1. The Living World – Part 3 AP Env Sci 2011-2012

2. Abiotic Factors Conditions: abiotic factors that vary in space and time but are not used up or made unavailable to other species Temperature, pH, wind, salinity…. Resources: factors that are consumed Water, nutrients, oxygen, space…

3. Survival Curve

4. Organisms Respond to Abiotic Factors Optimum: for every factor, there is a level at which organisms do best. Range of Tolerance: entire span that allows any growth at all. –Limits of tolerance –Zones of stress Individuals  Population

5. Law of Limiting Factors (Liebig) If any one factor (abiotic or biotic) is outside the optimal range, there will be stress –Places Limits on: Growth Reproduction Perhaps species survival –Garden Examples: can you think of any? –Might be too much or too little –Could be synergistic effects

6. Identifying Limiting Factors MiceMontgomery

7. 3 Scenarios: Ecosystems Under Stress: 1.All producers killed by toxic discharge to soil. 2.All parasites eliminated by “miracle” drug. 3.Decomposers wiped out by virus. What would happen to the ecosystem in each case?