7-4.2 - Food Chains Food Webs and Energy Pyramids

Energy Flow in Food Chains,
Food Webs, & Energy Pyramids
Mrs. Joelle R. King
Science Teacher
SC Indicator 7-4.2
Illustrate energy flow in food chains,
food webs, and energy pyramids.
Prior Knowledge
• In 3rd grade you learned about simple food
chains, including the roles of producers,
consumers, and decomposers.
• In 5th grade you identified the roles of
organisms as they interacted and depended
on one another through food chains and
food webs in an ecosystem.
• You learned a lot in 5th grade. Let’s review
what you learned.
• You learned about producers and consumers
like herbivores, carnivores, and omnivores.
• You learned about decomposers like
microorganisms, termites, worms, and fungi.
• You learned about the roles of predators and
• You also learned about parasites and their
• Wow! You really learned a lot in 5th grade.
Future Learning
• In high school biology you will learn how to
calculate the amount of energy
transferred from one level to another in
an energy pyramid.
• You will also learn the roles that
organisms play in the geochemical cycles
(such as the carbon cycle, nitrogen cycle,
and water cycle).
• You will learn more about predation,
competition, and symbiotic relationships as
Essential Question
What does a food chain
show us?
Essential Question
How is a food web
different from a food
Essential Question
How is a food chain or food web
related to owl pellets?
Essential Question
How does energy flow
through an ecosystem?
Essential Question
How does the amount of energy
change as it moves through an
energy pyramid?
Food Chains
• Food chains use pictures or words and
arrows to show the movement of
energy through the trophic levels of
• The trophic level of an organism
indicates the position that the
organism occupies in the food chain.
• It shows what it eats and what eats
Producers & Consumers
The levels are numbered according to how far the
particular organism is along the chain.
• Producers are at level 1. (Plants are
producers because they produce their own
• Herbivores are at level 2. (consumer)
• Predators are at level 3. (consumer)
And so on…
Anything that cannot make its
own food must eat to survive.
It must “consume” its food!
It is a consumer.
Note: There’s
something wrong.
What is it?
Why does this look more like a “cycle”
than a chain?
Let’s discuss this one in detail.
 In this food chain, what is the
 What is the first level
 What is the second level
 Is the polar bear the 3rd level
consumer? Explain.
Food Webs
• Food webs describe the organisms
found in interconnecting food chains
using pictures or words and arrows.
• In other words, food webs are a
bunch of food chains all together!
• They describe the complex patterns
of energy flow in an ecosystem by
modeling who consumes whom or what.
Energy Pyramids
• An energy pyramid shows the amount
of energy that moves from one
trophic level to another in a food
• The most energy is available at the
producer level of the pyramid.
• The availability of energy decreases
as it moves up the energy pyramid.
The Energy Pyramid
Awesome Web Site!
• Let’s take a look at the
above web site relating
to ecology and energy
Another Cool Site
After we look at the above web site, we’ll go on to
view the BrainPop video entitled FOOD CHAINS.
The BrainPop videos provide further enrichment of
topics discussed in class and are interesting as well
as easy to understand!
Making a Model
 Let’s make a model of an energy pyramid.
 The model you will construct will be simple. It will show
pictures of the producers and consumers at each level,
the names in words, and the trophic levels.
 The good news is that this model really is perfect for
meeting our objectives relating to energy pyramids.
 Make sure you follow all instructions for proper
completion of the model.
• All pictures were obtained from various
sources on Google Images.
• None of the pictures/illustrations are mine.
• Credit is given to all artists/photographers
for their work.

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