21 2.10 KEY TERMS DEFINED

Agricultural density: The number of farmers per unit area of arable land.

Arithmetic density: The population of a country divided by its total land area.

Carrying capacity: The maximum population size that the environment can sustain indefinitely.

Cartogram: map in which some thematic mapping variable—such as population—is substituted for land area or distance.

Cohort: A subset of a population, generally defined by an age range.

Crude birth rate: Total number of live births per 1,000 of a population in a year.

Crude death rate: Total number of deaths per 1,000 of a population in a year.

Demographic transition: The transition from high birth and death rates to lower birth and death rates as a country or region develops.

Dependency ratio: The ratio of those not in the labor force (generally ages 0 to 14 and 65+) and those in the labor force.

Doubling time: The period of time required for a population to double in size.

Ecological Fallacy: Characteristics about the nature of individuals are deduced from inference for the group to which those individuals belong.

Ecumene: The Greek concept of the habitable part of the Earth

Infant mortality rate: The number of infant deaths that occur for every 1,000 live births.

Life expectancy: The number of years that one is expected to live as determined by statistics.

Morbidity: The state of being diseased or unhealthy within a population.

Mortality: The number of people who have died within a population.

Overpopulation: A condition in which a place has outstripped its ability to provide for its own needs.

Physiological density: The number of people per unit area of arable land.

Population density: A measurement of population per areal unit, such as the world, a region, a country or other area.

Population momentum: The tendency for population growth to continue due to high concentrations of people in the childbearing years.

Population projection: An estimate of future population.

Population pyramid: Graphical illustration that shows the distribution of various age groups in a population.

Rate of natural increase: The crude birth rate minus the crude death rate. This rate excludes the effect of migration.

Replacement level: The average number of children a woman needs to have to ensure the population replaces itself. The number is roughly 2.1.

Total fertility rate: The average number of children that would be born to a woman over her lifetime.