1. The Human Population and Its Impact

2. Core Case Study: Planet Earth: Population 7 Billion
The evolution of Homo sapiens and a total population of 2 billion has taken 200,000 years
It has taken less than 50 years to reach the second 2 billion
It took 25 years to add the third 2 billion
Twelve years later, the population topped 7.1 billion

3. Human Population Growth Shows Certain Trends
Red =
Blue = projected
Rate of population growth has slowed in recent decades
Human population growth is unevenly distributed geographically
People are moving from rural to urban areas

4. The Human Population Can Grow, Decline, or Remain Fairly Stable
Population change =
(births + immigration) – (deaths + emigration)
Crude birth rate
The number of live births/1000/year
Crude death rate
The number of deaths/1000/year

5. Women Are Having Fewer Babies, But the World’s Population Is Still Growing
Fertility rate
Number of children born to a woman during her lifetime
Replacement-level fertility rate
Average number of children a couple must have to replace themselves
Approximately 2.1 in developed countries
Up to 2.5 in developing countries

6. The World’s Population Is Still Growing
Total fertility rate (TFR)
Average number of children born to women in a population
Between 1955 and 2012, the global TFR dropped from 5 to 2.4
However, to eventually halt population growth, the global TFR will have to drop to 2.1

7. Case Study: The U.S. Population – Third Largest and Growing
Population still growing and not leveling off
76 million in 1900
314 million by 2012
Drop in TFR in U.S.
Rate of population growth has slowed

8. Case Study: The U.S. Population – Third Largest and Growing
Immigration
U.S. has admitted almost twice as many immigrants and refugees as all other countries combined

9. Several Factors Affect Birth Rates and Fertility Rates
Average age of a woman at marriage
Availability of legal abortions
Availability of reliable birth control methods
Religious beliefs, traditions, and cultural norms
Children as part of the labor force
Cost of raising and educating children
Availability of private and public pension
Urbanization
Educational and employment opportunities for women

10. Several Factors Affect Death Rates
Life expectancy
Infant mortality rate
Number of live births that die in first year
High infant mortality rate indicates:
Insufficient food
Poor nutrition
High incidence of infectious disease

11. Migration Affects an Area’s Population Size
The movement of people into and out of specific geographic areas
Causes:
Economic improvement
Religious and political freedom
Wars
Environmental refugees

12. A Population’s Age Structure Helps Us Make Projections
Age structure categories
Prereproductive ages (0-14)
Reproductive ages (15-44)
Postreproductive ages (45 and older)
Seniors are the fastest-growing age group
The numbers of males and females in young, middle, and older age groups determine how fast a population grows or declines

13. A Population’s Age Structure Helps Us Make Projections
Male
Female
Male
Female
Male
Female
Male
Female
Animated Figure 6-11 Generalized 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. Question: Which of these diagrams best represents the country where you live?
Expanding Rapidly Guatemala Nigeria Saudi Arabia
Expanding Slowly United States Australia China
Stable Japan Italy Greece
Declining Germany Bulgaria Russia
Prereproductive ages 0–14
Reproductive ages 15–44
Postreproductive ages 45–85+
Fig. 6-11, p. 131

14. Case Study: The American Baby Boom
79 million people added from
36% of adults
Affect politics and economics
Now becoming senior citizens
Graying of America

15. Populations Made Up of Mostly Older People Can Decline Rapidly
Slow decline
Manageable
Rapid decline
Economic problems
Proportionally fewer young people working
Labor shortages

16. Populations Can Decline due to a Rising Death Rate: The AIDS Tragedy
AIDS has killed more than 30 million people
Many young adults die – loss of most productive workers
Sharp drop in life expectancy
International community
Reduce the spread of HIV through education and health care
Financial assistance and volunteers

17. The First Step Is to Promote Economic Development
Demographic transition
As countries become industrialized
First death rates decline
Then birth rates decline
Four stages
Preindustrial
Transitional
Industrial
Postindustrial

18. Empowering Women Can Slow Population Growth
Factors that decrease total fertility rates:
Education
Paying jobs
Ability to control fertility
Women:
Do most of the domestic work and child care
Provide unpaid health care
2/3 of all work for 10% of world’s income
Discriminated against legally and culturally

19. Family Planning Can Provide Several Benefits
Family planning in less-developed countries
Responsible for a 55% drop in TFRs
Financial benefits – money spent on family planning saves far more in health, education costs
Two problems
42% pregnancies unplanned, 26% end with abortion
Many couples do not have access to family planning

20. Case Study: Slowing Population Growth in India
Population: 1.26 billion people in 2012
Problems
Poverty, malnutrition, and environmental degradation
Causes
Bias toward having male children
Poor couples want many children
Only 47% of couples use family planning

21. Case Study: Slowing Population Growth in China: A Success Story
World’s most populous country
Threat of mass starvation in the 1960s
Government established a strict family planning and birth control program
Reduced number of children born per woman from 5.7 to 1.5
Having boys was prioritized: led to skewed gender ratio
Policy was eased in 2013: families were allowed to apply to have a second child
October 2015: policy is officially modified
Families allowed to have 2 children