8th GRADE INTEGRATED SCIENCE
UNIT: Bioenergy Unit
NAME________________________________
PERIOD_____
ENERGY FLOW THROUGH A FOOD CHAIN IN AN ECOSYSTEM
(THIS ASSIGMENT MUST BE SUBMITTED TO YOUR TEACHER BEFORE YOU CAN TAKE MAKE-UP QUIZ)
Standard II: Students will understand that energy from sunlight is changed
to chemical energy in plants, transfers between living organisms, and that
changing the environment may alter the amount of energy provided to living
organisms.
Objective 2: Generalize the dependent relationships between organisms.
Lesson Objectives: I can model and diagram the flow of energy in food
chains, food webs, and energy pyramids.
Vocabulary Words: producer, consumer, herbivore, carnivore, omnivore,
decomposer, food chain, energy, matter, autotroph, heterotroph
Part I: Background on Food Chains
B. YouTube Video
Watch the YouTube Video “The Food Chain” by following the directions:
 Google “YouTube” and click on the YouTube link.
 In YouTube Search Box, type “The Food Chain”.
 Click on the link “The Food Chain” by Richard Kern.
 Watch the video and fill in the blanks using the Word Bank. You
may use the words more than once.
Word Bank:
primary
food chain
carnivores
tertiary
energy
predator
secondary
herbivore
producers
matter
1. Every organism needs two things: ________________ and ____________.
2. The flow of energy and matter through a community can be shown in a
_________________ _______________.
A. Brief Review of Food Chains
B.
3. The sun is the source of ______________ for all living things on Earth.
4. The first link of life includes plants, cyanobacteria, and some algae that use
the sun’s energy to make their own in the form of sugars. These
organisms are called ___________________.
5. Producers start the ______________ _____________.
Produce
r
Primary
Consumer
Herbivore
6. The second link in our food chain is occupied by a _________________
consumer. This is called a ____________________ or plant eater.
Secondary Consumer
Carnivore
A food chain describes who eats whom in an ecosystem. It is a visual way of
showing how energy is passed from one organism to another. Arrows show
how energy is passed. Food chains begin with producers (plants), followed
by consumers (animals), and then decomposers (organisms that break
down dead things).
7. The third link in our food chain is a __________________ consumer.
which is an animal that eats other animals. These consumers are
classified as ______________________.
8. A ________________ consumer eats a secondary consumer.
9. The alligator is a top _______________.
10. There are only four to five links in a _________________ ____________.
Page 2
Energy Flowing Through A Food Chain In An Ecosystem
11. When one organism eats another organism, it uses up a lot of the food
____________________ taken in instead of passing all of it up to the
next link in the chain.
12. Much of that energy is used in digestion and metabolic processes as the
organism grows and passes out into the environment as heat
_______________.
13. At the same time, a lot of the __________________ is excreted as waste
and is incorporated into the soil.
14. In fact the rule of thumb is that only about 10% of the energy consumed
by an organism passes on to the next link in the ________________
_______________. This is called the Ten Percent Rule.
15. There can’t be too many links in the food chain or the
_______________(s) won’t have enough to eat to obtain energy for
them to survive.
Part II: Understanding the Vocabulary
Use your vocabulary words to complete the sentences by filling in the
blanks. Then search for the words in the word search. Words maybe
backwards, frontwards, sideways, or on diagonals.
1. Plants, algae, cyanobacteria, and phytoplankton are classified as
___________________ in the food chain.
2. A _________________ breaks down dead organisms into smaller
molecules and returns the materials as nutrients to the soil.
3. _________________ ______________ are a visual way of showing
how energy and matter flow through and ecosystem.
4. There are three levels of ____________________, which are organisms
that eat other organisms because they cannot make their own food.
5. Elephants, zooplankton, giraffes, zebras, horses, and other primary
consumers are known as _________________________ because they
can only eat, plants, algae, or phytoplankton.
6. Anything that takes up space (volume) or has mass is defined as
____________________________.
7. Second level consumers like tigers, lions, and cougars are organisms that
eat meat and are classified as _________________________.
8. The sun is the source of ______________________ that is essential for
all living things on Earth to survive.
9. Humans, bears, raccoons, rats, and other organism eat both plants and
Animals, and are classified as __________________________.
10. Organisms such as producers who feed themselves by making their own
food are called ____________________________.
11. Other organisms such as consumers who cannot make their own food are
called _______________________.
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Page 3
Energy Flowing Through A Food Chain In An Ecosystem
5.
Part III: Identifying Energy Roles in Food Chains
A. Identifying Energy Roles In a Food Chain
Organisms are either producers, consumers, or decomposers. Producers are
organisms that make their own food. Consumers are organisms that eat other
organisms. Consumers are classified as herbivores (only eat plants), carnivores
(only meat eaters), or omnivores (both plant and meat eaters). Decomposers eat
dead producers or consumers and breaks down the complex molecules in them.
Label each picture as a producer, herbivore, carnivore, omnivore, or
decomposer
1.
___________ __________
___________
___________ __________
B. Completing Food Chain
Complete the food chain by adding a picture that fits. Write below each
organism whether it is a producer, herbivore, carnivore, omnivore, or
decomposer.
6. desert life
________________
________________
________________
2.
producer
7. forest life
________________
________________
_______________
3.
8. mountain life
________________
________________
______________
4.
9. rain forest life
___________
______________
_____________
____________
herbivore
carnivore
Page 4
Energy Flowing Through A Food Chain In An Ecosystem
Part III: Making Food Chains
Part IV: Interpreting Food Chains
Copepods
Herring
Phytoplankton
Shark
Tuna
Use the diagram to answer the questions below
Make three food chains using the picture above. Write the name of each
organism in the food chain. Then write the energy role of that organism
below it. Use arrows to show how energy flows through the food chain.
1.
1. Describe using words, the food chain above. Start with the first organism
and who it eats, etc. until the last organism.
__________________________________________________________
__________________________________________________________
___________________________________________________________
2. If there was a decrease in the copepod population, what would happen to
the herring population? Why?
__________________________________________________________
__________________________________________________________
2.
3.
3. What would happen to the phytoplankton with the decrease in the
copepod population? Why?
___________________________________________________________
___________________________________________________________
4. The tuna population is endangered. What would happen to the other
organisms in the food chain? Why?
___________________________________________________________
___________________________________________________________
5. What does it mean when “the death of a species in the food chain upsets
the rest of the food chain?
__________________________________________________________
___________________________________________________________