1. (environmental resistance)
POPULATION SIZE
Growth factors
(biotic potential)
Favorable light
Favorable temperature
Favorable chemical environment
(optimal level of critical nutrients)
Abiotic
Biotic
High reproductive rate
Generalized niche
Adequate food supply
Suitable habitat
Ability to compete for resources
Ability to hide from or defend
against predators
Ability to resist diseases and parasites
Ability to migrate and live in other
habitats
Ability to adapt to environmental
change
Decrease factors
(environmental resistance)
Too much or too little light
Temperature too high or too low
Unfavorable chemical environment
(too much or too little of critical
nutrients)
Low reproductive rate
Specialized niche
Inadequate food supply
Unsuitable or destroyed habitat
Too many competitors
Insufficient ability to hide from or defend
Inability to resist diseases and parasites
Inability to migrate and live in other
Inability to adapt to environmental
© 2004 Brooks/Cole – Thomson Learning

2. Population Dispersion Factors
(a) Clumped (elephants)
(b) Uniform (creosote bush)
(c) Random (dandelions)
Population Dispersion Factors

3. Environmental resistance
Figure 9-4 Page 166
Environmental resistance
Carrying capacity (K)
Population size (N)
Biotic
potential
Exponential
growth
Time (t)

4. Number of sheep (millions)
2.0
Overshoot
Carrying capacity
1.5
Number of sheep (millions)
1.0 .5
1800
1825
1850
1875
1900
1925
Year

5. Population
overshoots
carrying
capacity
2,000
Population crashes
1,500
Number of reindeer
1,000
Carrying
capacity
500
1910
1920
1930
1940
1950
Year

6. © 2004 Brooks/Cole – Thomson Learning
(d) Irregular
(a) Stable
Number of individuals
(c) Cyclic
(b) Irruptive
Time

7. Population size (thousands)
160
Hare
140
Lynx
120
100
Population size (thousands) 80 60 40 20
1845
1855
1865
1875
1885
1895
1905
1915
1925
1935
Year

8. Reproductive Patterns and Survival
Asexual reproduction
r-selected species
Sexual reproduction
K-selected species
Fig p. 170

9. Carrying capacity K
K species;
experience
K selection
Number of individuals
r species;
experience
r selection
Time

10. Percentage surviving (log scale) Types of Survivorship Curves
Figure 9-11 Page 171
Late loss
100
Constant loss 10
Percentage surviving (log scale) 1
Early loss
Age
Types of Survivorship Curves

11. Exponential and Logistic Growth

12. World 21 9 All developed countries 11 10 All developing countries 24 8
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

13. Factors Affecting Human Population Size
Population change equation
Population
Change =
(Births + Immigration) – (Deaths + Emigration)
Crude birth rate (BR)
Crude death rate (DR)
Refer to Figure 10-3, p. 177

14. Describing Population Changes
Doubling Times
“Rule of 70”
Fertility
Replacement-level Fertility
Total Fertility Rate (TFR)

15. © 2004 Brooks/Cole – Thomson Learning
Africa 38
Figure 10-3b Page 177 14
Latin
America 22
© 2004 Brooks/Cole – Thomson Learning 6
Asia 20 7
Oceania 18 7
United
States 14 8
North
America 14 8
Europe 10 12

16. © 2004 Brooks/Cole – Thomson Learning
China
© 2004 Brooks/Cole – Thomson Learning
1.3 billion
Figure 10-4 Page 178
1.4 billion
India
1.1 billion
1.4 billion
USA
294 million
349 million
Indonesia
219 million
308 million
Brazil
179 million
211 million
Pakistan
159 million
229 million
Russia
144 million
137 million
Bangladesh
141 million
205 million
Japan
128 million
121 million
Nigeria
137 million
206 million
2004
2025

17. Population Age Structure
Rapid Growth
Guatemala
Nigeria
Saudi Arabia
Slow Growth
United States
Australia
Canada
Male
Female
Zero Growth
Spain
Austria
Greece
Negative Growth
Germany
Bulgaria
Sweden

18. © 2004 Brooks/Cole – Thomson Learning
Figure 10-14b Page 184
Male
Female
Male
Female
Zero Growth
Spain
Austria
Greece
Negative Growth
Germany
Bulgaria
Sweden
Ages 0-14
Ages 15-44
Ages
© 2004 Brooks/Cole – Thomson Learning

19. Iraq Population Pyramids
Population Pyramid Summary for Iraq
                                                                                                                                                                                                                                                                                     

20. Italy Population Pyramids
Population Pyramid Summary for Italy
                                                                                                                                                                                                                                                                                     

21. Somalia Population Pyramids

22. © 2004 Brooks/Cole – Thomson Learning
Age
Age
Figure 10-18a Page 186
Females
Males
Females
Males 24 20 20 16 16 12 12 8
1955 8
1985 4 4 4 4 8 8 12 12 16
Millions 16 20
Millions 20 24
© 2004 Brooks/Cole – Thomson Learning

23. © 2004 Brooks/Cole – Thomson Learning
Age
Age
Figure 10-18b Page 186
Females
Males
Females
Males 20 20 20 20 16 16 12 12 8 8
1955 4
2035 4 4 4 8 8 12 12 16 16 20 20
Millions 24
Millions 24
© 2004 Brooks/Cole – Thomson Learning

24. Relative population size Birth rate and death rate
Figure Page 189
Stage 1
Preindustrial
Stage 2
Transitional
Stage 3
Industrial
Stage 4
Postindustrial
Low
High
Relative population size
(number per 1,000 per year)
Birth rate and death rate 80 70 60 50 40 30 20 10
Birth rate
Death rate
Total population
Low
Increasing
Very high
Decreasing
Low
Zero
Negative
Growth rate over time