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The Human Population. Section 1 – Studying Human Populations. Studying Human Populations. Demography - study of the characteristics of human populations. Developed and Developing Countries. Developed - higher average incomes slower population growth diverse industrial economies
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The Human Population Section 1 – Studying Human Populations
Studying Human Populations • Demography - study of the characteristics of human populations
Developed and Developing Countries • Developed - higher average incomes • slower population growth • diverse industrial economies • stronger social support systems.
Developed and Developing Countries • Developing - lower average incomes • simple and agriculture-based economics • rapid population growth.
The Human Population Over Time • Exponential growth in the 1800s • population growth rates increased during each decade • Increases in food production • Improvements in hygiene • industrial and scientific revolution.
The Human Population Over Time • Unlikely Earth can sustain this growth for much longer
Age Structure • Age structure - classification of members of a population • Grouped by age or distribution of members of a population in terms of age groups • helps demographers make predictions
Age Structure • High rates of growth • more young people than older people. • Slow rates of growth • even distribution of ages in the population.
Survivorship • Survivorship - percentage of newborns that can be expected to survive to a given age • predict population trends
Survivorship • Wealthy countries • Type I survivorship curve • most people live to be very old. • Type II populations - similar death rate at all ages. • Type III survivorship • very poor human populations in which many children die. • Both Type I and Type III may result in populations that remain the same size or grow slowly.
Fertility Rates • Fertility rate - number of births per 1,000 women of childbearing age (usually 15 to 44). • Replacement level - average number of children each parent must have in order to “replace” themselves.
Migration • Migration- any movement of individuals or populations from one location to another. • Movement into an area is immigration and movement out of an area is emigration.
Declining Death Rates • Increase in Earth’s population in last 200 years • death rates have declined more rapidly than birth rates. • Vaccines • Clean water • Food
Life expectancy • Life expectancy -average length of time that an individual is expected to live. • Affected by infant mortality, the death rate of infants less than a year old.
Demographic Transition • Demographic transition - general pattern of demographic change from high birth and death rates to low birth and death rates • observed in the history of more-developed countries.
Transition Stages • 1st stage – preindustrial stage • 2nd stage – population explosion • 3rd stage – population slows • Birth rate decreases • 4th stage - birth rate drops below replacement level
Women and Fertility • Lower death rate of the second stage is usually the result of increased levels of education. • Women are able to contribute to their family’s increasing prosperity while spending less energy bearing and caring for children.
