1. Human Population
What is the world population now?

2. Human Population Growth
Industrial
Revolution
begins
Agriculture
begins
Bubonic
plague
Plowing
and
irrigation

3. World Population Growth Through History
Billions 12 11
2100 10 9
Modern
Age 8
Old
Stone
Bronze
Iron
Middle 7
Age
New Stone Age
Age
Age
Ages 6
2000
Future 5 4
1975 3
1950 2
1900 1
Black Death —
The Plague
1800
1+ million
7000
6000
5000
4000
3000
2000
1000
A.D.
A.D.
A.D.
A.D.
A.D.
A.D.
years
B.C.
B.C.
B.C.
B.C.
B.C.
B.C.
B.C. 1
1000
2000
3000
4000
5000
Source: Population Reference Bureau; and United Nations, World Population Projections to 2100 (1998).

4. Growth in More, Less Developed Countries
Billions
Less Developed Regions
More Developed Regions
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

5. World Population Clock
2005
Natural Increase per
World
More Developed Countries
Less Developed Countries
Less Developed Countries (less China)
Year
80,794,218
1,234,907
79,559,311
71,906,587
Day
221,354
3,383
217,971
197,004
Minute
154 2
151
137
Source: Population Reference Bureau, 2005 World Population Data Sheet.

6. Projected Population Change, by Country
Percent Population Change,
Women worldwide are having fewer children in their lifetimes, from an average of five children born per woman in the 1950s to below three in 2000.
All of the most recent projections put forth by the UN assume that levels of childbearing will continue to decline in the next century.
Source: Population Reference Bureau, 2005 World Population Data Sheet.

7. The Classic Stages of Demographic Transition
Women worldwide are having fewer children in their lifetimes, from an average of five children born per woman in the 1950s to below three in 2000.
All of the most recent projections put forth by the UN assume that levels of childbearing will continue to decline in the next century.
Note: Natural increase is produced from the excess of births over deaths.

8. Birth and Death Rates, Worldwide
Rates of birth, death, and natural increase per 1,000 population
Natural Increase
Birth rates and death rates are declining around the world. Overall economic development, public health programs, and improvements in food production and distribution, water, and sanitation have led to dramatic declines in death rates. And women now have fewer children than they did in the 1950s.
Nevertheless, if death rates are lower than birth rates, populations will still grow.
Also, it is possible for absolute numbers of births to increase even when birth rates decline.
Source: United Nations, World Population Prospects: The 2004 Revision, 2005.

9. Trends in Life Expectancy, by Region
Life Expectancy at Birth, in Years
In , infants born around the world can expect to live an average of 75 years — up ten years from today.
Africa will experience the largest increase in life expectancy: from 49 years to 65 years.
Life expectancy varies widely by region. In more developed countries, life expectancy averages 76 years, compared with only 49 years in Africa.
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

10. Women of Childbearing Age and Fertility
Worldwide
The number of women in their childbearing years has increased since the 1950s and is projected to continue to increase to 2050.
The number of children per woman has declined since the 1950s and is projected to continue to decline.
Even though women have on average fewer children than their mothers, the absolute number of babies being born continues to increase because of the increases in the total number of women of childbearing age.
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

11. Trends in Aging, by World Region
Population Ages 65 and Older
Percent
By 2025, over 20 percent of the population in more developed regions will be ages 65 and older.
By 2025, one-tenth of the world’s population will be over age 65.
Asia will see the proportion of its elderly population almost double, from about 6 percent in 2000 to 10 percent in In absolute terms, this represents a stark increase in just 25 years: from about 216 million to about 480 million older people.
Aging pop clock: PRB
Source: United Nations, World Population Prospects: The 2004 Revision (medium scenario), 2005.

12. Age Distribution of the World’s Population
Population Structures by Age and Sex, 2005
Millions
Less Developed Regions
More Developed Regions
Age
0-4
Male
Female
Male
Female
Sex and age distributions show that less developed countries have significantly younger populations than more developed countries.
Almost one-third of the population in less developed countries is under age 15. In contrast, less than one-fifth of the population in more developed countries is under 15.
Today there are more than 2 billion young people below age 20 in less developed regions—the age cohort that will soon become the world’s newest group of parents.
Young age structures in the less developed countries are due mainly to higher levels of childbearing in recent decades.
Current data
Source: United Nations, World Population Prospects: The 2004 Revision, 2005.

13. Age Distribution U.S. Population Rwandan Population Males Females

14. Human Impact

15. Resources
Renewable
Non-renewable
Sustainable practices

16. Formation of Acid Rain
Emissions from burning fossil fuels mix with water vapor in atmosphere to form acids.
Chemical Transformation
Nitric acid
Sulfuric acid
Condensation
Emissions to Atmosphere
Nitrogen oxides
Sulfur dioxide
Precipitation
Acid rain, fog, snow, and mist
Dry Fallout
Particulates
Gases
Acid rain results from the chemical transformation of nitrogen and sulfur products that come from human activities.
Industry
Transportation
Ore smelting
Power generation

17. pH
Measures acidity

18. How does acid rain affect leaves?
Vinegar is an acid:
pH = 2.2
How will vinegar affect:
An eggshell?
A leaf?
A paperclip?
Write a hypothesis.
Experimental setup
Eggshell, leaf and paperclip in vinegar in sealed container
Control setup
Eggshell, leaf and paperclip in water in sealed container
Wait 24 hours to observe results.

19. Ozone Depletion
CFCs – chlorofluorcarbons from spray cans and refrigerants depletes the ozone layer
Ozone Hole over Antarctica Dec 25, 2008
(NASA Ozone Hole Watch)

20. Greenhouse Effect  Global Warming
Greenhouse effect: greenhouse gases (carbon dioxide, etc.) keep heat in the atmosphere
Global warming: increase in average temperature on Earth
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s surface

21. Invasive species
Non-native species introduced into a habitat that out-compete native species for resources
Hydrilla
Japanese Honeysuckle

22. Biological Magnification
Magnification of
DDT Concentration
Fish-Eating Birds
10,000,000
Large
Fish
1,000,000
100,000
Small Fish
10,000
Zooplankton
1000
Producers
Water 1

23. Mercury Bioaccumulation
Mercury released from power plants and incinerators.
Absorbed by organisms in the water
Concentration increases as it is passed up the food chain.
Damages nervous systems and impairs reproductive health
Graphic from National Wildlife Federation

24. How does acid rain affect leaves?
Observe experiment.
Record observations: water & vinegar
Write conclusion:
Restate the question
Explain what you did
Results: state the results, including whether or not your hypothesis was correct
Uncertainties: Give reasons for any potential errors
New information: What did you learn from this?

25. Question
How is global warming related to the carbon cycle?.

26. Carbon Cycle CO2 in Atmosphere CO2 in Ocean Carbonate Rocks
Photosynthesis
Volcanic activity
feeding
Respiration
Erosion
Human activity
Respiration
Decomposition
CO2 in Ocean
Uplift
Carbon is found in several large reservoirs in the biosphere. In the atmosphere, it is found as carbon dioxide gas; in the oceans as dissolved carbon dioxide; on land in organisms, rocks, and soil; and underground as coal, petroleum, and calcium carbonate rock. 
Deposition
Photosynthesis
feeding
Fossil fuel
Deposition
Carbonate Rocks

27. Capturing Carbon PBS NOVA Science Now 7/2/2008

28. Senegal Former French colony in West Africa Stable democracy
Point of departure during slave trade era
Link to YouTube video

29. Senegal
Discuss factors that may influence population growth in Senegal.

30. Senegal
We will construct and compare age structure graphs for Senegal and the United States.

31. Senegal vs. United States
Compare and contrast the shapes of the two pyramids.
What inferences can be drawn about social and economic circumstances in each country?
What may be some reasons for differences in the two pyramids?