AP Human Geography Unit 2 Cheatsheet: Population and Migration Patterns and Processes

Physical factors: climate, landforms, water bodies

Human factors: culture, economics, history, politics

Scale matters: factors vary by local, regional, or global analysis

Three density calculation methods:

• Arithmetic: total population ÷ total land area (most common, simplest)
• Physiological: population ÷ arable land only (shows pressure on farmable land)
• Agricultural density: number of farmers ÷ arable land (indicates the level of farming intensity and can help compare agricultural efficiency)

Key insight: Method chosen reveals different information about land pressure and resource strain.

Causes: low birth rates + high life expectancy = aging population

Dependency ratio: (young + old dependents) ÷ working-age population

• High ratio = more non-workers per worker
• Strains pensions, health care, social services

Consequences:

• Economic: labor shortages, pension/health-care costs, reduced consumer demand
• Social: isolation, caregiver burden, intergenerational tension
• Political: policy shifts toward elderly, immigration debates

Effects on society: population distribution and density affect political, economic, and social processes—especially service provision (medical care, education, infrastructure).

Effects on environment: carrying capacity = maximum population an environment can sustain.

• High density → resource depletion, pollution, waste management strain
• Low density → underutilized infrastructure, sprawl
• Uneven distribution → regional inequality in resource access

Test focus: link density patterns to real-world service gaps and environmental stress.