Definition of Population 

Population refers to the total number of people living in a particular geographic area at any given time. For example, the population of Nigeria by the 2006 census was said to be 140.43 million people, including men, women and children, young and old, able bodied and disabled people. The larger the population of a country, the larger the labor force and the greater the productive capacity. It is affected by birth rate, etc. 

Factors determining population growth or size

The following are the factors determining population growth or size;

  1. Birth rate
  2. Death rate 
  3. Migration
  4. Population growth rate


  1. Birth rate 

The birth rate is the number of births recorded per thousand population in a year. The birth rate is generally higher in developing countries like West African countries than in the more industrialized countries. This is due to early marriages, need for more children, etc. Assuming in a population of 2 million, 250,000 births were recorded in a given year,  

then BR = (250,000/2,000,000) X (1000/1) = 125% 

Factors affecting birth rate 

  1. The culture and religion of the people 
  2. The proportion of females in the population
  3. Age distribution of the population
  4. The knowledge and attitude of people to family planning

2. Death rate 

The death-rate is the number of deaths occurring per thousand of people in a given population per annum. The death-rate is higher in West Africa than in the more industrialized countries of America and Europe. In a population of 2m, 100,000 deaths were recorded in a given year therefore 

DR = (100,000/2,000,000) X (1000/1) = 50%

Factors affecting death rate 

  1. The age distribution of the population, the older the population, the higher the death-rate.
  2. Level of medical and health facilities.
  3. Standard of living.
  4. Natural calamities or disasters such as epidemics, wars, earthquakes, flood, drought etc.

3. Migration 

Migration is the net balance between migration and emigration. 

Migration means the movement of people from one place to another. This movement can take two forms:

  1. Immigration – This involves the movement of people from one geographical area into another, such as movement of Ghanians into Nigeria. Such people are called immigrants. 
  2. Emigration – This involves the movement of people out of a given area such as movement of Nigerian professionals from Nigeria to Saudi Arabia.

Factors affecting migration 

  1. Political crises such as war may encourage movement of people.
  2. Natural disasters such as famine may lead people to move to better areas.
  3. Economic opportunities normally attract people from poor areas to economically better areas. 
  4. Political and economic groupings such as ECOWAS, provide opportunities for people to move from one country to another.

4. Population growth rate 

The population growth rate is the annual rate of growth of the population of a particular geographical entity. It is always the net value of birthrate, death rate and migration.

  1. A higher birth rate normally leads to a higher population growth. Its reverse is true of a lower birth rate.
  2. A higher death rate tends to reduce population growth.
  3. Migration affects this distribution of population; the higher in areas where people move to and lower in areas where people move away from.

Population Types 

There are three types of population which are;

  1. Optimum population
  2. Under-population
  3. Over-population


  1. Optimum population 

This refers to the size of population which when combined with existing land, capital and technique yields the highest level of income per head.

Optimum Population

The population that brings about the highest income of N400 is 10 million, so the optimum population is 10 million people. Any population less or more than this will result in less income per head.

  1. Under – population 

A country is under-populated if her total population is not enough to bring about the highest level of income . In the example I used above, any country with less than 10 million people is under-populated. The number of people is not large enough to put the total resources into use. In such a situation an increase in its population is desirable.

Economic consequences of under-population 

  1. There will be a relatively low supply of labor in the country. 
  2. With a low demand for goods and services, the general level of prices in the country will persistently fall. This is simply deflation.
  3. There will likely be under-production in the economy.
  4. There will be low savings and investment in the economy.
  5. The economic consequence of d is a low standard of living in the country.
  6. There will be loss of experts due to under-production in the economy.
  7. The country will experience a balance of payment difficulties.
  8. There will be equilibrium output at less than full-employment in the economy.
  9. There will be under-utilization of resources in the economy.
  1. Over-population 

A country is overpopulated if her population is more than the size that could bring about the highest income per head. It means the population is greater than the resources available. Under this condition, a reduction in the size of the population will raise the income or welfare of the people.

Population Theories 

There have been many theories of population . For convenience, we shall discuss only two of them here.

  1. Malthusian population theory 

The most widely acclaimed theory is the Malthusian Population Theory named after the originator, Reverend Thomas Malthus. His arguments could be summarized into the following three propositions:

  1. that population is limited by the means of subsistence e.g. food.
  2. that population increases when the means of subsistence increases unless prevented by some powerful checks.
  3. that these checks are in the form of moral restraints, vice and misery.

According to him, while the means of subsistence (food) increases in arithmetic progression, 1, 2, 3, 4, etc., population increases by geometrical ratio, 1, 2, 4, 8, 16, 32, etc. This means that, if left uncontrolled, the population has a tendency of rising faster than the means of subsistence.

  1. Demographic transition theory 

This theory explains the three stages of modern population history and why most of the developed countries have passed through three similar stages. The stages are:

Stage 1 

Prior to economic modernization. At this stage most of the countries have a stable population. The explanation for the stability was that the birth-rate and the death-rate were equally high; hence no growth.

Stage 2 

Period of modernization resulting in improved health services. This period witnessed a significant fall in the death-rate side by side a rise in the birthrate . This led to a transition from stable or low to a rapid increase in population.

Stage 3 

At this stage modernization and development cause birth rates to fall and eventually merge with lower death rates . This will result in little or no increase in population.

This theory appears to be relevant to African countries. Some years ago, most of them were in Stage 1 with high birth and death-rates. With general socioeconomic development they are now witnessing a significant improvement in medical facilities leading to a fall in the death rate and little or no effect on the birth rate. This is causing rapid population increases in most of these countries. They can therefore be said to be in Stage 2 of the Demographic Transition

Population Distribution 

Population distribution refers to the structure of the population. The structure includes geographical, age, sex and occupational distribution. 

Factors affecting geographical distribution

By geographical distribution of population, we mean the dispersion of people throughout the length and breadth of a particular country. Factors affecting the distribution are: 

  1. Availability of agricultural land.
  2. Availability of mineral wealth.
  3. Climatic conditions of the different parts of the country.
  4. Relief 
  5. Availability of rivers which may support fishing and allied industries.
  6. Existence of commercial industrial and service activities established by private individuals and governments.

Factors affecting the age distribution of population 

  1. Areas of high birth rate tend to have a young population.
  2. Areas of lower death rate tend to have an aging or old population.
  3. Migration: areas where more people move to, tend to have a higher rate of population than where people move out from.
  4. Government policies such as the distribution of industries affect the distribution of population

Factors affecting sex distribution of population 

  1. Birthrate: The proportional distribution of births between male and female sexes will affect the distribution of population.
  2. Deathrate: The distribution of death-rate between the male and female in an area will effect the sex distribution of the remaining population.
  3. Migration: Men usually move more than women, thus a higher migration of people from one area will reduce the proportion of men in the area from which they move and increase the proportion of men.
  4. Culture of the people: Some cultures allow men to move to other areas, leaving their wives at home. In such cultures there will be more women than men in the remaining population.

Factors affecting occupational distribution of population

  1. Culture of the people: In some societies women are not allowed to occupy certain positions. Their culture forbids it.
  2. Availability of educational institutions: The kinds and varieties of educational institutions will affect the occupational distribution of the labor force.
  3. Distribution of educational facilities: Some states have more educational facilities than others such as polytechnics, colleges of education and colleges of agriculture. Such states will have more varied occupations than states with less of such facilities.
  4. Migration: Areas with greater and better economic opportunities will attract more people. The wider the varieties of such opportunities, the wider the distribution of occupational groups.
  5. Natural endowment: The localization of natural endowment will influence the distribution of people with natural talents. The availability of hides and skins in Kano State influences the concentration of leather work experts in Kano.
  6. Level of Technological Development: A country that is more technologically developed will have a wider spread of different occupations than the less developed country.

Population Census and its Importance 

What is population census? 

This is the counting of the number of people residing in a particular country. It is done on a periodic basis e.g. in Nigeria it is done every ten years. The 1991 census in Nigeria revealed that the size of her population was 88.5 million. 

But the census of population and housing conducted by the Nigeria Population Commission in 2006, in its final release in 2009, put the size of the nation’s population at 140,431,790. This showed that the country’s population has grown by 51,931,790 i.e. 58.68 % within a period of fifteen years.

  1. The knowledge of the population size and distribution helps planners to plan accurately
  2. The structure of the population determines the size of its labor force.
  3. Knowledge of a country’s population helps in comparing the welfare index of one country with another . Such an index is often used as a basis of international aid and grants.
  4. International organizations such as the UN use the size of the population of its member countries to determine their financial and other contributions.
  5. In many countries, the population is used in the distribution of amenities such as parliamentary seats and revenue allocation.
  6. Accurate knowledge of a country’s population is required for the provision and distribution of socio-economic benefits such as education and health. 
  7. Knowledge of both the size and distribution of the population is required to promote even development of a country.

Problems of population census

The problems of conducting an acceptable census include the following:

  1. It is very costly to carry out a census exercise 
  2. Not having enough experts in many areas of census operations.
  3. Shortages of infrastructural facilities which are required for a successful census such as maps all weather roads and poor communication facilities.
  4. In some countries, most people are illiterate they can not provide accurate information , such as their ages.  
  5. Ignorance about the purpose of the census affects the quality of census data.
  6. Over – politicization of the census affects the quality of census data.
  7. Religion and culture prevent some people from presenting themselves for counting.

Economic Effects of High Population Density 

Population density refers to the degree of concentration of people per square-kilometer in a country. It denotes the manner in which population is distributed over the whole country, especially the urban centers with heavy concentration of industrial and commercial activities. The rural areas seem to be sparsely populated. Population density is affected by physical factors, registration and other factors which also affect geographical distribution of population. Its economic effects are as follows: 

  1. It may lead to a fall in per capita income and standard of living.
  2. It may lead to balance of payments difficulties.
  3. Unemployment may result.
  4. It may lead to increased dependency ratio.
  5. Inadequate food supply may arise.
  6. Pressure on social amenities such as schools, hospitals and roads may result from concentration of population.
  7. Increased demand for commodities leads to inflation.
  8. Excess supply of labor may arise.

Measures to Control Population

  1. The government should encourage families to adopt family planning.
  2. The government should make laws to limit the number of children per woman.
  3. Abortion could be legalized.
  4. The minimum age of marriage could be increased.
  5. Employment of a larger number of women in modern economic activities Acould be promoted.
  6. Improvement in female education could be widely embarked upon.
  7. The government could restrict immigration of people
  8. Incentives for emigrants could be provided.

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By Teezab

His name is Tiamiy Abdulbazeet. He is a writer and loves to write about Education, and all types of news. If he is not writing, then know that he is playing a game!😃

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