Ecological Pyramids

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Ecological Pyramids
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Trophic levels

• Trophic levels describe the various stages within
  ecological food chains or webs.

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5 course meal!

• Primary Producers
• Primary Consumers
• Secondary Consumers
• Tertiary Consumers
• Decomposers

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How trophic levels work

• Pyramids
• Trophic levels
• Food Chains

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Primary Producers

• Definition A
• photosynthetic or
• chemosynthetic
• organism that
• synthesizes complex
• organic molecules from
• simple inorganic ones.
• These are usually referred to as AUTOTROPHS

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Primary Consumers

• Definition An organism that feeds on producers
• An herbivore
• These gain their energy from eating plants.
• An Omnivore
• These gain their energy from eating plants or
  animals

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Secondary consumers

• Definition An organism that eats primary
  consumers
• A carnivore
• These get their energy by eating other animals

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Tertiary Consumers

• Definition An organism that eats secondary
  consumers

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Decomposers

• Definition Organisms, such as many bacteria and
  most fungi, that play beneficial roles in all
  ecosystems by breaking down and absorbing
  nutrients from dead and decaying organic matter

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What about humans?

• Humans screw it up again!!!
• Humans can fit in 3 of the 5 categories depending
  on diet.

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Pyramids

• Three pyramids that we use in Ecology
• Pyramid of Numbers
• Pyramid of Biomass
• Pyramid of Energy

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Pyramid of Numbers

• This pyramid is constructed by taking the
  population statistics of each of the trophic
  levels.
• Notice how the numbers drop significantly between
  levels.

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Pyramid of Biomass

• Biomass is calculated using the combined weight
  of all species of plants and animals that may
  exist within an ecosystem.

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Pyramid of Energy

• Energy is passed from one level to the next.
  Notice the approximate loss of energy between the
  levels.

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Rule of 10s

• When progressing up the pyramid of energy there
  is a 90 drop in the amount of energy between
  levels.
• Example If we start with the primary producer
  containing 1000 units of energy how much energy
  will be present for the tertiary consumer?

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• Primary Producers 1000 units of energy
• Primary Consumers 100 units of energy
• Secondary Consumers 10 units of energy
• Tertiary consumers 1 unit of energy
• It takes the energy of 1000 plants to feed a
  tertiary consumer 1 unit of energy!

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Conclusion