5. Causes of rapid population growth
1. The rapid population growth is due to
decrease in death rate and increase in birth
2. The availability of antibiotics, immunization,
increased food production, clean water and air
decreases the famine-related deaths and infant
3. In agricultural based countries, children are
required to help parents in the fields that is
why population increases in the developing
6. Characteristics of Population Growth
1. Exponential growth:
Now population growth occurs
exponentially like 10,10²,10³ etc., which shows the dramatic
increase in global population in the past 160 years
2. Doubling time:
It is the time required for a population to
double its size at a constant annual rate. It is calculated as follows
where r=annual growth rate
3. Infant morality rate:
It is the percentage of infants died out of
those born in one year. Eventhough this rate has decreased in the
last 50 years, the pateern differs widely in eveloping and
7. Characteristics of Population Growth
4.Total fertility rate:
It is the average number of children
delivered by a woman in her life time. The TFR value varies
from 2 in developed countries to 4.7 in developing countries.
Two parents bearing two children will be
replaced by their of spring, Due to infant morality this
replacement level is changed. But, due to high infant morality
the replacement level is generally high in developing countries.
6. Male-Female ratio:
The ratio of girls and boys should be fairly
balanced in a society to flourish. But the ratio has been upset in
many countries including china and India. In china the ratio of
girls is 100:140.
8. Characteristics of Population Growth
Population growth is generally
related to economic development. The death rates and
birth rate fall due to improve living conditions. This
results in low population growth. This phenomenon is
referred to as demographic transition.
9. Problems of population growth
Increasing demands for food and natural resources.
Inadequate housing and health services.
Loss of agricultural lands.
Unemployment and socio-political unrest.
10. Variation of population based on
Pre-productive population (0-14
Reproductive population(15-44 years)
Post reproductive population(above
11. Pyramid shaped variation of
EX: India, Bangladesh, Ethiopia, Nigeria
The large no. of young age people will soon enter into
reproductive age group population, which increases the
population growth. But the les no. of old age people
indicates less of population due to death.
12. Bell shaped variation of
EX: France, UK, Canada etc.
Pre-productive an Reproductive age
groups population are equal. So
Population Growth is stable.
13. Urn shaped variation of population
EX: Germany, Italy, Sweden, Japan etc.,
Pre-productive age group population is less than the
Reproductive age group.