Who Eats Who in the Antarctic?

Instructional Module #7



  Kim Kovich
  Coon Rapids Junior High School
  Coon Rapids, Minnesota


You will need to know the meanings and importance of certain terms in order
to discuss with your students the food chains, food webs, and food pyramids
found in the Antarctic.  The following is a quick overview of specific
terms used in this module, their meanings, and their importance.
Additional information on these terms can be found in the Concept Invention
portion of this module.


Organisms in any community can be divided into two broad groups based on how
they get their food.  Producers -- green plants -- are the only living
things capable of transforming light energy into the chemical energy found
in their tissues.  The plant takes light energy and chlorophyll and uses it
to combine carbon dioxide and water to make a sugar.  Animals that eat
plants use the energy stored in plant sugar to carry on their own life

Consumers are organisms that cannot make their own food and eat other
organisms to survive.  There are four types of consumers classified on the
basis of what they eat:  herbivores, carnivores, omnivores, and scavengers.
Herbivores are animals that feed on plants.  Carnivores or meat eaters are
animals that eat other animals.  Omnivores are organisms that eat both
plants and animals.  Scavengers are organisms similar to omnivores except
they also feed on the bodies of dead organisms.  Decomposers break down the
waste materials of living organism and the remains of dead organisms for
their food supply.  During the process, decomposers return organic matter to
the soil.  Decay bacteria and non-green plants are examples of decomposers.


A food chain shows how energy is passed from one organism to another.
Remember, the light energy comes from the sun.  Green plants are the only
organism that can trap and change this light energy into a form useful to
other organisms.

All the consumers in a food chain depend on other organisms (producers) for
their food.  At the end of the food chain is the secondary consumer or top
carnivore.  The top carnivore is usually not eaten by another organism.
When any consumer dies decomposers or scavengers will use it as a food

During the decomposition process, decomposers break down the remains of the
consumer into its basic chemical parts.  Products of the decomposition
process (basic chemicals) are then returned to the air, soil, and water.
Producers use the basic chemicals produced during decomposition and
sunlight to produce food.  This food forms the basis of a food chains.
When a food chain is broken, the flow of energy is interrupted.

A food pyramid illustrates the distribution of energy in a community.
Producers form the base of the pyramid.  Above producers are the herbivores
which eat the producers and at the top of the pyramid are the carnivores or
omnivores.  The number of organisms decreases as you up the food pyramid.
There are two reasons for this decrease.  One, organisms use most of their
energy by feeding to carry on their life functions.  This energy is not
available to producers until the animal dies or produces waste products.
Two, some energy is lost in moving from one level to the next.  Together
these factors contribute to the decline in the numbers of organisms as you
move up the pyramid.

Please note that the matter in the community is not lost.  It is recombined
by each organism, and recycled through the community.  In any community
there are likely to be several food chains.  The total picture of a
community with all its food chains defines the condition of food sources
within the community.

A food chain or food pyramid does not show the true feeding patterns of
living things in a community.  From a food chain or food pyramid, you would
assume that an organism eats only one other organism.  But most living
things eat many types of organisms.  A food web shows overlapping
relationships of many food chains and a combination of two or more food
chains that share some of the same organisms.

A food chain and a food pyramid diagram is one way to illustrate the
predator/prey relation between organisms.  The predator/prey relationship
usually involves two animals.  The predator is an animal that feeds on the
prey, a second animal.

The background information in this section is available as a handout in the
Concept Invention section of the module.  Feel free to photocopy the
handout and distribute it to your students.



1-The student will know some of the life forms found in the Antarctic.

2-The student will know what whales, seals, penguins, fish, winged birds,
krill, and diatoms feed on.

3-The student will know what food webs, food chains, or food pyramids exist
in Antarctica.

4-The student will know and be able to describe the Antarctic food webs,
food chains, and food pyramids.


1-Using food webs and food chain diagrams students will be able to explain
and diagram the life forms found in the Antarctic and how they are
dependent on each other.


Application Activity 1:

Pencil, paper.

Application Activity 1A:

Pencil, paper, copies of "Who Eats Who? How Does It Work?" and "Antarctic
Waters: Who Lives There?."

Application Activity 2:

30 index cards, pencil or pen, magazines (National Geographic would work)
or reference books.

Application Activity 3:

Pencil or pen, paper, string.


This is an activity designed to stimulate student interest in the topic and
provide an indication of students' prior knowledge of the topic.  The
information is important for determining the starting point and the level of
difficulty for instruction.

Have the students answer the following questions:

1-List all the life forms that live around or on Antarctica.

2-Describe what a food web or food chain is.

3-Draw a food chain or food web found in a local ecosystem and include
drawings of the animals and plants involved in them (e.g., neighborhood
pond, wooded area, field, garden, yard).


Here are two suggested ways to present the background materials for this

1-Give a lecture based on the background material.  Make copies of the
handouts "Who Eats Who?  How Does it Work?" and "Antarctic Waters: Who
Lives There?"  These handouts can be used by students as references.

2-Students will read and take notes on the handouts "Who Eats Who?  How
Does it Work?" and "Antarctic Waters: Who Lives There?"



The sun is the source of energy for all life.  Only green plants can
"capture" this energy.  Plants store this energy in the food they make
during photosynthesis.  Green plants are called producers because they
produce their own food.

Consumers are organisms that eat or consume other organisms.  Animals,
non-green plants, and many microorganisms are consumers and either
directly or indirectly need green plants for their food.  Predators are
examples of consumers who catch and eat other animals.  The animal that is
caught and eaten is the prey.

Decomposers use the wastes and remains of producers and consumers for food.
They break down the wastes of living organisms and the remains of
organisms.  In the process of decomposition, the broken-down materials are
returned to the soil where they are recycled and used again.  Decay
bacteria and fungi are examples of decomposers.

Some animals eat plants.  Some animals eat other animals that have eaten
plants.  Thus, food and energy passes from plants to animals to other
animals.  This food relationship is like a series of chain links.  By
itself, each link is not useful.  Put the links together and you have a
chain.  Living things are related to each other by what they eat and this
relationship is called a food chain.

There are special names for each link in a food chain.  The plants are the
producers.  The plant-eating animals are called first level consumers;
animals that eat the plant-eating animals are called second level
consumers; and the last animals in the chain are the decomposers or
scavengers.  Scavengers are organisms that can eat plants, animals, or the
remains of other organisms.

There are three classifications of animals: herbivores, carnivores, and
omnivores.  Herbivores are animals that feed on plants.  Carnivores, also
called meat eaters, are animals that eat other animals.  Omnivores are
animals that eats both plants and animals.

One point that was mentioned before should be repeated.  A food chain is
really an energy chain.  Energy from the sun is captured by the producers
and passed on to the consumers.  Through these chains, living things can
access the energy they need to live.  The following are some examples of
food chains:

  -Sun, grass, cow, human, mosquito.

  -Sun, grass, mouse, snake, hawk.

  -Sun, seeds, rat, cat, flea.

  -Sun, corn, chicken, human.

  -Sun, seed, insect, turtle, raccoon, mountain lion.

  -Sun, leaves, deer, wolf, vulture, mite.

  -Sun, algae, shrimp, small fish, tuna, human.

There are usually more producers in a food chain than other organisms.  As
you move to the next level, the number of organisms decreases.  For
example, a grass field feeds thousands of plant-eating insects.  These
insects feed a few hundred sparrows.  Finally, the sparrows feed only a few
hawks.  Food chains are often shown as food pyramids.  A pyramid shows how
energy is transferred from one population to another.  Food represents
stored energy and storage begins at the level of the producers.  The stored
energy is the energy that remains after the producers have used what they
need for themselves to grow and reproduce.

The producers are eaten by the first level consumers.  The consumers
receive only the energy which remains stored by the producers.  This is
only a small part of the energy received by the producers from the sun so
they need to eat many producers.

Next, the second level consumer eats the first level consumer.  The second
level consumer receives the remaining energy stored in the first level

An ecosystem may have many food chains.  Most animals in a food chain eat a
variety of foods.  An animal in one chain often eats animals from other
chains.  As a result, food chains overlap and this network of overlapping
food chains is called a food web.



Almost all of the life found in Antarctica is located in the waters
surrounding the continent.  These waters support a large expanse of
floating, speck-sized plants called phytoplankton.  These phytoplankton are
the producers for the whole Antarctic community.

In the green waters surrounding Antarctica tiny crustaceans (krill) and
fish devour the plankton by the billions.  These are then caught and eaten
by larger fish and squids.  These, in turn, will be eaten by penguins,
winged birds, seals, and whales.  Here is a closer look at some of these
animals and what they eat:


-Phytoplankton are speck-sized plants that are the major producers of the

-Zooplankton are microscopic animals, who along with the phytoplankton,
make up a group of animals called plankton

-Algae are very small plants found free-floating in the Antarctic waters

-Plankton and algae are the base for the Antarctic food pyramid.


-Small (1cm to 15cm) red, shrimp-like creatures.

-Looks like a crayfish without the front claws.

-Provides food source for most of the other life forms.

-Sometimes found in groups called swarms.


-There are about 100 species of fish found in the waters off Antarctica.

-Very small fish may feed on the plankton and algae.

-Most feed on krill and on each other.


-There are many species (30-40) found in Antarctic waters.

-Sometimes found in groups called shoals.

-Is a food source for many larger animals.

-Feeds on small fish and krill.


-A flightless bird, "wings" adapted to be effective paddles for swimming.

-Only large animals to inhabit the Antarctic mainland during winter

-Have no predators on land.

-Feed on fish and krill.

-Is preyed on by leopard seals and killer whales.

-Six types are found in Antarctica including the Emperor and Adelie.


-A large variety of birds visit the Antarctic region.

-The Skua is a scavenger, feeding on eggs and young penguins and wounded or
dead animals.

-Many of the seabirds also feed on fish, squid, and krill.


-Along with whales are the most significant food consumers.


-Is preyed upon by the killer whale.

-Feeds on penguins, young crabeater seals, fish, squid, krill.


-Is preyed upon by killer whales, and when young, leopard seals.

-Feeds on krill not crabs; has unusual teeth which are effective strainers.

-Is the most abundant seal in the world.


-It feeds mostly on cod and silverfish.

-Is preyed upon by killer whales and when young, leopard seals.

-Is at times killed by man because it's found close to many of the
Antarctic bases (killed to feed sled dogs).

-Very deep diver, can stay submerged for up to an hour and a half.


-Along with seals are the most significant food consumers.  Importance as
consumers has declined as a result of a reduction in their population due
to hunting.


-Largest animal found on earth.

-Feeds on krill which it strains through its baleen.

-Only natural predator is the killer whale.

-Man has killed so many that it has brought them close to extinction.


-Is a toothed whale.

-Feeds on fish and squid.

-Is occasionally preyed upon by the killer whale.

-Deep diver, using echolocation to find prey in dark deep waters.


-Top carnivore of the Antarctic  travels in packs or family groups called

-Feeds on seals, penguins, fish, and occasionally other whales.


-The only plant life found on Antarctica is sparse growth of mosses,
lichen, fungi, and fresh-water algae.

-Plant life survives on exposed patches of ground during the summer.

-Bacteria and fungi are the main decomposers.

-The largest group of animals are the insects (mites and ticks).

-Largest animal is the wingless flying measuring one-half an inch.


Select one or more of the following activities to provide students with
practice applying their new knowledge.




You will be able to identify organisms found in the Antarctic as producers,
primary consumers, secondary consumers, and scavengers.  This will allow
you to become aware of the roles these organisms play in the Antarctic


Pencil, paper.


1-Make a list of Antarctic organisms described in the Concept Invention

2-Complete the data table with the name of each organism under the column
that best describes how that organisms gets its food.


                      Primary        Secondary
  Producer            Consumer       Consumer       Scavenger


1-Of the four columns, which one are all the rest dependent on?  Why?

2-Of the four columns, which one are the others least dependent on?  Why?

3-What is one way that organisms in a community depend on each other?




Now that you've completed activity 1 (Who is Who in the Antarctic?) you
will take the organisms from that activity and put them into food chains.
This will allow you to become familiar with the Antarctic food chains.


Pencil, paper, completed copy of Activity 1.


1-Look at the data table in Activity 1.  From this table you are to make as
many different food chains as possible.  Set up your food chain diagrams 1
to look like the following example:

  Producers ---> primary consumer ----> secondary consumer ----> scavenger

                   [Note:    ------  means "eaten by."]

2-Draw the food chains into the data table.  You can draw a picture of the
organisms or just write their names.

Data Table:  Food Chain Drawings


1-What patterns do you see in the food chains?

2-Which organisms do you think are the most abundant if all the food chains
you made actually occur in the Antarctic? (remember the food pyramids).

3-Can you think of a food chain where you live?  Write it down or draw it.




You will be able to put the organisms found in the Antarctic into food
chains.  By doing this, you will become aware of what food chains are and
how they work.


30 index cards, pencil or pen, magazines or reference books (National
Geographic would work well).


1) Get 30 index cards to represent fifteen different organisms that are
found in the Antarctic community (all fifteen Antarctic organisms can be
found in the concept invention activity portion of this module).  You will
need two cards per organism.

2-To make a card you need a picture of the organism.  The picture of the
organisms may be drawn or cut out and then attached to the top of the card.
Below the picture you need to make two columns.  Label one column "eats" and
another "eaten by".  Fill in the columns with the appropriate organisms.
There should be at least one to four organisms in each column.  If the
organism at the top of the card is a plant, write "makes its own food" under
"eats".  Make cards for the organisms listed in the "eats" and "eaten by"
columns.  Remember to make two cards for each organism.

3-Now you are ready to play the food chain game.  Two to six players may
play.  Shuffle the cards.  Deal five cards to each player.  Place the rest
of the cards face down on the table.

4-The player on the dealer's left selects a card from his/her hand which
serves as the base for the food chain.  The second player selects a card
from his/her hand and builds to the left or right of the base card.  A card
representing an organism eaten by the organism on the base card is placed
to the left.  A card representing an organism that eats the organisms on
the base card is placed to the right.

5-If a player cannot place a card down, the player must draw from the deck
until a card can be played.  If no cards are left on the table, the player
must pass.  Play continues until a food chain is completed.  The winner is
the player with no cards remaining or the fewest cards remaining when the
food chain is completed.

6-Before you play again, list the organisms in the data table that made up
your food chain.  Play the game several times to build up several food

Data Table:  Food chain lists from number six in the procedure.


1-Which organisms in your card deck are herbivores?

2-Which organisms in your card deck are carnivores?

3-Which organism in your card are omnivores or scavengers?

4-What are some of the predator/prey relationships?

5-What is being passed from one organism to another in the food chain?




This activity will illustrate the interdependence of plants and animals
found in the Antarctic.  It will picture for the student the main Antarctic
food web.


Pencils or pens, paper, pins or tape, string.


1-Randomly pick 15 students from the class and ask each of them to pretend
to be an organism from the following list:

  Emperor Penguin              Large Fish

  Adelie Penguin               Small Fish

  Leopard Seal                 Squid Crabeater

  Seal                         Krill

  Killer Whale                 Winged Bird

  Weddell Seal                 Blue

  Whale Algae                  Sperm Whale


2-Have each student make a name tag with the animal they are pretending to
be.  Have the student put the name tag on so it can be clearly seen.

3-Pass a string from each organism (student) to each of its source of food.
Ask the class to suggest food sources.  Make sure each organism is
connected by a string to every other organism that is uses for food.

4-Draw the food web you've created in the data table.

Data Table:  Food Web Drawing


1-What organisms are the most important to the food web?  How can you tell?

2-If you pull the krill out of the food web, what happens?

3-If you pull the killer whale out of the food web, what happens?

4-Which one affects the food web more when you pull it out, the Krill or
the Killer Whale?  Why?

5-Can you suggest how the Killer Whale or Krill might disappear from the


Match the number of the term with the letter of the phrase that best
explains it.

  1-Consumer          a-All possible food pathways in an ecosystem

  2-Food chain        b-Green plants that carry on photosynthesis

  3-Food pyramid      c-Passing of food energy from one organism to another

  4-Food web          d-Shows the amount of energy or mass that is passed
                        from one organism to another in a community
                      e-Organisms that depend on green plants for their food

                      f-Organisms that get their food from wastes and dead


1-What life forms are found in the Antarctic and why are they found there
and not in other places?

2-Draw and label the life forms found in at least one food chain in the

Patricia A. Weeg
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