Population & Migration
What this unit covers
The topics below follow the published Human Geo course framework for Unit 2. This unit is worth 12–17% of the exam, so budget your time against that rather than against how long the unit takes to teach.
Lessons in this unit
- Population Distribution & Density13 min · 3 objectivesExplain how physical and human factors shape where people live · Calculate and interpret arithmetic, physiological, and agricultural density · Read population pyramids to describe a place’s age–sex structure
- The Demographic Transition Model15 min · 3 objectivesDescribe the birth rates, death rates, and growth in each DTM stage · Calculate natural increase rate and doubling time from vital rates · Apply the Epidemiologic Transition and evaluate the model’s limits
- Migration & Population Policy14 min · 3 objectivesClassify migration types and apply push and pull factors · Explain Ravenstein’s laws and the gravity model of migration · Compare pronatalist and antinatalist population policies and their effects
Formulas in Unit 2
Every term in Unit 2
All 18 terms we publish for Population & Migration, with definitions. Reading them through is the fastest way to find the ones you cannot define — then drill those in cram mode until you can produce them without the prompt.
- Arithmetic, physiological and agricultural density
- Arithmetic is people per total land, physiological per arable land, agricultural is farmers per arable land. Physiological best indicates pressure on food supply.
- Carrying capacity
- The population an environment can support given its technology and resources. Not fixed, since technology changes it.
- Crude birth and death rate
- Births or deaths per 1,000 people per year. "Crude" because they ignore age structure, which is why they mislead for aging populations.
- Rate of natural increase
- Birth rate minus death rate, expressed as a percentage. Excludes migration, so a country can grow while its RNI is negative.
- Total fertility rate
- Average births per woman. Replacement is about 2.1; below that a population eventually shrinks without immigration.
- Demographic transition model
- Stage 1 high birth and death rates, 2 death rate falls and population booms, 3 birth rate falls, 4 both low, 5 possible decline.
- Criticisms of the demographic transition model
- Based on European experience, assumes industrialization causes the transition, and cannot account for states where fertility fell without it.
- Epidemiological transition
- The shift from infectious to chronic degenerative disease as the main cause of death, paired to each demographic stage.
- Population pyramid
- Age-sex structure. A wide base predicts growth, a column stability, a narrow base decline and a heavy old-age dependency burden.
- Dependency ratio
- Non-working (under 15 and over 64) to working-age population. High ratios strain either schools or pensions depending on which end dominates.
- Malthusian theory
- Population grows geometrically while food grows arithmetically, so famine checks growth. Underestimated agricultural technology, but Neo-Malthusians extend it to all resources.
- Anti-natalist and pro-natalist policies
- China's one-child policy discouraged births and skewed the sex ratio; France and Japan offer incentives to raise fertility.
- Push and pull factors
- Push drives people from a place — conflict, unemployment, disaster; pull draws them to another — jobs, safety, family. Most migration involves both.
- Ravenstein's laws of migration
- Most migrants move short distances, in steps, toward economic opportunity, and each flow generates a counterflow.
- Voluntary vs forced migration
- Forced migration includes refugees and trafficking. A refugee has crossed a border fleeing persecution; an internally displaced person has not.
- Chain migration
- Migrants follow relatives and neighbors to the same destination, which is why immigrant communities cluster so tightly.
- Guest worker programs
- Temporary labor migration intended to be reversible. Migrants frequently settle, which produces long-term populations the policy did not plan for.
- Remittances
- Money sent home by migrants, exceeding foreign aid for many countries and a major source of national income for some.
What examiners penalize here
- When a prompt gives arable land, expect **physiological** or **agricultural** density, not arithmetic. Label your units (“people per km² of arable land”) and interpret the number — high physiological density = pressure on farmland; low agricultural density = developed, mechanized farming.
Practice Human Geo
Our practice bank is drawn from across the whole course rather than filtered to one unit, which is closer to how the exam asks anyway — it will not tell you which unit a question is testing.
Questions about this unit
How much of the AP Human Geography exam is Unit 2?
Unit 2, Population & Migration, is worth 12–17% of the Human Geo multiple-choice section according to the published course framework. Across all 7 units that makes it a substantial share — heavier than an even split would give it.
What topics are covered in Human Geo Unit 2?
Population & Migration covers Density, Demographic transition, Migration and Policies. We publish 18 terms with definitions for this unit, all of them on this page.
How should I study Human Geo Unit 2?
Read the 3 lessons below first — about 40 minutes — then drill the 18 terms in cram mode until you can produce each definition from memory rather than just recognize it. Recognition is what makes a unit feel finished when it is not. Finish with practice questions and read the explanation for every one you get right by elimination as well as the ones you miss.
All 7 units of AP Human Geography
Unit names, topics and exam weights follow the published College Board course framework for AP Human Geography. AP® is a trademark registered by the College Board, which does not endorse this site.