World Population distribution, density & Growth NCERT Chapter Notes CBSE Class 12 Humanitas

CBSE Class 12  NCERT Chapter Notes for World Population Distribution, density & growth
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Geography relates to the study of populations, denoting how people are dispersed over the Earth's surface. Population distribution implies how people get scattered in an area and is influenced by such factors as climate, resources, and economy. Density, on the other hand, is the number of people per unit area and it shows the population pressure, while population growth studies the changes in the size due to births, deaths, and migration. Some areas that grow very fast place pressure on resources while some are slowly growing and have negative effects on development. These patterns will be very helpful in planning and resource management.

Population Density 

The density of population is a measure of human and land relationship. It is expressed as the number of persons per unit area. It helps in getting a better understanding of spatial distribution of population in relation to land. 

Population Distribution 

Population distribution is the way in which people are distributed over an area. It differs based on climate, geography, economy, and infrastructure. People can be evenly distributed, concentrated in cities, have linear patterns, or be randomly distributed depending on resources and opportunities.

Population Growth 

Population growth is an increase in the number of inhabitants of a geographical area over a period of time. It depends on birth rates, death rates, migration, and policies. Healthcare, economy, and living standards affect the rate of growth, resulting in rapid or slow growth.

Three types of factors affecting distribution of world population

1. The geographical factors influencing distribution of population in the world:- 

• Availability of water: Water is the most important factor for life. So, people prefer to live in areas where fresh water is easily available. 
• Landforms: People prefer living on flat plains and gentle slopes. This is because such areas are favourable for the production of crops and to build roads and industries. 
• Climate: An extreme climate such as very hot or cold deserts are uncomfortable for human habitation.
• Soils: Fertile soils are important for agricultural and allied activities.

2. The economic factors influencing distribution of population in the world:- 

• Minerals: Areas with mineral deposits attract industries. Mining and industrial activities generate employment. So, skilled and semi–skilled workers move to these areas and make them densely populated. 
• Urbanisation: Cities offer better employment opportunities, educational and medical facilities, better means of transport and communication. 
• Industrialisation: Industrial belts provide job opportunities and attract large numbers of people.

3. The social and cultural factors influencing distribution of population in the world:- 

• Some places attract more people as they have cultural significance. 
• People tend to move away from places where there is a social and cultural unrest.
• Government offers incentives to people to live in sparsely populated.
• People move away from overcrowded places.

Components of Population Change

Births (Crude Birth Rate - CBR)

• Live births per 1,000 individuals per year.
• Formula: CBR = (B/P) × 1000 (B = live births, P = mid-year population).

Deaths (Crude Death Rate - CDR)

• Deaths per 1,000 individuals per year.
• Formula: CDR = (D/P) × 1000 (D = deaths, P = mid-year population).

Migration- People moving in and out of an area, influencing population numbers.

Factors influencing migration :- 

1. Migration may be permanent, temporary or seasonal. It may take place from rural to urban areas, rural to rural areas, urban to urban areas and urban to rural areas. 
2. People migrate for a better economic and social life.
3. The push factors make the place of origin seem less attractive for reasons like unemployment, poor living conditions, political turmoil, unpleasant climate, natural disasters, epidemics and socio-economic backward ness.
4. The pull factors make the place of destination seem more attractive than the place of origin for reasons like better job opportunities and living conditions, peace and stability, security of life and property and pleasant climate.

Demographic transition theory 

Stages of demographic transition theory-

STAGE 1

1. The first stage has high fertility and high mortality because people reproduce more to compensate the loss by deaths. 
2. The population is slow and people are engaged in agriculture where large families are assets and life expectancy are low. 
3. Eg. Bangladesh, Rainforest tribes, two hundred years ago all the countries were in this stage.

STAGE-2 

1. In the second stage fertility remains high in the beginning but declines with time. It is accompanied by reduced mortality rate. 
2. Improvements in sanitation and health conditions led to the decline in the mortality. 
3. Eg. Sri Lanka, Kenya, Peru 

STAGE-3 

1. In the third stage both fertility and mortality decline considerably. The population becomes stable or grows very slowly.
2. The population becomes urbanised, literate and has high technical knowledge and controls the family size.
3. Eg. Canada, Japan, USA.

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