The Demographic Transition Model is based on transitions in the birth and death rates in more developed economies over the past twocenturies. It describes the population change or shift in demographic pattern over a period of time. The model was put forwarded by Warren Thompson in the year 1929.
The theory states that the increase in world population results from a decrease in death rate. In effect the birth rate also declines. This is the demographic transition ' a shift from high to low rates of births and deaths which also includes the shift from large to small family sizes. The theory proposes the shift of birth rate and death rate in terms of four stages, and each stage depicts the stage of development and thus it effects on the birth rate and death rate.
STAGE ONE is associated with pre Modern times, and is characterized by a balance between birth rates and death rates. This situation was true of all human populations up until the late 18th.C when the balance was broken in Western Europe. It shows the characteristic of a pre- industrial society experiencing both high birth and high death rates and here the infant mortality is very high. Here the birth and death rate are fairly high and the resultant population grows very slow and the population doubling time was quite high. With regard to these characters this stage is also referred as highly stationary stage.
STAGE TWO sees a rise in population caused by a decline in the death rate while the birth rate remains high, or perhaps even rises slightly. It starts when the death rate begins to drop for years, and often decades, until the beginning of its stabilization at a new, low level. A consequence of the decline in mortality in Stage Two is an increasingly rapid rise in population growth (a "population explosion") as the gap between deaths and births grows wider. This growth is not due to an increase in fertility (or birth rates) but...