Food Webs and Pyramids

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Food Webs and Pyramids
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Feeding Interactions Terms

• Autotroph(Producers) - Plants, produce energy
  from the sun. How?
• Heterotroph(Consumers) - obtain energy from
  consuming (eating)
• Herbivores - consumers that only eat plants
• Predators - eat other animals
• Carnivores - meat only
• Omnivores - meat and plants
• Decomposers organisms that obtain energy from
  dead organic material, return organic material to
  the abiotic ecosystem
• Bacteria
• Fungi, slime molds

Photosynthesis
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Food Chain

• Shows energy movement through a single feeding
  interaction in an Ecosystem.
• Arrows represent energy movement

Grass Grasshopper Frog
Snake Red tailed Hawk
Top-level Consumer
Primary Consumer
Producer
Tertiary Consumer
Secondary Consumer
Herbivore
Predator
Predator
Predator
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Food Web

• Shows all the feeding relationships in an
  community.
• Arrows show the movement of energy

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Trophic Levels
Grass Grasshopper Frog
Snake Red tailed Hawk
Top-level Consumer
Primary Consumer
Producer
Tertiary Consumer
Secondary Consumer

• Trophic levels in a food chain
• Producer, Primary Consumer, Secondary Consumer,
  Tertiary Consumer, Top-level Consumer
• -or-
• Producer, 1st level consumer, 2nd level consumer,
  3rd level consumer, top-level consumer

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Trophic Levels Food Web

• Organisms can play multiple roles in an ecosystem
• Ex. The Bat is both a primary consumer and a
  secondary consumer

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What is Biomass?

• Total dry mass of all the living material in an
  ecosystem.
• Used to quantify the biotic components of an
  ecosystem

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Ecological Pyramids

• Diagrams that display a feeding relationship in
  an ecosystem and another aspect of that feeding
  relationship, such as
• Energy at each trophic level
• Biomass at each trophic level
• Population at each trophic level

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Energy Pyramid

• Diagram showing a feeding relationship and the
  total energy at each trophic level.
• Energy measured in kJ, J, or cal.
• 10 rule approximately 10 of energy contained
  in a trophic level is available to the next
  trophic level (90 is used)

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Biomass Pyramid

• Shows the consumable Biomass for each trophic
  level.

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Pyramid of numbers

• Shows the population of each trophic level

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Lab 2-3 Owl Pellets

• Calculate a pyramid of numbers and biomass
  pyramid for the barred owl based on observations
  from its pellets

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Owl-Pellet Pyramid of Numbers Consumption for 1
owl for 1 year
Predator Top-level consumer
1 Owl
Prey Herbivores (mostly) Primary Consumers
2000-4000 Prey (mice, shrew, moles, birds)
? Producers (Plants)
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Owl-Pellet Biomass PyramidConsumption for 1 owl
for 1 year
Top-level Consumer
.8 Kg Owl
Primary Consumers
80 kg Mice, Shrews, Moles, Birds
Producers
3,648 kg Plants, seeds, nuts, grains