3 - 3. Four stages of demographic transition are:...

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3. Four stages of demographic transition are: Preindustrial stage, when there is little population growth because harsh living conditions lead to both a high birth rate (to compensate for high infant mortality) and a high death rate. Transitional stage, when industrialization begins, food production rises, and health care improves. Death rates drop and birth rates remain high, so the populations grow rapidly (typically 2.5 % – 3 % a year). Industrial stage, when the birth rate drops and eventually approaches the death rate as industrialization and modernization become widespread. Population growth continues, but at a slower and perhaps fluctuating rate, depending on economic conditions. Most developed countries are now in this third stage, and a few developing countries are entering this stage. Postindustrial stage, when the birth rate declines further, equaling the death rate and thus reaching zero population growth. Then the birth rate falls below the death rate and total population size decreases slowly. 38% of countries (most of them in Europe) containing about 13% of the world’s population have entered this stage. 4. Density-dependent factors (have a greater effect as a population’s density increases) that affect population growth are (1) competition for resources, (2) predation, (3) parasitism, and (4) disease. As prey populations
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This note was uploaded on 10/05/2010 for the course ENVR 101 taught by Professor Staff during the Spring '08 term at UNC.

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3 - 3. Four stages of demographic transition are:...

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