Download Overview of Chapter 8 Principles of Population Ecology

10/20/2014
Chapter 8
Population Change
Overview of Chapter 8
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Principles of Population Ecology
Factors that Affect Population Size
Reproductive Strategies
The Human Population
Demographics
Principles of Population Ecology
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Population Ecology
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Study of populations and why their numbers
change over time
Important for
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Endangered species
Invasive species
Population
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Group of individuals of same species living in the
same geographic area at the same time
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Population Density
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Population density
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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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Calculating Population Change
Growth
rate
Death
rate
Emigration
rate
r = (b – d) + (i – e)
Birth
rate
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Immigration
rate
Birth (b), Death (d), Immigration (i) and
Emigration (e) are calculated per 1000 people
Maximum Population Growth
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Intrinsic Rate of Growth (Biotic Potential)
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Growth rate under ideal conditions
J- Shaped Curve (exponential growth)
Environmental Resistance
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Environmental Resistance
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Prevent indefinite reproduction
Available food, water, shelter, predation, etc.
Carrying Capacity (K)
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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
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Overshooting carrying capacity can lead to
population crash
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Abrupt decline in population density
Boom and Bust Population Cycles
Boom and Bust = rapid population growth and
consumption followed by sudden collapse
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Often caused by density-dependent factors
 Effect on population changes as population density
changes
 Examples:
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Predation
Disease
Competition
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Human Population
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Human population in modern age is J-shaped
curve
Population Increase in Mexico
Projecting Future Populations
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Population is increasing
Growth rate (r) has
started to decline
Projections for 2050
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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
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Pre-industrial Stage
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Birth and death rates high, modest population
growth
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Transitional Stage
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Industrial Stage
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Post Industrial Stage
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Lowered death rate, rapid population growth
Birth rate decline, population growth slow
Low birth and death rates, population growth very
slow
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Demographic Stages
Age Structure Diagrams
Population and Quality of Life
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Difficult to meet basic needs in developing
countries
Problems associated with overpopulation:
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Environmental
degradation
Hunger
Persistent poverty
Economic stagnation
Urban deterioration
Health issues
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Food insecurity
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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 Traditions
Cultural influences:
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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
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Social & Economic Status of Women
Gender inequality is common worldwide
Disparities
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Political participation
Social status
Economic status
Legal rights
Education
Employment and
earnings
Illiteracy rates in 2002
Educational Opportunities and Fertility
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Women with
more education
tend to:
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Marry later
Have fewer
children
United States
Family Planning
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Family planning services offer information to men
and women on contraception, STDs, and parenting
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Often hindered by religious or cultural values
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Achieving Population Stabilization
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How can developing country governments help?
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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?
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Provide financial support
Support research and development of new birth
control methods
Chapter 9
The Urban Environment
Population and Urbanization
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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:
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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 in
cities of developed
nations
Substandard Housing
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1/3 of urban population in
developing countries are
squatters
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no legal ownership of land
or housing
Few or no city services
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Water
Sewage treatment
Garbage collection
Police and fire protection
Schools
Libraries
Urbanization Trends
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Urban Agglomeration
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Urbanized core region that consists of several
adjunct cities or megacities and their surrounding
developed suburbs
United States Urban
Agglomerations
(Population of 50,000
or above)
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Environmental Problems in Urban
Areas
Growing urban areas affect land use patterns
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Fragment wildlife
Encroach wetlands, forests, desert, etc.
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Impermeable surfaces and urban runoff
discharged into waterways
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Motor oil, lawn fertilizers, heavy metals, etc.
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Noise pollution
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Suburban Sprawl
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Suburban Sprawl
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Patchwork of developed tracts around the edges
of larger cities
Drawbacks
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Air pollution
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Water pollution
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Loss of habitat
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Increased traffic
Runoff
Suburban Sprawl
How far can it go? - Los Angeles
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Making Cities More Sustainable
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Clear urban growth policies and planning
Reduction of pollution and waste
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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
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Reduce need for commuting
Sustainable Cities
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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
Portland
Austin
http://billmoyers.com/content/12-citiesleading-the-way-in-sustainability/
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