Population Distribution: Spread of people across the earth, highlighting clustering and dispersion.
Population Density: Average population per square mile or kilometer, measuring how crowded a place is.
Factors Influencing Population Distribution
Physical Factors: Climate, landforms, bodies of water.
Human Factors: Culture, economics, history, politics.
Physical Factors
Climate: Most people live in mid-latitudes (30° - 60° N and S) due to moderate climates and better soil.
Landforms: Most people live in low altitudes, with better soil and closer to oceans.
Fresh Water: Majority of people live near lakes and rivers, which are necessary to sustain life.
Human Factors
Cultural Factors: Populations concentrate in areas with access to education, healthcare, and entertainment.
Economic Factors: Populations concentrate in areas with ports, good roads, railways, airports, industrialized zones, and developed tourism.
History: Populations concentrate in areas where life could be sustained.
Politics: Populations tend to grow in areas with political stability and opportunity.
Population Density Calculation Methods
Arithmetic Density: Total population / Total land area.
Physiological Density: Total population / Arable land; measures carrying capacity.
Agricultural Density: Number of farmers / Arable land; indicates farming efficiency.
Consequences of Population Distribution and Density
Political, economic, and social power is greater in areas with larger populations and higher densities.
Affects the environment and natural resources; growth and expansion alter landscape; increases resource use.
Carrying Capacity: The number of people a location can sustain without environmental degradation, can be increased or decreased by technologies or disasters.
Elements of Population Composition
Includes language, religion, ethnicity, age, and gender.
Population Pyramids
Used to assess population growth and decline and provides information about economic development as well as past events.
Visual representation of a country’s population structure based on age and gender data.
Males on the left, females on the right, shown in 5-year age groups (cohorts).
Analyzing Population Pyramids
Wide base and narrow top (evergreen tree): indicative of lesser developed countries, high birth rate, high death rate.
Vase shape: indicative of a developed country, low birth rate, low death rate, bulge in the middle represents workers.
Muffin shape (top heavy): indicative of a developed country, very low birth rate, a large number of elderly who need care.
Dependency Ratio
Compares the working (15-64) to the non-working (0-14 and 65+) parts of the population.
Historical Trends in Population Growth
Increased life expectancy, drop in infant mortality, better food production and nutrition, advances in public sanitation, and improvements in healthcare.
Demographic Factors
Fertility: Crude Birth Rate, Total Fertility Rate.
Mortality: Crude Death Rate, Infant Mortality Rate, Child Mortality Rate.
Migration: Immigration, Emigration.
Fertility
Crude Birth Rate (CBR): Number of live births per year per 1000 people, high CBR is in 30s, low CBR is in single digits.
Total Fertility Rate (TFR): Average number of babies a woman is expected to have during childbearing years (15-49), replacement rate is 2.1.
Mortality
Crude Death Rate: Annual number of deaths per 1000 people (all ages), high CDR is in the mid-teens, low CDR is in low single digits.
Infant Mortality Rate (IMR): Number of deaths of infants under one year per 1000 live births, reflects the quality of the health system.
Child Mortality Rate (CMR): Number of children who die before age 5 per 1,000 live births, low number indicates access to good healthcare and nutrition.
Migration
Emigration: Act of leaving a location to settle someplace else, high rates in lesser developed countries.
Immigration: Act of migrating to a new location, destinations tend to be more developed.
Explanations of Population Growth and Decline
Rate of Natural Increase (RNI): (CBR-CDR)/10.
Doubling Time: 70/RNI.
Demographic Transition Model
Explains population change over time.
Epidemiological Transition Model
Identifies predictable stages of disease and life expectancy countries experience as they develop.
Stage 1: Pestilence and Famine: parasitic or infectious diseases, accidents, animal attacks, and/or human conflicts cause most deaths; high death rate; low life expectancy.
Stage 2: Receding Pandemics: The number of pandemics declines as a result of improved sanitation, nutrition, and medicine; decreasing death rate; increasing life expectancy.
Stage 3: Degenerative and Human-Created Diseases: Infectious and parasitic diseases continue to decrease, but diseases associated with aging increase; low death rate; increasing life expectancy.
Stage 4: Delayed Degenerative Diseases: Age-related diseases are delayed through medical procedures; death rate reaches its lowest level and life expectancy reaches a peak.
Stage 5: Reemerging of Infectious and Parasitic Diseases: Infectious and parasitic diseases increase as some bacteria and parasites become resistant to antibiotics and vaccines; life expectancy decreases.
Malthusian Theory
Population grows exponentially while the food supply grows arithmetically.
Disease, famine, war, or intervention needed to prevent human suffering.
Neo-Malthusian Theory
Advocates for contraception and family planning to keep population low, protect resources, and prevent famine and war.
Population Policies
Pro-Natalist Policies: Policies promoting the birth of babies, examples include extended paid time off after giving birth and subsidies for childcare.
Anti-Natalist Policies: Policies discouraging women from having children, examples include countries promoting family planning and China’s one/two child policy.
Changing Role of Females
Empowering women through education lowers fertility rates.
Women are more likely to be international migrants and have opportunities as guest workers.
Aging Populations
Characterized by declining birth rate, rising life expectancy, and eventually rising death rate.
Political consequences: Governments developing pro-natalist policies.
Social consequences: Who will care for the aging?
Economic consequences: Non-dependent population must support them and there will be fewer workers leads to economic stagnation.
Causes of Migration
Push and Pull Factors: Push is negative circumstances at the point of origin, pull is a positive circumstance at the point of destination.
Intervening Opportunities: Something that diminishes attractiveness of sites farther away.
Intervening Obstacle: Something limiting human migration.
Ravenstein’s Laws of Migration
Most migrants travel short distances and usually settle in large urban areas.
Each migration flow produces movement in opposite direction.
Most migrants are aged 20 - 45.
International migrants are more likely to be male, and internal migrants are more likely to be female.
Forced Migration
People relocate due to the threat of violence.
Refugees: People who cross international borders due to well-founded fear they will be harmed if they stay in their country of origin.
Internally Displaced People: Moving to another part of the same country for similar reasons as refugees migrate internationally.
Voluntary Migration
Transnational: Migrant crosses an international border.
Transhumance: Seasonal migration of livestock herders.
Guest Worker: Migrant that comes to a state as a temporary worker.
Step Migration: Migrants move in small steps to an ultimate large city destination.
Chain Migration: Migrant follows the path of a previous migrant.
Rural to Urban: People move from small villages and farming communities to large urban areas.
Effects of Migration
Political Effects: Immigrants often have different political beliefs than native-born Americans.
Economic Effects: Source countries may suffer brain drain, but will receive remittances.