unit 2 ap human geo

Population distribution

The pattern of where people live on Earth.

Population density

The number of people per unit area of land.

Arithmetic density

Total population divided by total land area.

Physiological density

Population divided by arable (farmable) land.

Agricultural density

Farmers divided by arable land.

Ecumene

The portion of Earth’s surface permanently inhabited by humans.

Carrying capacity

The maximum population size an area can support.

Population concentration

Areas where populations are clustered.

Infrastructure

Basic systems such as transportation, water, and power that support settlement.

Urbanization

Growth of cities and migration of people to urban areas.

Population pressure

Stress placed on resources due to high population density.

Overpopulation

When population exceeds the area’s carrying capacity.

Underpopulation

When population is too small to fully use available resources.

Infrastructure strain

Pressure on housing, transportation, and services due to population growth.

Political consequences

Redistribution of power or representation due to population shifts.

Social consequences

Cultural diversity or inequality resulting from uneven population distribution.

Population pyramid

Graph showing age and sex distribution of a population.

Age-sex ratio

Ratio of males to females in each age group.

Cohort

A group of people who share a common characteristic, usually age.

Dependency ratio

Ratio of dependents (under 15 and over 64) to the working-age population.

Sex ratio

Number of males per 100 females.

Fertility

The ability to produce offspring, measured with TFR or CBR.

Crude birth rate (CBR)

Number of live births per 1,000 people per year.

Crude death rate (CDR)

Number of deaths per 1,000 people per year.

Natural increase rate (NIR)

Difference between CBR and CDR, showing growth rate.

Total fertility rate (TFR)

Average number of children a woman will have during her lifetime.

Replacement fertility rate

Number of children needed to maintain population size (about 2.1).

Infant mortality rate (IMR)

Number of infant deaths per 1,000 live births.

Life expectancy

Average number of years a person is expected to live.

Doubling time

Time it takes for a population to double in size.

Demographic Transition Model (DTM)

Explains population growth and change through stages.

Stage 1

High birth and death rates; slow population growth (pre-industrial).

Stage 2

High birth rates and declining death rates; rapid population growth.

Stage 3

Declining birth rates; population growth slows.

Stage 4

Low birth and death rates; stable population.

Stage 5

Very low birth rates; possible population decline.

Zero population growth (ZPG)

When births equal deaths.

Population momentum

Continued population growth after fertility decline due to a large base of young people.

Thomas Malthus

Economist who predicted population would outgrow food supply.

Malthusian theory

Argues population grows exponentially while food supply grows linearly.

Neo-Malthusians

Believe modern population growth still threatens sustainability.

Boserup theory

Argues human innovation can increase food supply as population grows.

Pronatalist policy

Government policy encouraging higher birth rates.

Antinatalist policy

Government policy aimed at reducing birth rates.

Eugenic policy

Policy favoring one racial or cultural group over others.

Immigration policy

Laws that control who can enter or leave a country.

Population policy

Government actions to manage population growth or distribution.

Migration

Permanent or semi-permanent movement of people to a new location.

Push factors

Negative conditions that drive people to leave an area.

Pull factors

Positive conditions that attract people to a new area.

Intervening obstacle

A barrier that makes migration difficult (distance, cost, laws).

Intervening opportunity

A nearer opportunity that causes migrants to stop before reaching their original destination.

Friction of distance

The idea that interaction and migration decrease as distance increases.

Distance decay

The declining influence or interaction between two places as distance grows.

Voluntary migration

Movement made by choice for better opportunities.

Forced migration

Movement compelled by threats, war, or natural disasters.

Internally displaced person (IDP)

Person forced to move within their own country.

Refugee

Person forced to flee across borders to escape danger or persecution.

Asylum seeker

Refugee applying for protection in another country.

Step migration

Migration that occurs in stages toward a final destination.

Chain migration

Migration of people to a specific location because relatives or members of the same community previously migrated there.

Transnational migration

Migrants maintain connections with both their home and host countries.

Guest worker

Migrant temporarily allowed to work in another country.

Ravenstein’s Laws of Migration

Historical patterns describing migration tendencies (short distances, economic motives, urban destinations).

Gravity model of migration

Predicts migration between two places based on their population size and distance.

Lee’s Model of Migration

Explains migration decisions using push, pull, and intervening factors.

Zelinsky’s Migration Transition Model

Links migration patterns to the stages of the Demographic Transition Model.

Remittances

Money migrants send home to support their families.

Brain drain

Loss of educated or skilled workers from a country due to emigration.

Brain gain

Inflow of skilled workers into a country.

Demographic effects

Changes in population size, age structure, or distribution due to migration.

Economic effects

Impacts of migration on jobs, wages, and economic growth.

Social effects

Impacts on culture, family, and social diversity.

Political effects

Policy debates and shifts in government response to migration.

Cultural diffusion

The spread of cultural beliefs and practices from one group to another.

Acculturation

The adoption of some traits of another culture while maintaining one’s own.

Assimilation

Complete absorption into another culture, losing original cultural traits.

Multiculturalism

The coexistence of multiple cultural groups within one society.

Syncretism

Blending of cultural traits from different traditions.

Ethnic enclave

Neighborhood or area dominated by one ethnic group that maintains its culture.

Diaspora

Dispersion of a group of people from their homeland to other places.