Food Chains and Food Webs - PowerPoint by gbZk9SD

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									Food Chains and Food
       Webs
    Energy Flow in Nature
     Energy Roles

• An organism’s energy
  role in an ecosystem
  may be that of a
  producer, consumer, or
  decomposer.
        Producers
• An organism that can make its
  own food is a producer.
• Autotroph
• Source of all food in an
  ecosystem.
• Capture energy from sunlight
  and stores it as food energy.
            Consumers
• Consumers are heterotrophs, or
  living things that cannot make food
  for themselves.
• A food chain contains several kinds
  of consumers, each of which
  occupies a different trophic level.
• Herbivore, carnivores, omnivores
   Consumer Tropic Levels
• Primary consumers eat producers
  (herbivores)
• Secondary consumers eat primary
  consumers (carnivores)
• Tertiary consumers eat secondary
  consumers (carnivores)
• Scavengers are carnivores that feed
  on the bodies of dead organisms.
      Decomposers
• Help break down wastes
  and dead organisms and
  return the raw materials
  to the environment
• Bacteria and fungi
       Food Chains
• Series of events where one
  organism eats another and
  obtains energy.
• First organism in chain is
  the producer.
• The second organism is the
  consumer that eats the
  producer.
Plankton—Crab—Seal—Orca
This is only one possible chain
in a marine ecosystem.
Come up with an example to fill in
the blocks of a food chain in two
different ecosytems.
      Food Webs
• Consists of many
  overlapping food chains in
  an ecosystem.
• Some organisms may play
  more than one role by
  changing consumer levels.
What happens in a food web
  if one or more of the
  organisms disappear?
Which
animals are
carnivores
and
herbivores?
   Energy Pyramids
• A diagram that shows the
  amount of energy that
  moves from one feeding level
  to another in a food web.
• Represented in a triangle
  with the most energy at the
  producer level.
  Energy Loss and Use
• 10% of energy transferred to
  next higher level.
• 90% of energy is used by
  organisms’ life processes.
• Due to energy loss, ecosystem
  cannot support many feeding
  levels.

								
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