Population
ICSE Class 8 · Geography · Chapter 2
What this chapter covers
- People as a part of geography
- Distribution of world population
- Density of population
- Factors affecting the population of a place
- Overpopulation and underpopulation
- Impact of overpopulation and underpopulation on society
- Composition of population
- Population pyramid
Key points
- Population is the number of people living in a place at a given time; a census counts them officially, and the 2011 Census gives India's latest complete figures.
- World population is unevenly distributed: river plains, coasts and fertile lowlands are crowded, while deserts, high mountains, dense forests and polar lands are nearly empty.
- Relief, climate, water, soil and minerals, along with jobs, transport and services, decide where people live.
- Population density = population ÷ area, given in persons per square kilometre; it is an average that can hide large differences within a country.
- Population changes through births, deaths, immigration and emigration: population change = births − deaths + immigrants − emigrants.
- Natural growth rate = birth rate − death rate, both measured per thousand people per year.
- Overpopulation means more people than resources can support; underpopulation means too few people to use the resources fully. Both depend on resources and technology, not on numbers alone.
- Overpopulation brings unemployment, housing shortages, strained services and environmental damage; underpopulation brings labour shortages and costly services.
- Population composition describes a population by age, sex and rural or urban residence; sex ratio in India is females per 1,000 males.
- A population pyramid shows age and sex composition: expanding (wide base, young and growing), stationary (straight sides, slow growth) and contracting (narrow base, ageing).
Questions answered
What is population density, and how is it calculated?
Population density is the average number of people living on one square kilometre of land. It is calculated by dividing the total population of an area by its land area in square kilometres.
Give three geographical reasons why the Ganga plain is densely populated.
It is flat land that is easy to farm and build on, it has fertile alluvial soil, and its rivers provide plenty of water. A suitable climate with monsoon rain also helps.
Name two thinly populated regions of the world and give one reason for each.
The Sahara Desert is too dry for most farming, and Greenland is covered by an ice sheet and is too cold. (The Amazon rainforest, Siberia and Antarctica are also correct answers.)
A town has 40,000 people. In one year there are 1,000 births and 320 deaths. Find the natural growth rate per thousand.
Birth rate = (1,000 ÷ 40,000) × 1,000 = 25 per thousand. Death rate = (320 ÷ 40,000) × 1,000 = 8 per thousand. Natural growth rate = 25 − 8 = 17 per thousand.
Distinguish between immigration and emigration.
Immigration is the movement of people into a country to settle there, and it increases that country's population. Emigration is the movement of people out of their own country to settle elsewhere, and it reduces the population.
Why is a crowded country not always overpopulated?
Overpopulation depends on whether resources can support the people, not on crowding alone. A densely populated country with wealth, trade and modern technology, such as Singapore, can support its people well.
State two effects of overpopulation and two effects of underpopulation.
Overpopulation causes unemployment and shortages of housing, food and services. Underpopulation causes a shortage of workers and makes services costly to provide over a large, empty area.
What does a population pyramid with a wide base and a narrow top tell you about a country?
It shows a high birth rate, a short life expectancy and a young, fast-growing population. This is an expanding pyramid.