2.1 Introduction to Population and Migration Patterns and Processes

Where people live: population distribution

Population distribution describes where people live across Earth's surface. Most people cluster in areas with fertile soil, temperate climates, freshwater access, and flat land (e.g., East Asia, South Asia, Western Europe). Population density measures people per unit area, calculated using arithmetic density (total population ÷ total land area), which helps geographers compare crowding between places.

Beyond arithmetic density

Geographers also use physiological density (population ÷ arable land) to show pressure on farmland, and agricultural density (number of farmers ÷ arable land) to compare efficiency of farming. High physiological density (like Egypt) signals heavy reliance on limited farmable land, while low agricultural density suggests mechanized, efficient agriculture.

Studying migration

Migration is the permanent or semi-permanent movement of people from one place to another. Geographers study push factors (reasons people leave) and pull factors (reasons people are attracted to a destination), along with patterns of movement to understand demographic change, cultural diffusion, and regional development over time.

Key terms

Population distribution

The pattern of where people live across Earth's surface.

Arithmetic density

Total population divided by total land area.

Physiological density

Population divided by arable land; shows pressure on farmland.

Agricultural density

Number of farmers divided by arable land; shows farming efficiency.

Push vs. pull factors

Push factors drive people away from a place (e.g., war); pull factors attract them to a new place (e.g., jobs).

Try an AP-style question

Most of the world's population lives in…

1. Africa, Australia, and Canada
2. Oceania only
3. the Arctic and deserts
4. East Asia, South Asia, and Europe