Lesson Notes By Weeks and Term - Senior Secondary School 1

SUBJECT: ECONOMICS                                    

CLASS: SS 1

TERM: 2ND TERM

WEEK TEN

TOPIC: POPULATION DENSITY

CONTENT

• Meaning of Population Density
• Over – Population
• Under – Population
• Optimum -Population
• Malthusian Theory of Population
• Demographic Transition Theory of Population

POPULATION DENSITY 

This refers to the number of people residing per square kilometer (Km2) of the geographical land area of the country. The population density of a country can be expressed mathematically as:

1.   Population Density = Total Population / Land Area
2. Total Population = Population Density x Land Area

 iii. Land Area = Total Population / Population Density

Population density may either be high or low depending on the number of people residing in a specific area or country. Generally, high population density leads to over-population. Similarly, a low population density refers to a situation where there are few people in a specific area or country

OVER -POPULATION 

This exist when the size of the population is too large in relation to the available resources and level of technology such that output per person falls below the optimum. When this happens, the standard of living falls. Output can be increased by reducing population size.

CONSEQUENCES OF OVER-POPULATION

1. Congestion on land 
2. Fall in PCI 
3. High level of unemployment 
4. Excess supply of labour 
5. High level of government spending 
6. Emigration 
7. Social problems will increase 
8. High dependency ratio
9. Existence of large market
10. Attraction to foreign investors
11. Respect from international bodies
12. Emergence of urbanization

UNDER- POPULATION 

Under population exists when the size of a country’s population is too small in relation to the resources and the level of technical knowledge. There will be labour shortages, but abundance of other factors or resources. The standard of living of the people will be low as reflected by the low per capital income (PCI), hence, the country needs more people to exploit its natural resources if its standard of living were to increase.

CONSEQUENCES OF UNDER-POPULATION

1. Existence of abundant resources
2. Low pressure on social amenities
3. Low crime rate 
4. Low congestion
5. Inadequate labour force
6. Under utilization of resources 
7. Low level of productivity
8. Low saving and investment
9. Low standard of living
10. Small size of market

OPTIMUM POPULATION 

This provides a labour force which when combined with available resources (factors of production) and the giving level of existing technology  yields the maximum output per head.

There will be a high standard of living since the size of the population is adequate to tap the available resources fully. This population differs from country to country and from time to time, therefore it is not static but dynamic and changes according to changing quality and quantity of a country’s available resources.

IMPLICATIONS OF OPTIMUM POPULATION

1. It balances population with available resources
2. Control of economy under optimum population is easy
3. It secures a maximum returns per head
4. It produces full employment
5. It ensures the highest standard of living in a country
6. It is dynamic as it changes with the changing quantity and quality of a country’s available resources

MALTHUSIAN THEORY OF POPULATION 

An English Reverend Thomas Robert Malthus in 1798, published a book on population titled “Essay on the Principle of population as it affects the future improvement of society “he stated that there is a constant tendency for the population of a place to grow faster than its means of subsistence. The theory was based on the law of diminished returns.

According to Malthus, population grows in geometric progression e.g. 2,4,8,16,32,64 etc) while food production only grows in arithmetic progression (e.g. 2,4,6,8,10,12 etc) . He then warned that if left unchecked , there will be a time when population would outstrip food supply leading to a fall in the standard of living unless it was prevented by some positive checks such as war, famine, epidemics etc. He later advocated preventive checks to help reduce population growth rate such as celibacy, moral restraint, late marriage, child quota etc.

EVENTS THAT HAVE PROVED MALTHUSIAN THEORY RIGHT

1. Negative attitude of people like practice of polygamy and raising of large family
2. Low productive capacity with high population
3. High level of poverty with difficulty in its eradication
4. Poor economic development
5. High level of illiteracy

EVENTS THAT HAVE PROVED MALTHUSIAN THEORY WRONG

1. Technical knowledge development and mechanization in agriculture
2. Efficient transport system
3. Industrial revolution
4. Medical improvement with modern equipment
5. Opening of colonies
6. Inter-dependence of nations
7. Discovery of new worlds

EVALUATION

1. Write a short note on Robert Malthus.
2. Explain his theory of population. 

DEMOGRAPHIC TRANSITION THEORY 

This is the most recent of all the population theory. It is concerned with historical population growth of a society by explaining the relationship between fertility (birth rate) and mortality (death rate) on population growth. It is based on the observed decline in the population of advance industrialized European countries therefore proving that population is not static but dynamic.

The three stages of demographic transition are: 

Stage 1 ( Pre-transition phase)

The main features of this stage is high birth rate and high death rate. That is, this period shows high fertility and mortality which are not under secure control. The potential for growth is large.

This stage is characterized by high level of illiteracy, absence of birth control, poor medication, poor sanitation, poor diet, high level of ignorance and superstition beliefs. 

Stage 2 (Transition Phase) 

Modernization associated with better diets, higher incomes, improved health etc. leads to an increase in life expectancy and a marked reduction in mortality rates. This stage marks the beginning of demographic transition from stable or slow growing population to rapidly increasing population. Many of the developing countries are presently at this stage.

Stage 3 (Post-Transition) 

Both fertility and mortality are low due to modernization and development. That is, this stage is characterized by a low birth rate and low death rate. In other words, there is a relatively stable population with an older population. This stage is associated with most developed countries of the world

CRITICISM AGAINST DEMOGRAPHIC TRANSITION THEORY

1. It is wrong to use the theory for general application since all countries are not the same
2. It uses crude birth rate to measure fertility
3. Decline in population varies in each country and caused by different factors
4. It fails to predicts the level of birth rate and death rate

EVALUATION 

1. Explain the Malthusian theory of population 
2. How valuable is the demographic transition theory 
3. What feasible solution is available to the high population growth in west Africa

FACTORS RESPONSIBLE FOR HIGH POPULATION GROWTH IN WEST AFRICA

1. High birth rate: the birth rate is so high at present because of A. improved medical facilitiesB. early marriages C. polygamy 
2. Low death rate: this is as a result of modern medical facilities and improved standard of living which generally make people live longer 
3. Migration: Government and regional policies encourage free movement of nationals of other countries 

CONTROL OF POPULATION GROWTH IN WEST AFRICA

Controlling population growth in most West African countries can be achieved through the following methods.

1. Birth control  or family planning
2. Child quota
3. Late marriage
4. Strict migration policies
5. Sex education
6. Tax incentives / Government policy  e.g enforcement of monogamy 
7. Job opportunity for women

EVALUATION 

1. How can over-population be controlled?
2. Mention five factors responsible for high population growth.

READING ASSIGNMENT

Amplified and Simplified Economics for SSS by Femi Longe pages 191-194.

Comprehensive Economics for SSS By J.U. Anyaele chapter 10 pages 84 – 86 , 90 

New Approach economics By K.U. Nnadi and A.B. Falodun chapter 6 pages 59 – 60

GENERAL EVALUATION QUESTIONS

1. What are capital goods?
2. Explain the term net migration.
3. What are the problems of public corporation?
4. Distinguish between public limited liability company and private limited liability company.
5. What is population census?

WEEKEND ASSIGNMENT

SECTION A. 

1. Which of these best explains the Malthusian theory of population A. increase in population causes hunger and death B. the population increases faster than supply C. the population grows at arithmetic progression while food grows at geometric progression .D. people could be sent to no mans` land when the population increase.
2. The population size which harness available resources to yield maximum average output is A. ageing population B. optimum population C. under-population D. over-population
3. Occupational distribution of population is mainly influenced by A. economic factors B. religious factors C. geographical factors  D. social factors 
4. One economic implication of over population is that it A. leads to low demand of goods B. reduces balance of payment difficulties C. leads to a fall in PCI  D. reduces pressure on the available social facilities
5. When the death rate of old people and the infant mortality rate are high , with no migration, there will be in the population a higher number of A. younger people in the population B. children in the population C. old people in the population D. men in the population 

SECTION B 

1. Explain the Malthusian Theory of Population 
2. How can population growth be controlled in West Africa countries