1. Chapter 8
Population Change

2. 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

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

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

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

6. 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

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

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

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

10. 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

11. Reproductive Strategies
Survivorship

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

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

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

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

16. The Human Population
Human population size

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

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

19. Demographics of Countries
Most Populous Countries
Insert Table 8.1

20. Demographic Transition Model
As countries become industrialized, first death rates drop, then birth rates drop

21. Demographics of Countries
Demographic Stages

22. Demographics of Countries
Age Structure of Countries
Generalized Age Structure

23. Demographics of Countries
Examples:

24. Demographics of Countries
Examples:

25. Demographics of Countries
Examples:

26. Demographics of Countries
Population Under Age 15: