Dynamics of Population Class 8: Notes and Questions

What Dynamics of Population is about

Weightage: CBSE sets no Class 8 Social Science paper or marks: Class 8 is assessed by your school, which teaches from NCERT Exploring Society: India and Beyond. School papers usually mix MCQs, short answers (2-3 marks), source or picture-based questions and longer answers (5 marks).Source: docs/research/cbse-8-2026-27.md (NCERT book list, Reprint 2026-27)

Key concepts

What is demography? Why study it?

NCERT section What Is Demography?; Population at a Glance

Demography: the study of the human population's size, structure and composition (age, sex, education, occupation, religion, etc.) and how these change over time through births, deaths and movement of people. Components: size, structure and composition, pattern and trend.

Uses:

• Governments plan infrastructure (schools, hospitals, roads, housing) and services (water, energy, waste). Many young children → more schools; more elderly → more healthcare; a large young working-age population (15-64) → need for jobs.
• Businesses design products for customers by age, gender, income.

Census: in India usually every 10 years; the official count of people at a particular time, collecting age, gender, marital status, education, languages, religion, family size, occupation, employment, income, etc.

Population at a glance:

• India overtook China in 2023 as the most populous country; about 17% of the world's people.
• World: 2.5 billion (1950) → 8.2 billion (2025) → 9.7 billion (2050); UN projection: peak about 10.3 billion in the mid-2080s, then decline.
• Rapid growth after the 1950s came from antibiotics, vaccines, ORS, better water and sanitation, fewer child deaths from malaria and diarrhoea, and spreading prosperity: people lived longer.
• China, Japan and Italy are already shrinking; Nigeria and Ethiopia are growing fast.
• 2025 regional shares: Asia about 4.8 billion, Africa about 1.5 billion.

Worked example

World population was 2.5 billion in 1950 and 8.2 billion in 2025. By how many times did it grow, and what mainly explains the growth? (2 marks)

Try it first, then show the solutionSolution

1. 8.2 ÷ 2.5 = 3.28, so about 3.3 times.
2. Improved healthcare (antibiotics, vaccines, ORS), sanitation; people lived longer.

Answer: It grew about 3.3 times (8.2 ÷ 2.5 = 3.28). The main reason was improved healthcare, such as antibiotics, vaccines and ORS, and better water and sanitation, so fewer people, especially children, died and people lived longer.

Birth, fertility and replacement level

NCERT section Birth and fertility rates

Birth rate: live births per 1,000 population in a year. High birth rate → faster growth; low → slow growth or even shrinking.

Fertility rate: the average number of children a woman would have in her lifetime.

• 2.1 = replacement level fertility: the number needed to replace the parents in the population and keep it stable. Above 2.1 the population tends to grow; below 2.1 it may shrink over time. (The book asks why it is 2.1, not 2.)
• When fertility falls, the birth rate falls and growth slows.

China's One-Child Policy (1979): fearing shortages of food, jobs and housing, China allowed most families one child (fines or job loss for breaking the rule). Fertility fell from 7.5 (1963) to 1 (2025); population peaked at 1.43 billion (2022) and may fall to 1.31 billion by 2050; the elderly (65+) share may rise from 14% (2023) to 26% (2050): fewer young workers, possibly slower growth; a generation without siblings. The policy ended in 2015 (now up to three children), yet fertility stays below replacement.

India: campaigns like 'Hum do humare do' (from 1952) encouraged two children. Fertility fell from 5.7 (1950) to 1.9 (2025). Low fertility is also seen in South Korea, Taiwan, Singapore, Japan, China, Italy, Spain and France.

Why fertility falls: more education for girls, women in formal jobs marrying later and having fewer children, and the high cost of living in cities.

Fertility vs female literacy (Fig. 6.11), from most literate to least: Delhi (literacy 83.7%, fertility 1.6), Punjab (79.4%, 1.6), Karnataka (73.4%, 1.7), Uttar Pradesh (66.1%, 2.4), Jharkhand (61.7%, 2.3), Bihar (55%, 3.0): higher female literacy goes with lower fertility.

Worked example

Using the book's table, compare Bihar and Delhi on fertility and female literacy. What relationship do you see? (3 marks)

Try it first, then show the solutionSolution

1. Bihar: fertility 3.0, female literacy 55%.
2. Delhi: fertility 1.6, female literacy 83.7%.
3. Higher female literacy → lower fertility (education, later marriage, jobs).

Answer: Bihar has a fertility rate of 3.0 and female literacy of 55%, while Delhi has fertility of 1.6 and female literacy of 83.7%. States with higher female literacy have lower fertility, because educated women often marry later, work in formal jobs and choose smaller families.

Death rate, life expectancy and migration

NCERT section Death or mortality rate; Migration

Death (mortality) rate: deaths per 1,000 people in a year. A lower rate shows better healthcare and nutrition.

• Child mortality (deaths of children under 5 per 1,000 live births) in India fell from 271 (1950) to 28 (2023).
• Life expectancy at birth rose from about 30 years at Independence to 70 years (2024). It is the average number of years a newborn is expected to live under current conditions, not an exact age for everyone.

Migration: movement of people within or outside a country, temporarily or permanently, for jobs, education, or because of disasters or political instability. Cities like Delhi, Mumbai, Bengaluru have grown through migration, which can strain water, air, land, transport and housing. The book asks what happens to villages when young people leave.

Current population of any country = the result of years of births, deaths and migration.

Worked example

India's child mortality fell from 271 to 28 per 1,000 between 1950 and 2023. By what percentage did it fall, and what does this show? (3 marks)

Try it first, then show the solutionSolution

1. Fall = 271 - 28 = 243.
2. 243 ÷ 271 × 100 ≈ 89.7%.
3. Shows better healthcare and nutrition.

Answer: It fell by 243 per 1,000, which is about 89.7% (243 ÷ 271 × 100). This huge decline shows the spread of better healthcare, vaccines, sanitation and nutrition, which also helped raise life expectancy from about 30 to 70 years.

Demographic transition: three stages

NCERT section How Do Countries Experience Population Change?

Like people passing through childhood, adulthood and old age, countries pass through demographic transitions linked to economic development, healthcare, education and women's role in household decisions.

Stage	Birth rate	Death rate	Growth	India
1	high	high	very slow or stagnant	1901-1921 (poor healthcare, low literacy)
2	high	falls (better healthcare)	rapid	after 1951
3	falls (urbanisation, income, education, women working)	low	slows; may shrink if fertility drops a lot	fertility falling since mid-1980s; now below replacement

Shrinking populations in stage 3: Italy, Japan, South Korea and other European and East Asian countries. A youth bulge (large 16-30 population) is common in countries at stage 2.

Worked example

Why does population grow fastest in stage 2 of the demographic transition? (2 marks)

Try it first, then show the solutionSolution

1. Death rate falls due to better healthcare.
2. Birth rate stays high; gap between births and deaths widens.

Answer: In stage 2, better healthcare lowers the death rate while the birth rate is still high, so many more people are born than die each year and the population grows rapidly, as in India after 1951.

Population composition: sex ratio and pyramids

NCERT section India's Population: Composition and Trends

Population composition (structure): age, gender, occupation, education, etc. Uttar Pradesh has the largest share of India's population (about 16%), followed by Maharashtra and Bihar (about 9% each).

Sex ratio: number of females per 1,000 males; measures gender balance and reflects socio-economic and cultural conditions. India: 933 (2001) → 943 (2011), when women were 48.5% of the population. Kerala, Puducherry, Tamil Nadu had ratios over or near 1,000. A balanced ratio supports equitable development and social stability.

Population pyramid (structure diagram): a graph of population by age groups and gender:

• Wide base: many children: young, growing population (India, Nigeria).
• Widest middle: mostly working adults: stable population.
• Wide top: more elderly than young adults: ageing (Japan).

(It is really a 3-D idea shown in 2-D, more triangle than pyramid.)

India's changing pyramid:

• 1950s: narrow triangle: many children, few elderly; high birth rate; life expectancy about 30-35.
• Recently: more bell-shaped: narrower base (fewer children), much wider middle (15-60): the demographic dividend; top slowly widening (longer lives).
• Future: may age slowly like Japan or China.

Worked example

In 2011 India's sex ratio was 943. How many males were there for every 1,000 females, roughly? (2 marks)

Try it first, then show the solutionSolution

1. 943 females : 1,000 males.
2. Males per 1,000 females = 1,000 × 1,000 ÷ 943 ≈ 1,060.

Answer: 943 females per 1,000 males means about 1,000 × 1,000 ÷ 943 ≈ 1,060 males for every 1,000 females, so men outnumbered women.

Demographic dividend: a limited window

NCERT section India's Demographic Dividend: A Limited Window of Opportunity

Demographic dividend: the economic growth potential from a young, productive age structure. Young people work in factories, offices and farms or start businesses; workers earn and pay taxes that fund schools, hospitals, roads and parks.

India's figures: about 27% under 15 and nearly 65% of working age (15-59). Median age: India 28; Japan 50; Italy 48; Germany 47; China 40; USA 39.

A limited window: children under five peaked in 2007; under-15s peaked in 2011 and are declining; the young population's growth is expected to fall after 2050, when India begins moving towards an older population. Kerala and Tamil Nadu already have much larger elderly shares than Bihar and UP (2011: 12.6% vs 6.7% at the extremes shown).

Ageing challenges: more elderly needing care and healthcare; fewer workers to replace retirees; slower economy; harder to pay pensions with fewer young taxpayers.

Responses:

• Developed countries: Japan raised the retirement age, uses technology, automation, community centres, robots and AI assistants for elder care.
• Developing countries: invest in education, skilling and healthcare to harness the dividend; support working women facing the 'double burden' (job plus housework) with childcare/daycare, family support and flexible hours.
• Many nations' policies to raise fertility have not succeeded much.

Āshrama dharma: life's four phases (brahmacharya, gṛihastāshrama, vānaprastha, sanyāsa); elders withdraw from economic work but share wisdom, guide rituals and storytelling and ensure cultural continuity.

Worked example

Why is India's demographic dividend called a 'limited window of opportunity'? (3 marks)

Try it first, then show the solutionSolution

1. Large working-age population now (about 65%); median age 28.
2. Children under 5 peaked 2007; under-15 peaked 2011; young growth falls after 2050.
3. After that ageing begins, so benefits must be reaped now through education, skills, health.

Answer: India now has a large working-age population (nearly 65%, median age 28) that can boost growth. But the number of children under five peaked in 2007 and under-15s in 2011, and growth of the young population is expected to fall after 2050, when India starts to age. So the advantage lasts only a few decades and must be used now by investing in education, skilling, healthcare and jobs.

Dynamics of Population in real life

Each concept, met in an everyday situation. Read the situation, answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Topics in this chapter

• Demography, Population Change and Demographic Transition
• Population Composition, Pyramids and the Demographic Dividend

Dynamics of Population: key facts

Rates

• •Birth rate = live births per 1,000 people per year
• •Death rate = deaths per 1,000 per year
• •Child mortality = under-5 deaths per 1,000 live births
• •Sex ratio = females per 1,000 males

Replacement level

Fertility rate 2.1 = replacement; > 2.1 grows; < 2.1 may shrink

India 5.7 (1950) → 1.9 (2025); China 7.5 (1963) → 1 (2025).

Population change

Population change = births - deaths + (in-migrants - out-migrants)

The three drivers named in the chapter.

World and India numbers

1. 1.World: 2.5 bn (1950)
2. 2.8.2 bn (2025)
3. 3.9.7 bn (2050)
4. 4.peak 10.3 bn (mid-2080s) | India: most populous from 2023; about 17% of world

India's indicators

• •Child mortality 271 → 28
• •Life expectancy 30 → 70
• •Sex ratio 933 (2001) → 943 (2011)
• •27% under 15; about 65% aged 15-59
• •Median age 28

Transition stages

Stage 1	high births, high deaths (slow)
Stage 2	deaths fall, births high (rapid)
Stage 3	deaths low, births fall (slows/shrinks)

India: 1901-21 → after 1951 → after mid-1980s.

How the school exam asks Dynamics of Population

The question patterns to expect, and the method that works for each.

Tricks to remember Dynamics of Population

Short memory aids. Say each one aloud once, then use it on a question the same day.

• Four drivers and indicators

  'B-F-D-M': Birth rate, Fertility rate, Death rate, Migration.

  Use it when: Key indicators of demography.

• Replacement rate

  'Two to replace, plus a little extra (0.1) for safety': 2.1.

  Use it when: Replacement level.

• Transition stages

  'Both High → Death Drops → Births Bend': stages 1, 2, 3.

  Use it when: Demographic transition.

• Pyramid shapes

  'Wide feet = young (India, Nigeria); fat belly = working; big head = ageing (Japan)'.

  Use it when: Reading pyramids.

• Dividend dates

  'Under-5 peak '07, under-15 peak '11, window closes around '50'.

  Use it when: Limited window.

Dynamics of Population: exam-level solved questions

Ordered from exam level to HOTS. Cover the solution, write your own, then compare step by step.

Case-study practice (Section E style)

Read the situation, then answer every part. In a school exam set on the board pattern this is a 4-mark question split into 1 + 1 + 2 marks.

Where the marks are

How a typical answer is split into step marks. Show every step: a right final answer alone rarely earns full marks.

Where students lose marks in Dynamics of Population

The slips examiners see most often, and what to write instead.

• ✗Mistake: Confusing birth rate with fertility rate

  Both concern births.

  Wrong working

  Fertility rate is the number of births per 1,000 people.

  Right working

  Birth rate = live births per 1,000 people per year; fertility rate = average children a woman has in her lifetime.

  ✓Do this: Per 1,000 people vs per woman.

  Usually costs: 1 mark.

• ✗Mistake: Reading life expectancy as everyone's age at death

  Literal reading.

  Wrong working

  Life expectancy 70 means every Indian dies at 70.

  Right working

  It is the average number of years a newborn is expected to live under current conditions; many live longer or shorter.

  ✓Do this: Write 'on average'.

  Usually costs: 1 mark.

• ✗Mistake: Writing sex ratio as males per 1,000 females

  Reversed definition.

  Wrong working

  Sex ratio 943 means 943 males per 1,000 females.

  Right working

  Sex ratio is females per 1,000 males; 943 means 943 females for every 1,000 males.

  ✓Do this: Females on top.

  Usually costs: 1 mark.

• ✗Mistake: Thinking the demographic dividend is permanent

  India is young now.

  Wrong working

  India will always have a young workforce.

  Right working

  The window is limited: young population growth is expected to fall after 2050 and India will begin to age.

  ✓Do this: Add 'limited window'.

  Usually costs: 1-2 marks.

• ✗Mistake: Misplacing India in the transition

  India's population is still large and growing.

  Wrong working

  India is still in stage 2 with high fertility.

  Right working

  India's fertility has fallen since the mid-1980s and is now below replacement (1.9): stage 3, though the population is still growing for now.

  ✓Do this: Check fertility (1.9 < 2.1).

  Usually costs: 1 mark.

NCERT exercise guide: Dynamics of Population

What each exercise in the NCERT chapter tests, how to approach it, and a question of the same kind solved step by step. Questions here are written in our own words.

Practice questions on Dynamics of Population

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

1. Q1 · 1 mark · MCQExam level

   Which country did India overtake to become the most populous in 2023?
   (a) USA (b) Indonesia (c) China (d) Pakistan

   Hint

   Neighbour.

   Answer

   (c) China

2. Q2 · 1 mark · Very short answerExam level

   What is child mortality?

   Hint

   Under 5.

   Answer

   The number of deaths of children under 5 years per 1,000 live births.

3. Q3 · 1 mark · Very short answerExam level

   Name the Indian population campaign mentioned in the chapter.

   Hint

   Two children.

   Answer

   'Hum do humare do'.

4. Q4 · 1 mark · Very short answerExam level

   What is a census?

   Hint

   Official count.

   Answer

   The official count of people in a country at a particular time, with information on age, gender, education, occupation and other features.

5. Q5 · 2 marks · Short answerHarder exam level

   Why have cities like Delhi, Mumbai and Bengaluru grown rapidly, and what problem does this cause?

   Hint

   Migration.

   Answer

   People migrate there for jobs and education, so their populations rise; heavy concentration strains water, air, land, transport and housing.

6. Q6 · 2 marks · Short answerHarder exam level

   Kerala and Tamil Nadu have older populations than Bihar and Uttar Pradesh. Suggest two reasons using the chapter.

   Hint

   Fertility and healthcare.

   Answer

   Their fertility fell earlier (linked with higher female literacy), so fewer children are born; and better healthcare means people live longer, raising the elderly share.

7. Q7 · 1 mark · Assertion-reasonHarder exam level

   Assertion (A): India's population is still growing though its fertility rate is 1.9.
   Reason (R): A large number of people are currently in their child-bearing and working years.
   (a) Both true, R explains A (b) Both true, R does not explain A (c) A true, R false (d) A false, R true

   Hint

   Population momentum.

   Answer

   (a) Both true and R explains A: the large young cohorts keep total births high for a while even with fewer children per woman.

8. Q8 · 2 marks · Short answerHarder exam level

   The world population is projected to peak at 10.3 billion and then decline. From 8.2 billion in 2025, how much more growth is that, in billions and per cent?

   Hint

   Difference ÷ 8.2.

   Answer

   10.3 - 8.2 = 2.1 billion more, about 25.6% (2.1 ÷ 8.2 × 100).

9. Q9 · 2 marks · Short answerHOTS / competency

   What social effects did China's One-Child Policy have beyond numbers?

   Hint

   Siblings, kinship.

   Answer

   A whole generation grew up without siblings and with smaller kinship networks; even after the policy ended, families still have few children, showing a lasting effect on society and the economy.

10. Q10 · 3 marks · Short answerHOTS / competency

    Suppose a country's fertility rate stays at 1.2 for decades. Describe its likely pyramid and two challenges it will face.

    Hint

    Below replacement.

    Answer

    Its pyramid will have a narrow base and a wide top, perhaps fewer children than elderly, and the population will shrink. Challenges: fewer young workers to replace retirees, slowing the economy; heavier healthcare and pension costs with fewer taxpayers to fund them.

11. Q11 · 2 marks · Short answerHOTS / competency

    How does the idea of āshrama dharma suggest a positive role for the elderly in an ageing society?

    Hint

    Four phases.

    Answer

    It divides life into four phases; in later phases people withdraw from economic work but share wisdom, guide rituals and storytelling and keep culture alive, so the elderly remain valuable to families and society, not just dependants.

12. Q12 · 5 marks · Long answerHOTS / competency

    Country A has crowded cities and a fertility rate of 3.0; Country B has a fertility rate of 1.2 and a median age of 50. Which faces the bigger long-term problem? Argue both sides using the chapter, then give your conclusion.

    Hint

    Pressure vs ageing.

    Answer

    For: fewer people can mean less pressure on land, water, housing, transport and jobs; more resources per person for education and health (fast-growing cities face severe strain). Against: shrinking populations, as in Japan, Italy and China, age quickly; there are fewer workers and taxpayers to support the elderly, healthcare and pension costs rise and growth may slow; many countries have tried and failed to raise fertility again. Conclusion: neither extreme is ideal; what matters is a balanced age structure and investment in people's education, skills and health, so that a population becomes an asset, as India's demographic dividend shows.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1. 1.What is demography?Show answer

   The study of a population's size, structure and composition and how they change over time through births, deaths and migration.

2. 2.How often is India's census usually held?Show answer

   Every 10 years.

3. 3.When did India become the most populous country?Show answer

   2023.

4. 4.What is the replacement level fertility rate?Show answer

   2.1.

5. 5.What was India's fertility rate in 1950 and 2025?Show answer

   5.7 and 1.9.

6. 6.When did China introduce and end its One-Child Policy?Show answer

   Introduced 1979; ended 2015.

7. 7.What was India's sex ratio in 2011?Show answer

   943 females per 1,000 males.

8. 8.What is India's life expectancy now?Show answer

   About 70 years (2024), up from about 30 at Independence.

9. 9.What is the working-age population?Show answer

   People aged 15-64 (the book also uses 15-59 for India's share).

10. 10.What is India's median age?Show answer

    28 years.

11. 11.What is a youth bulge?Show answer

    A large young population (16-30 years), common at stage 2 of the transition.

12. 12.What is the 'double burden'?Show answer

    Working women managing both job responsibilities and household duties.

Quick revision checklist

The night before the exam: can you do each of these without looking?

• ☐Demography: size, structure, composition and change (births, deaths, migration).
• ☐Uses: planning schools, hospitals, jobs; businesses target customers.
• ☐Census: every 10 years in India.
• ☐India most populous since 2023 (about 17% of world).
• ☐World: 2.5 bn → 8.2 bn → 9.7 bn (2050) → peak 10.3 bn (mid-2080s).
• ☐Fertility: replacement 2.1; India 5.7 → 1.9; China 7.5 → 1 (One-Child Policy 1979-2015).
• ☐Female literacy up, fertility down (Bihar 3.0 vs Delhi 1.6).
• ☐Child mortality 271 → 28; life expectancy 30 → 70.
• ☐Migration to cities strains resources.
• ☐Transition: 1 high-high; 2 deaths fall; 3 births fall.
• ☐Sex ratio 933 → 943; pyramids: wide base young, wide top ageing.
• ☐Dividend: 65% working age, median age 28; window closes around 2050; ageing needs planning.

Dynamics of Population: frequently asked questions