Bell Reading

Read for understanding the case studies at the end of the textbook on page S 46 and S 48

The Human Population and Its Impact

Chapter 8

Crowded Street in China

Exponential growth in a savings account

0 $1000 10 $1629 20 $2653 40 $7040 60 $18,779 80 $45,561

4

The power of exponential growth. IIUnder ideal conditions, some bacteria can

divide and double their numbers in about 20 min. How many hours would it take for a population of bacteria to reach 4096 in a person with an inner ear infection?

No calculators.

Sex ratios

57% of college students are female!

5 MAJOR RECODED EXTINTION EPISODES

The K-T mass extinction

Global Connections: The World’s 10 Most Populous Countries in 2008

Human Population Growth Continues but It Is Unevenly Distributed (1)

Reasons for human population increase• Movement into new habitats and climate zones• Early and modern agriculture methods• Control of infectious diseases through• Sanitation systems• Antibiotics• Vaccines (Small pox virus)

Amniocentesis

Consider this

• In 1905 the three leading causes of death in the United States were pneumonia, tuberculosis and diarrhea.

• 90% of US doctors had NO college education

• Cocaine was sold over the counter until 1914

• X rays were first discovered 1899

Some Major Changes That Took Place in the U.S. between 1900 and 2000

TFR Rates for the U.S. between 1917 and 2008

Science Focus: How Long Can the Human Population Keep Growing?

Thomas Malthus and population growth: 1798

Humans have altered 83% of the earth’s land surface

Can the human population grow indefinitely?

The Human Population Can Grow, Decline, or Remain Fairly Stable

Population change• Births or (natality): fertility• Deaths: mortality• Migration

Population change =

(births + immigration) – (deaths + emigration) Crude birth rate- the number of live

births/1000 in a given year. Crude death rate- the number of deaths per

1000 in a given year

Several Factors Affect Death Rates (1)

Life expectancy-average number of years a newborn infant can expect to live.

Infant mortality rate – the number of babies out of every 1000 that die before their first birthday

Women Having Fewer Babies but Not Few Enough to Stabilize the World’s Population

Fertility rate • Replacement-level fertility rate- the number of

children a couple must bear to replace themselves. Du huh???????

• Total fertility rate (TFR)- the number of children a woman has during her reproductive years World wide in 1950-6.5 2001-2.5

Birth Rates in the U.S. from 1910 to 2008

1

A population has 28 births and 8 deaths per 1000 in a given year. How fast is that population growing or shrinking?

2

• How many more times stronger is a earthquake of 6 than a earthquake of 4?

3

• A population of 10 million is growing at 3.5% per year. How many years will it take to reach 20 million?

4 pH

• . How many more times acidic is a pH of 3 than a pH of 5?

• . Tell whether the below would be parasitism, commensalism or mutualism

• 5 _________________ tick and a dog• 6 _______________ shark and remora fish• 7 ________________ lichens (algae and fungi)• 8 ________________ mistletoe and oak trees• 9 ________________ whales and barnacles

10.Which group has the highest species diversity?

Answer Choices A, or B or Both are the same or Neither

Spp1

Spp 2

Spp 3

Spp 4

Spp 5

Comm

A

10 10 10 10 10

Comm

B

46 1 1 1 1

Multiple Choice

12. In an energy pyramid, the lowest level has:

a. less energy than the top level

b. less energy than the second level

c. more energy than the top level

d. the same amount of energy as the second level

13

• Which term applies to the average number of babies a woman in a particular demographic grouping would have in her lifetime?

• A. Replacement level fertility

• B. Infant fertility rate

• C. Total Fertility Rate

• D. Total Natility rate

14-17

• Cite four (4) scientific principles of sustainability. You have three minutes with the book.

2. Czech Republic

• In 2007 the Czech republic had a crude birth rate of 19.6 and a crude death rate of 10.6. What is the annual rate of change?

Fig. 6-5, p. 127

3230

28262422

201816 End of World War II

14 Depression Baby boom Baby bust Echo baby boomDemographic

transition

Bir

ths

pe

r th

ou

sa

nd

po

pu

lati

on

0

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Year

Why are people living longer and fewer infants dying?Increased food supply and distributionBetter nutritionMedical advancesImproved sanitation

Migration Affects an Area’s Population Size

Economic improvement

Religious freedom

Political freedom

Wars

Environmental refugees

Case Study: The United States: A Nation of Immigrants

Historical role of immigration in the U.S.

Legal immigration

Illegal immigration

Legal Immigration to the U.S. between 1820 and 2003

Fig. 6-7, p. 129

2,000

1,800

1,600

19071,400

1914 New laws restrict immigration

1,200

1,000

800Great Depression600

400

Nu

mb

er o

f le

gal

im

mig

ran

ts (

tho

usa

nd

s)

200

Year

0

20102000198019601940192019001880186018401820

6-3 How Does a Population’s Age Structure Affect Its Growth or Decline?

Concept 6-3 The numbers of males and females in young, middle, and older age groups determine how fast a population grows or declines.

Populations Made Up Mostly of Young People Can Grow Rapidly

Age structure categories• Prereproductive ages• Reproductive ages• Postreproductive ages

Generalized Population Age Structure Diagrams

Fig. 6-8, p. 131

Male Female Male Female Male Female Male Female

Expanding Rapidly Guatemala

Nigeria Saudi Arabia

Expanding Slowly United States

Australia China

Stable Japan Italy

Greece

Declining GermanyBulgaria Russia

Prereproductive ages 0–14

Reproductive ages 15–44

Postreproductive ages 45–85+

Population Structure by Age and Sex in Developing and Developed Countries

Fig. 6-9a, p. 131

Fig. 6-9a, p. 131

Developed Countries

80–8585+

75–7970–74 Male Female

60–6465–69

55–5950–5445–49

35–39Ag

e 40–44

25–2930–34

20–24

10–1415–19

5–90–4

300 200 100 0 100 200 300

Population (millions)

Fig. 6-9b, p. 131

Fig. 6-9b, p. 131

Developing Countries

80–8585+

75–7970–74

Male Female

60–6465–69

55–5950–5445–49

35–39Ag

e 40–44

25–2930–34

20–24

10–1415–19

5–90–4

300 200 100 0 100 200 300

Population (millions)

Tracking the Baby-Boom Generation in the United States

Some Problems with Rapid Population Decline

4 principles of sustainability

Nutrient recycling Reliance on solar energy Population control* ----family planning Biodiversity

READ CASE STUDY ON CHINA ON PAGE 187

• A population of pansies increases by 12% every year. Calculate the doubling time for this population.

• As of 1995, the human population was expected to double within 50 years. Calculate (r) or the percent rate of change for the population.

• In your research of the dynamics of June beetles count the population size at 1000. Over the course of a month you record 40 births and 20 deaths. What is the % rate (r) increase in the population.

Solutions for reducing human population growth

r

Increased improved family planning. RESULT: fewer pregnancies/control of fertility/ choice in the number of children born.

Increased education and improved social status of women. RESULT: Delay having children and choosing to have fewer children.

More women enter the workforce. RESULT: delay having children.

Reduced need for children in the workforce such as agriculture (farming)

RESULT: Increase urbanization and more industrialization.

Human activities are having an impact on the Earth’s biodiversity.

Deforestation for farming, housing, fuel, mining RESULTS in destruction of habitats and reduced biodiversity,

Fossil-fuel burning releases carbon dioxide. RESULTS: altering global temperature and precipitation patterns

Diversion of water for irrigation, municipal and industrial use. RESULT: reduces water supply for freshwater organisms.

Pollution: _______________ RESULT can have have a – impact on biodiversity.

6-4 How Can We Slow Human Population Growth?

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.

Women from a Village in Burkina Faso Returning with Fuelwood

As Countries Develop, Their Populations Tend to Grow More Slowly

Demographic transition stages • Preindustrial• Transitional• May lead to a demographic trap

• Industrial• Postindustrial

Four Stages of the Demographic Transition

Planning for Babies Works

Family Planning• Responsible for a 55% drop in TFRs• In developing countries• Expansion of program• Include teenagers, sexually active unmarried

women, and men

Slow and stabilize population growth• Invest in family planning• Reduce poverty• Elevate the social and economic status of women

Empowering Women Can Slow Population Growth

Education

Paying jobs

Human rights without suppression

“For poor women the only holiday is when you are asleep”

Case Study: Slowing Population Growth in China: the One-Child Policy

Encourages fewer children

Gender imbalance

Fast-growing economy

Face serious resource and environmental problems