Population is defined as the total number of people living within a country or a geographical areas at a particular time. Population, in other words, refers to the total number of children, adults (men and women), youth (boys and girls) living in a given geographical area, which may be a town, village or country, at a specific time.
The study of population is very important for many reasons. Such reasons include the determination of the working population, allocation of resources, the availability of labour etc
Population census may be defined as the head count of all nationals of a country at a particular time. It refers to the counting by government of all the children, boys, girls, men and women, including the disabled, in a country at a given period of time.
Censuses are usually taken every 10 years. When a series of censuses has been undertaken properly, it becomes easier, using the rate of growth, to estimate the population between the periods of counts.
Population census provides information about age, sex, occupation, residence, etc. In Nigeria, several population censuses were taken by the government. The census of 1952/1953 was given a 31.12 million people. This figure, according to observers at that time, was underestimated.
Another census was conducted in 1962/63 which put the country’s population at 55.670 million. This figure, as of that time, was over inflated. This raised a lot of controversy regarding its reliability and acceptability.
In 1973, another count gave a population of 79 million people. This figure was rejected due to double counting and overestimation. In 1991, another population census, the most recent in the country, was taken. It was given as 88, 514, 501 people. Since then there has been no population census and the current estimate of Nigeria’s population as of 2019 is at 180 million people.
Characteristics of a Good Population Census
i. It must be conducted by the government of the state or country where the census is taking place.
ii. It must be conducted at the same time (simultaneously) throughout the country.
iii. It must involve regular counting at specific intervals of time, e.g Nigeria’s population taken in 1953, 1963, 1973, etc, i.e at an interval of 10 years.
iv. It must reveal the population of a country at a specific period of time, e.g Nigeria’s population census at of 1973.
v. It must involve the physical counting of people rather than by proxy.
vi. It must involve experts who are knowledgeable in population studies and they must be of high integrity.
Types of Population Census
There are two main types of population census. They are:
1. Defacto population census: This is the type of population census which involves the counting of only those who are present people physically during census. In this group, only those that are present people physically or seen are counted.
2. De jure population census: This is the type of population census which involves the counting of people who have been permanent residents of a specific area. It does not matter whether the person is present or not. This is the population census commonly referred to as counting by proxy.
Importance or Reasons for Population Census
i. Population size: Population census helps the government to know the number of people living in the country and the structure of the population.
ii. Revenue estimates: It also helps in the determination of taxable adults so as to know the amount of revenue expected from that sector.
iii. Forecasts future economic needs: The population census also enables the country to forecast her future economic needs, e.g housing, food, etc.
iv. Determination of standard of living: Population census also assists in the determination of the standard of living of the people in a country through per capital income.
v. Determines the level of unemployment: Population census provides government with statistics to determine the level of unemployment in the country.
vi. Number of immigrants: The number of immigrants in a country can be known or estimated based on population.
vii. Provision of social amenities: Population census gives the government an idea of the different population in various parts of the country and this will help it in the provision of social amenities like housing, water, electricity, roads, schools, hospital, etc.
viii. Determination of population density: Population census helps the government to know areas in the country where population per land area is high or low.
ix. Allocation of parliamentary seats: Population is often used in Nigeria to allocate parliamentary seats. States with high population are given more parliamentary seats than states with low population.
Problems Associated with Population Census
i. High level of illiteracy: As a result of the high level of Illiteracy in many developing countries, it has become very difficult to conduct a successful population census as these people do not give relevant and useful statistics. Information gathered from these sets of people are usually false and misleading.
ii. High cost: Huge amount of money is involved in the conduct of population census. Since most West African countries are poor, the resources required to conduct a successful census are not available.
iii. Political problem: Since population census is used in many countries to allocate resources to component states, population figures are usually falsified to enable some state gain more resources than others.
iv. Geographical barriers: Most communities are inaccessible due to mountains, valleys, rivers, etc. This makes population census difficult in these areas.
v. Lack of trained personnel: Trained personnel like demographers are not available hence the use of untrained personnel in the conduct of census lear to inaccurate results.
vi. Religious beliefs: The religious belief of some people is a major problem encountered during population census. Muslim women that are in purdah are not to be seen by men and this makes counting of such people difficult as they are counted by proxy.
vii. Lack of transportation: Most rural areas do not have motorable roads and this prevents or restricts enumerators from getting in touch with some communities.
viii. Lack of communication Facilities: Poor or total lack of communication facilities make population census very difficult, especially in rural areas.
ix. Poor regional planning: Most towns and villages are not planned. In most cases, the buildings are scattered, some without numbers. This makes it difficult for population officers to conduct a successful population census.
Determinants of Population Size and Growth
There are three main factors that determines the population size and growth of a given country. These three factors are birth rate, death rate and migration.
(A) Birth rate
The birth rate (or natality rate) of a country refers to the rate at which children are being given birth to in that country. Generally, high birth rate may lead to increase in population or over population while low birth rate can lead to local population.
Factors affecting birth rate
i. Early marriage: In many communities, people encourage early marriage and this gives rise to increase in population as many children are being given birth to.
ii. Desire for large families: In most communities, people tend to have many children as this places them in a special class. To achieve this, they will go ahead to marry many wives.
iii. Religious belief: While certain religion, e.g Christianity, discourages polygamy, others like Islam encourage the marrying of many wives that will give birth to many children.
iv. Improved medical services: As a result of improved medical services, death rate has reduced while birth rate has been boosted.
v. Government aids: What the government increases the aids it gives to people, families are encouraged to have more children thereby increasing the population.
(B) Death rate
Death rate (or mortality rate) of a country refers to the rate at which people (both adult and children) die in a country. Generally, high death rate leads to popular decrease or low population, while low death rate leads to increase in population.
Factors affecting death rate
i. Ratio of male to female: When there are more males than females, there will be a low child-bearing rate, which will reduce the population.
ii. Poor medical services: When medical services are poor, death rate tends to increase.
iii. High rate of infant mortality: High rate of infant mortality leads to decrease in population.
iv. Poverty: High level of poverty among the people leads to high death rate, as such people may not have the means of taking care of their families.
v. Natural disasters: Natural disasters like earthquakes, flooding can lead to high death rate.
vi. Man-made disasters: The occurrence of man-made disasters like wars, conflicts, pollutions, is capable of leading to high death rate.
Migration is defined as the movement of people from one geographical area to another, involving permanent or temporary residence or settlement. In migration, the region where people are leaving is called the source region while the region people are entering is called the receiving or destination region.
Types of migration
There are two many types of migration. These are emigration and immigration.
I. Emigration: This is the type of migration in which people leave their own countries, i.e, movement out of a country.
II. Immigration: This is the type of migration in which people enter into another country, i.e, movement into another country.
Forms of migration
Migration from one place to another takes different forms. These includes:
i. Rural-urban migration: This is the movement of people from rural areas, e.g village, to urban centres like Ibadan
ii. Rural-rural migration: This is the movement of people from one rural area to another rural area.
iii. Urban-rural migration: This is the movement of people from one urban centres to rural areas.
iv. Urban-urban migration: This is the movement of people from one urban centre ( town or city) to another.
v. International migration: This is the movement of people from my country into another.
vi. Seasonal migration: This is the movement of people from one place to another at a particular season, e.g summer holidays abroad.
Factors Affecting Migration
The following factors account for the migration of people from one area to another.
i. Natural disasters: The occurrence of natural disasters like floods, famines, drought, earthquakes, etc could make people to migrate out of a place to another.
ii. Physical conditions: The physical conditions of a place such as climate, soils, relief may also be responsible when such conditions are unfavourable.
iii. Insecurity: Fear of insecurity arising from war, political instability, etc could make people to migrate.
iv. Differences in economic opportunities: As a result of these, people tend to migrate to where there are more economic opportunities like jobs and business transactions.
v. Change in status: Change in status, e.g high level of education and wealth, could make people to migrate, e.g from rural to urban centres.
vi. Differences in social amenities: Owing to differences in the availability of water, roads, electricity, etc people tend to move to where these amenities are present.
Advantages of migration
i. It reduces population pressure on agricultural land at the source region.
ii. It reduces population pressure on social amenities at the source region.
iii. It supplies migrant labour at the receiving region.
iv. It ensures the flow of capital to the receiving region.
v. It leads to the development of social amenities at the receiving region.
vi. It boosts markets at the receiving region.
vii. It promotes cultural integration, e.g intermarriage at the receiving region.
Disadvantages of migration
i. It breeds social vices like crime and armed robbery at the receiving region.
ii. It increases high cost of living at the receiving region.
iii. It leads to pressure on social amenities at the receiving region.
iv. It leads to the loss of able-bodied men and youth at the source region.
v. It leads to congestion in housing and transportation at the receiving region.
vi. It leads to decline in production at the source region.
Solutions to rural-urban migration
One of the major forms of migration that tends to create problems in all developing countries is that of rural-urban migration. Since we recognise that this form of migration is a major problem, solutions have to be provided in order to prevent the occurrence of over population at the receiving regions. The solution to the problems of rural-urban migration include:
i. Provision of social amenities: The provision of social amenities such as water, roads, electricity, and telephone in rural areas will go a long way in reducing the rate at which youth move to urban areas.
ii. Transformation of traditional agricultural to modern agricultural: This will enable the youth to engage in agriculture as the system will make farming interesting.
iii. Establishment of industries: The establishment of industries, projects and businesses that will absorb the rural working population and reverse labour movement will go a long way in reducing rural-urban drift.
iv. Establishment of educational institutions: The establishment of colleges and other institutions of higher the learning in rural areas will also help to reduce movement to urban centres.
v. Establishment of corporate branches: Government departments, business firms and financial institutions should be encouraged to establish their branches in turns areas.
vi. Provision of recreation facilities: If recreational facilities such as stadia, swimming pools, cinema houses, amusement park, etc are made available in rural areas, this will reduce the propensity of our youth to move to urban areas.
Factors that can affect the size of a Country’s Population or Reasons for High Population Growth in West Africa
i. Increase in birth rate: Ij West African countries, there is increase in birth rate as it is the desire of every family to have many children.
ii. Decrease in death rate: There seem to be a reduction in the death rate. This generally may be due to more knowledge in modern medical services and this tends to increase population.
iii. Type of marriage: In West Africa, polygamous marriage is widespread. Here, a man marries between two to five wives. The number of children given birth to by these women will definitely increase the population.
iv. Religion: The type of religion practised by West African countries determines to a large extent the population of such countries. While Christianity does not support polygamy, the Islamic religion supports polygamy and this encourages rapid population.
v. Improved medical services: The availability of medical services has helped to reduce the rate of death hence population is sure to increase under this condition.
vi. Illiteracy: Majority of the people are illiterates and they do not know any medical way of controlling birth or family planning hence they continue to give birth and this increases the population.
vii. Poverty: A poor man believes in giving birth to many children. He has a strong conviction that one or more of his children will become wealthy and influential and this changes the status of the family.
Advantages of Large Population
i. Large labour: High population provides large labour force for the industries.
ii. Large market: High population is a source of large market for the goods produced by the industries.
iii. Defence: Organised army and other law enforcement agencies are easy to recruit in highly populated areas.
iv. Quick information dissemination: Because people stay everywhere in these areas, it is very easy for information to go around very quickly.
v. Attraction to investors: Investors are easily attracted to areas of high population because of large market for finished products.
vi. Urbanisation: Areas with large population do lead to urbanisation.
Implication or Disadvantages of Large Population
The economic effect of a large population or high population density include:
i. Pressure on natural resources: Natural resources like fertile farmlands, minerals, etc become over exploited where there is high population growth in an area.
ii. Increase in crime wave: Areas of high population density are usually associated with high crime rate like armed robbery, car snatching, hired assassination etc. This may be due to lack of jobs, hence, people resort to crimes.
iii. Insufficient food: As a result of the high influx of people into an area, there will not be sufficient food to cater for the high population which leads to food shortage.
iv. Unemployment/Under employment: Areas of high population density usually do not have enough jobs for the ever increasing influx of people. This leads to unemployment and under-employment.
v. Inadequate housing: High population concentration leads to poor accommodation as the houses available may not be enough for the high population.
vi. Traffic congestion: Many people travel on the roads at the same time and this leads to traffic congestions most of the time.
vii. Environmental pollution: Poor housing, turn out of waste materialsfor due to high level of human activities generally lead to environmental pollution.
viii. High cost of living: As a result of high population density, it will result in a corresponding demand for goods and services and where these are not forthcoming in sufficient quantities, it will lead to high cost of purchasing them thereby leading to high cost of living.
Population density is defined as the number of persons per square kilometre of land. The population of density of a country can be expressed mathematically as:
Population density = Total population / Land area
Calculate the population density of Nigeria, having a total population of 88,514,501 as of 1991 with a total land area of 923,768sq km.
Total population = 88,541,501
Total land area = 923,768sq km
Population density = Total population / Total land area
Population density = 88,541,501 / 923,768
Population density = 95.6 = 96 persons / sq km.
Population density may either be high or low depending on the number of people in a specified area or country. Generally, high population density occurs where there are many people in an area which leads to over population.
Similarly, a low population density refers to a situation where there are few people in a specified area of land.
Ageing or Declining Population
Ageing population is defined as a declining population with an increasing percentage of old people, while the relative percentage of children and workers are decreasing. Ageing or declining population is also known as a stationary or static population.
Factors Responsible for Ageing Population
i. Decrease in birth rate: A fall or decrease in birth rate generally leads to declining population. This might be due to implementation of birth control and late marriages.
ii. Increase in death rate: A rise or increase in the death rate of the young ones through epidemics or poor medical facilities generally leads to a reduction in the number of people in the country.
iii. Emigration: The movement of young men or youth out of a country can also lead to declining population.
iv. War: The existence of war also lead to declining population as able-bodied youth are lost during war.
v. Disease: The outbreak of diseases can also lead to decrease in population as this reduces the number of young ones within the country.
vi. Natural Disasters: Natural disasters like flood, earthquakes, etc can lead to declining population, especially when the young ones are mostly affected.
vii. Poor medical facilities: Poor medical facilities generally lead to a decrease in population and when the young ones are the victims, ageing population is bound to set in.
Advantages of Declining Population
i. Reduction in government expenditure: A declining population have fewer people to cater for and as a result there will be a reduction in expenditure by government.
ii. High standard of living: Standard of living has something to do with the number of people and available resources. With fewer people coupled with increasing resources, this will cause an increase in per capita income, which will result in higher standard of living.
iii. Reduction in congestion: As a result of decrease in the number of people, there will be a corresponding decree in congestion in terms of human, accommodation and vehicular traffic.
iv. Creation of job: As a result of increase in the number of old people, there will be creation of more employment opportunities for the few labour force.
v. Increase in savings: With decreasing population there is an increase in savings on the part of government.
vi. Increase in investment: As a result of the increase in savings, there will be enough capital for investment in important sectors of the economy.
Implications or Disadvantages of Declining Population
i. Reduction in labour force: As a result of the decrease in the number of working class citizens or increase in the number of old people, there will be a reduction in the number of the labour force.
ii. Fall in gross domestic product: The fall in the size of the labour force would result in the fall in the productivity capacity of the country. The small labour force, combined with its liability to make optimum use of available resources, results in low savings and a fall in gross domestic product.
iii. Less mobility of Labour: As a result of the increasing number of old people, mobility of labour becomes difficult as old people may either stay at home or refuse to accept new ways of doing things.
iv. Risk of invasion: Due to the increase in the number of old people in a country, the risk of invasion by external forces is very high.
v. High dependency ratio: When the population of old people and the children are higher than that of the working class population, it will result in a high dependency ratio.
vi. Reduction in tax: As a result of the increase in the number of old people, who are not taxable, the tax expected from the few that are working will be reduced.
vii. Changes in pattern of demand: In a decreasing population, there will be a shift in demand in favour of goods and services used by old people.
viii. Lower reward for factors of production: There will be a fall in demand as a result of decrease in total demand for goods and services. Consequently, the amount of rewards associated with the factors of production will fall.
Overpopulation is defined as a situation where a country has more people than its physical and human resources can support with adequate living standards. In other words, overpopulation refers to a situation where the population exceeds the available resources of the country.
As a result of overpopulation people will compete for the available resources and due to the relative shortage of resources, there will be a general fall in standard of living of the people.
Control of overpopulation
i. Family planning: People should go for family planning to enable them determine the number of children they can have and successfully cater for.
ii. Discouragement of early marriage: Early marriages which promotes high birth rate should be discouraged.
iii. Increase in food supply: This should be encouraged through mechanisation of agriculture, use of modern farming systems, fertilizers and improved seeds to boost agricultural production.
iv. Stiffening of immigration laws: This will make it difficult for people to migrate to areas already populated.
v. Sex and mass education: Mass education ought to be practised and sex education should also be taught to enlighten the people on the dangers of overpopulation.
Under-population may be defined as the type of population that is less than the available resources of a country. It then means that the size of the population is so small that when combined with the available resources of a country and given the level of existing technology, it will secure minimum returns per head. In summary, under-population is a situation where the population is too small relative to the available resources. The standard of living of the area can be increased if the population is increased.
Causes of under-population
i. A decrease in birth rate: A decrease in the birth rate in any country for whatever reason generally leads to under-population.
ii. An increase in death rate: An increase in death rate of the people in any country for whatever reason, be it war, diseases, old age, flood, famine, etc, also leads to under-population.
iii. High level of emigration: When the rate at which people leave a country (emigration) is higher than that at which people come in (immigration), under-population is bound to occur.
Advantages of under-population
i. Abundant resources: There will be abundance of resources in areas where there are resources endowment.
ii. Availability of Employment: Due to the small size of the population and abundance of resources, employment opportunities will readily be available.
iii. Low pressure on social amenities: Owing to low population, there is also low pressure on social amenities in the area.
iv. Low congestion: Also, due to low population, there will be low or no congestion in housing, traffic etc.
v. Adequate planning: Owing to low population, these areas are properly planned for decent living.
Implications and Disadvantages of under-population
i. Inadequate labour force: The available labour force is grossly inadequate to manage the abundant resources available in the state.
ii. Low level of production: As a result of low level of manpower available production is generally very low.
iii. Low savings and investment: Workers generally earn low as a result of low level of production income and this leads to low savings and investments.
iv. Low standard of living: Due to inadequate labour force that would have promoted output, the standard of living will eventually fall.
v. Small size of market: As a result of low level of income per capital and fewer number of people, the size of the market is usually very small due to low demand.
Optimum population may be defined as the type of population which when combined with the available resources and the given level of existing technology secure a maximum return per head.
Optimum production is neither too small nor too large. In other words, optimum population stands in-between the two other extremes of over population and under population. It is the best type of population and it differs from country to country and from time to time. Optimum population is dynamic hence it changes according to the changing quantity and quality of a country’s available resources.
Mathematical Approach to Population Studies
The total number of males in a country which has a total land area of 140,000sq Km is 150,000,000 while that of the females is 130,000,000 including all migrants. Calculate
(a) The total population of the country
(b) The population density of the country
(a) Total population = No of males + No of females
= 150,000,000 + 130,000,000 = 280,000,000 People
(b) Population Density = Total Population / Land area
= 280,000,000 / 140,000 = 2,000 persons per sq Km.
If the population density of Tanko district is 3,500 persons per sq Km, and the total population is 1,400,000 people. Calculate the total land area of Tanko district.
Land area = Total Population / Population Density
Land area = 1,400,000 / 3, 500
Land area = 400 sq Km.
Some Population Formulae
Rate of population growth R = Birth rate – Death rate + Net migration
Net migration = Immigrants – Emigrants
I.e the difference between the number of immigrants and emigrants is Net migration.
Natural increase = Birth rate – Death rate
Percentage Increase = New Population – old Population. × 100
Dependency ratio = Dependent population / Working or independent population.
Use the information table and answer the following questions
(a) The natural increase of the population in 1996
(b) Determine the net migration within the period.
(c) The rate of growth of the population in 1996
(d) The population of the country in 1996
(e) What is the percentage increase in the population of the country from 1980 to 1996
(a) Natural increase = Birth rate – Death rate
= 48 million – 12 million = 36 million
(b) Net migration = Immigrants – Emigrants
= 10 million – 4 million = 6 million
(c) Rate of population growth, R = Birth rate – Death rate + Net migration
= 48 million – 12 million + 6 million = 42 million
(d) Population of the country in 1996 = 1980 Population + Net migration + Birth rate – Death rate
= 56 million + 6 million + 48 million – 12 million = 98 million
(e) Percentage increase from 1980 to 1996
= New Population – old population. × 100
Old Population. 1
= 98 million – 56 million. × 100
56 million 1
= 42 million. × 100
= 0.75 × 100
The pie chart below represents the age of distribution of population. The total population is 240 million.
From the information above, Calculate:
(a) The population of children between 0 and 17 years
(b) The population of old people (60 + years)
(c) The dependency ratio
(a) Population of children between 0 and 17 years = 120 × 240
= 80 million
N.B “the 360 is gotten by adding the percentage of each age in the pie chart, i.e 120% + 150% + 90% = 360 and the 240 used is the total population given in the question”.
(b) Population of old people (60 + years) = 90 × 240
= 60 million
(c) working Population (18 – 59 years) = 150 × 240
= 100 million
Dependency ratio = Population of children ( 0 – 17 years) + Population of old people (60+ years)
Working Population (18 – 59 years)
= 80 million + 60 million
= 140 million
= 1.4 / 1 or 1.4 : 1