1. Interactions in Ecosystems
Chapter 14

2. Every organism in the biosphere lives in a given habitat. The address
The conditions that must exist for it to live within it’s habitat is the niche.

3. Resource availability determines the structure of a community

4. Resource Partitioning
Increases Biodiversity

5. Competitive Exclusion Principle
Two living separately okay,
living together one will cause the other to go extinct

6. Species interactions defines the role and success of each organism within the biosphere

7. Predator Prey Interaction
What factors effect predator-prey relationships?

8. Symbiosis- three forms
1. Mutualism- they both benefit!
Lichen- fungus and an algae, fungus provides the home, algae provides the food, pioneer organism

9. Symbiosis continued…..
2. Commensalism one benefits the other is neither helped nor harmed
3. Parasitism one benefits, the other is harmed

10. There are two types of population growth curves

11. Exponential growth- J curve
Human Population Growth
Overshoots carrying capacity, does not respond to limiting factors, can cause a sudden die off
Our population is currently 6.7 billion people
We reached 6 billion in August 1999

12. Logistic Growth- S curve
Curve found in nature where species population is held in check by limiting factors.
Limit of population is called the carrying capacity, fluctuates with climatic changes

13. Limiting Factors factors that hold a population in check
Density-Independent factors
Will kill everyone no matter what the density is
Earthquakes, floods, volcanic eruptions
Density-Dependent factors
Increase as the population of species increases
Competition, predation, disease

14. P= population B= births I= immigration D= death E= emigration
P= (B + I) – (D- E)
P= population
B= births
I= immigration
D= death
E= emigration

15. Survivorship Curves- describe the life history of a species
Type I few young take care of young for a long period of time
Type III no care of young, they become part of the food chain
Type II Have equal chances of living or dying

16. Primary Succession
There is no soil

17. Secondary Succession A disturbed environment
Begins with weeds

18. Fire Succession A form of secondary succession
Many plant communities depend upon fire to germinate seeds and maintain health