Overview of Chapter 8 - Napa Valley College · PDF fileOverview of Chapter 8 ... Causes...
Transcript of Overview of Chapter 8 - Napa Valley College · PDF fileOverview of Chapter 8 ... Causes...
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Chapter 8Population Change
Overview of Chapter 8
Principles of Population Ecology
Factors that Affect Population Size
Reproductive Strategies
The Human Population
Demographics
Principles of Population Ecology
Population Ecology
Study of populations and why their numbers change over time
Important for
Endangered species
Invasive species
Population
Group of individuals of same species living in the same geographic area at the same time
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Population Density
Population density
The number of individuals of a species per unit area or volume at a given time
Ovals below have same population, and different densities
Change in Population Size
Change in Population Size
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Growth
rate
Birth
rate
Death
rate
Immigration
rate
Emigration
rate
r = (b – d) + (i – e)
Calculating Population Change
Birth (b), Death (d), Immigration (i) and Emigration (e) are calculated per 1000 people
Maximum Population Growth
Intrinsic Rate of Growth (Biotic Potential)
Growth rate under ideal conditions
J- Shaped Curve (exponential growth)
Environmental Resistance
Environmental Resistance
Prevent indefinite reproduction
Available food, water, shelter, predation, etc.
Carrying Capacity (K)
Maximum # of individuals an environment can support
Causes leveling off of exponential growth
S-shaped curve of logistic population growth
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Population Crash
Overshooting carrying capacity can lead to population crash
Abrupt decline in population density
Boom and Bust = rapid population growth and consumption followed by sudden collapse
Often caused by density-dependent factors
Effect on population changes as population density changes
Examples:
Predation
Disease
Competition
Boom and Bust Population Cycles
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Human Population
Human population in modern age is J-shaped curve
Population Increase in Mexico
Projecting Future Populations
Population is increasing
Growth rate (r) has started to decline
Projections for 2050
Low = 7.7 billion
High = 10.6 billion
Most likely = 9.1 billion
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Demographics of Countries
Demographics of Countries
Demographic Stages
Pre-industrial Stage
Birth and death rates high, modest population growth
Transitional Stage
Lowered death rate, rapid population growth
Industrial Stage
Birth rate decline, population growth slow
Post Industrial Stage
Low birth and death rates, population growth very slow
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Demographic Stages
Age Structure Diagrams
Population and Quality of Life
Difficult to meet basic needs in developing countries
Problems associated with overpopulation: Environmental
degradation
Hunger
Persistent poverty
Economic stagnation
Urban deterioration
Health issues
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Food insecurity
In shaded countries, more than 20% of population is undernourished
Reducing the Total Fertility Rate
Three major influences on total fertility rate
1. Cultural traditions
2. Social & economic status of women
3. Family planning
Single most important factor = low social status of women worldwide
Cultural influences: Marriage age
Number of children – often related to infant mortality rates
Whether children work in family business
Religious values and views on gender roles and birth control
Cultural Traditions
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Gender inequality is common worldwide
Disparities
Political participation
Social status
Economic status
Legal rights
Education
Employment and
earningsIlliteracy rates in 2002
Social & Economic Status of Women
Educational Opportunities and Fertility
Women with more education tend to:
Marry later
Have fewer children
United States
Family Planning
Family planning services offer information to men and women on contraception, STDs, and parenting
Often hindered by religious or cultural values
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Achieving Population Stabilization
How can developing country governments help? Increase funding to pubic health and family planning
services
Education on methods of birth control
Increase average level of education
How can developed country governments help? Provide financial support
Support research and development of new birth control methods
Chapter 9
The Urban Environment
Population and Urbanization
Milestone: As of 2008, more than half of the world’s population lives in urban areas
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Characteristics of Urban Populations
Basic characteristics of city populations:
Diverse population in terms of race, ethnicity, religion, and socioeconomic status
Younger population than local rural area
More males in cities of developing nations
More females incities of developednations
Substandard Housing
1/3 of urban population in developing countries are squatters
no legal ownership of land or housing
Few or no city services
Water
Sewage treatment
Garbage collection
Police and fire protection
Schools
Libraries
United States Urban Agglomerations
(Population of 50,000 or above)
Urbanization Trends
Urban Agglomeration
Urbanized core region that consists of several adjunct cities or megacities and their surrounding developed suburbs
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Environmental Problems in Urban Areas
Growing urban areas affect land use patterns
Fragment wildlife
Encroach wetlands, forests, desert, etc.
Impermeable surfaces and urban runoff discharged into waterways
Motor oil, lawn fertilizers, heavy metals, etc.
Noise pollution
Suburban Sprawl
Suburban Sprawl
Patchwork of developed tracts around the edges of larger cities
Drawbacks
Air pollution
Increased traffic
Water pollution
Runoff
Loss of habitat
Suburban Sprawl
How far can it go? - Los Angeles
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Making Cities More Sustainable
Clear urban growth policies and planning
Reduction of pollution and waste
Collect runoff water (slow it, spread it, sink it)
Open space: parks, greenbelts, preserves
People-centered, not car-centered
Food grown in or near city
Rooftop gardens, local farms
Compact development
Living wage for residents
Reduce need for commuting
Sustainable Cities
Portland, OR
San Francisco, CA
Seattle, WA
Minneapolis, MN
Austin, TX
Eugene, OR
New York City, NY
Salt Lake City, UT
Grand Rapids, MI
Philadelphia, PA
Chicago, IL
Los Angeles, CA
http://billmoyers.com/content/12-cities-leading-the-way-in-sustainability/
Portland
Austin