Chapter 9: Applying Population Ecology: The Human Population and Its Impact

1. Chapter 9: Applying Population Ecology: The Human Population and Its Impact December 2011

2. Human Population Growth: Historical Perspective • The human population has experienced exponential growth over the past 200 years. Why? • Expanded into diverse habitats and climate zones. • Development of modern agriculture • Modern sanitation and public health advances • Development of antibiotics and vaccinations • Harnessed concentrated sources of energy

4. The Bottom Line • No population can continue to grow indefinitely. • Degradation of natural systems and resources jeopardizes our ability to sustain populations and build economies. • Differential effect of developed vs. developing countries • In 2006, developed countries added 1.2 million people • Developing countries added 79.5 million people.

5. Population Growth Projections By 2050, human population is projected to be between 7.2 and 10.6 billion people. 97% of the growth in developing countries.

6. Factors Affecting Human Population Size When births plus immigration exceed deaths plus emigration, population increases; when the reverse is true, population declines. This is true of other species as well as humans.

7. Comparison of birth rates and death rates Demographers use: Birth rate or crude birth rate: number of live births per 1,000 people in a population in a given year (U.S. – 14.18) Death rate or crude death rate: number of deaths per 1,000 people in a population in a given year (U.S. – 8.27)

8. Declining Population: Observing Fertility Rates • Fertility – number of children born to a woman during her lifetime. • replacement –level fertility - number of children a couple must bear to replace themselves • Typically between 2.1 and 2.5 children per couple • Total fertility (TFR) – average number of children a woman typically has during her reproductive years • Global average about 2.7 • Developed countries about 1.6 • United States – 2.06 • Developing countries about 2.9 • Range according to CIA (0.91 in Macau and 7.68 in Niger)

9. Population Projections

10. Case Study: Fertility and Birth Rates in the U.S.

11. Case Study: Fertility and Birth Rates in the U.S. • 1900 – 76 million Americans • Baby boom – post WWII – 1946 to 1964 • Birth rate up to 3.7 at one point • Corresponding “baby bust” – 1964 to 1977 • Due to delayed marriage, contraceptive use, and abortion • 2007 – saw 300 millionth American • 56% growth due to birth rate, 44% due to immigration • Immigration shift from Europe to Latin American/Southeast Asia • High per capita resource use

12. Case Study: Fertility and Birth Rates in the U.S.

13. Case Study: Fertility and Birth Rates in the U.S. Think about how life has changed… Tractor-plow, 1905 • In the United States NOW… • Three leading causes of death: heart disease, cancer, stroke • Common path to becoming a physician requires 8 years of college and 3-8 years of internship and residency • 99% literate • Average U.S. worker earns $42,028 per year (2005 figures according to Worldsalaries.com) • 450 million cars in the U.S. with 5.7 million miles of paved roads • 3 minute phone call costs $0.51 (according to Mr. Bromwell’s cell phone plan) • 567,641people live in Las Vegas, NV • I would imagine hair washing is daily among other things… • In the United States in 1905… • Three leading causes of death: pneumonia, tuberculosis, and diarrhea • 90% of doctors had no college education • 1 out 5 adults cannot read or write • Average U.S. worker earns $200-$400 per year • Only 9,000 cars in the U.S. with 144 miles of paved roads • 3 minute phone call cost $11 • 30 people live in Las Vegas, NV • Most women washed their hair once a month

14. Factors Affecting Birth Rates and Fertility Rates • Importance of children as part of the labor force • Cost of raising and educating children • Availability of private and public pension systems • Urbanization • Educational and employment opportunities available for women • Infant mortality rate • Average age at marriage (or first child) • Availability of legal abortions • Availability of reliable birth control methods • Religious beliefs, traditions and cultural norms

15. Factors Affecting Death Rates • Availability of food supplies • Nutrition quality of available food supplies • Availability of medical care, immunization, and antibiotics • Sanitation • Safe drinking water supplies • Civil, governmental, or societal unrest or disadvantage • Infant mortality rate

16. Life Expectancy and Infant Mortality Rate • Two useful indicators of overall health of a population: • Life expectancy – average number of years a newborn infant can expect to live • Infant mortality rate – number of babies out of every 1,000 born who die before their first birthday • Single best measure of a society’s quality • Reflects overall nutrition and health care

17. Infant Mortality in the U.S. • In U.S. approximately 6.3 deaths / 1,000 births • Higher than expected due to inadequate health care for poor women during pregnancy, • drug addiction among pregnant women, • and a high birth rate among teenagers.

18. Migration • Immigration + emigration • Since 1820, U.S. admitted twice as many immigrants as all other nations combined! • Legal vs. illegal immigration • Racial/ethnic shift • Pros • ‘land of opportunity’ • Accept undesirable jobs, pay taxes, create jobs • Will replace aging boomer generation • Cons • Increase countries population, strain resources • Magnet for world’s poor

19. Population Age Structure • The distribution of males and females in each age group in the world’s population • Age structure diagrams  • Examine # of people in three age categories • prereproductive • reproductive • postreproductive

20. Population Age Structure Diagrams

21. The Baby-Boomers • This generation makes up half of all adult workers and dominates demand for goods and services.

22. Consequences of Population Decline • • Can threaten economic growth • • Less government revenues with fewer workers • Reduces availability of young people for military service • • Less entrepreneurship and new business formation • • Less likelihood for new technology development • • Increasing public deficits to fund higher pension and healthcare costs

23. Global Aging

24. The Demographic Transition

25. Percentage of world population India 17% China 20% 1.1 billion Population 1.3 billion 1.4 billion Population (2050) (estimated) 1.6 billion 47% Illiteracy (% of adults) 17% 36% Population under age 15 (%) 20% 1.6% Population growth rate (%) 0.6% 2.9 children per women (down from 5.3 in 1970) Total fertility rate 1.6 children per women (down from 5.7 in 1972) 58 Infant mortality rate 27 62 years Life expectancy 70 years Percentage living below $2 per day 80 47 $3,120 GDP PPP per capita $5,890 Fig. 9-15, p. 186

26. References Annual Estimates of the Resident Population for Incorporated Places in Nevada: April 1, 2000 to July 1, 2009" (CSV). United States Census Bureau, Population Division. 2010-09. http://www.census.gov/popest/cities/tables/SUB-EST2009-04-32.csv. Retrieved 2010-11-16 “Infant Mortality Rate (per 1,000 live births)” Digital Image. Unnatural Causes. 2008. California Newsreel. 11 January, 2009. http://www.unnaturalcauses.org/interactivities_04-6.php Miller, G.T. Living in the Environment: 15th edition. Brooks/Cole, Belmont, CA, 2007. “Population by region” Digital Image. The Sustainable Scale Project. 2003. The Santa-Barbara Family Foundation. 11 January, 2009. http://www.sustainablescale.org/AreasofConcern/Population/PopulationandScale/QuickFacts.aspx “Population growth” Digital Image. The Sustainable Scale Project. 2003. The Santa-Barbara Family Foundation. 11 January, 2009. http://www.sustainablescale.org/AreasofConcern/Population/PopulationandScale/QuickFacts.aspx "Rank Order - Total Fertility Rate." CIA - The World Fact Book. 18 Dec 2008. Central Intelligence Agency. 11 Jan 2009 <https://www.cia.gov/library/publications/the-world-factbook/rankorder/2127rank.html>.