1. Chapter 5 Populations

2. Biotic Potential: The size a population would reach if all offspring were to survive and reproduce

3. Conditions have to be ideal- enough food and living space

4. Population Density- Number of individuals in an area
What Determines density and distribution?

6. Geographic Distribution- range- the area the population inhabits

7. Population Growth Affected by -Birth rate (natality)
-Death rate (mortality)
-Immigration- entering an area
-Emigration- leaving an area

8. Populations increase if births exceed deaths and immigration exceeds emigration

9. Exponential Growth
Exponential Growth occurs when the individuals in a population increase at a constant rate
Look at graph on p.121

10. -under ideal conditions
-population grows slowly at first
-rises to an infinitely large size
-J-shaped curve

12. Logistic Growth
Logistic growth occurs when a population’s growth slows or stops following a period of exponential growth.
S-shaped curve-graph levels off

13. Carrying capacity- Usually population fluctuates around this point- s-shape
Look at graph on p. 122

15. Carrying Capacity
The number of individuals an area can support without ruining the area.

16. Limiting Factors Something that causes population growth to decrease
Density dependent
Density independent

17. Density- Dependent Factors
Limit a population when the number of individuals reach a certain level
Competition for food, water, space, sunlight, etc.

18. Predation
Parasitism + disease

19. Wolf/Moose graph

20. Density -Independent Factors
Affect all populations regardless of size
Weather, natural disasters, seasonal change, human interventions (dams,logging, housing developments)

21. Populations usually decrease dramatically after such an event
Can be permanent + cause extinction

22. Human Population Growth
Slow growth historically
Now, exponential growth- 6-7 billion

23. Some countries have higher growth rates than others

24. Demographic Transition
Dramatic change in birth and death rates
Nutrition, medicine, clean water supplies increase survival rates

25. Some countries, population stabilizes, but for a while, births may exceed deaths

26. Age diagram

27. In some cases, populations may even decrease- U.S., Japan, Europe

28. Some countries are still growing exponentially
Parts of Africa, Mexico, India

29. Many young people, of an age where they will still be having children

30. 9 billion predicted by 2050
What will stop/slow the growth?