1. Bellringer
List 3 reasons why a population might decrease in size

2. Population
Limiting Factor: A factor that causes population growth to decrease
2 Types:
1. Density-dependent: Factors that depend on the size of the population
Only become limiting when the population density becomes very high
Effects are intensified as the pop. Density increases
2. Density-independent: Factors that do not depend, or are independent, of the size of the population
Are limiting regardless of the size of the population
Affect all populations in similar ways

3. Limiting Factors

4. Deforestation Density-Independent Human activities
Deforestation; over-hunting/fishing
Effects are harmful on population regardless of size

5. Predation Density-Dependent Predation
The effect of predation intensifies as the population density of predators increases.

6. Disease Density-Dependent Disease
High population densities make the spread of disease easier to transmit

7. Natural Disasters Density-Independent Natural Disasters
Hurricane, tornado, flood, severe drought
Equally devastating to populations regardless of size

8. Competition Competition:
More members of a population = Less Available resources = More competition
Less members of a population = More available resources = Less competition

9. Parasitism Density-Dependent Parasitism
High densities make it easier for parasites to find hosts, and spread diseases

10. Severe frost Density-Independent Weather
Extremely hot/cold temperatures; frost
Adversely effects all populations regardless of their size.

11. Creative Writing
Each group will work together to develop the beginning of a story.
Introduce your characters, setting, problem (limiting factor), and size of population in that characters community
Pass your story to the next group
2. Each group will read the introduction of the their new story, and:
Explain how the characters are being affected by the problem introduced in Part 1 (what fears/concerns does this organism have for his/herself and his population
3. Each group will read their new story, and write its ending:
Explain what happened to the character and his/her population as a result of the problem; will they be doing anything to re-build their population?
Explain the impact this problem had on the overall population size?