Population I: Factors Affecting Population Growth – SS1 Economics Lesson Note (Second Term)

Population is the total number of people living within a geographical area or country at a particular time. Its size and growth rate depend on three factors: birth rate, death rate and net migration. Net migration is the difference between the number of immigrants and emigrants.

Behavioural objectives

By the end of the lesson, students should be able to:

• define population, birth rate, death rate and migration;
• state the formula for the rate of population growth;
• list the factors that affect birth rate and death rate;
• distinguish between emigration and immigration;
• state the consequences of a rapidly growing population;
• state the causes, advantages and disadvantages of an ageing or declining population.

What factors affect population growth?

Three major factors determine the size and rate of growth of a country’s population. They can be summarised in the following formula:

r = Birth Rate – Death Rate + Net Migration

Here, r is the rate of growth of the population. Net migration is the difference between the number of immigrants and emigrants. The major factors affecting population size and growth are therefore birth rate, death rate and migration.

Birth rate

Birth rate is the total number of births per thousand people in a particular year. It is determined by the following factors:

1. Early marriage: The birth rate will be higher if people marry at earlier ages.
2. Health of the people: As a result of improved medical services, the death rate has reduced while the birth rate has been boosted.
3. Ratio of women of childbearing age: The greater the number of women who are of childbearing age, the higher the birth rate.
4. Religious beliefs: The religious beliefs of the people may also play a role. For example, Islam allows polygamy and that can lead to a high birth rate.
5. Desire for large families.
6. Improved standard of living.

Death rate

Death rate is the number of deaths per thousand of the population in a year.

What factors affect death rate?

1. Availability of health and medical facilities
2. Standard of personal hygiene and environmental sanitation
3. Standard of living
4. Incidence of epidemics, wars, famine and natural disasters such as floods and earthquakes
5. Age distribution of the population: if there are many elderly people, there may be a tendency for the death rate to be high.

What is migration?

Migration is the movement of people from one place to another, involving permanent or temporary residence or settlement.

Types of migration

1. Emigration: the movement of people out of a country to another country.
2. Immigration: the movement of people into a country.

Note: The difference between the number of immigrants and emigrants is called net migration. Immigration increases the population, while emigration decreases it.

What factors are responsible for an increase in population?

1. Increase in birth rate
2. Decrease in death rate
3. Medical improvement
4. Early marriage
5. A large population of women of childbearing age
6. Illiteracy
7. Immigration
8. Absence of family planning

What are the consequences of a rapidly growing population?

1. An enlarged market: The total demand for goods and services will be higher.
2. A higher dependency ratio: Workers will have more dependents (especially children) to cater for.
3. Heavy pressure on infrastructural facilities
4. Possible unemployment
5. Urban congestion
6. A high cost of living
7. Low standard of living and fall in per capita income
8. Increase in government expenditure
9. Problems of overpopulation

What is an ageing or declining population?

An ageing population is a declining population with an increasing percentage of old people, while the relative percentages of children and workers are decreasing.

An ageing population is also referred to as a decreasing population, stationary population or static population.

Factors responsible for an ageing population

1. Decrease in birth rate
2. Increase in death rate
3. Emigration
4. War
5. Diseases
6. Natural disasters

Advantages of a declining or decreasing population

1. Reduction in government expenditure
2. Increase in government savings
3. Increase or high standard of living
4. It may lead to under-population
5. Creation of jobs

Disadvantages of a declining or decreasing population

1. Reduction in labour force
2. It discourages investment
3. Rise in prices of goods and services
4. It may lead to under-population
5. High dependency ratio
6. It discourages foreign aid

Evaluation

1. Define population and state the formula for the rate of population growth.
2. List four factors that affect birth rate.
3. List four factors that affect death rate.
4. Distinguish between emigration and immigration.
5. State four consequences of a rapidly growing population.

Assignment

1. State three advantages and three disadvantages of a declining population.
2. List four factors responsible for an ageing population.