Chapter 4: Human Populations

ecological footprint

An estimate of our individual and collective environmental impacts. It is usually calculated and expressed as the area of bioproductive land require to support a particular lifestyle.

demography

The statistical study of human populations relating to growth rate, age structure, geographic distribution, etc., and their effects on social, economic, and environmental conditions.

crude birth rate

The number of births per thousand persons in a given year (using the midyear population).

Total Fertility Rate (TFR)

The average number of children born to a woman during her childbearing years.

Zero Population Growth (ZPG)

Occurs when birth plus immigration in a population just equal deaths plus emigration.

replacement rate

The number of children per couple needed to maintain an stable population. Because of early deaths, infertility, and nonreproducing individuals, this is usually about 2.1 children per couple.

population momentum

A potential for increased population growth as young members reach reproductive age.

crude death rates

The number of deaths per thousand persons in a given year (using the midyear population).

life span

The oldest age to which a species is known to survive.

life expectancy

The average age that a newborn infant can be expected to attain in any given society.

dependency ration

The number of nonworking compared with working individuals in a population.

pronatalist pressures

Factors that increase people's desires to have babies.

demographic transition

A pattern of falling death rates and birth rates in response to improved living conditions; typically leads to rapid then stabilizing population growth.

birth control

Any method used to reduce births.