Archive | Geography

Neolithic age started when man had completely adopted the Mesolithic invention of agriculture. In this age, his life was so completely transformed that the age is termed the ‘Neolithic Revolution’.

Mesolithic age lasted from 11,000 to 9,000 years ago and also marked the beginning of Holocine period.

It is tri atomic oxygen (03) and is a gas found in the troposphere as well as in the stratosphere. Tropospheric ozone is undesirable since it is a pollutant these, causing photochemical smog and greenhouse effect. In the stratosphere, it acts as a protectant since,

Rainfall is normally somewhat acidic with a pH of 5.6 to 6.0. However, as a result of air pollution effects much stronger acidities are often observed in polluted air. Some of the major atmospheric pollutant by industrial emission are sulphur dioxide (S02) and nitrogen oxides (NO and N02).

1. Biological extinction – Disappearance of species unable to adapt

i. There are three different layers of the ocean from top to bottom in the tropics.

a. Algae are the most primitive of all plant life.

The El Nino and La Nina are oceanic phenomenon driven by atmospheric circulation. It is caused by the Walker Circulation.

Currents are movement of oceanic water in a fairly defined direction under the influence of various forces. The origin and nature of movement of currents are related to various factors.

In the equatorial belt of the Atlantic Ocean, the Trade wind drives two streams of surface water westwards. One stream flows north of equator and other south of equator. They are known as the North Equatorial Current and South Equatorial Current respectively.

In the Pacific Ocean, the general pattern of circulation is similar to that of Atlantic Ocean.

In the South Indian Ocean, the South Equatorial Current, strengthened by its corresponding current of the Pacific Ocean, flows east to west. It turns southwards along the coast of Mozambique in Africa.

Since much of the Arctic Ocean is permanently covered with solid ice or by broken ice-drifts, Arctic surface currents may be traced directly by the drift of ice-flows.

The rise and fall of the sea water due to gravitational attraction of the Sun and Moon are called tides.

This is observed when the moon’s ray falls vertical on the equator every month.

Geographic information systems (GIS) are in widespread use by both public and private organizations. any more organizations would like to implement the technology, but they must first justify this major purchase.