of smoke will be towards the candle and then upwards it is so because the patterns revealed by the smoke show us the direction in which the hot and cold air move. The air above the burning candle gets heated and therefore rises creating a low pressure below. Therefore, air from adjacent cold area moves towards this low pressure zone.