The essence of this chapter for last-minute revision: definitions, formulas, the factors influencing distribution, the three stages of demographic transition, and named examples. The full notes, with the complete explanation, are available separately.
1 Six definitions to learn
Density of population is the ratio between the number of people and the size of land in a region. Density = Population / Area, usually measured in persons per square kilometre.
Natural Growth = Births − Deaths. Actual Growth = Births − Deaths + In-Migration − Out-Migration (migration is added to natural growth).
Positive Growth happens when the birth rate is more than the death rate, or when people migrate permanently into a region. Negative Growth happens when the birth rate falls below the death rate, or when people migrate out to other countries.
Crude Birth Rate (CBR) = (live births in a year / mid-year estimated population) × 1000. Crude Death Rate (CDR) = (deaths in a year / mid-year estimated population) × 1000.
Place of Origin is where migrants move from (population decreases). Place of Destination is where migrants move to (population increases). Those who move into a new place are Immigrants; those who move out are Emigrants.
Demographic Transition Theory says population changes from high births/high deaths to low births/low deaths in three stages, as society moves from rural-agrarian-illiterate to urban-industrial-literate.
2 Factors influencing population distribution
| Group | Factor | Example / meaning in one line |
|---|---|---|
| Geographical | Availability of water | River valleys are among the world’s most densely populated areas |
| Landforms | Ganga plains dense; Himalayan mountain zones scarcely populated | |
| Climate | Mediterranean regions settled early for their pleasant climate | |
| Soils | Fertile loamy soils support intensive agriculture | |
| Economic | Minerals | Katanga-Zambia copper belt (Africa) |
| Urbanisation | Better jobs/education/medical care; mega cities attract migrants | |
| Industrialisation | Kobe-Osaka region (Japan) | |
| Social-cultural | Religious/cultural significance; social-political unrest | Unrest drives people away; governments sometimes offer incentives to settle sparse areas |
The chapter gives these three groups in exactly this order: I. Geographical, II. Economic, III. Social and Cultural. Remember that about 90% of the world’s population lives on about 10% of its land area, since this percentage is frequently tested, so watch for mixed-up distractors like 60%/10% or 90%/60%.
3 Population growth: types and formulas
| Term | Formula / meaning |
|---|---|
| Density of Population | Population / Area |
| Growth of Population | Change in population between two points of time (in absolute numbers) |
| Growth Rate of Population | Same change, expressed as a percentage |
| Natural Growth | Births − Deaths |
| Actual Growth | Births − Deaths + In-Migration − Out-Migration |
| Crude Birth Rate (CBR) | (B/P) × 1000 |
| Crude Death Rate (CDR) | (D/P) × 1000 |
Region X: area 100 sq km, population 1,50,000 → density = 1,50,000/100 = 1,500 persons/sq km.
India: population 102.70 crore in 2001, 121.02 crore in 2011 → growth = 18.15 crore (the book’s own figures).
4 Migration: push and pull factors
| Push factors (make origin less attractive) | Pull factors (make destination more attractive) |
|---|---|
| Unemployment | Better job opportunities |
| Poor living conditions | Better living conditions |
| Political turmoil | Peace and stability |
| Unpleasant climate | Pleasant climate |
| Natural disasters, epidemics | Security of life and property |
| Socio-economic backwardness | — |
Migration may be permanent, temporary or seasonal, and can take place rural to rural, rural to urban, urban to urban, and urban to rural.
5 The three stages of demographic transition
| Stage | Characteristics | Example countries/groups |
|---|---|---|
| I, High Fluctuating | High birth & death rates, slow growth, agriculture-based, low life expectancy | Present-day rainforest tribes, Bangladesh (all countries 200 years ago) |
| II, Expanding | Fertility high but declining, mortality falling faster, high net addition | Peru, Kenya, Sri Lanka |
| III, Low Fluctuating | Both fertility and mortality low, urbanised, family size controlled | Canada, Japan, USA |
Do not write population growth as “high” in Stage I. It is “slow” (high birth and high death rates compensate for each other). “High” describes the birth and death rates themselves, not the growth rate.
6 Population control and Thomas Malthus
Population grows faster than food supply; unchecked growth ends in a crash from famine, disease and war. Preventive checks (like family planning) are better than physical checks.
Population control measures: family planning (spacing/preventing births), propaganda, free availability of contraceptives, tax disincentives for large families.
7 “Did you know” facts and the ten most populous countries
- Human population increased more than 10 times in the past 500 years; 4 times in the 20th century alone
- World population crossed 6 billion at the start of the 21st century
- 90% of world population on 10% of its land area; the 10 most populous countries hold 60% of world population, 6 of them in Asia
- Fig. 2.1, most to least populous: China, India, U.S.A, Indonesia, Brazil, Pakistan, Nigeria, Bangladesh, Russia, Mexico. The six in Asia: China, India, Indonesia, Pakistan, Bangladesh, Russia
- India: 102.70 crore in 2001 → 121.02 crore in 2011, growth of 18.15 crore (the book’s own figure)
- Named examples: Katanga-Zambia copper belt (Africa, minerals), Kobe-Osaka (Japan, industrialisation), Ganga plains vs Himalaya (landforms), Mediterranean region (climate)
- Demographic transition examples: rainforest tribes-Bangladesh (Stage I), Peru-Kenya-Sri Lanka (Stage II), Canada-Japan-USA (Stage III)
- Thomas Malthus, 1798, said preventive checks are better than physical checks
- NCERT Q1(iv): the English edition prints only 2 options; the statement “growth is high in Stage I” is the one that is not a fact