Unit 2 AP Human Geo

**Population distribution**

The pattern in which humans are spread out on Earth’s surface.

**Population density**

The number of people per unit of land area.

**Physical factors affecting population distribution**

Climate, landforms, and water bodies that influence where people live.

**Human factors affecting population distribution**

Culture, economics, politics, and history influencing settlement patterns.

**Arithmetic density**

Total population divided by total land area.

**Physiological density**

Total population divided by arable (farmable) land area.

**Agricultural density**

Number of farmers per unit of arable land.

**High agricultural density**

Found in developing countries with less technology and more manual farming.

**Low agricultural density**

Found in developed countries using advanced farming technology.

**Population density and land pressure**

Higher density increases pressure on land for food, housing, and services.

**Consequences of population distribution**

Political, economic, social, and environmental effects based on density.

**Political consequences of low density**

Less representation, fewer voters, but more local influence.

**Political consequences of high density**

More representation, but diverse political opinions.

**Economic consequences of low density**

Fewer job opportunities, higher service cost, lower cost of living.

**Economic consequences of high density**

More jobs and businesses, lower service cost, higher living costs.

**Social consequences of low density**

Close community ties, lower crime, slower pace of life.

**Social consequences of high density**

Less community connection, higher crime, faster pace of life.

**Environmental consequences of low density**

More green space, less pollution.

**Environmental consequences of high density**

Less green space, more pollution.

**Challenges of high population density**

Increased demand for infrastructure, housing, jobs, and sanitation.

**Population composition**

Characteristics of a population such as age and sex.

**Population pyramid**

Bar graph showing population by age and sex.

**Age distribution**

Division of population into age groups.

**Sex ratio**

Ratio of males to females in a population.

**Causes of fewer women**

Sex selection, maternal mortality, male labor migration.

**Causes of fewer men**

Wars, labor migration, shorter life expectancy.

**Life expectancy**

Average number of years a person is expected to live.

**Dependency ratio**

Ratio of dependents (young + elderly) to the working-age population.

**Elderly dependency ratio**

Number of people aged 65+ dependent on workers.

**Youth dependency ratio**

Number of children (0–14) dependent on workers.

**Impact of inequality on life expectancy**

Wealth and access to healthcare create unequal life spans within and between countries.

**Youthful population (expansive)**

High fertility, large youth population, high dependency.

**Maturing population**

More middle-aged people, moderate fertility and dependency.

**Aging population**

High elderly share, low fertility, high dependency.

**Declining population**

Decrease in all age groups, low fertility and dependency.

**Migration effects on sex balance**

Large-scale migration can skew male-to-female ratios.

**Population dynamics**

Growth and change of human population over time.

**Crude birth rate (CBR)**

Number of births per 1,000 people per year.

**Crude death rate (CDR)**

Number of deaths per 1,000 people per year.

**Total fertility rate (TFR)**

Average number of children born per woman.

**Replacement level fertility**

2.1 children per woman, needed to maintain population stability.

**Infant mortality rate (IMR)**

Number of infant deaths (under age 1) per 1,000 live births.

**Child mortality rate**

Number of children who die before age 5 per 1,000 live births.

**Factors reducing mortality**

Improved healthcare, sanitation, and nutrition.

**Rate of natural increase (RNI)**

CBR minus CDR; annual population growth rate.

**Zero population growth (ZPG)**

Equal number of births and deaths; RNI = 0.

**Doubling time**

Number of years required for population to double.

**Rule of 70**

70 ÷ RNI (%) = doubling time estimate.

**Demographic equation**

Population change = births + immigrants − deaths − emigrants.

**Demographic Transition Model (DTM)**

Model showing how population changes through economic and social development.

**Stage 1: High stationary**

High birth and death rates; stable population; subsistence farming.

**Stage 2: Early expanding**

Falling death rates; high birth rates; rapid growth; early industrialization.

**Stage 3: Late expanding**

Declining birth rates; low death rates; slower growth; urbanization.

**Stage 4: Low stationary**

Low birth and death rates; stable or zero growth; strong economy and healthcare.

**Stage 5: Declining**

Death rate exceeds birth rate; population decline.

**Epidemiological Transition Model (ETM)**

Model showing how causes of death change with development (from infectious to chronic diseases).

**Carrying capacity**

Maximum population size the environment can sustain with available resources.

**Malthusian theory**

Population grows faster than food supply, leading to famine and crisis.

**Positive checks (Malthus)**

War, famine, disease that increase death rates.

**Preventive checks (Malthus)**

Family planning, delayed marriage, fewer births.

**Criticisms of Malthus**

Food production increased with technology; birth rates naturally declined.

**Neo-Malthusians**

Modern theorists warning that rapid growth strains global resources.

**Cornucopian theory**

Belief that human innovation can overcome resource limits.

**Ester Boserup’s theory**

Population growth stimulates technological and agricultural innovation.

**Anti-natalist policy**

Government efforts to reduce birth rates and population growth.

**Pro-natalist policy**

Government efforts to encourage childbirth and raise fertility.

**Anti-natalist methods**

Birth permits, family planning, propaganda, financial penalties.

**Anti-natalist rewards**

Free healthcare, housing, salary bonuses for small families.

**Pro-natalist methods**

Parental leave, child bonuses, childcare support, housing incentives.

**Pro-natalist social impacts**

Supports aging population but may not overcome cultural barriers.

**Cultural influence on fertility**

Traditions and gender norms shape family size regardless of policy.

**Women’s status in developed countries**

Higher education, better jobs, access to healthcare, lower fertility (~2.0).

**Women’s status in developing countries**

Lower education, rural life, limited healthcare, higher fertility (~5.0).

**Education and fertility**

More education

**Work and fertility**

Employment delays childbirth and reduces family size.

**Healthcare and fertility**

Access to healthcare and family planning reduces fertility.

**Aging population**

Rising percentage of people aged 65 and older.

**Causes of aging population**

Declining fertility and increasing life expectancy.

**Median age**

Age dividing population into two equal halves.

**Elderly population share**

Percentage of people aged 65+.

**Economic consequences of aging**

Fewer workers, lower productivity, higher elderly care costs.

**Political consequences of aging**

Older voters dominate elections; more focus on healthcare policies.

**Social consequences of aging**

Greater need for elderly housing, caregivers, and family support.

**Migration**

Movement of people from one place to another to settle permanently.

**Emigration**

Leaving one’s country to live elsewhere.

**Immigration**

Entering a new country to live there.

**Push factors**

Negative conditions driving people to leave (war, poverty, disasters).

**Pull factors**

Positive conditions attracting people (jobs, safety, education).

**Lee’s Migration Model**

Explains migration through push/pull factors, obstacles, and opportunities.

**Intervening obstacles**

Barriers like borders, cost, or distance that hinder migration.

**Intervening opportunities**

New opportunities that cause migrants to stop before original destination.

**Ravenstein’s laws of migration**

Patterns showing most migrants move short distances toward cities.

**Key Ravenstein laws**

Most migrants are young adults; urban dwellers migrate less; migration increases with industrial growth.

**Forced migration**

Involuntary movement due to conflict, persecution, or disaster.

**Voluntary migration**

Movement by choice for better opportunities.

**Economic migration**

Moving for jobs and higher income.

**Internal migration**

Movement within the same country.

**Transnational migration**

Movement across regions or countries for work and lifestyle.

**Rural-to-urban migration**

Movement from countryside to cities for opportunities.

**Chain migration**

Family or community members follow earlier migrants.