Chapter 9

Applying Population Ecology:The Human Population and

Its Impact

Is the World Overpopulated?

• Much of the world’s population growth occurs in developing countries like China and India. The world’s population is projected to increase from 6.6 billion to 8.9 billion between 2006 and 2050. Figure 9-1Figure 9-1

HUMAN POPULATION GROWTH:

A BRIEF HISTORY• The human population has grown rapidly

because of the expansion of agriculture and industrial production and lower death rates from improvements in hygiene and medicine.– In 2006, the population of developed countries

grew exponentially at 0.1% per year. – Developing countries grew (15 times faster at

1.5% per year.

Demographic Facts:The nations that will

experience the most growth over the next 50 years , in order:

1. India

2. China

3. Pakistan

4. Nigeria

5. Bangladesh

6. Indonesia

5 most populated countries, in order: (2004)

1. China

2. India

3. U.S.

4. Indonesia

5. Brazil

Where Are We Headed?

• U.N. world population projection based on women having an average of 2.5 (high), 2.0 (medium), or 1.5 (low) children.

Figure 9-2Figure 9-2

Declining Fertility Rates: Fewer Babies per Woman

• The average number of children that a woman bears has dropped sharply.

• This decline is not low enough to stabilize the world’s population in the near future.– Replacement-level fertility: the number of

children a couple must bear to replace themselves.

– Total fertility rate (TFR): the average number of children a woman has during her reproductive years.

Fertility Rates• The replacement level to

sustain a population is 2.1 children.

• In 2006, the average global Total Fertility Rate was 2.7 children per woman.– 1.6 in developed countries

(down from 2.5 in 1950).– 3.0 in developing countries

(down from 6.5 in 1950).

Fertility and Birth Rates in U.S.• Nearly 2.9 million people were added to the

U.S. in 2006:– 59% occurred because of births outnumbering

deaths.– 41% came from illegal and legal immigration.– total fertility rate in the United States was slightly

> 2.0

Fertility and Birth Rates in U.S.

• The baby bust that followed the baby boom was largely due to delayed marriage, contraception, and abortion.

Figure 9-6Figure 9-6

Fig. 9-7, p. 176

47 years

Homicides per100,000 people

Hourly manufacturing job wage (adjusted for inflation)

Living insuburbs

Homes withelectricity

Homes withflush toilets

High schoolgraduates

Married women workingoutside the home

Life expectancy

1.25.8

$15$3

52%10%

99%2%

98%10%

83%15%

81%

2000

1900

8%

77 years

1900 vs. 2000

Factors Affecting Birth Rates and Fertility Rates

• The number of children women have is affected by:– 1) The cost of raising and educating them.– 2) Availability of pensions.– 3) Urbanization.– 4) Education and employment opportunities (the

importance of child and/or woman as part of labor force).

– 5) Infant deaths.– 6) Marriage age.– 7) Availability of contraception and abortion.

Factors Affecting Death Rates

• Death rates have declined because of:– 1) Increased food supplies, better nutrition.– 2) Advances in medicine.– 3) Improved sanitation and personal hygiene.– 4) Safer water supplies.

• U.S. infant mortality is higher than it could be (ranked 46th world-wide) due to:– 1) Inadequate pre- and post-natal care for poor.– 2) Drug addiction.– 3) High teenage birth rate.

POPULATION AGE STRUCTURE

• Populations with a large proportion of its people in the preproductive ages (1-14) have a large potential for rapid population growth.

Figure 9-9Figure 9-9

POPULATION AGE STRUCTURE• 32% of the

people in developing countries were under 15 years old in 2006 versus only 17% in developed countries.

Figure 9-10Figure 9-10

POPULATION AGE STRUCTURE

• Today, baby boomers make up nearly half of all adult Americans and dominate the populations demand for goods and services.

Figure 9-11Figure 9-11

INFLUENCING POPULATION SIZE

• Demographic Transition: As countries become economically developed, their birth and death rates tend to decline.– Preindustrial stage: little population growth due to

high infant mortality.– Transitional stage: industrialization begins, death

rates drops and birth rates remain high.– Industrial stage: birth rate drops and approaches

death rate.– Post-industrial stage: birth rates continue to drop –

may enter negative population growth

Demographic Transition Model2

Transitional

1

Preindustrial

3

Industrial

4

Post- industrial

SOLUTIONS: INFLUENCING POPULATION SIZE

• Women tend to have fewer children if they are:– Educated.– Hold a paying job outside the home.– Do not have their human rights suppressed.

• The best way to slow population growth is a combination of:– Investing in family planning.– Reducing poverty.– Elevating the status of women.

GROWTH IN INDIA AND CHINA

• For more than five decades, India has tried to control its population growth with only modest success.

• Since 1970, China has used a government-enforced program to cut its birth rate in half and sharply reduce its fertility rate.

Fig. 9-15, p. 186

Total fertility rate

Percentageof world

populationPopulation

Population (2050)(estimated)

Illiteracy (% of adults)

Population under age 15 (%)

Population growth rate (%)

17%20%

1.1 billion1.3 billion

1.6 billion

IndiaChina

GDP PPP per capita

Percentage livingbelow $2 per day

Life expectancy

47%17%

36%20%

1.6%0.6%

1.4 billion

$5,890$3,120

4780

70 years62 years

2758

1.6 children per women (down from 5.7 in 1972)

Infant mortality rate

2.9 children per women (down from 5.3 in 1970)

India’s Failed Family Planning Program

• Poor planning.

• Bureaucratic inefficiency.

• Low status of women.

• Extreme poverty.

• Lack of administrative financial support.

• Disagreement over the best ways to slow population growth.

China’s Family Planning Program• Currently, China’s TFR is 1.6 children per

women.

• China has moved 300 million people out of poverty.

• Economic incentives, free medical care, & preferential treatment has helped.

• Problems:– Strong male preference leads to gender

imbalance.– Average population age is increasing.