Dear Student,
Demographic transition is a theory which can be used to describe and predict the future population of any area. It shows the changes of population of any region from high births and high deaths to low births and low deaths as society progresses and develops.
These changes occur in three stages which are collectively known as the demographic cycle.
Stages of Demographic Cycle
1) Stage I : It has high fertility and high mortality because people reproduce more to compensate for the deaths due to many reasons. Large families were considered as an asset. Life expectancy is low, people are mostly illiterate and have low levels of technology. Two hundred years ago all the countries of the world were in Stage I
2) Stage 2 : Fertility remains high in the beginning of second stage but it declines with time with reduced mortality rate. Improvements in sanitation and health conditions lead to decline in mortality. So the net addition to population is high.
3) Stage 3 : In the last stage, both fertility and mortality decline considerably. The population is almost stable . The population becomes urbanised, literate and knows to controls the family size.
Regards