Human Geography 101: Population Geography Population - Distribution and Density Physiological Agricultural Arithmetic Density

What This Is

Population distribution and density refer to the way people are spread out across the Earth's surface. Understanding these concepts is crucial for grasping spatial patterns and human-environment interactions. For instance, the growth of cities in the United States, such as Los Angeles, is a result of suburbanization, where people move from rural areas to cities in search of better job opportunities.

Key Models, Theories & Terms

• Demographic Transition Model (DTM): A five-stage model linking population growth to economic development (Stage 1: high CBR & CDR-… Stage 4: low CBR & CDR) – explains why some countries still have high birth rates. For example, in 2019, Niger had a high birth rate of 46.7 births per 1,000 people, while Japan had a low birth rate of 1.4 births per 1,000 people.
• Von Thünen’s Model of Agricultural Land Use: Concentric rings around a city (dairy, forest, grains, livestock) determined by transportation costs – explains where different crops are grown. For example, in Germany, dairy farming is concentrated in the north, while grains are grown in the south.
• Physiological Density: The number of people per square kilometer of arable land – measures the pressure on the land. For example, in 2019, the physiological density of Bangladesh was 2,200 people per square kilometer, while that of Australia was 2.5 people per square kilometer.
• Agricultural Density: The number of people per square kilometer of agricultural land – measures the pressure on agricultural land. For example, in 2019, the agricultural density of Egypt was 1,300 people per square kilometer, while that of the United States was 40 people per square kilometer.
• Arithmetic Density: The total number of people per square kilometer of land – measures the overall population density. For example, in 2019, the arithmetic density of Singapore was 8,000 people per square kilometer, while that of Australia was 3.5 people per square kilometer.
• Central Place Theory: A model explaining the spacing of towns and cities based on their economic functions – explains why some cities are larger than others. For example, in the United States, cities like New York and Los Angeles are larger than smaller cities like Des Moines and Omaha.
• Rank-Size Rule: A model explaining the distribution of city sizes based on their economic functions – explains why some cities are larger than others. For example, in the United States, the rank-size rule holds true for cities like New York and Los Angeles, but not for smaller cities like Des Moines and Omaha.
• Urbanization: The process of people moving from rural areas to cities – explains why cities are growing rapidly in developing countries. For example, in China, urbanization has led to the growth of megacities like Shanghai and Beijing.
• Suburbanization: The process of people moving from cities to suburbs – explains why suburbs are growing rapidly in developed countries. For example, in the United States, suburbanization has led to the growth of suburbs like Los Angeles and Chicago.

Step-by-Step Application

1. When analyzing a real-world map, identify the type of population distribution (e.g., uniform, patchy, or random) and explain its causes.
2. When analyzing a population pyramid, identify the age structure of a population and explain its implications for economic development.
3. When analyzing a city's growth, identify the dominant migration pattern (e.g., rural-urban, urban-urban, or international) and explain its causes.
4. When analyzing a city's structure, identify the type of urban model (e.g., concentric zone, sector, or multiple nuclei) and explain its causes.
5. When analyzing a country's population growth, identify the stage of the demographic transition model and explain its implications for economic development.

Common Misconceptions

• Misconception: All migration is permanent.
• Correction: Not all migration is permanent, as some people may migrate temporarily for work or education. For example, in the United States, many people migrate seasonally to work in agriculture.
• Misconception: GDP per capita is the same as standard of living.
• Correction: GDP per capita is a measure of economic output, while standard of living is a measure of well-being. For example, in 2019, GDP per capita in the United States was $69,862, but the standard of living in some rural areas was lower due to limited access to healthcare and education.
• Misconception: Rank-size rule applies to every country.
• Correction: Rank-size rule applies to some countries, but not all. For example, in the United States, the rank-size rule holds true for cities like New York and Los Angeles, but not for smaller cities like Des Moines and Omaha.

AP Exam / Free-Response Tips

• When answering FRQs, make sure to identify the task verb (e.g., identify, describe, explain, compare) and follow the instructions carefully.
• When integrating models into essays, make sure to explain how they apply to the specific case study and provide evidence to support your arguments.
• When discussing population distribution and density, make sure to use specific examples and data to support your arguments.
• When discussing urbanization and suburbanization, make sure to explain the causes and consequences of these processes.

Quick Practice Scenario

A megacity in a developing country grows rapidly as rural residents move in for factory jobs. Identify the dominant migration pattern and one likely urban model that describes its structure.

Answer: The dominant migration pattern is rural-urban migration, and one likely urban model is the concentric zone model.

Explanation: Rural residents move to the megacity for factory jobs, leading to a growth in the city's population. The concentric zone model explains the city's structure, with different zones (e.g., industrial, commercial, residential) forming around the city center.

Last-Minute Cram Sheet

• Demographic Transition Model (DTM): A five-stage model linking population growth to economic development.
• Von Thünen’s Model of Agricultural Land Use: Concentric rings around a city determined by transportation costs.
• Physiological Density: The number of people per square kilometer of arable land.
• Agricultural Density: The number of people per square kilometer of agricultural land.
• Arithmetic Density: The total number of people per square kilometer of land.
• Central Place Theory: A model explaining the spacing of towns and cities based on their economic functions.
• Rank-Size Rule: A model explaining the distribution of city sizes based on their economic functions.
• Urbanization: The process of people moving from rural areas to cities.
• Suburbanization: The process of people moving from cities to suburbs.
• Concentric Zone Model: A model explaining the structure of cities with different zones (e.g., industrial, commercial, residential) forming around the city center.
• Sector Model: A model explaining the structure of cities with different zones (e.g., industrial, commercial, residential) forming in a linear pattern.
• Multiple Nuclei Model: A model explaining the structure of cities with multiple centers of activity (e.g., shopping centers, entertainment districts).
• Ethnicity vs. Nationality: Ethnicity refers to a person's cultural identity, while nationality refers to a person's citizenship.
• Site vs. Situation: Site refers to the physical location of a place, while situation refers to the social and economic context of a place.
• Centripetal vs. Centrifugal Forces: Centripetal forces refer to the forces that pull people towards a central location, while centrifugal forces refer to the forces that push people away from a central location.