The Human Population and Its Impact Chapter 6 (Miller and Spoolman , 2010). Figure 6.1
The Human Population and Its ImpactChapter 6 (Miller and Spoolman, 2010)
Crowded street in China. Together, China and India have 36% of the world’s population and the resource use per person in these countries is projected to grow rapidly as they become more modernized (Case Study, p. 15).
Concept 6-1 We do not know how long we can continue increasing the earth’s carrying capacity for humans without seriously degrading the life-support system for humans and many other species.
Figure 6.2Global connections: UN world population projections, assuming that by 2050 women will have an average of 2.5 children (high), 2.0 children (medium), or 1.5 children (low). The most likely projection is the medium one—9.3 billion by 2050. (Data from United Nations).
Figure 6.AMajor ways in which humans have altered the rest of nature to meet our growing population’s resource needs and wants. Questions: Which three of these items do you believe have been the most harmful? Explain. How does your lifestyle contribute directly or indirectly to each of these three items?
Concept 6-2A Population size increases because of births and immigration and decreases through deaths and emigration.
Concept 6-2B The average number of children born to women in a population (total fertility rate) is the key factor that determines population size.
Figure 6.3Global connections: the world’s 10 most populous countries in 2008, with projections of their population sizes in 2025. (Data from World Bank and Population Reference Bureau)
Another measurement used in population studies is fertility rate—the number of children born to a woman during her lifetime.
Two types of fertility rates affect a countries population size and growth rate.
Figure 6.4Total fertility rates for the United States between 1917 and 2008. Question: The U.S. fertility rate has declined and remained at or below replacement levels since 1972, so why is the population of the United States still increasing? (Data from Population Reference Bureau and U.S. Census Bureau)
Figure 6.5Birth rates in the United States, 1910–2008. Use this figure to trace changes in crude birth rates during your lifetime. (Data from U.S. Bureau of Census and U.S. Commerce Department)
Figure 6.6Some major changes that took place in the United States between 1900 and 2000. Question: Which two of these changes do you think were the most important? (Data from U.S. Census Bureau and Department of Commerce)
See p. 127, 2nd to last paragraph for other changes.
Children as part of the labor force
Cost of raising and educating children
Availability of private and public pension
Educational and employment opportunities for women
Infant mortality rate – the number of children per 1000 live births who die before one year of age.
Average age of a woman at birth of first child
Availability of legal abortions
Availability of reliable birth control methods
Religious beliefs, traditions, and cultural norms
Figure 6.7Legal immigration to the United States, 1820–2003 (the last year for which data are available). The large increase in immigration since 1989 resulted mostly from the Immigration Reform and Control Act of 1986, which granted legal status to illegal immigrants who could show they had been living in the country for several years. (Data from U.S. Immigration and Naturalization Service and the Pew Hispanic Center)
Concept 6-3 The numbers of males and females in young, middle, and older age groups determine how fast a population grows or declines.
Figure 6.8Generalized population age structure diagrams for countries with rapid (1.5–3%), slow (0.3–1.4%), zero (0–0.2%), and negative (declining) population growth rates. A population with a large proportion of its people in the prereproductive age group (far left) has a large potential for rapid population growth. Question: Which of these figures best represents the country where you live? (Data from Population Reference Bureau)
Figure 6.9Global outlook: population structure by age and sex in developing countries and developed countries, 2006. Question: If all girls under 15 had only one child during their lifetimes, how do you think these structures would change over time? (Data from United Nations Population Division and Population Reference Bureau)
Concept 6-4 Experience indicates that the most effective ways to slow human population growth are to encourage family planning, to reduce poverty, and to elevate the status of women.
Figure 6.12Four stages of the demographic transition, which the population of a country can experience when it becomes industrialized. There is uncertainty about whether this model will apply to some of today’s developing countries. Question: At what stage is the country where you live?
Figure 6.13Women from a village in the West African country of Burkina Faso returning with fuelwood. Typically they spend 2 hours a day two or three times a week searching for and hauling fuelwood.