Nicole Ruggiero
Food Chains/Food Webs
Grade level: 3rd
Standards:
5.5.4 Matter, Energy and Organization in Living Systems: Identify the
roles that organisms may serve in a food chain.
Objective: SWBAT use the information from the marine organism cards to contrast
an interactive food web using yarn and then demonstrate their knowledge of
the relationships between the organisms in a particular food web.
Materials:
 2 Food Chains
 1 Food Web
 Marine organism cards
 Skein of yarn
Background Information:
 Food chain: diagram that shows how food moves through a community
 Food web: arrangement of food chains put together
 Producers: all plants; need sunlight; make their own food
 Consumers: eat other organisms
o Herbivores: eat only plants
o Carnivores: eat only meat
o Omnivores: eat both plants and animals
 Predator: animals that do the hunting
 Prey: animals that are hunted
Procedure
Activate Prior Knowledge:
 Today we are going to be talking about food chains and food webs. (Hold
up a picture of a food chain) Can anyone tell me what this is a picture of?
(allow students to answer)
Mentor-teach and model
 This is a food chain. Food chains are diagrams that show how food moves
through a community of organisms. In this food chain, it shows that the
large sharks eat the smaller sharks, the small sharks eat the ocean
sunfish, the ocean sunfish eat the copepods, and finally the copepods eat
the dinoflagellates. The dinoflagellates in this food chain are producers,
which means that they get their energy from the sun and they make their
own food. Producers can be plants—like grass, crops, and algae—or
single celled organisms—like diatoms. All of the other organisms in the
food chain are consumers—because they eat (or “consume”) other
organisms. There are three types of consumers: herbivores, carnivores,
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and omnivores. Herbivores eat only plants (“herb”), carnivores eat only
meat (“carne” in Spanish means meat) and omnivores eat both plants and
animals. In this food chain, we also have predators and prey. The
predators are the animals that hunt other animals and the prey are the
animals that are hunted. So in this food chain, the large shark is a
predator and a carnivore and the copepods are the prey of the ocean
sunfish.
 Now, does anyone know what a food web is? Can you describe it? Here is
another food chain—notice how there are some of the same animals in
this food chain as the other one. If we combine these two food chains, we
can create a food web. Food webs are just and arrangement of food chains
put together. So if we were to put these two food chains together, it would
look something like this (hold up food web—point out the two separate
food chains within the food web).
Activity
 Now you all have been learning about the ocean and the adaptations that
many ocean animals have. Today we are going to do an activity that will
help us examine a food web of ocean organisms. Every student is going to
be assigned an organism from the ocean at random. I am going to hand
each of you a card that describes your ocean organism and lists the ocean
organisms that your organism eats and that eats them.
 (go outside if weather permits or stand in back of the room) Have
students stand in a circle. “We are going to start with the diatoms. What I
want each of you to do is check your cards. On the back of your cards you
will see the name of the organism that you will be representing during
this activity. The second line tells you whether your organism is a
consumer, producer, predator, or prey. Below that, the predators and
prey are listed. Look at your cards, who has the diatom card? (give yarn
to diatom) Now, what does it say on the back of the diatom card?
(producer, predators: shrimp, copepods, & pteropods). I want you to
choose one of your predators and give the ball of yarn to that
person.”(repeat until reach everyone gets the string at least once—kids
can throw the yarn to an organism that has already gone if they do not
have any predators or prey who have not been included yet).
 “Now, we have a problem, the ocean has become so polluted that many of
the ocean organisms are starting to die off and become scarce. The
pollution has formed a layer of film on top of the water that prevents the
producers from receiving sunlight. So, if you are a producer (diatoms and
dinoflagellates), I would like you to drop their string—you can no longer
survive. Now, this affects any organism that ate either of those producers,
so now they no longer have their food source, so they are going to die too.
Any of you who consumed the producers, drop your string. Next, if any of
the remaining organisms ate the organisms that just died off, drop your
string as well because your food source is no longer available. After first
round of predators die off, say: “Now what can happen, since those
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predators just died, the remaining predators may become overpopulated
and over-feed, overusing their environmental resources, so the ocean
environment becomes even more unbalanced. And, eventually due to the
overpopulation, the food available becomes scarce, so everyone who ate
any of the predators who just died off, drop your string because you are
no longer able to survive. (repeat until left with shark). And finally, we
are left with the shark. The shark no longer has any food left to eat, so
shark will die off too, so drop your string.“
Closure
 “What does this tell you about the relationship between the organisms in
the ocean? How did the destruction of just some tiny little organisms
impact the whole marine ecosystem? How important do you think it is for
the ocean environment to be balanced? What can happen if it becomes
imbalanced? (Hint: think of when we dropped our strings)”
Assessment
The students will have met the objective if they are able to use their marine animal
cards to create a food web. The student will demonstrate their understanding of the
relationships between the organisms in the food web during the closing discussion
and on the exit ticket that will be handed in.
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(Print these on legal sized paper)
Name:_____________________________
Nicole Ruggiero
Date:_______________
Explain one thing that you learned about food webs and the relationships
between the organisms in each food web.
Name:_____________________________
Date:_______________
Explain one thing that you learned about food webs and the relationships
between the organisms in each food web.
Name:_____________________________
Date:_______________
Explain one thing that you learned about food webs and the relationships
between the organisms in each food web.
Name:_____________________________
Date:_______________
Explain one thing that you learned about food webs and the relationships
between the organisms in each food web.