Population Dynamics

The literacy rate is important because it shows how much of the country is educated. A country with high literacy rate has educated, trained and skilled population. The high literacy rate in developed countries like USA, France, Japan etc., have proved how human resource can develop a country, in spite of lack of natural resources.

The sparsely populated regions of the world are-

1. The hot deserts like Sahara and Kalahari of Africa, the Arabian desert and Thar desert of Asia, Atacama and Patagonia desert of South America, Great Australian desert and Arizona desert of USA and arid areas of Western Mexico.
2. The cold deserts of Central Asia, the Gobi and Takla Makan desert, a portion of Ladakh in India.
3. Cold polar regions of Arctic in North America, Eurasia and Antarctica
4. The dense Equatorial Rainforests of the Amazon and Zaire basin.

The total number of people in a country in relation to its land, is known as population density.

It can be measured as follows-

Population density = Total population of a country / Total land area of the country

People migrate with the intention of settling permanently in the new location, so migration of people leads to decrease of the population of a country i.e., shortage of skilled and competent people in a country.

Two problems of overpopulation are-

1. Rapid population growth: In most of the under developed countries, population increases rapidly and family planning is not practised on a large scale due to illiteracy and ignorance.
2. Unemployment: In many underdeveloped countries industry is not well-established and there are very few employment opportunities for unskilled workers. Unemployment is therefore high.

Two problems of under population are-

1. Uneven distribution of population: Average population densities for underpopulated countries are low, and in many areas there are practically no people at all.
2. Slow growth of industry: The growth of industry is often slow in underpopulated countries because there is a shortage of labour, especially skilled labour

Population change is the change in the number of people during a specific time. It occurs due to births, deaths and migration of people.

A population pyramid is a graphical representation that shows the distribution of various age groups and gender in a population. Population pyramid for youthful population is shown below:

For example, Niger's population pyramid has mostly aged 15 and under and the majority of the population is under 5 years old, which shows how half of the population dies before they reach 30. But in developed countries like USA, Japan, the decrease in birth rate and death rate have kept the base and top at medium level and life expectancy is higher.

The following points compare and contrast the impact of overpopulation and underpopulation of a country-

1. Utilisation of Resources — Overpopulation may increase the pressure on the natural resources and the food and fresh water supplies would be inadequate or insufficient which may result in depletion of natural resources while underpopulation may lead to under utilization of resources due to the shortage of labour and less demand.
2. Impact on Environment — Overpopulation would increase the demand for area and this would result in deforestation or loss of natural habitat and increase in pollution levels while underpopulation decreases the pressure on natural resources and the pollution level would also decrease.
3. Impact on Employment — Overpopulation would result in scarcity of jobs while underpopulation would create labour shortage which would have both positive and negative impacts.

In conclusion, both overpopulation and underpopulation are not considered good for the economy.

Population pyramid of India — In India, where the death rates are decreasing, the pyramid is broad at the base in the younger age group, as more infants survive to adulthood. Population pyramid of India is shown below:

Population pyramid of Japan — In Japan, low birth rates make the pyramid narrow at the base, decreased death rates allow number of people to reach old age. Population pyramid of Japan is shown below:

MEDCs stands for More Economically Developed Countries.

LEDCs stands for Less Economically Developed Countries.

The population between the age of 15 to 64 years is the productive section of the population. It is termed as working population.

The percentage of population who know how to read and write is known as the literacy rate.

Birth rate refers to the number of live births per 1000 persons in a given geographical area per year.

It refers to the number of deaths of children below 1 year of age per 1000 persons in a given geographical area per year.

The difference between the birth rate and the death rate of a country is called the natural growth rate of the population.

Life expectancy is the average age at which people die in a given geographical area.

(i) natural resources, valuable resources

(ii) producer, consumer

(iii) Human, adaptation

(iv) greater

(v) Rural

People are the greatest resource of the world because man plays the dual role of both the producer and consumer of resources.

A country which is underpopulated cannot exploit its natural resources to the maximum because there is a shortage of skilled labour.

The fertility rate in many developed and developing countries has dropped to about two children per woman due to the factors like literacy, economic development or urbanization making the idea of having big families impractical.

Emigration always has negative effect on the population because the higher educated people leave the country and this leads to shortage of skilled and competent people.

India has a low sex ratio of 940 females per 1000 males because of high maternal mortality, female infanticide, sex-selective female abortions and neglect of the girl child leading to a higher mortality among girls at a young age, and change in sex ratio.

Working population

Urban population

Fertile plains

Oil wells

Moderately populated

High birth rate

Population Change

Choropleth map

20° & 60°N

No of live births per 1000 persons in a given geographical area per year.

Decrease

North Eastern USA

It exists when the number of existing human population exceeds the carrying capacity of the land

Both (1) & (2)

940 females/1000 males

Kenya