According to (Wright and Boorse, 2011)Demographic Transition is the tendency of a population to shift from high birth and death rates to low birth and death rates as a result of the epidemiologic and fertility transitions. The result is a population that grows very slowly, if at all. In my words Demographic Transition is the medical breakthroughs lowered child mortality and populations exploded.
The first phase of demographic transition is a balance between birth rate and death rate. The human population was based on food supplies in the 18th century. These country were tribes with a small standard of living with low birth rate. No great population growth but some factors no family planning because of the faith in people. Phase one is growing.
The second phase of demographic transition is decline in the death rate but remains high in the birth rate. The death went down because of the infinite that died and decrease. There were significant improvements in public health that reduced mortality, particularly in childhood. However, bear in mind that killer infectious diseases such as TB are airborne and not water borne, so public engineering works such as sewer and water supply cannot take all the credit. More infinite are surviving and lead to arise and a difference. Phase two is decline.
The third phase of demographic transition is a decline in the birth rate. The death rates were the primary cause of population…