•Population dynamics Class 8 icse notes

DISTRIBUTION OF POPULATION 

The way in which people are spread across the earth surface is known as the pattern of population distribution. The distribution of population depends upon the natural, geographical and economic environment.  

Factors affecting distribution of population: 

(i) Topography : Topography is the most important physical factor which affects the distribution of population. Generally mountains and plateaus do not have a high density of population due to the lack of basic facilities. Mountains and plateaus have other problems also such as cold climate, lack of cultivable land, lack of transportation and communication facilities. On the other hand plains such as Ganga and Brahmaputra in India, Hwang-Ho, Chang Jiang in China and Nile in Egypt are densely populated.

(ii) Climate : Climate has a direct influence on human beings. Areas having very high temperature and very low temperature are unfit for habitation. Rainfall also affects distribution of the population. Dry areas have sparse population whereas areas having good rainfall have dense population.

(iii) Soils: All the fertile plains have a high density of population because plains form the base for high agricultural productivity. Density of Ganga-Brahmaputra delta is very high due to fertile soil. 

(iv) Minerals : The availability of minerals in a region also affects human population. Areas rich in minerals have high density of population. For example, North- West Europe has high density of population due to availability of minerals and location of industry.

(v) Economic factors : Economic factors like development of industry, technological developments, urbanization, means of transportation and communication have a direct impact on the density of population. Industries attract large number of workers which results in the increase of population. Most of the industrial countries of the world are densely populated. North-eastern U.S.A. and North-western. Europe have high density of population due to economic factors.

•Density of Population

Number of persons living per unit of land is called density of population. The estimated global population in the year 2012 was 6908.7 million. The population of the whole world is not evenly distributed. Some countries have high density of population whereas some have low density of population. High increase in the density of population is a matter of great concern as it puts immense pressure on our natural resources and adversely affects the quality of life. There are some

continents like Antarctica which are almost uninhabited. More than 40% of world's population lives in Asia.

Areas of low density : Areas having a population density of 1 to 2 persons per square km. are known as areas of low density. These include hot deserts like Sahara, Kalahari, Atacama and cold deserts like some parts of Canada, Greenland, Antarctic, Gobi, etc. Amazon Basin of South America and Congo Basin of Africa are the main areas of equatorial region. These are areas with high temperature and high humidity and very dense forests and so the density of population in these areas is also very low.

Areas of moderate density : Areas having a population density below 200 persons per square km. are known as areas of moderate density. South India, Western part of China, Denmark, Norway, Western parts of U.S.A. have moderate density of population.

Areas of high density : Areas having a density above 200 persons per square km. are known as areas of high density. The main areas of high density are Monsoon Asia, Europe and Eastern part of U.S.A. The Monsoon Asia includes the countries like China, India, Bangladesh, Singapore, Japan, Korea, etc. Eastern coastal parts of U.S.A. and Canada also have a very high density of population. The main areas of high population density in Europe extend from English Channel in west of Dnieper river in the east. This belt is also known as the 'population axis of Europe.' The main countries included in this belt are Netherlands, Belgium, Germany.

•Migration and Population Change

Migration is another way by which population size changes. Migration may be broadly classified as international or internal:

International migration : "Movement of people from one country to another, across the international borders is called international migration." Countries like Australia, United States, Canada, etc. have gained population because of immigrants, i.e. the people who are arriving in these countries. 

But there are some countries like Sudan, India, Sri Lanka who are experiencing a loss in population due to immigration, i.e. the people who have left their countries.

The general trend of international migrations is from the less developed nations to the more developed nations in search of better employment opportunities and high living standard.


Internal migration : "The movement of people from one region to another within the country is known as internal migration." Internal migration does not have any impact on the size of population. Within countries large number of people may move from the rural to urban areas in search of employment, education and health facilities.