The Human Population Studying Human Population Chapter Nine Section One

Demography – study of populations Developed countries –Higher average income –Slower pop. growth –Diverse industrial economy –Strong social support systems: health care, family support, food services Developing countries –Lower average income –Simple and agricultural based economies –Rapid population growth

Exponential population growth

Age structure diagrams Distribution of ages in a specific population at a certain time Can be graphed as a population pyramid – a double sided bar graph

Population Pyramids

Survivorship Curves Survivorship – percentage of members of a group that are likely to survive to any given age Type I – wealthy developed countries, most people live to old age Type II – similar death rate at all ages Type III – many children die

Fertility Rates and Migration Fertility rate - # of babies born each year per 1000 women Migration – movement of individuals between areas Immigration – movement in (keeping population of developed nations from decreasing) Emigration - movement out

Fertility rates in the U. S.

Declining Death Rates Death rates declined more than birth rates because of clean water, adequate food, safe sewage disposal, vaccines Life expectancy – average number of years a person is expected to live –Most affected by infant mortality, the death rate of infants less than 1 year old