Mentor’s Comment:
The question is very basic and it would be better to draw some diagram to clear the picture. Introduction should talk about the various factors responsible for temperature and vegetation, like latitudinal factor, altitudinal factor, sun’s angle on earth and solar incidence etc.
Further, in the main body establish the relationship between temperature distribution and vegetation. If possible bring examples as well and conclude.
Model Answer:
Temperature and vegetation in any region of the earth are governed by multiple factors, latitude and altitude being the prominent ones. These factors can be elaborated as under:
Latitude is one of the main factors affecting temperature. With increase in distance from the equator the amount of insolation on an area decreases due to the round shape of the earth so, not every place receives the same amount of sunlight.
Another reason is the differing angle of solar incidence. This is the angle at which the Sun’s rays strike the Earth’s surface. At the Equator, the Sun’s rays strike the Earth at a right angle, which makes the heat more intense and concentrated over a small area. Less heat is lost to the atmosphere as the rays travel a shorter distance through the atmosphere.
At the poles, the Sun’s rays strike the Earth at an acute angle; this spreads the heat over a larger area. More heat is lost to the atmosphere as the rays travel a longer distance through the atmosphere.
The atmosphere primarily gets heated by the long wave radiation that is emitted by the earth after absorbing solar insolation and not directly by sun’ s rays. So altitude affects temperature as lower altitude regions are closer to the source of terrestrial radiation than higher altitude.
Also, air molecules at low altitudes are crowded together and there subsequent collisions increases their kinetic energy and temperature while at high altitude less air molecules are present in large volume which results into low temperature.
Thus temperature generally decreases with increase in altitude.
The vegetation in an area depends on the prevailing climate which is primarily dependent on the temperature and thus vegetation is also dependent on latitude and altitude.This can be discussed as under:
- The vegetation around equatorial regions is abundant, diverse and evergreen due to hot and humid climatic conditions due to ample amount of Insolation received in the region.
- As we move away from the equator towards the tropics, the insolation received The climate does not provide with torrential rains hence, the vegetation becomes thinner characterized by tropical forest or grasslands depending on the rains the regions receive.
- Towards the temperate region the vegetation is scantily dispersed, characterized by mixed forests or temperate grasslands.
- The Sibartctic regions and the regions closer to poles have vegetation with coniferous trees, as we move further closer to poles the vegetation becomeslimited to mosses, lichens etc. which can better accommodate to the cold climate. . As the latitude increases (towards the poles) the vegetation also generally decreases.
Altitude affect the type and amount of sunlight that plants receive, the amount of water that plants can absorb and the nutrients that are available in the soil. As a result, certain plants grow very well in high elevations, whereas others can only grow in middle or lower elevations but in general with increase in altitude the vegetation decrease.
The vegetation generally decreases with the increasing altitude and the sun facing side of a mountain also has better vegetation growth.
Thus the Latitude and altitude determine the climatic conditions and insolation of a region which in turn determine the vegetation of a region.
