Woodolph M. Richard
06/16/2014
Week 2 I.P

The demographic transition model is a model that describes population change over time. It is based on an interpretation begun in 1929 by the American demographer Warren Thompson, of the observed changes, or transitions, in birth and death rates in industrialized societies over the past two hundred years or so. American geographer, Warren Thompson, developed this model in 1929 in NYC in the midst of the stock market crash and onset of the Depression. (Keith Montgomery, 2013)
There are four phases of demographic transition. In phase 1, preindustrial cultures that have both high birth and death rates. During this phase the population size doesn't increase very fast at all. Phase 2 is the also called the "mortality transition". Death rates drop due to improved health of the population, including infants. The end of phase 2 and the beginning of phase 3 have the highest net growth rates (birth - death rates). Phase 3 is also called either the "industrial" stage or the "fertility transition". This phase represents the decrease in births that can be correlated to many factors. The factors that lead to the decrease in fertility are the point of this case study. Phase 4 represents post-industrial stage. Populations in this phase have low net growth rates again, leading to net zero population growth, and in some cases negative net growth rate. Three living conditions in developed countries that have reached phase four, and contrast them with these same conditions in developing countries that remain in earlier phases are family planning, disease, and medical advancement.
Vaccination has eradicated smallpox, nearly eradicated poliomyelitis and greatly reduced many other highly dangerous infections such as diphtheria, tetanus and measles. New diseases such as HIV and new forms of influenza have taken both professional and popular