Unit 2 covers two of the most exam-heavy topics in AP Human Geography: population patterns and migration processes. Together they make up roughly 12–17% of the AP exam, and they are the foundation for understanding how human settlement, economics, and culture work globally.
The population section centers on the Demographic Transition Model (DTM) — the five-stage model showing how birth rates, death rates, and population growth change as countries develop. You’ll also master population pyramids, the difference between CBR, CDR, NIR, and TFR, the Epidemiological Transition Model, and the real-world policy responses to demographic change.
The migration section covers push and pull factors, types of migration (voluntary, forced, internal, international), Ravenstein’s Laws, chain migration, step migration, remittances, and the geographic consequences of migration in both origin and destination areas.
Key terms preview
A taste of what you’ll find in The Essentials and Flashcards.
Demographic Transition Model
Five-stage model showing how birth and death rates change with economic development.
Total Fertility Rate (TFR)
Average children per woman; 2.1 = replacement level needed to maintain stable population.
Push/Pull Factors
Push factors drive people away from a place; pull factors attract them to a new destination.
Epidemiological Transition
Shift in primary causes of death from infectious to chronic diseases as nations develop.
Remittances
Money sent by migrants to family back home — often exceeds foreign aid in value.
Dependency Ratio
Ratio of non-workers (youth + elderly) to working-age population; high = economic strain.
1. Population is unevenly distributed — and geography explains why
Most of the world's 8 billion people live in a few densely populated clusters: East Asia, South Asia, Europe, and eastern North America. Physical geography (climate, terrain, water), history, and economic opportunity all explain these patterns. Understanding where people do NOT live — the ecumene — is equally important.
2. The Demographic Transition Model reveals development patterns
Countries move through predictable stages of population change as they develop economically — from high birth/death rates to low birth/death rates. Understanding where a country sits in the DTM explains its population challenges, policy needs, and future trajectory. The model's limitations matter too.
3. Migration reshapes populations, economies, and cultures
Migration is one of the most powerful forces in human geography. It transfers labor, remittances, and cultural practices across borders. Understanding push/pull factors, migration streams, intervening obstacles, and the consequences of migration in both origin and destination countries is central to AP Human Geography.
4. Population policies reflect political values and demographic realities
Governments respond to population trends with policies — pro-natalist (encouraging births), anti-natalist (discouraging births), or migration-focused. These policies reflect both demographic needs and political ideologies, and often have unintended consequences (e.g., China's one-child policy creating gender imbalance).