GRN 250 Lecture Notes - Lecture 3: Anne H. Ehrlich, Demographic Transition, Population Pyramid
Document Summary
Migration (in and out) of the elderly. Migration (in and out) of the non-elderly. Developed the hypothesis that malthus was right and that in the 70"s and 80"s we would have war and famine because we were having too many children at the time. There are two key things influencing population fertility and mortality. Stage 1 lower societies, lots of kids. Lots of pregnancies also equals lots of deaths. Stage 2 drop in death rates but birth rates remain high because having children is a cultural phenomenon. High fertility and a falling mortality so the population is increasing in size. Stage 3 lag, birth rate starts to drop. Population is still growing but it is beginning to level off because low birth and death rate. Stage 4 developed society, lower birth rates because people realize that they don"t need to have as many children. Stage 5 low birth rates and low death rates.