CBSE Class 8 Geography Chapter 2 Population Dynamics Notes

CBSE Class 8 Geography Chapter 2 Population Dynamics

Population refers to the total number of people 1 inhabiting an area, a region or a country.

• It is these people, who use resources of a nation, produce goods and services, help to develop its economy and society and create the social and cultural environment. In this way, people themselves act like an important resource of a countiy, known as the human resource.
• Thus, population forms the centre around which all the other elements revolve.
• It acts as a reference point for studying various aspects of a nation, like its economic growth and development, health care, literacy and standard of living of people.

Population is a dynamic phenomenon. The numbers, distribution and composition of the population are constantly changing. Population Dynamics is the branch of science that focuses on the changes in the size and age composition of populations and tries to find out how, when and why these changes occur.

The five key properties of a population are:

1. Spatial distribution

2. Size and Density

Population by Continent: 1980 to 2050:

[In millions, except per cent (4,453 represents 4,453,000,000). As of midyear]

World Population by Country (2023):

3. Age structure

4. Birth Rate (Natality)

5. Death Rate (Mortality)

CBSE Class 8 Geography Chapter 2 Distribution Of Population In The World

Population distribution:

Population distribution refers to how members of a population are dispersed physically in a specific area.

• The population of the world is unevenly distributed. About 90 per cent of the world population lives in 10 per cent of its land area.
• The ten most populous countries of the world contribute about 60 per cent of the world’s population. Of these 10 countries, six are located in Asia.
• When early man settled down and started practising agriculture, in about 8000 B.C., the population of the world was approximately 5 million.
• There was a gradual increase in population over the years.
• However, the Industrial Revolution gave rise to rapid population growth.
• Around 1800, the world population had reached one billion; the second billion was achieved in only 130 years (1930),
• The third billion in 30 years (1960), the fourth billion in 15 years (1974), and the fifth billion in only 13 years (1987).
• During the 20th century alone, the population in the world grew from 1.65 billion to 6 billion. According to the United

Nations the global human population has reached eight billion in mid-November 2022, and India has surpassed China as the most populated country in April 2023. This rapid growth in population is called Population explosion.

Population Density

Population Density refers to the number of people living in an area of one square kilometre

Density of Population = Population/Area

The density of population differs from area to area. Some areas are thickly populated, whereas others are moderately populated. Besides, there are many areas, which areuninhabited. Population density of the world is estimated at around 50 persons per square kilometre, i.e., 50 people live in every square kilometre of land.

• This includes all continental and island land areas, including Antarctica.
• Monaco is the most densely populated country in the world, with a population density of 26,105 people per sq. kilometre.
• Many parts of the world are densely populated with more than 200 persons per sq. kilometre.
• These are the North-Eastern part of the USA, North-Western part of Europe, South, South-East and East Asia.
• Mongolia is the least densely populated country in the world. The five least densely populated countries with having population of 10 million are Australia, Canada, Kazakhstan, the Russian Federation and Bolivia.

Among the continents, Asia is the most populated continent in the world with a population of approximately 4.7 billion, occupying one-fifth of the world’s land area.

• However, the country with the highest population density in Asia is Bangladesh. Europe has a population of about 742 million people.
• Around 9.3 per cent of the world’s population lives in Europe.
• The north-western part of Europe, comprising the highly industrialised countries like the UK, Germany, Denmark and France, is heavily populated.
• This is because of the mild climate, availability of diverse natural resources and development of highly advanced industries that this region has a high density of population.
• In North America and South America, over 65 per cent of the population lives in one of the three most populous countries, i.e., the United States, Brazil and Mexico.
• These areas are concentrated in the fertile Temperate regions.
• Africa with a population of 1.5 billion, representing approximately 18 per cent of the population.
• In Africa, the densely populated areas include the Nile Valley, Mediterranean Coast, Guinea Coast and coastal South Africa.
• Mauritius is the most densely populated African country.

Many areas of the world have a moderate density of population.

• There are 11 to 50 persons per sq. km in these areas.
• These include central China, the Deccan plateau of India, Eastern Europe, the Central part of the USA, Russia and Tropical Western Africa.
• This is due to the prevalence of extreme climatic conditions, inadequate rainfall and scarcity of important natural resources.
• Areas near the North and South Poles, the hot and the cold deserts and high rainfall zones near the Equator have a very low density of population.
• These are the sparsely populated regions of the world with less than 01 person per sq. km.

Factors Influencing Population Density

The population of the world is unevenly distributed. There are many factors responsible for this uneven distribution of population.

Population from 1950 to 2021:

These include the following:

1. Relief:

The plains and gentle slopes are more densely populated than the mountainous or hilly areas.

• This is because such areas are favourable for agriculture, building houses and other establishments, industrialisation and transportation.
• The Ganga Plains of India are among the most densely populated areas of the world, whereas the Himalayas are comparatively scarcely populated

2. Climate:

Climate greatly influences the concentration of population in an area. Areas with extreme climates, such as very hot or cold deserts or harsh climates, are thinly populated.

For example:

Mongolia, a desert country in Asia, is one of the most sparsely populated countries in the world.

• It has very little arable land and much of its area is covered by grassy Steppes.
• Australia also has a low density of population due to vast stretches of desert areas and mainly arid, inaccessible interiors and remote coasts called the outbacks.
• Botswana, Iceland, Namibia, Suriname and northern Canada are some of the other sparsely populated countries of the world.
• Areas with a moderate climate attract settlements.

For example:

The Mediterranean regions, having warm to hot, dry summers and mild to cool, wet winters Eire densely populated due to their pleasant climate.

3. Soil and Water:

Fertile soils are needed for agricultural and allied activities. So the areas which have fertile loamy soils and can support intensive agriculture, have high density of population.

• Similarly, areas with poor soils are thinly populated.
• Water is a basic necessity of life. It is needed for drinking, bathing, cooking, washing clothes, for cattle, crops, industries and navigation.
• That is why river valleys are among the most densely populated regions of the world.

4. Natural Resources:

Areas which have abundant natural resources, like minerals and power resources, attract large populations.

• Industries are set up in areas where minerals and power resources (mineral fuels, water power, solar energy, biomass, geothermal and wind energy) are easily available.
• These industries generate employment for both skilled and semi-skilled workers, who move to these areas and make them densely populated.

For example:

The Kobe-Osaka region of Japan is thickly populated because of the presence of several industries.

5. Urbanisation:

Cities attract more people, especially in developing countries, as they offer better employment opportunities, educational and health-care facilities, and better means of transport and communication. Better civic amenities and the attraction of city life lead to the migration of rural people to the cities, and the cities grow in size.

6. Political, Social and Cultural Factors:

Countries which have stable governments tend to have a high density of population.

• People usually tend to move away from places where there is social and political unrest.
• Groups of people based on ethnicity, religion occupation tend to live in communities in a particular region.
• Besides, some places attract more people due to their religious, historical or cultural significance

CBSE Class 8 Geography Chapter 2 Overpopulation

Overpopulation refers to the condition when the human population is more than the available natural resources which can support it.

• This is caused by increased birth rates, declining mortality rates, breakthroughs in medical science and migration of people to a particular area.
• When there exists a state of balance between population and the available resources in a particular area, it is known as the optimum population.
• At this stage, people have sufficient job opportunities and enjoy high standards of living.
• This balance gets disturbed when the population of an area increases or decreases drastically in comparison to the availability of resources.
• Thus, population growth beyond a certain level leads to problems

Impact of Overpopulation

The following are the impacts of overpopulation:

Pressure on Existing Resources:

As the human population increases, it puts pressure on the existing natural resources such as cultivable land, fresh water, fossil fuels and minerals.

• This leads to degradation and depletion of resources and contributes to an incredible decline in the quality of life.
• Excessive human consumption of non¬ renewable resources can outstrip the availability of these resources shortly and remarkably deplete them for future generations.

Shortage of Basic Necessities:

Overpopulation causes shortage of food, fresh water, shelter, health-care and educational facilities and other basic necessities of life.

• This lowers the standard of living as it creates stress on the vital resources for survival.
• Consequently, it makes the poor to become poorer and they are forced to opt for poor living conditions for survival.

Unemployment and Poverty:

Increased population demands more job opportunities.

• These cannot be created with the existing resources and create stiff competition for the fewer available jobs.
• This leads to unemployment and poverty, which in turn causes problems like increased crime rates, conflicts and violence.

Destruction of Natural Habitats of Animals:

Theincreasedloss offorestlands forcultivation and for human settlements for the growing population leads to the destruction of the natural habitats of a large number of animals and plant species, threatens their existence and finally causes their extinction.

Increased Use of Energy Resources:

Overpopulation results in increased consumption of resources.

• The more the number of people, the more is the number of goods produced by industries, the more the number of vehicles used, and the more the use of energy resources like coal, petroleum and natural gas.
• All these contribute to an increase in greenhouse gas emissions and thereby, global warming and climate change.

Increase in Human Diseases:

According to the WHO, overpopulation is one of the main causes of the increased occurrence of human diseases.

• Overpopulation worsens environmental and social factors like pollution, malnutrition, education and healthcare facilities, and creates overcrowded, unhygienic living conditions in slums.
• These make poor people vulnerable to many infectious diseases. Diseases like tuberculosis, malaria, dysentery, HIV, etc., spread faster in overpopulated countries.

Increase in Cost of Living:

Increasing demand for resources and fewer supplies raise the price of commodities and thereby, increase the cost of living.

CBSE Class 8 Geography Chapter 2 Underpopulation

Underpopulation refers to the condition when the size of population of an area is too small to fully utilise the available resources of that area. In such a situation the resources of a nation remain underutilised. The Prairies of North America, Canada, Equatorial Congo, parts of Australia and New Zealand, Russia and Namibia are underpopulated.

Underpopulation is usually caused by

• Increase in death rate caused by natural calamities like floods, earthquakes, etc.
• A falling birth rate, and
• An increase in the emigration of a large population to another area.

It is generally believed that large countries with small populations are underpopulated whereas small countries with large populations are overpopulated. But this is not correct as overpopulation and underpopulation is not related to the density or size of the population. It depends on the availability and effective utilisation of resources of that area by its people.

Impact of Underpopulation

Underpopulation has both positive and negative impacts.

Positive Impacts:

• The positive impacts of underpopulation are the following:
• Food, shelter, education, healthcare and other amenities are available to everyone.
• There are enough resources for everybody to utilise.
• Underpopulated countries experience little or no congestion.
• There are fewer people, therefore less resources are required and therefore there are fewer of industries and less waste generated. Consequently, there is less pollution and environmental degradation.
• Job opportunities are ample for all those willing to work, as there are fewer people. Income levels and standards of living are usually high in underpopulated areas.

Negative Impacts:

• The negative impacts of underpopulation are the following:
• Resources remain highly underutilised in underpopulated countries.
• Due to a lack of adequate manpower, production levels remain low, and the cost of hiring labour is quite high.

CBSE Class 8 Geography Chapter 2 Factors Affecting The Population Of A Place

Population is a dynamic phenomenon. Its number, distribution and composition keep on changing constantly.

Population change:

Population change refers to the change in several inhabitants of an area during a specific period.

The major factors that bring about a change in the population ofa place, whether in an individual country or the whole world, are the following:

Birth Rate:

Birth rate, also known as Crude Birth Rate (CBR) is the number of live births per thousand persons in a year.

It is calculated as:

CBR – Bi/P × 1000

Where, Bi = live births during the year and P = Mid-year population of the area.

Death Rate:

Death rate or Crude Death Rate (CDR) is the number of deaths per thousand persons in a year. It is calculated as:

CDR – D/P × 1000

Where D = number of deaths; P = Mid-year population of that year.

When birth rates are higher than death rates, the population of an area increases

Migration:

Migration is the movement of people across regions and territories. When people migrate from one place to another within a territory or a country, it is called internal migration.

• When migration occurs between countries, it is called international migration.
• Internal migration does not change the size of the population but influences the distribution of the population within a country.
• When people migrate from one place to another, the place they move from is called the ‘Place of Origin’ and the place they move to is called the ‘Place of Destination’.
• Due to migration of people, the place of origin shows a decrease in population, whereas the place of destination shows an increase in population.
• Migrants who move into a new country are called immigrants, and the process is called immigration.
• Similarly, when migrants move out of a country, they are called emigrants and the process is called emigration.
• The same people are both immigrants and emigrants.

For example:

People who left Ireland during the famine were referred to as emigrants by the people left behind in Ireland.

• The same people, when they arrived in the USA, were referred to as immigrants by the Americans.
• People move out of their country due to a lack of employment opportunities, poor living conditions, political turmoil, unpleasant climatic conditions, natural disasters, epidemics and socio-economic backwardness.
• We will read about migration in detail in the next chapter.

CBSE Class 8 Geography Chapter 2 Composition Of Population

Each region or country has a diversity ofpopulation based on their age, sex, place of residence, education, occupation and life expectancy. These diverse features help us to understand the various qualities of that population and enable the governments to plan and implement different policies based on these determinants.

Age Composition

Age Composition of a population refers to the number of people in different age groups in a country.

• It is one of the important characteristics of a population. This is because a person’s age influences every aspect of his life like his health, capacity to perform, working habits and needs and aspirations.
• Consequently, the number and percentage of different categories of people determine the population’s social and economic structure.

The population of a country is usually grouped into three categories:

• Children (generally below 15 years): This group is economically unproductive and needs to be provided with the necessities like food, clothing, shelter, education and medical care.
• Adults (15-59 years): They are economically productive and biologically reproductive. They comprise the working population.
• Aged (Above 59 years): They can be economically productive, though they are at the stage of retirement from service. They may work voluntarily, but they are not eligible for employment through recruitment.

Thus, children and old people aged above 59 do not contribute in production and constitute the dependent population of a country.

• In the developed countries of the world, the percentage of dependent population is low.
• The world is home to 1.8 billion young people between the ages of 10 and 24 years. This means that 9 out of 10 people in the world belonging to this age group live in less developed countries of the world.
• With 356 million people in the 10-24 years old (28 per cent of India’s population), India has the world’s largest youth population. Two-thirds of India’s population is less than 35 years.

Sex Ratio

Sex Ratio refers to the number of females per 1000 males in the population. In India, the sex ratio is worked out using the formula

Sex Ratio = female Population/Male Population x 1000

According to the Population Census of 2011, the sex ratio in India is 940 females per 1000 males.

• The states of Kerala and the Union Territory of Puducherry are places where the number of women is more than the number of men. Haryana has the lowest sex ratio in India, i.e., 877 females per thousand men.
• However, infamous for skewed sex ratio, Haryana saw an improvement in it with the number of females crossing 900 mark in December 2015.
• The sex ratio is an indicator of the status of womeninacountry.Itis alsoanimportant indicator to check the extent of gender equality between males and females in a society at a given time.
• In regions or countries where gender discrimination is prevalent, the sex ratio is unfavourable to women. These are the areas where there are high instances ofthe practice of female foeticide, female infanticide and domestic violence against women

Rural Urban Composition

The division of population into rural and urban is based on the location of people. This division shows how the rural and urban lifestyles differ from each other in terms of their livelihood and social conditions.

• The age-sex occupational structure, density of population and level of development vary between rural and urban areas.
• These criteria for differentiating rural and urban populations vary from country to country.
• Generally, rural areas are those where people are engaged in primary activities, while urban areas are those where the majority ofthe working population is engaged in non-primary activities.

The rural and urban differences in Sex Ratio in Canada and Western European countries like Finland are just the opposite of those in African and Asian countries like Zimbabwe and Nepal, respectively.

In Western countries, males are more than females in rural areas, and females outnumber males in urban areas. In countries like Nepal, Pakistan and India, the case is reverse.

• The excess offemales in urban areas of USA, Canada and Europe is the result of migration of females from rural areas to workin cities.
• Since farmingin developed countries is highly mechanised it remains largely a male occupation. By contrast the Sex Ratio in Asian urban areas remains male dominated due to the predominance ofmale migration.
• In countries like India, female participation in farming activities in rural areas is fairly high.
• Shortage of housing, high cost of living, lack of job opportunities and lack of security in cities discourage women from migrating from rural to urban areas

Population Pyramid

The population Pyramid refers to the graphical representation age-sex structure ofa population. It can be drawn for any area, from a whole continent or country to an individual town, city or village.

• In this representation, the size of the population under investigation is distributed on the horizontal X-axis, whereas the Y-axis represents the age group, which is distributed from 0 to 80 years, and each is broken down to a 5-year age interval.
• The female population is shown on the right, whereas the male population is shown on the left.
• The shape of the population pyramid reflects the characteristics of the population like life expectancy, fertility rate and migration.

Based on the information deciphered from the shapes of the pyramids, they are grouped into three types.

1. Underdeveloped Countries:

The population pyramids for Underdeveloped countries like Mozambique, Somalia, Afghanistan, Bangladesh, etc. have the following characteristics:

• The pyramid is broad at the base and narrow, tapering towards the top
• The broad base shows a high birth rate and a large number of children aged below 15 years.
• The tapering top shows that though the birth rates are high, life expectancy is lower.
• Many children die in their infancy. Due to the high death rate, fewer people reach old age.
• High birth and death rates, and lower life expectancy, show that the country lacks in providing a nutritious diet, adequate medical facilities, education and a decent standard of living to its people.

2. Developing Countries:

The population pyramids for developing countries like India have the following characteristics:

• The pyramid is broad at the base, has a less steep , narrowing top and a slightly broader top
• The broad base indicates high birth rate, but it is less broad as in the case of developed countries due to decreasing birth rates.
• The less steep narrowing pyramid indicates a falling death rate, especially among young people and a large number of people of working age.
• It’s life expectancy. Slightly broader top shows increasing decreasing birth and death rates and increasing life expectancy, indicating that the country is improving its standards in nutrition, healthcare, education and standard of living, though much still needs to be done.

3. Developed Countries:

The population pyramids of developed countries like Japan, the USA, and Germany have the following characteristics:

• The pyramid has a narrow base, going straight and has a broader top
• The narrow base shows a low birth rate and a relatively small number of children below the age of 15.
• The straighter pyramid shows a low death rate, and the broader top shows high life expectancy and more people reaching old age.
• Lowbirth and deathrate, highlife expectancy shows that the country has higher living standards, best healthcare facilities, good quality of education and lifestyle.

A population pyramid provides useful information about the following:

• It tells us about the birth and death rates and the life expectancy (the average number of years one is expected to live).
• It shows the number of people in each age group separately for males and females.
• It tells us about the number of males and females in the working and dependent population.
• It can be used to study the future prospects of a nation in terms of economy, birth and mortality rate, sustainability of society, etc.