1. Census:

   This is a complete head count of people in a population. It gives the information about the total number of people in an area. This is the best source of information. It is also a very expensive process so it is carried only after 5-10 years.

2. Surveys:

     This counting only selected parts and aspects of a population. From this general conclusions are made about the population. The processes of obtaining this information are called Sampling.

3. Vital Registration:

       This gives information on aspects of the population as births, marriages and deaths. This is obtained by councils and presbyteries.

4. Migration Records:

       This gives information about the migration of people. This can be obtained at borders between territories, motor parks, police stations, air ports and sea ports.

Implications of rapid population growth

This rapid increase in the population of planet earth has created serious problems o the resource. The population of the world is growing faster than the available resource. This situation is described as the global population problem. The challenge now is how to provide enough food for the world population. This is because the available resources are becoming insufficient to support the growing population. At the moment there is great exploitation of these resources to take care of the population. This has cause pressure on the available resources.

                   The negative effects of the rapid population growth of the world are the following:

• Much pressure on resources
• Food shortage in many parts of the world especially in the poor countries, this has led to starvation in many part of the poor world.
• Exhaustion of resources through over exploitation as; over fishing, over grazing, over cropping and over felling of forest.
• Environmental problems as pollution
• Environmental degradation as deforestation, soil erosion and impoverishment
• Overcrowding over space and other infrastructure

How can global population problem be solved?

Possible solutions to the global population problem are the following;

• Improvement in agriculture so as to increase food supply
• Encourage industrialization which will increase money to buy food and also discover new types of food and resources.
• Improve transport networks so that foods and resources can be distributed easily from area with surplus to the needy ones
• Development of technology that help in the discovery of new resource thereby increasing the amount of available resources
• Control the rate of population growth. This is by reducing the number of children born. This is the best solution because population that grows uncontrolled will always grow faster than the increase in resources.

Theoretical basis: Demographic indices

These are the aspect of the population that can be calculated. Through them information and population change is obtained. This population change can either be increase or decrease.

The main indices of population change are; Birth, Death, and Migration.

1. Natural indices:

1. Birth rate (BR);

       These are the number of children born in a population alive in a period of time usually one year expressed as a percentage of the total population. The formula for the calculation is as follows;

BR= NUM OF LIVE BIRTH × 100

            TOTAL POPULATION

2. Death rate (DR);

           There are total numbers of people who die in a population during a period of time usually one year expressed a percentage of the total population. The formula for calculation is as follows;

DR= number of deaths in a year × 100

             Total population of in that year

3. Natural population growth rate (NPGR);

             This is the change in total population resulting from the differences in the number of births and deaths expressed as a percentage of the total population in a year. It is calculated as follow;

That is;

NGR= BIRTH – DEATH × 100

          Total population

4. Natural growth: it is the difference between birth and death. It is given as;

        NG= B - D

2. Economic indices

1. Migration:

               Migration is the movement of people from one place to another. Those that are moving in a region is called Immigrants while those leaving a country are called Emigrants.

2. Net migration:

               Net migration is therefore the difference between Immigrants and Emigrants.

      Net migration= Immigrants(I) – Emigrants(E)

3. POPULATION GROWTH RATE :

               This is the difference between the birth and death (NATURAL GROWTH) plus or minus Net migration expressed as a percentage of the total population. It is calculated as;

        PGR=NATURAL GROWTH – NET MIGRATION × 100

                                                   TOTAL POPULATION

                QUESTION

In 2005, the population of a country Y was 25,000,000 people. 60,000 children were born alive that same year, given that 25,000 people died that same year. Calculate the BR, DR and NPGR.

BR= 60,000   × 100 = 2.4%

      25,000,000

DR= 25,000 × 100= 1%

      25,000,000

NPGR= 60,000 – 25,000 × 100= 1.4%

             25,000,000