View
6
Download
0
Category
Preview:
Citation preview
Chapter 8 Population 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
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
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 limits (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
Population Crash
Overshooting carrying capacity can lead to population crash Abrupt decline in population density
Factors That Affect Population Size
Density Dependent Factor Factor whose effect on population changes as
population density changes Examples:
Predation Disease Competition
Sometimes cause Boom-or-Bust Population Cycles
Boom-Or-Bust Population Cycles
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
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
Demographic Stages
Fertility Changes in Select Countries
Age Structure Diagrams
Worldwide
29% of human population is under age 15 Could cause large increase in birth rates
Chapter 9 Addressing Population Issues
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
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
Gender inequality is common worldwide Disparities Political participation Social status Economic status Health status Legal rights Education Employment and earnings Illiteracy 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 Services
Family planning services offer information to both men and women on sexuality, contraception, STDs, and parenting
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 10 The Urban World
Population and Urbanization
Milestone: As of 2008, half of the world’s population lives in urban areas
Characteristics of Urban Population
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 developing nation cities More females in developed nation cities
Substandard Housing Typically occupied by
“squatters” – no legal ownership
No city services Water, sewage, garbage
collection, police and fire protection
1/3 of urban population in developing countries are squatters
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
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
Noise pollution
Suburban Sprawl
Suburban Sprawl Patchwork of vacant and developed tracts around
the edges of cities
Problems Loss of wetlands Air & water pollution Loss of biological habitat
Making Cities More Sustainable
Characteristics of a sustainable city Clear, cohesive urban growth policies Reduction of pollution and waste Large areas of green space People-centers, not car-centered Food grown in or near city (rooftop gardens) Compact development
Copenhagen, Denmark A People-centered City
Recommended