Each card: ⚡ core definition | 📊 key table | 🎯 practice MCQ | ❌ fatal error
Urbanization = rising proportion of population in urban areas (structural shift). Urban growth = absolute increase in city population. Overurbanization = city grows faster than economy can absorb (informal settlements, unemployment). World cities (global cities): centers of global finance, media, and culture that command international networks regardless of national borders.
| Type | Measure | Example |
|---|---|---|
| Urbanization | % of population that is urban | Sub-Saharan Africa: rising rapidly |
| Urban growth | Absolute population increase | Lagos, Kinshasa growing fastest in absolute numbers |
| Overurbanization | Growth exceeds economic absorption | Lagos informal settlements |
| World city | Global command center (finance/culture) | New York, London, Tokyo (Tier 1) |
Lagos, Nigeria is one of the fastest-growing cities in the world. Despite this growth, large portions of its population live in informal settlements without secure housing or basic services. This combination of rapid growth and inadequate formal infrastructure is best described as
Urbanization ≠ urban growth. Urbanization is a proportion (% urban); urban growth is absolute numbers. A country can have rapid urban growth without urbanization if rural areas grow equally fast. Also: urbanization is not inherently negative — overurbanization is the problem when growth outpaces infrastructure.
Rank-Size Rule: the nth-largest city = 1/n × the largest city (2nd city = 1/2 of 1st; 3rd = 1/3 of 1st). Suggests a balanced, developed urban hierarchy. Primate City: largest city is disproportionately large (≥2× the 2nd city). Suggests colonial history, extreme centralization, or underdevelopment of secondary cities.
| Pattern | Hierarchy | Associated with | Examples |
|---|---|---|---|
| Rank-size rule | Proportional hierarchy | Large, diverse, developed economies | USA, Germany, Brazil |
| Primate city | 1st city dominates | Colonial history, centralized states | Bangkok, Paris, Mexico City |
Thailand's capital Bangkok has a population roughly 40 times larger than the country's second-largest city. This pattern is best described as
Rank-size rule: 2nd city = 1/2 of 1st; 3rd = 1/3, etc. Primate city = 1st city MUCH larger than this ratio predicts. Bangkok, Mexico City, and Lima are classic primate city examples. New York, Chicago, and LA follow the rank-size rule much more closely (US cities have a proportional hierarchy).
Three models for understanding North American city structure, each reflecting a different era and analytic focus. All place the CBD at center. Key diagnostic: shape of zones and income gradient direction.
| Model | Year | Structure | Income gradient | Era |
|---|---|---|---|---|
| Burgess | 1925 | 5 concentric rings | Poor near CBD; wealthy outer suburbs | Industrial, walking city |
| Hoyt | 1939 | Wedge-shaped sectors along transport lines | Sectors by income type | Early automobile era |
| Harris-Ullman | 1945 | Multiple nuclei (nodes) | Irregular — based on agglomeration | Post-automobile, polycentric |
A diagram shows a city organized around a central business district with five concentric rings. The ring immediately around the CBD contains factories and deteriorating housing; income and housing quality increase with distance from the center. This diagram represents which model?
Burgess vs. Griffin-Ford income gradient is the most frequently tested urban model distinction. Burgess (North American industrial): poor near CBD — wealthy outer suburbs. Griffin-Ford (Latin American): wealthy near CBD along commercial spine — poor on periphery. They are literally opposites. If the question says "Latin American city," reverse the income gradient.
Gentrification: higher-income residents move into lower-income neighborhoods, raising property values and displacing existing residents. Market-driven. Redlining: 1930s US practice of denying mortgages to residents of minority-majority neighborhoods (marked red on risk maps) — creating systematic disinvestment that produced the low-income inner-city neighborhoods that later gentrified.
| Process | Agent | Effect on low-income residents |
|---|---|---|
| Redlining (historical) | Government/lenders | Denied wealth-building through homeownership |
| Gentrification (contemporary) | Private market, higher-income movers | Displacement through rising rents/property values |
| Urban renewal | Government | Demolition of existing housing; sometimes displacement |
Research shows that many neighborhoods experiencing rapid gentrification today were previously subject to redlining in the 1930s-50s. Which geographic explanation BEST connects these two phenomena?
Gentrification is not simply neighborhood improvement. The AP exam expects you to explain the displacement mechanism: rising property values and rents force existing low-income (often minority) residents out. "Bringing investment" to previously disinvested neighborhoods does NOT reverse historical inequality — it often deepens it by displacing the communities that survived the disinvestment.
Contemporary cities face sustainability challenges: Urban Heat Island (UHI) effect (paved surfaces absorb and retain heat), urban sprawl (low-density expansion consuming farmland), and inadequate infrastructure for growing populations. Smart growth and new urbanism strategies promote compact, transit-oriented, mixed-use development.
| Challenge | Cause | Sustainable response |
|---|---|---|
| Urban Heat Island | Dark impervious surfaces absorb heat; less vegetation | Green roofs, urban forests, permeable pavement |
| Urban sprawl | Auto-dependent low-density zoning | Smart growth: infill, mixed-use, density |
| Informal settlements | Overurbanization; lack of affordable formal housing | Upgrading programs, land tenure security |
| Water/flooding | Impervious surfaces increase runoff | Permeable pavement, constructed wetlands |
Singapore has mandated green roofs on new buildings, planted millions of trees along roads, and built elevated gardens above highways. From a sustainability perspective, these initiatives primarily address which urban challenge?
Urban Heat Island mechanism: dark impervious surfaces + less vegetation = higher temperatures. The mechanism is critical for FRQ credit — just naming UHI earns 0 points; explaining how dark surfaces absorb radiation and reduced vegetation decreases evaporative cooling earns full mechanism credit.
Five economic sectors describe the evolution of economic activity. Weber's Least-Cost Theory: industries locate where total costs (transportation + labor + agglomeration economies) are minimized. Key: weight-losing industries locate near raw materials; weight-gaining near markets; footloose follow labor/agglomeration.
| Sector | Activities | Examples |
|---|---|---|
| Primary | Extracting natural resources | Mining, fishing, farming, forestry |
| Secondary | Manufacturing/processing | Steelmaking, textiles, auto assembly |
| Tertiary | Services | Retail, banking, education, healthcare |
| Quaternary | Information, R&D, finance | Tech firms, research universities |
| Quinary | Highest decision-making | Government, NGO leadership, top executives |
A copper mining company locates its smelting operation (which reduces 10 tons of ore to 1 ton of refined copper) at the mine site rather than near the consumer market 500 km away. Which principle from Weber's location theory explains this decision?
Weight-losing = near raw materials; weight-gaining = near markets. The key is: which end of the production process weighs more? Transport the LIGHTER thing farther. Steel (weight-losing: ore to steel) locates near coal/iron ore. Soft drinks (weight-gaining: adding water/carbonation) locate near consumers. Footloose industries have no dominant cost and locate based on labor or agglomeration.
HDI (Human Development Index) = composite of GNI per capita + life expectancy + education (mean + expected years schooling). Range 0–1. Designed to show human outcomes beyond income. GINI coefficient measures income inequality within a country (NOT part of HDI). High GDP can coexist with low HDI (oil states).
| Indicator | Measures | Limitation |
|---|---|---|
| GNI per capita | Average income per person | Masks inequality; doesn't capture health/education |
| HDI | Income + health + education | Doesn't capture inequality, political freedom, environmental quality |
| GINI coefficient | Income inequality (0=equal; 1=maximum inequality) | Not part of HDI — separate measure |
| TFR | Fertility rate | Demographic, not developmental |
| Infant mortality rate | Child health, access to healthcare | Indirect development proxy |
Country A has GNI per capita of $58,000 but an HDI of 0.82. Country B has GNI per capita of $42,000 but an HDI of 0.91. Which explanation BEST accounts for Country B's higher HDI despite lower income?
GINI coefficient is NOT part of HDI. This is tested repeatedly. HDI = income + health + education. GINI measures inequality within a country — a completely separate dimension. A country can have high HDI (average outcomes are good) but high inequality (good outcomes are concentrated among the wealthy). These are different things.
Two competing explanations for global wealth inequality — the AP exam's most-tested Unit 7 comparison. Rostow: all countries can develop through the same 5-stage linear path (traditional → high mass consumption). Wallerstein: global system is permanently stratified (core/semi-periphery/periphery) — core nations extract from periphery, structurally preventing development.
| Dimension | Rostow | World-Systems Theory |
|---|---|---|
| Cause of inequality | Developmental lag (they haven't reached Stage 4 yet) | Structural extraction (core keeps periphery poor) |
| Future for poor nations | Can develop through same path as rich nations | Structural barriers limit upward mobility |
| Role of trade | Investment and exports enable takeoff | Trade terms disadvantage periphery |
| Historical lens | Progress narrative | Colonial exploitation narrative |
A dependency theorist argues that sub-Saharan Africa remains poor not because it is "developing toward Stage 4" but because colonial-era extraction of resources and labor created structural conditions that actively prevent capital accumulation and industrial development. This argument challenges Rostow's model by
Rostow = developmental lag (they'll get there eventually). WST = structural disadvantage (the system prevents it). For AP FRQs asking you to evaluate development theories: Rostow's strength is explaining some East Asian success stories (South Korea, Taiwan). WST's strength is explaining why most former colonies remain peripheral despite decades of "development" efforts.
Sustainable development: meets present needs without compromising future generations' ability to meet their own needs (Brundtland Commission, 1987). Triple Bottom Line: People (social equity) + Planet (environmental sustainability) + Profit (economic viability). SDGs: 17 UN Sustainable Development Goals (2015–2030); address poverty, health, education, gender equality, climate, and more.
| Framework | Core concept | AP application |
|---|---|---|
| Triple Bottom Line | People + Planet + Profit simultaneously | Evaluate development projects on all 3 dimensions |
| SDGs | 17 goals for 2030 | Goal 1 (no poverty), 5 (gender equality), 13 (climate action) |
| Brundtland | Intergenerational equity | Current choices must not compromise future options |
A palm oil plantation in Indonesia increases national export earnings (Profit) but requires clearing rainforest (Planet) and displacing indigenous communities (People). Which framework BEST evaluates whether this constitutes sustainable development?
Sustainable development requires ALL THREE: People + Planet + Profit. Economic growth alone is NOT sustainable development. High GDP growth that destroys ecosystems (Amazon deforestation) or exploits workers (sweatshop labor) fails the sustainability test. FRQs asking to "evaluate using sustainable development" require you to assess all three dimensions and explain why trade-offs disqualify a project.