Basic Population Terms
The number of people living in a specific area per square mile or kilometer
Population density
The geographic arrangement of settlements across a landscape
Settlement pattern
The permanent movement of people from one place to another
Migration
The process of renovating urban areas often displaces lower-income residents
Gentrification
The portion of Earth's surface that is permanently settled by humans
Ecumene
The composition of a population by age and gender
Population structure
The pattern of where people live across Earth's surface
Population distribution
The physical characteristics of a place where a settlement is located
Site
Movement of people into a country or region
Immigration
An informal settlement of makeshift housing in urban areas
Squatter settlement
The tendency for population growth to continue even after birth rates decline
Population momentum
A group of people born in the same time period
Age cohort
The process by which an increasing percentage of people live in cities
Urbanization
The relative location of a place in relation to other places
Situation
Movement of people out of a country or region
Emigration
A city that is much larger than other cities in the same country
Primate city
The ratio of non-working age people to working age people
Dependency ratio
The average number of years a person can expect to live
Life expectancy
The movement of people from the countryside to cities
Rural-to-urban migration
The commercial heart of a city with offices, banks, and retail stores
Central Business District (CBD)
Conditions that drive people to leave their current location
Push factors
The movement of people from cities to the surrounding suburban areas
Suburbanization
Predicts interaction between places based on population size and distance
Gravity model
The number of deaths of infants under one year per 1,000 live births
Infant mortality rate
The difference between the birth rate and the death rate in a population
Natural increase rate
The spread of urban development into surrounding rural areas
Urban sprawl
Conditions that attract people to a new location
Pull factors
Government programs to rebuild deteriorated urban areas
Urban renewal
The principle that interaction decreases as distance increases
Distance decay
The average number of children born to women during their lifetime
Total fertility rate
A graph showing the age and gender structure of a population
Population pyramid
A residential area outside the central city
Suburb
A constant flow of migrants from one origin to the same destination
Migration stream
Laws that designate specific areas for residential, commercial, or industrial use
Zoning
The minimum number of people needed to support a business or service
Threshold population
The fertility rate needed to maintain a stable population (about 2.1)
Replacement level fertility
The maximum population an environment can support sustainably
Carrying capacity
A large city and its surrounding urban and suburban areas
Metropolitan area
A barrier that makes migration more difficult
Intervening obstacle
Basic facilities like roads, water systems, and electrical grids
Infrastructure
The maximum distance people will travel to obtain a service
Range of a service
The time it takes for a population to double in size
Population doubling time
Shows how birth and death rates change as a country develops
Demographic transition model
A chain of connected metropolitan areas
Megalopolis
An alternative destination that migrants encounter along their route
Intervening opportunity
Government-provided services like schools, hospitals, and police
Public services
The area served by a city or urban center
Hinterland
When birth rates equal death rates, resulting in no population change
Zero population growth
The number of births per 1,000 people in a population per year
Birth rate
Multiple cities that have grown together into one large urban area
Conurbation
When migrants help family and friends follow the same path
Chain migration
The number of housing units per acre or square mile
Housing density
States that the second largest city should be half the size of the largest
Rank-size rule
When population exceeds the carrying capacity of an area
Overpopulation
The number of deaths per 1,000 people in a population per year
Death rate
Explains the size and spacing of cities based on the services they provide
Central place theory
Movement of people against their will due to conflict or disaster
Forced migration
The ranking of cities by size and importance
Urban hierarchy
Meeting present needs without compromising future generations' ability to meet theirs
Sustainable development
When population is too small to effectively use available resources
Underpopulation