Population is dynamic. The situation of population depends on birth, death and migration. Birth, death and migration change the size of the population of any place or country. The overuse natural resources affects the the environmental status. The degradation of natural resources depends on the cultural status too.
Birth, death and migration are the three main factors that have to do with the study of population change. They show the population and its size.
Birth is one of the major factors of population growth. It increases the number of people. Birth is released to fertility which is a responsible element for population change. It takes place in 15-49 years age group women.
Death is the second major factor responsible for responsible for population change. In a demographic process it is called mortality. According to WHO, "Death is the permanent disappearance of all evidence of life at any time after birth has taken place." It is a natural process.
Migration is the third factor to change population. If the people move within the country it is called internal migration. If they move out of the country, it is called international migration. Emigration decreases the population at the place of departure and immigration increases the population at the place of destination.
The process of finding the rate of birth, death and migration is called population measurement. The mid-year population is used to find out the population measures. To find the mid year population, the population is counted in the beginning of the year and at the end of the year are added together and then divided by 2.
Fertility means the number of live births from a women during her child bearing age. The fertility period of a women is from 15 to 49 years. The fertility rate can be measured in four ways.
The total number of live births in a year is divided by the total mid-year population of the same year and multiplied by 1000 to calculate CBR.
Crude Birth Rate =
General Fertility Rate (GFR)
The general fertility rate is also one of the methods of measuring the fertility rate. GFR is the number of birth that comes per 1000 women of childbearing age in a year. It is calculated by dividing the total number of births is a year by the mid year female population of 15 to 49 years and then multiplied by 1000.
General Fertility Rate =
i.e. GFR =
Age specific fertility rate (ASFR)
The age specific fertility rate refers to the number of births created by the women belonging to the specified age group. To calculate ASFR, the number of live births given by women of a specific age group in a year is divided by the number of mid-year female population of the same age group. That in turn is multiplied by 1000.
Age-Specific Fertility Rate =
i.e. ASFR =
Total Fertility Rate (TFR)
The total fertility rate means to the arrange births a women in her childbearing period. It can be calculated by dividing the sum of ASFR by 1000 and multiplying by 5.
Total fertility Rate (TFR) =
What are the main factor of population change?
The main factor of population change are:
What do you mean by population measurement?
The process of finding the rate of birth, death and migration is called population measurement.
What do you mean by internal migration?
If the people move within the country it is called internal migration. For example: Ram moves Dharan to Dhan Kuta.
What do you mean by international migration?
The movement of people from one country to another is known as international migration.
Define death according to WHO.
According to WHO, "Death is the permanent disappearance of all evidence of life at any time after birth has taken place."
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