Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
10/20/2014 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 1 10/20/2014 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 2 10/20/2014 Calculating Population Change Growth rate Death rate Emigration rate r = (b – d) + (i – e) Birth rate Immigration rate 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 3 10/20/2014 Population Crash Overshooting carrying capacity can lead to population crash Abrupt decline in population density Boom and Bust Population Cycles 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 4 10/20/2014 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 5 10/20/2014 Demographics of Countries Demographics of Countries Demographic Stages Pre-industrial Stage Birth and death rates high, modest population growth Transitional Stage Industrial Stage Post Industrial Stage Lowered death rate, rapid population growth Birth rate decline, population growth slow Low birth and death rates, population growth very slow 6 10/20/2014 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 7 10/20/2014 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 Traditions 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 8 10/20/2014 Social & Economic Status of Women Gender inequality is common worldwide Disparities Political participation Social status Economic status Legal rights Education Employment and earnings Illiteracy rates in 2002 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 9 10/20/2014 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 10 10/20/2014 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 in cities of developed nations 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 Urbanization Trends Urban Agglomeration 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) 11 10/20/2014 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 Water pollution Loss of habitat Increased traffic Runoff Suburban Sprawl How far can it go? - Los Angeles 12 10/20/2014 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 Portland Austin http://billmoyers.com/content/12-citiesleading-the-way-in-sustainability/ 13