Food Webs by zH37CPH8

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									               Teacher Information!
   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
Food Chains and Webs



                 Principles of Ecology
Students will be able to…
   Describe food chains and webs
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)
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
“Biogeochemical” cycles
   Recycles chemicals
       Carbon cycle
       Phosphorous cycle
       Nitrogen cycle
   Life on earth depends on these cycles &
    photosynthesis
Producers
   The base of ecosystems
       Convert sunlight energy to chemical energy
       Construct organic compounds from inorganic raw
        materials
Producers
   Photosynthesis  a very fundamental
    process !!
       Chlorophyll
   Producer = autotroph = plants & algae (green
    organisms)
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
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
Food chains & webs
   Food chain  pathways of feeding
    relationships
       Producer-consumer relationships
       Parasite-host relationships
   Food web  Complex pattern of
    interconnected food chains
A food chain
A food web
Review
   Describe food chains and webs
   What can happen with a disruption in a food
    web?

								
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