1. Carrying Capacity and the Factors That Determine It

2. Carrying Capacity The maximum number of organisms an ecosystem can handle. Before the agricultural revolution the carrying capacity for humans was around 1 billion. What happened? Factors that influence carrying capacity are called limiting factors and can be density dependent or density independent

3. A typical Carrying Capacity Graph There are fluctuations because of inconsistencies in birth/death rate, among other factors.

4. Density Dependent Factors Density refers to how many animals occupy a certain amount of space, for instance there are about 30 students per classroom or 3 fish per gallon of pond water. Density dependent factors include: – Competition (for what?) – Predation – Parasitism and disease

5. Density Independent Factors The number of organisms doesn’t matter (it is INDEPENDENT OF DENSITY) Affects most organisms equally – Seasonal Cycles – Natural disasters – Human activities

6. What is symbiosis? What it means: Two organisms that live together Temporarily or for a longer time At least one of the organisms benefits from the relationship Literal definition: the act of living together

7. What are the different kinds of symbiosis? Mutualism Parasitism Commensalism both organisms benefit one organism benefits one organism is unaffected one organism is harmed

8. Parasitism: one benefits, one is harmed Example 1: Acacia plant with ant galls Ants lay eggs on acacia tree Acacia covers the infected area with brown flesh (gall)

9. Mutualism: both benefit Example 2: Moray Eel with Cleaner Fish Moray Eel gets a clean mouth Cleaner Fish gets a meal

10. Commensalism: one benefits, one is unaffected Example 3: Cattle with cattle egrets Cattle stir up insects as they eat grass Egrets hang around and eat insects

11. Commensalism: one benefits, one is unaffected Example 4: Clown fish with anemone Clown fish gets protection Anemone is unaffected

12. Mutualism: both benefit Example 5: Antelope with Oxbird Antelope gets rid of parasites Oxbird gets a meal

13. Parasitism: one benefits, one is harmed Example 6: Taenia worm in human eye Worm infects human blood stream Human may go blind