ICSE • Class 10 • Biology
Population
Population growth, population explosion, and control measures.
Chapter 5
Verified Curriculum Topic
What is Population?
Population growth, population explosion, and control measures.
Population matters because it helps students explain living systems with precise vocabulary and clear cause-and-effect reasoning. At Class 10 level, strong performance usually depends on understanding processes, structures, functions, and diagram-based explanations.
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Summary
The One Thing
Population size changes according to the balance between births and deaths and between immigration and emigration. Rapid growth becomes a population explosion when it exceeds the carrying capacity of the environment, so control requires education, healthcare, voluntary family planning and sustainable resource use.
Reactions, Processes and Experiments
| What happens | Equation or process | What you observe | Type |
|---|---|---|---|
| Births and immigration increase population size, while deaths and emigration decrease it. | Population change = (Births + Immigration) − (Deaths + Emigration). | Population increases when births and immigration exceed deaths and emigration; it decreases when deaths and emigration exceed births and immigration. | Population change |
| The excess of the birth rate over the death rate gives the natural increase. | Natural increase = Birth rate − Death rate. | A positive difference indicates natural population growth. | Natural population change |
| The annual birth rate is calculated relative to the mid-year population. | Birth rate = (Number of live births during a year ÷ Mid-year population) × 1,000. | The result is expressed as births per 1,000 people per year. | Demographic calculation |
| The annual death rate is calculated relative to the mid-year population. | Death rate = (Number of deaths during a year ÷ Mid-year population) × 1,000. | The result is expressed as deaths per 1,000 people per year. | Demographic calculation |
| Population density measures the number of individuals in a given area. | Population density = Number of individuals ÷ Area of the region. | A higher value indicates more individuals per unit area. | Population measurement |
| A high birth rate combined with a low death rate produces rapid population growth. | — | The population increases rapidly. | Population growth |
| Rapid and excessive human population growth places pressure on resources and the environment. | — | Unemployment, poverty, overcrowding, shortage of food and water, housing problems, pollution, deforestation, loss of biodiversity and depletion of natural resources may occur. | Population explosion |
| Population age composition is divided into three broad groups. | Pre-reproductive, reproductive and post-reproductive age groups. | A broad-based age pyramid shows many young individuals and the possibility of rapid future population growth. | Age structure |
| People move into a region or country. | — | Immigration increases the population of the receiving region or country. | Immigration |
| People move out of a region or country. | — | Emigration decreases the population of the region or country of origin. | Emigration |
| Population size is managed through social, medical and reproductive measures. | Education, especially of girls and women; delayed marriage; small-family principles; correct information about contraception; spacing between children; and access to healthcare. | Reduced population growth and improved family health and living standards. | Population control |
| Methods are used to prevent fertilisation or pregnancy. | Natural methods, barrier methods such as condoms, intrauterine devices, hormonal methods and permanent surgical methods such as vasectomy and tubectomy. | Contraceptive choices should be safe, informed, voluntary and medically appropriate. | Contraception |
| The first official census of India was conducted. | 1872. | Population information was formally collected in India. | Census |
| The first synchronous census of India was conducted. | 1881. | Population information was collected synchronously across India. | Census |
| India introduced a policy directed towards population stabilisation and reproductive health. | The National Population Policy of India was introduced in 2000 to promote population stabilisation, reproductive health, education and responsible family planning. | Greater emphasis on responsible family planning, education and reproductive healthcare. | Population policy |
Key Terms
- Population: The total number of individuals of the same species living in a particular area at a particular time.
- Population density: The number of individuals living per unit area, usually expressed as people per square kilometre.
- Natality: The birth rate of a population, or the number of births per 1,000 individuals in one year.
- Mortality: The death rate of a population, or the number of deaths per 1,000 individuals in one year.
- Immigration: The movement of people into a region or country, which increases its population.
- Emigration: The movement of people out of a region or country, which decreases its population.
- Population growth: The increase in the number of individuals in a population over a period of time.
- Population explosion: A very rapid and excessive increase in human population that creates pressure on resources and the environment.
- Carrying capacity: The maximum population that an environment can support sustainably with its available resources.
- Birth rate: The number of live births per 1,000 people in a year.
- Death rate: The number of deaths per 1,000 people in a year.
- Family planning: The voluntary planning of the number of children and the spacing between births.
- Contraception: The use of methods that prevent fertilisation or pregnancy.
- Demography: The scientific study of human populations, including their size, distribution, age structure and changes.
Easily Confused
- Natality and birth rate: Natality is the birth rate of a population; birth rate specifically refers to live births per 1,000 people in a year.
- Mortality and death rate: Mortality is the death rate of a population; death rate specifically refers to deaths per 1,000 people in a year.
- Immigration and emigration: Immigration is movement into a region and increases its population, whereas emigration is movement out and decreases its population.
- Population growth and population explosion: Population growth is any increase in population size, whereas population explosion is a very rapid and excessive increase that pressures resources and the environment.
- Birth rate and natural increase: Birth rate measures births alone, whereas natural increase is calculated as birth rate minus death rate.
- Family planning and contraception: Family planning includes voluntary decisions about the number and spacing of children, whereas contraception refers specifically to methods preventing fertilisation or pregnancy.
- Population size and population density: Population size is the total number of individuals, whereas population density is the number of individuals per unit area.
- Official and synchronous census in India: The first official census was conducted in 1872, whereas the first synchronous census was conducted in 1881.
What Gets Asked
- Calculate population change using Population change = (Births + Immigration) − (Deaths + Emigration); marks are lost by treating immigration and emigration as having the same effect.
- Calculate natural increase, birth rate, death rate or population density using the stated equations; marks are lost by omitting the factor of 1,000 in birth-rate and death-rate calculations or by confusing area with population.
- Explain the causes of population explosion, including high birth rate, reduced death rate, better medical facilities, control of epidemics, improved sanitation, increased food production and longer life expectancy.
- Describe the effects of population explosion, including unemployment, poverty, overcrowding, shortage of food and water, housing problems, pollution, deforestation, loss of biodiversity and depletion of natural resources.
- Interpret an age pyramid; a broad-based pyramid indicates many young individuals and the possibility of rapid future population growth.
- Explain population-control measures and their rationale, including education of girls and women, delayed marriage, small-family principles, spacing between children, access to healthcare and safe, informed, voluntary and medically appropriate contraception.
- Recall the Indian demographic milestones: the first official census in 1872, the first synchronous census in 1881, and the National Population Policy of India, introduced in 2000.
Flashcards
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What is a population?
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- B5.1Define population growth and distinguish between birth rate and death rate as factors affecting population size.
- B5.2Explain the term population explosion and describe the factors that have contributed to rapid human population growth.
- B5.3Describe the effects of a population explosion on natural resources, such as food, water, and land.
- B5.4Describe the effects of a population explosion on social factors, such as employment, housing, and healthcare.
- B5.5Describe measures that can be adopted to control population growth, including family planning methods.
- B5.6Explain why education, particularly of women, is considered an important factor in controlling population growth.
Practice questions
Q1. The population of a region will increase if:1 mark · core
- A. Birth rate is lower than death rate
- B. Birth rate equals death rate
- C. Birth rate is higher than death rate
- D. Both birth rate and death rate are zero
Answer: C
- • 1 mark for selecting C
A population grows when more individuals are born than die in a given period, i.e. when the birth rate exceeds the death rate.
Q2. State three effects of a rapidly growing human population on natural resources.3 marks · core
Answer: A rapidly growing population increases the demand for food, often leading to shortages or the need for intensive farming that degrades land; it increases the demand for fresh water, straining supplies; and it increases the pressure on land, often leading to deforestation and loss of natural habitats as land is converted for housing and agriculture.
- • 1 mark: valid effect on food resources
- • 1 mark: valid effect on water resources
- • 1 mark: valid effect on land/habitat resources
Q3. State two family planning measures that can help control population growth.2 marks · core
Answer: Use of contraceptive methods to prevent unwanted pregnancies, and spacing births further apart through family planning advice/services, allowing couples to have fewer children by choice.
- • 1 mark: valid measure, e.g. use of contraceptives
- • 1 mark: second valid measure, e.g. birth spacing/family planning advice
Q4. Explain why educating women is considered an important factor in controlling population growth.2 marks · core
Answer: Educated women are more likely to be aware of family planning methods, marry later, and have greater access to employment and decision-making within the family, all of which are associated with choosing to have fewer children, helping to slow population growth.
- • 1 mark: education increases awareness of family planning methods and later marriage
- • 1 mark: education gives women greater access to employment/decision-making, linked to smaller family size
Key ideas to master
- Master the important terms, labelled structures, and process sequences in Population.
- Explain how the system works step by step using accurate biological vocabulary.
- Practise diagram-based recall, comparisons, and function-based questions.
- Focus on causes, effects, and interactions rather than memorising isolated points.
Common exam prompts
- Describe the process or structure in Population in the correct sequence.
- Label or explain a likely diagram-based question from this topic.
- Compare related systems, tissues, organs, or processes where the chapter requires it.
- Summarise the functional importance of Population in concise exam language.
How to study Population effectively
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Step 2
Turn it into active recall
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Step 3
Ask the tutor where you are weak
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Quick answers students usually need
What is Population in ICSE Class 10 Biology?
Population growth, population explosion, and control measures.
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