Q.(a) The graphs given below, A and B, represent population of elephants in two different National Parks (a hypothetical situation) at different times. Study the graphs and comment upon the pattern of growth observed. Mention the possible reason for such patterns seen in nature.
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Population Growth Factors: A First Look
Think about a village, a city, or even your own family. Why do some families grow larger over time, while others stay the same size or shrink? Why do some cities burst with new people while others seem to lose residents? The answer lies in population growth factors — the forces that determine whether a population increases, decreases, or stays stable.
The Core Idea
At its simplest, a population changes because of two things: people being added and people being taken away. But what adds people? Only one thing: births. What takes people away? Only one thing: deaths. That is the natural rhythm of any population.
But there is a third force that matters enormously for a country, state, or city: migration. People move in (immigration) and people move out (emigration). So the real equation — though we are not using numbers here — is:
Births + Immigration = Additions
Deaths + Emigration = Subtractions
When additions are greater than subtractions, the population grows. When subtractions are greater, it shrinks. When they are equal, it stays the same.
The Three Main Factors
The NCERT textbook identifies three broad categories of factors that influence these additions and subtractions:
1. Fertility (the birth side)
Fertility is not just about biology — it is deeply shaped by society. Why do people in some regions have many children, while in others they have few? The factors include:
- Age at marriage: Earlier marriage generally means a longer childbearing period.
- Education and employment of women: Educated women who work tend to have fewer children and have them later.
- Economic conditions: In agricultural societies, children are often seen as economic assets (help on the farm). In urban industrial societies, children are more of an expense.
- Cultural and religious norms: Some communities encourage large families; others do not.
- Government policies: Think of China's former one-child policy or India's family planning programmes.
2. Mortality (the death side)
Why do people die earlier in some places than in others? The key factors are:
- Healthcare infrastructure: Access to hospitals, vaccines, and medicines.
- Nutrition and sanitation: Malnutrition and unclean water kill millions.
- Disease patterns: Epidemics like malaria, tuberculosis, or HIV/AIDS.
- Natural disasters and conflicts: Famines, wars, earthquakes.
- Age structure: A population with many elderly people will naturally have more deaths.
The most dramatic change in human history came from a decline in mortality — not a rise in fertility. Better medicine, sanitation, and food supply caused death rates to fall sharply, especially in the 20th century. This is why the world's population exploded.
3. Migration (the movement side)
People move for reasons that pull them towards a place or push them away from another.
Push factors (reasons to leave):
- Unemployment or low wages
- Political instability or persecution
- Natural disasters or environmental degradation
- Lack of educational opportunities
Pull factors (reasons to come):
- Better job prospects and higher incomes
- Peace and security
- Better schools and universities
- Family reunification
Migration can be internal (within a country, like rural-to-urban movement) or international (across borders).
Why This Matters
Population growth factors are not just academic. They shape everything:
- Economic planning: A rapidly growing population needs more schools, hospitals, jobs, and housing. A shrinking population faces labour shortages and an ageing society.
- Resource use: More people mean more demand for water, food, energy, and land. …
Part (b)Concept understanding — Population Growth Factors
Population Growth Factors: A First Look
Think about a village, a city, or even your own family. Why do some families grow larger over time, while others stay the same size or shrink? Why do some cities burst with new people while others seem to lose residents? The answer lies in population growth factors — the forces that determine whether a population increases, decreases, or stays stable.
The Core Idea
At its simplest, a population changes because of two things: people being added and people being taken away. But what adds people? Only one thing: births. What takes people away? Only one thing: deaths. That is the natural rhythm of any population.
But there is a third force that matters enormously for a country, state, or city: migration. People move in (immigration) and people move out (emigration). So the real equation — though we are not using numbers here — is:
Births + Immigration = Additions
Deaths + Emigration = Subtractions
When additions are greater than subtractions, the population grows. When subtractions are greater, it shrinks. When they are equal, it stays the same.
The Three Main Factors
The NCERT textbook identifies three broad categories of factors that influence these additions and subtractions:
1. Fertility (the birth side)
Fertility is not just about biology — it is deeply shaped by society. Why do people in some regions have many children, while in others they have few? The factors include:
- Age at marriage: Earlier marriage generally means a longer childbearing period.
- Education and employment of women: Educated women who work tend to have fewer children and have them later.
- Economic conditions: In agricultural societies, children are often seen as economic assets (help on the farm). In urban industrial societies, children are more of an expense.
- Cultural and religious norms: Some communities encourage large families; others do not.
- Government policies: Think of China's former one-child policy or India's family planning programmes.
2. Mortality (the death side)
Why do people die earlier in some places than in others? The key factors are:
- Healthcare infrastructure: Access to hospitals, vaccines, and medicines.
- Nutrition and sanitation: Malnutrition and unclean water kill millions.
- Disease patterns: Epidemics like malaria, tuberculosis, or HIV/AIDS.
- Natural disasters and conflicts: Famines, wars, earthquakes.
- Age structure: A population with many elderly people will naturally have more deaths.
The most dramatic change in human history came from a decline in mortality — not a rise in fertility. Better medicine, sanitation, and food supply caused death rates to fall sharply, especially in the 20th century. This is why the world's population exploded.
3. Migration (the movement side)
People move for reasons that pull them towards a place or push them away from another.
Push factors (reasons to leave):
- Unemployment or low wages
- Political instability or persecution
- Natural disasters or environmental degradation
- Lack of educational opportunities
Pull factors (reasons to come):
- Better job prospects and higher incomes
- Peace and security
- Better schools and universities
- Family reunification
Migration can be internal (within a country, like rural-to-urban movement) or international (across borders).
Why This Matters
Population growth factors are not just academic. They shape everything:
- Economic planning: A rapidly growing population needs more schools, hospitals, jobs, and housing. A shrinking population faces labour shortages and an ageing society.
- Resource use: More people mean more demand for water, food, energy, and land. …
Part (a)
- Graph A — J-shaped (exponential) growth: the population rises steeply with no levelling off. It occurs when food and space are unlimited and there is no check from predators/competition — a temporary situation in nature.
- Graph B — S-shaped (logistic/sigmoid) growth: the population rises and then levels off at the carrying capacity (K) of the habitat. This is the common natural pattern, arising when resources become limiting and density-dependent factors (competition, predation, disease) slow the growth until births balance deaths. …
Part (a): Graph A is J-shaped exponential growth (unlimited resources, no check) and Graph B is S-shaped logistic growth that plateaus at the carrying capacity because resources are limited. Part (b): A country's population growth rate falls chiefly when natality (birth rate) drops and/or mortality/emigration rises.
Part (a)
No population can grow indefinitely, because every habitat has a limited carrying capacity (K) — the maximum number it can support. The two graphs illustrate the two basic growth patterns.
Graph A — exponential (J-shaped) growth. The population climbs faster and faster and shows no plateau. This happens only when food, space and other resources are unlimited and there is no predation, competition or disease to check growth. It follows dN/dt = rN. Such growth is temporary: in nature resources soon become limiting, so it either crashes or shifts to logistic growth. …
- CBSE 2025Set X11 markMCQQ.Select the one among the given that is a probable reason for explosive growth of population in India.(a) A rapid increase in MMR(b) A rapid increase in IMR(c) Increase in the number of people in reproducible age(d) A rapid increase in death rate
›Reveal solutionSolution
The explosive population growth in India is largely due to a rise in the number of people in the reproducible (reproductive) age group.
A decline in maternal mortality rate (MMR) and infant mortality rate (IMR), plus an increase in the number of people reaching reproductive age, are the main reasons for the rapid rise in India's population. Among the given options, an increase in the number of people in the reproducible age directly increases the birth rat …
- CBSE 2025Set ANNUAL1 markMCQQ.The most effective way to decrease the population of a country is :(a) to educate people(b) to have better houses and infrastructure(c) to eradicate poverty(d) to practice and implement family planning
›Reveal solutionSolution
Practising and implementing family planning (contraception, spacing, small family norm) is the most direct and effective lever to reduce population growth rate.
While education, better infrastructure and poverty eradication all indirectly influence fertility rates over long timeframes by changing social attitudes, the most direct and immediately effective method to reduce population growth is the active practice and implementation of family planning — the use of contraceptive methods (natural, barrier, IUDs, oral pills, surgical methods like vasectomy/tubectomy) to control the number and spacing of children, alongside government promotio …
- CBSE 2024Set E1 markMCQQ.What is the population growth rate of India as per 2001 census?(a) 1.1%(b) 3.7%(c) Approximately 2%(d) 3%
›Reveal solutionSolution
India's population growth rate at the 2001 census was approximately 2%.
The alarming rise in India's population was a major reason for adopting family planning and reproductive-health programmes. Around the 2000–2001 census, the population growth rate was still high — approximately 2% (about 20 per 1000 people per year) — meaning the population could nearly double in a short span. This high growth r …
- CBSE 2023Set 57/1/11 markMCQQ.The status of the human population reflected in the human age pyramid given below is :(a) Declining population(b) Stable population(c) Expanding population(d) Extinct population
›Reveal solutionSolution
An age pyramid's shape reveals population growth trend: a broad base tapering upward means high birth rates and growth; roughly equal widths mean a stable population; a narrow base with a wider middle/top means decline.
Understanding Age Pyramids
An age pyramid is a graphical representation showing the distribution of a population across different age groups, typically divided by sex. The shape of this pyramid indicates whether a population is growing, stable, or shrinking.
The key lies in the base of the pyramid. A population's future depends on how many individuals are in, or approaching, reproductive age. When the base is wide, a large number of births are occurring relative to older age groups — this population has momentum to grow.
Reading the Pyramid Shape
Expanding (growing) population: the pyramid has a broad base that tapers steadily toward the top, reflecting high birth rates, with each younger age group larger than the one above it.
Stable population: the pyramid resembles a column or bell, with roughly equal proportions across reproductive age groups — birth rates approximately equal death rates.
Declining population: the pyramid is narrow at the base and wider in the middle or upper sections — fewer children are being born than there are adults, and the population will shrink as older generations are not replaced.
Extinct population: this would show virtually no individuals in younger age groups — a theoretical extreme, not a shape a real census pyramid shows.
Applying this to the pyramid in the question
- Look at the base first — is it the widest part of the pyramid?
- Check the progression — does each age group get progressively smaller moving up? …
- CBSE 2021Set TERM11 markMCQQ.IMR stands for :(a) Infant Mortality Rate(b) Intact Mortality Rate(c) Instant Mortality Rate(d) Infact Mortality Rate
›Reveal solutionSolution
IMR is a standard demographic/health statistic used to gauge maternal-and-child health and healthcare quality in a population.
IMR (Infant Mortality Rate) measures the number of deaths of infants under one year of age per 1,000 live births in a year. It is widely used, alongside the Maternal Mortality Rate (MMR) and Sex Ratio, as an indicator of a population's reproductive and general health status, and of the quality/reach of healthcare servi …
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