Unit 3: Human Population Dynamics

Unit 3 AP Environmental Science

Age Structure

The distribution of individuals within a population according to age groups.

Expansive Pyramid

A population pyramid that shows rapid growth with a larger base and a smaller top.

Stationary Pyramid

A population pyramid that represents a stable population with little or no growth.

Constrictive Pyramid

A population pyramid indicating a declining population.

Total Fertility Rate (TFR)

The average number of children a woman is expected to have during her lifetime.

Replacement Level Fertility

The TFR at which a population exactly replaces itself from one generation to the next.

Crude Birth Rate

The number of live births per 1,000 individuals in a population per year.

Crude Death Rate

The number of deaths per 1,000 individuals in a population per year.

Population Density

The number of individuals per unit of area.

Population Growth Rate

The rate at which a population is increasing or decreasing.

Demographic Transition Model

A model describing the shift from high birth and death rates to low rates as a country develops.

Population Momentum

The tendency for a population to continue growing even after fertility rates decline.

Mortality Rate

The number of deaths in a population per unit of time, expressed as a death rate.

Infant Mortality Rate

The number of deaths of infants under one year of age per 1,000 live births in a population.

Emigration

The act of leaving one's country of origin to settle permanently in another.

Family Planning

The practice of regulating the number and spacing of children through contraception and other methods.

Carrying Capacity

The maximum number of individuals an environment can sustain over a long period.

Density-Dependent Factors

Factors affecting a population's growth rate based on population density.

Density-Independent Factors

Factors affecting a population's growth rate regardless of population density.

Age structure diagram

A graphical representation of the number of people in different age groups within a population. Also known as an age structure pyramid

Immigration

Refers to the movement of people into a country to establish permanent residence.

Rule of 70

A simple formula to estimate the doubling time of a population or investment.

Fertility rate

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