P O P U L A T I O N , U R B A N I Z A T I O N , A N D T H E
E N V I R O N M E N T

Key Topics
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15-1 Population Dynamics
15-2 Urbanization
15-3 Environmental Issues

Population Dynamics

Population Dynamics
Demography: the scientific study of human populations
 Examines size, composition, distribution of populations
 Looks at changes and causes of changes in populations

Population Dynamics
Population: a group of people who share a geographic territory
 Vary in size from a small town to the planet

Population Dynamics
World’s population
 Grown rapidly since 1800
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Reached 1 billion in 1804
6.5 billion by 2005
Expected to reach 9.4 billion by 2050

Population Dynamics

Population Dynamics
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Fertility: the number of babies born during a specific period in a particular society
Crude birth rate: the number of live births per
1,000 population in a given year
In 2011 the CBR was 20 worldwide, 36 for Africa, and 13 for the U.S.

Population Dynamics
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Birth rates vary within a country.
In the U.S., birth rates are lower for the more affluent and those with more education.

Population Dynamics
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Mortality: the number of deaths during specified period in a population
Crude death rate: the number of deaths per 1,000 people in a population in a given year
2011 crude death rate
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World 8
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U.S. 8
Some African countries 15

Population Dynamics
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Infant mortality rates: the number of deaths among infants under 1 year of age per 1,000 live births
2011 mortality rate
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U.S. 6
South America 18
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Afghanistan 131

Population Dynamics
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Life expectancy: the average number of years that people who were born at the same time will live
2011 life expectancy
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World 70
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U.S. 78 (below at least 25 other developed countries)

Population Dynamics
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Migration: the movement of people into or out of a specific geographic area
Push factors: encourage people to leave
Pull factors: attract people to new area

Population Dynamics
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International migration: the movement across a national border
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Emigrants move out of a country
Immigrants move into a country
Internal migration: movement within a country

Population Dynamics—Application
Identify the type of migration and push or pull factors.
 Josh’s family moved from Louisiana to Texas after
Hurricane Katrina.
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After a beef plant closed in Iowa, a family moved to
Minnesota in search of work.
A family moved from Afghanistan to France to escape the war.

Population Dynamics
 Sex ratio: the proportion of males to females in a group
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100—equal numbers of males and females
95—fewer males than females
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105—fewer females than males

Population Dynamics
Population pyramid: a visual representation of the age and sex structure of a population at a given point in time
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Allows demographers to predict future needs of a population

Population Dynamics

Population Dynamics
Malthusian theory: the belief that the population is growing faster than the food supply needed to sustain it (Thomas Malthus 1798)
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Population will outdistance food supply.
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Population grows geometrically.
Food supply grows arithmetically.

Population Dynamics
Neo-Mathusians agree that the world population is exploding beyond food supplies.
 Earth has become a dying planet with increasing population and pollution.
 Number of hungry people in the world increased to
1.02 billion in 2009.

Population Dynamics
Demographic transition theory: maintains the population growth is kept in check and stabilizes as countries experience economic development.
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Development involves industrialization, modernization, technological advancements, and urbanization.

Population Dynamics
Stages in the demographic transition:
 1—Preindustrial: high birth rates and high death rates
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2—Early industrialization: high birth rates and lower death rates (population growth)
3—Advanced industrialization: lower birth rates and death rates (lower growth rate)
4—Postindustrial: low birth and death rates
(stability or decrease in population)

Population Dynamics

Population Dynamics
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Zero population growth: each woman has no more than two children resulting in a stable population.
Many nations are now experiencing zero population growth.

Urbanization

Urbanization
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City: a geographic area where a large number of people live relatively permanently and make a living through nonagricultural activities
Urbanization: the movement of people from rural areas to cities

Urbanization
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The Industrial Revolution created a surge in urbanization as people moved to cities in search of jobs and improved living conditions.
In 2008, a majority of the world’s population lived in urban areas for the first time in history.

Urbanization

Urbanization
Megacities: metropolitan areas with at least 10 million inhabitants
 Becoming more common
 By 2025, there will be 37 megacities in the world with 3 in the U.S.

Urbanization
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In U.S., the fastest growing counties are near metropolitan areas.
Suburbanization: movement from cities to the areas surrounding them.
More than 60% of Americans reside in suburbs.

Urbanization
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Edge cities: business centers that are within or close to suburban residential areas
Exurbs: areas of new development beyond suburbs on the fringe of urbanized areas

Urbanization
 Urban sprawl: the rapid, unplanned, and uncontrolled spread of urban development into neighboring regions
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Loss of farmland, wildlife habitats, forests, and open recreation areas
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Increased cost of purchasing and maintaining automobiles
Air and water pollution
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Job sprawl

Urbanization
Gentrification: the process of buying and renovating houses and stores by middle-class and affluent people in downtown urban neighborhoods
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Revitalizes urban areas and augments taxes
 Results in displacement of low-income people and small business

Urbanization
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Racial segregation: as suburbs expanded, lowincome African Americans were left in the central cities with few housing and employment choices
Decreasing but average black or Latino household lives in a poorer neighborhood
Suburbs are becoming “ethnoburbs.”

Urbanization
Sociological explanations of urbanization:
 How and why do cities change?
 How do the changes affect populations?

Urbanization: Functionalism
Functionalists developed theories of urban ecology: the study of the relationships between people and their urban environment
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Theories analyzed the growth of cities into different patterns.

Urbanization: Functionalism
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Concentric zone: city grows outward in a series of rings
Sector theory: pie-shaped wedges radiate from central business district
Multi-nuclei: city contains multiple centers
Peripheral: suburbs and edge cities develop through highway development

Urbanization: Conflict
Conflict theory: heavily influenced new urban sociology
 Economic and political factors determine urban growth or decline.
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Urban changes are influenced by the dominant social class and powerful capitalists.
Urban space is a commodity to be bought and sold.

Urbanization: Feminist
Feminist scholars emphasize gender-related constraints.
 Developers ignored women’s changing roles.
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Poor women and minorities have the least access to decent housing.
Safe public transportation and other public areas are limited.

Urbanization: Symbolic Interactionists
Symbolic interactionists are interested in the impact of urban life on its residents.
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Urbanism is a way of life characterized by tolerance of different lifestyles but superficial interaction and social isolation.
Recent studies find satisfying lives for urbanites.

Urbanization—Application
Identify the theoretical perspective:
 People create suburbs to enhance their quality of life.
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Financial institutions determine the shape of cities.
Urbanites are more socially isolated than those in rural areas.

Environmental Issues

Environmental Issues
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Ecosystem: involves a physical environment and all forms of life living in relation to one another
Environmental problems threaten our ecosystem.

Environmental Issues
Access to clean water:
 More than 1 billion people do not have clean water.
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Over 3 million children die every year because of diarrheal diseases.
Water-related diseases cause 50% of illnesses and deaths.

Environmental Issues
Threats to water supply:
 Pollution:
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Toxins from cities, factories, and farms
The Clean Water Act (1972) and Safe Drinking Water Act
(1974) are often violated with little punishment.

Environmental Issues
Threats to water supply:
 Privatization: transferring assets or operations of public water systems into private hands
 Bottled water depletes local water sources and creates plastic water garbage.

Environmental Issues
Threats to the water supply:
 Mismanagement
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Most water-related problems are due to human mismanagement, corruption, and bureaucratic bungling.
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Many water and sewage pipes are old and deteriorating.
Agricultural waste includes production of water-hungry crops in arid areas.

Environmental Issues
The most common sources of air pollution are:
 Fossil fuels
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Manufacturing
Winds blowing contaminants to other areas
Government policies including lack of enforcement of pollution law

Environmental Issues
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Global warming: increased temperature of the earth’s atmosphere
The greenhouse effect: heating of the earth’s temperature due to atmospheric gases

Environmental Issues
Climate change: change of overall temperatures and water conditions over time
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Increases in ocean acidity
Loss of livelihoods
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Coastal erosion and loss of homes
Floods and droughts

Environmental Issues
Sustainable development: economic activities that meet the needs of the present without threatening the environmental legacy of future generations

Chapter Review
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Describe the dynamics of population.
What are the concerns regarding changing population?
Describe the urbanization trends.
Distinguish among the sociological explanations of urbanization.
What are the environmental issues facing the world?