1.  Necessary materials: PowerPoint Guide Teacher may wish to hand out these note guides:  Carbon Cycle Guided Discussion  Phosphorous Cycle Guided Discussion  Nitrogen Cycle Guided Discussion Teacher Information!

2. Food Chains and Webs Principles of Ecology

3. Students will be able to…  Describe food chains and webs

4. The flow of energy “Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass.” —G. Tyler Miller, Jr., American Chemist (1971)

5. Ecosystems  Definition reviewed: Community + abiotic factors  interact to form stable system  Depends on: One-way flow of energy  Energy input from sun Cycling of materials  Nutrient inputs

6. “Biogeochemical” cycles  Recycles chemicals Carbon cycle Phosphorous cycle Nitrogen cycle  Life on earth depends on these cycles & photosynthesis

7. Producers  The base of ecosystems Convert sunlight energy to chemical energy Construct organic compounds from inorganic raw materials

8. Producers  Photosynthesis  a very fundamental process !! Chlorophyll  Producer = autotroph = plants & algae (green organisms)

9. Consumers  Organisms that eat other living plants, animals or microbes  Get energy from preformed organic molecules  heterotrophs  Primary consumers  eat producers  Secondary  eat primary consumers  Tertiary  eat secondary consumers

10. Detrivores  Organisms that eat detritus  Detritus  Dead plants, animals, & microbes & fecal wastes of animals  Get energy from preformed organic molecules  Decomposers  Live on detritus in such a way that it decays Subgroup of detrivores

11. Food chains & webs  Food chain  pathways of feeding relationships Producer-consumer relationships Parasite-host relationships  Food web  Complex pattern of interconnected food chains

12. A food chain Nutrients

13. A food web Nutrients

14. Review  Describe food chains and webs  What can happen with a disruption in a food web?