Download Human Population Growth

Human
Population
Growth
Environmental
Science
NSC 22304
Video: World Population
http://www.populationconnection.org
Graph Human Population Growth
N (billions)
9
8
7
2011
6
1999
5
4
1975
3
Black Death
2
1930
1850
1
0
8000
B.C.
6000
B.C.
4000
B.C.
Time
2000
B.C.
1000 2000
A.D. A.D.
Current Population Size
http://www.populationconnection.org
7,065,101,298
9/13/2012 4:00 PM EDT
Activity
• Observations
• Questions
• Hypotheses
5
Observations
• Less than 1 billion for most of history
• Rapid growth in last 160 years
• 1 billion 1830, 2 billion 1930, 4 billion
1975, 6 billion 1999
• Black plague caused dip 1300’s-1400’s
• More populated on coast
• Asia and India have majority of
population
6
Black Death
also called black plague, bubonic plague
caused by bacteria (Yersinia pestis)
spread by fleas on rats
main symptom is buboes - swellings
Questions
•
•
•
•
Why the rapid growth since 1900?
What will happen in future?
What is the carrying capacity?
Is high growth a problem?
8
Hypotheses/Predictions
• Population will level off
• Population will crash
• Advances in medicine/sanitation
decreased death rates
9
Information
• Prior to early 1800’s, diseases such as
smallpox, diptheria, measles, scarlet
fever were prevalent. High birth rates
(7-10 children) but high death rates
• 1800’s - learned that diseases were
caused by microbes and transmitted by
sewage, rats, insects - increased
sanitation reduced mortality
• 1930’s antibiotics
• 1850’s vaccines
10