Physical geography describes the changes that take place in landscapes and
river systems, and the temporary nature of many land formations.
The structure of the earth consists of an outer
crust of rock upto tweny-five miles thick above a mantle of dense rock. The outer crust consists of continents that are formed of granite and extends downward to a considerable depth. The mantle in turn surrounds a much denser core made up of iron and nickel at high temperature and pressure.
The appearance of a
landscape depends largely on the forces of nature. Landscapes may be formed either under humid conditions or under arid conditions. The physical
features that we see today are not
permanent because the landscape is ever changing. These changes are brought about by the process of weathering or breaking up of rocks (due to atmospheric contact), erosion, transport and deposition (due to water, wind and ice), and movements of the earth’s crust.
In areas where the land meets the sea, the coastline is also attacked by waves. But the action of waves is much more rapid as compared to other processes. Each river forms a river valley, carries a load of worn material, and later deposits it.
Lakes are seldom permanent features on the surface of the earth. A lake may reduce in size or even disappear for a number of reasons.
The study of climates and soils is important because of their impact on the vegetation. Plants compete with each other for moisture, light, soil or minerals. One type of
Plant usually becomes dominant in an area, and along with other trees, shrubs and grasses forms the local vegetation. Factors affecting
vegetation (plant life) include the amount and intensity of precipitation, sunlight and evaporation. Economic activities by man and competition between plant species also affects the plant’s ability to thrive. All these factors interact with each other to give shape to the local vegetation.
More abstracts about the Basic Geography