Regional Variations and Patterns of Population Growth The demographic transition model provides one with insight into the transformation or transition which occurs in several steps as the industrialization of a country progresses. By using the demographic transition as a model one can describe regional variations and patterns of population growth on a global level. The demographic transition model includes four stages: the pre industrialized society, the agricultural revolution, the industrial revolution, and the post industrial societies/developed. The first stage of the demographic transition model is the pre industrial stage. In this stage birth and death rates are both usually high, which normally leads to almost no population growth within a country. The second stage of the demographic transition model is the Agricultural revolution stage, where one finds a reduction in death rates (DR), but birth rates (BR) remain high. In this stage there is also a population explosion, which is found mainly in underdeveloped and developing countries. Moving on to the third stage known as the industrial revolution stage one sees a drastic change in population. Some of the change is due to advances in medicine and improvements in diet. These changes caused a drop in death rates and birth rates drop. Human life expectancy in the industrialized countries soared from an average of 35 years in the eighteenth century to 75 years or more at present. In this stage we find that the birth rates are about the same and death rates are lower. The last stage known as the post industrial period produces zero population growth. The zero population growth is achieved when there is both a halt or decline in both birth rates and death rates. Many countries however do not pass all the way through the demographic transition, but rather have a prolonged period during stage two, where the population explosion is in full effect, this causes for some prob...
