Population Revision Notes

The birth rate is the number of live births per 1,000 people in a population within one year. A higher birth rate means more new individuals are added to the population, contributing to growth. For example, if a country has a birth rate of 20 per 1,000 and a population of 1 million, approximately 20,000 babies are born annually.

Birth rate is influenced by factors such as cultural norms, access to healthcare, economic conditions, and government policies. For instance, countries with better maternal healthcare often have lower infant mortality, which can affect birth rates indirectly.

• Birth rate = (Number of live births ÷ Total population) × 1,000
• Higher birth rates increase population size

The death rate is the number of deaths per 1,000 people in a population within one year. It reduces the population size by removing individuals. For example, a death rate of 10 per 1,000 in a population of 1 million means about 10,000 people die annually.

Death rates depend on healthcare quality, nutrition, sanitation, and age structure. A country with poor healthcare may have a high death rate, slowing population growth or even causing decline.

• Death rate = (Number of deaths ÷ Total population) × 1,000
• Higher death rates decrease population size

Net migration is the difference between the number of immigrants (people moving into a country) and emigrants (people leaving a country) over a period. It can be positive or negative.

For example, if 50,000 people immigrate to a country and 30,000 emigrate, net migration is +20,000, increasing population size. Conversely, if more people leave than arrive, net migration is negative, reducing population.

Net migration is influenced by economic opportunities, political stability, conflicts, and environmental factors.

• Net migration = Immigration − Emigration
• Positive net migration increases population
• Negative net migration decreases population

Immigration refers to people moving into a country to live, work, or study. It adds to the population and can affect the age and skill structure of the population.

Emigration is when people leave their country to live elsewhere. It reduces the population and can lead to a loss of working-age individuals if many young people emigrate.

For example, a country experiencing high emigration of young adults may face labour shortages and slower economic growth.

• Immigration increases population size
• Emigration decreases population size

Population growth rate can be calculated by combining natural change (birth rate minus death rate) and net migration.

Formula: Population growth rate = (Birth rate − Death rate) + Net migration (all per 1,000 population)

For example, if a country has a birth rate of 18, death rate of 10, and net migration of +2 per 1,000, the population growth rate is (18 − 10) + 2 = 10 per 1,000, meaning the population grows by 1% annually (10 ÷ 1,000).

• Population growth rate = (Birth rate − Death rate) + Net migration
• Expressed per 1,000 population or as a percentage

Birth rate is the number of live births per 1,000 people in a population per year. Countries with high birth rates tend to experience faster population growth because more babies are born relative to the total population size.

High birth rates often occur in developing countries where access to contraception is limited, education levels are lower, and cultural or religious norms encourage larger families. For example, Niger has a birth rate exceeding 40 births per 1,000 people, contributing to rapid population growth.

Conversely, developed countries typically have lower birth rates due to widespread family planning, higher female education and employment, and urbanisation. For instance, Germany’s birth rate is around 9 births per 1,000 people, leading to slower natural population increase or even decline.

• Birth rate = (Number of live births ÷ Total population) × 1,000
• High birth rates increase population growth rate
• Cultural, economic, and educational factors influence birth rates

Death rate is the number of deaths per 1,000 people in a population per year. High death rates reduce population growth because more people die relative to the population size.

Countries with poor healthcare, malnutrition, disease, and unsafe living conditions often have high death rates. For example, some sub-Saharan African countries have death rates above 15 per 1,000, which slows population growth despite high birth rates.

In contrast, countries with advanced healthcare systems, sanitation, and nutrition have low death rates, often below 10 per 1,000. This supports population growth or stability, as fewer people die each year. Japan, for example, has a low death rate but an ageing population, which affects overall growth differently.

• Death rate = (Number of deaths ÷ Total population) × 1,000
• High death rates reduce population growth
• Healthcare and living standards strongly affect death rates

Net migration is the difference between the number of immigrants (people entering a country) and emigrants (people leaving a country) per 1,000 population per year.

A positive net migration means more people enter than leave, increasing the population. For example, Canada experiences positive net migration, which contributes significantly to its population growth.

A negative net migration occurs when more people leave than enter, reducing population size. Countries facing economic hardship or conflict, such as Syria during its civil war, have experienced negative net migration and population decline in affected areas.

• Net migration = Immigrants − Emigrants per 1,000 population
• Positive net migration increases population size
• Negative net migration decreases population size

Population growth rate is determined by the combined effect of birth rate, death rate, and net migration. The formula for population growth rate per 1,000 people is:

Population growth rate = Birth rate − Death rate + Net migration rate

For example, if a country has a birth rate of 30, death rate of 10, and net migration of +5 per 1,000, the population growth rate is 30 − 10 + 5 = 25 per 1,000, indicating rapid growth. Conversely, a country with birth rate 10, death rate 12, and net migration −3 would have a growth rate of 10 − 12 − 3 = −5 per 1,000, indicating population decline.

• Population growth rate = Birth rate − Death rate + Net migration rate
• Positive growth rate means population increase
• Negative growth rate means population decrease

Nigeria has a high birth rate (around 38 per 1,000), a moderate death rate (about 12 per 1,000), and low net migration, resulting in rapid population growth.

Italy has a low birth rate (about 7 per 1,000), low death rate (around 10 per 1,000), and slight positive net migration, leading to a stable or slowly declining population.

Australia has moderate birth and death rates but a high positive net migration rate, which significantly contributes to its population growth.

• High birth rate + moderate death rate + low migration = rapid growth (Nigeria)
• Low birth rate + low death rate + slight positive migration = stable/declining (Italy)

Population size directly affects a country's demand for resources such as food, housing, education, and healthcare. A rapidly growing population increases pressure on these resources, potentially leading to shortages or reduced quality of services. Conversely, a declining population may reduce demand but can cause labour shortages and lower economic growth.

For example, a country with a population increasing by 3% annually may struggle to provide enough schools and jobs, while a country with a shrinking population might face difficulties maintaining its workforce and supporting pension systems.

• Large populations require more resources and infrastructure.
• Rapid growth can strain public services and natural resources.
• Declining populations may lead to labour shortages and economic stagnation.

Optimum population refers to the ideal number of people that allows a country to use its resources efficiently to maximise economic welfare. It balances the available natural resources, technology, and capital with the labour force size.

If the population is below the optimum, resources may be underutilised, leading to lower economic output. If it exceeds the optimum, resources become overstretched, causing unemployment, environmental degradation, and lower living standards.

For instance, a country rich in arable land but with a small population might not fully exploit its agricultural potential, whereas an overcrowded country with limited land may suffer from food shortages and unemployment.

• Optimum population maximises resource use and economic output.
• Population below optimum leads to underutilisation of resources.
• Population above optimum causes resource scarcity and unemployment.

Age distribution affects the dependency ratio, which is the ratio of dependents (young and elderly) to the working-age population. A high proportion of young dependents requires investment in education and childcare, while a large elderly population increases demand for healthcare and pensions.

An ageing population, common in developed countries, can lead to labour shortages and higher government spending on social services. Conversely, a youthful population, typical in many developing countries, may provide a future labour force but requires current investment in education and job creation.

For example, Japan faces challenges from an ageing population needing extensive healthcare, while Nigeria has a youthful population requiring expanded schools and jobs.

• Age distribution determines dependency ratios.
• High youth population demands education and job creation.
• Ageing populations increase healthcare and pension costs.
• Dependency ratios influence economic growth potential.

Gender distribution influences labour market participation and economic productivity. Societies with balanced gender ratios can benefit from a diverse workforce. However, cultural or social factors may limit participation of one gender, affecting overall economic output.

For example, if a country has more males than females but cultural norms restrict female employment, the effective labour supply is reduced. Conversely, increasing female participation in the workforce can boost economic growth and reduce dependency ratios.

Gender imbalances can also affect social stability and long-term demographic trends, such as birth rates.

• Balanced gender ratios support diverse labour markets.
• Cultural factors may limit workforce participation by gender.
• Increasing female employment can enhance economic growth.
• Gender imbalances affect social and demographic dynamics.

A population pyramid is a graphical representation showing the distribution of various age groups in a population, typically separated by gender. The horizontal axis shows population size or percentage, and the vertical axis shows age groups from youngest at the bottom to oldest at the top.

The shape of the pyramid indicates demographic trends: a wide base suggests high birth rates and a youthful population; a narrow base indicates low birth rates and an ageing population; a uniform shape suggests stable population growth.

For example, a pyramid with a broad base and narrow top is typical of developing countries with high fertility rates, while a more rectangular shape is common in developed countries with low birth and death rates. Understanding these shapes helps predict future economic needs, such as schooling or healthcare demand.

• Population pyramids display age and gender distribution visually.
• Wide base indicates high birth rates and youthful population.
• Narrow base suggests low birth rates and ageing population.
• Shape helps forecast economic and social service needs.