Topic: How many humans can
Earth support?
http://www.census.gov/popclock/
http://www.worldometers.info/
Exponential GrowthWhen a population
increases by a fixed
percentage each
year.
Calculating Population Growth
Individuals added – Individuals subtracted
(birth rate – death rate)
per 1,000 people in a population in a given
year.
10 births – 8 deaths =
Increase of 2 in population.
Average crude birth rate
Average crude death rate
World
21
9
All developed
countries
11
10
All developing
countries
24
8
Developing
countries
(w/o China)
27
9
© 2004 Brooks/Cole – Thomson Learning
© 2004 Brooks/Cole – Thomson Learning
Africa
38
14
Latin
America
22
6
Asia
20
7
Oceania
18
7
United
States
14
8
North
America
14
8
Europe
10
12
Growth Rate as a %
Growth rate x 100%
Ex) 2/1000 X 100 = .2%
Human population growth rate Today:
World – 1.14%
US -.79%
(according to worldometers)
Growing Cities
USA Population
1900 = 76 million
2014 = 318 million
Suffolk County
1970 = 1.133 million
2013 = 1.499 million
http://www.census.gov/popclock/
Total Fertility Rate (TFR) – average number of
children a female will have
Global TFR (2012) = 2.47 children per woman.
Baby Boom Years
4.0
Births per woman
3.5
3.0
2.5
2.1
2.0
1.5
Baby boom
(1946-64)
1.0
Replacement
level
0.5
0
1920
1930
1940
1950
1960
1970
Year
1980
1990
2000
2010
USA TFR Changes
1957 (peak baby boom) TFR = 3.7
2014 TFR = 1.99
2013– 2.06
© 2004 Brooks/Cole – Thomson Learning
World
5 children per woman
2.8
Developed
countries
2.5
1.6
Developing
countries
6.5
3.1
Africa
6.6
5.1
Latin
America
5.9
2.6
Asia
5.9
2.6
Oceania
3.8
2.1
North
America
3.5
2.0
Europe
2.6
1.4
1950
2004
Carrying Capacity: the largest population an
environment can support.
Limiting Factors: environmental
characteristics that limit population growth.