1. Chapter 8
Population Change

2. Principles of Population Ecology
Population ecologists ask:
1) How many are in the population?
2) Are its numbers increasing / decreasing?
3) What is its pattern of reproduction?
4) What is its pattern of mortality?

3. Principles of Population Ecology
Population Density:
Not enough to know just how many.
Need to know per unit area.
20 / 100 m2
20 / 25 m2

4. Principles of Population Ecology
How Do Populations Change in Size?
On a global scale (closed system):

5. Principles of Population Ecology
How Do Populations Change in Size?
On a local scale (open system):

6. Principles of Population Ecology
How Do Populations Change in Size?
Global scale:
Death rate
Growth rate
r = b – d
Birth rate

7. Principles of Population Ecology
How Do Populations Change in Size?
Local scale:
Death rate
Growth rate
Emigration rate
r = (b – d) + (i – e)
Birth rate
Immigration rate

8. Principles of Population Ecology
Maximum Population Growth-
under ideal conditions = intrinsic rate of increase
J-shaped curve (exponential growth)

9. Principles of Population Ecology
Environmental Resistance-
Exponential growth cannot occur forever.
What factors prevent it from doing so?
S-shaped curve (logistic growth)

10. Principles of Population Ecology
Overshooting the carrying capacity can lead to a population crash.

11. Reproductive Strategies
Life History Strategies
r-selected
K-selected
vs.
high growth rate
slow growth rate
small body size
large body size
early maturity
late maturity
short life span
long life span
large broods
small broods
little / no parental care
high parental care

12. Reproductive Strategies
Survivorship

13. Factors that Affect Population Size
Density-Dependent Factors-
Factors that influence population growth when its density is high.
Predation, competition, disease.

14. Factors that Affect Population Size
Density-Dependence and Boom-or-Bust Population Cycles

15. Factors that Affect Population Size
Case-in-Point: Predatory Prey Dynamics on Isle Royale

16. Factors that Affect Population Size
Density-Independent Factors-
Regardless of population density, influences population growth.
Weather, fire.

17. The Human Population
Human population size

18. The Human Population Current Population Numbers In 2004 = ~6.4 billion
Check out:

19. The Human Population Current Population Numbers
Rapid growth primarily due to drop in death rates

20. The Human Population Projecting Future Population Numbers
When will zero population growth occur?

21. Demographics of Countries
Most Populous Countries
Insert Table 8.1

22. Demographics of Countries
Developed vs. Developing Countries Demographics
Insert Table 8.2 (note reconstruction)

23. Demographics of Countries
Developed vs. Developing Countries Demographics
Insert Table 8.2 (note reconstruction)

24. Demographics of Countries
Demographic Stages

25. Demographics of Countries
Age Structure of Countries
Generalized Age Structure

26. Demographics of Countries
Examples:

27. Demographics of Countries
Examples:

28. Demographics of Countries
Examples:

29. Demographics of Countries
Population Under Age 15:

30. Demographics of the US
Case-in-Point: US Immigration