8.L.3.3.Warm-Up
Complete Part 1 and Part 2 of the worksheet
on your desk.
Essential Question: How can you create a model of a food chain
that showcases the cycling of matter? You should include a
summary of how matter is cycled.
Activity
Who’s For Dinner: Build a food chain of
Antarctic organisms and discover how the
chain makes up part of a more complex
food web.
http://app.discoveryeducation.com/search?Ntt=flow+of+energy+in+ecosystems#selIte
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8.L.3.3.
Food Chain
• A series of organisms that shows that each
one eats the organism of the lower level.
• The arrows point in the direction of the
flow of energy.
Food Chain: Producers
1st trophic level:
 Also called autotrophs
 Use Sun’s energy to combine CO2 and water to produce
glucose and oxygen
 Releases oxygen and gains food through photosynthesis
Food Chain: Consumers
Animals that can’t make their own food
Get food by eating other organisms
Also called heterotrophs
An animal that feeds directly off of
producers is a first-order consumer
10% of the energy in one trophic level is
passed to the next
Food Chain: Herbivores
2nd trophic level:
 Eat producers.
 Use food for energy and other functions
 Most of consumed energy is lost as heat
 Include grasshoppers, deer,
and rabbits
Food Chain: Carnivores
3rd trophic level:
 Eat producers and herbivores
 Use food energy things necessary for their function
 Include humans, wolves, hawks, bears
Food Chain: Decomposers
 Break down organic matter
 Return organic matter (nitrogen and carbon) to
environment and make the nutrients available to other
animals
 Include mushrooms, worms, bacteria, cockroaches
Producer
Herbivore
1-order
consumer
Carnivore
2-order
consumer
Carnivore
3-order
consumer
Carnivore
Decomposer
Roles of the trophic levels
• As different organisms use the energy in an
ecosystem, matter is being cycled.
• When producers use CO2 and make oxygen,
they cycle matter.
• When herbivores and carnivores eat and use
their food for their bodies and breath oxygen,
they cycle matter.
• When decomposers break down this
material, they cycle matter back into the soil
for producers.
Food Web
A food web is made up
of many connected
food chains that
show the flow of
energy in
ecosystems.
• Energy goes through various chemical reactions
in a food web.
• Transfers of matter happen in each trophic level.
• When molecules from food react with oxygen,
the carbon dioxide and water are transferred
back to the environment.
• Decomposers play their part by recycling dead
plant and animal matter back into the soil or in
the water.
• Energy in the environment is transferred in the
cycle between biotic and abiotic factors.
• http://app.discoveryeducation.com/search?Nt
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Practice
You will be filling in the food web. In the
food web you should write the trophic
level, what type of organisms are in that
trophic level (herbivores, carnivores, etc.),
and a brief description of how they aid in
cycling matter.
Practice
Answer the questions on the Energy Flow
worksheet independently. You can use
your notes if necessary.
Assessment
Without using your notes, complete the
fill in the blank paragraph with your new
knowledge and answer the question.
This is not group work: work
independently!