General Biology 101
Food Webs – Model Build
Assigned Ecosystem: __________________
Student: ____________________________
Purpose: To fully understand food webs it is necessary to have practice constructing a
model and to learn about different trophic levels. In this activity, you will construct a 2dimensional model on a piece of cardboard. The items to include will be outline below.
This model will take some time, so do not wait until the due date to begin the work.
Elements: Upon receiving your topic you will need to do a bit of research using your
textbook, Internet and other library resources e.g. films or biology books to help you
develop this assignment. The student will provide cardboard, string & glue.
1) Identify the following elements in the space below. (Common name is fine)
I. Producers (3 min)
II. Herbivores (3 min)
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III. Carnivores (2 min)
IV. Decomposers (2 min)
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V. Can you think of animals that might be omnivores in your ecosystem? List a few of those here, and
include them as part of your project. ________________, ________________, ________________
2) Obtain a clean piece of cardboard (light colored background preferred). The size needs to be
larger than 8.5x11, plan on approximately 12” wide x 18” tall.
3) Type out the names of your identified members from above. Include a title for your model.
4) Arrange the set into a large circle, where the names are placed on the furthest extent like
spokes on a wheel, alternating between I, II, III & IV above i.e. don’t clump all producers
together on one side of the cardboard.
5) Using yarn or string and some glue connect the organisms according to who eats who.
6) Place appropriate arrows to show the flow of energy. The arrow should point in the direction of
who is doing the consuming.
7) Color code your food web by underlining the different trophic levels of primary, secondary,
tertiary, quaternary and include a legend on a lower corner of your model.
8) If you find color pictures of your organisms, apply them to your model for extra credit will be
granted. (3 minimum – 1 should be a keystone species).
-----------------------------------------------------------------------------------------------------------Analysis:
 Choose one species that you think may be a keystone species, and write a short
paragraph in the space below (or on the back of this page) to indicate what would happen
to the ecosystem or community if that species were to go extinct. Another way to look at
this is who would be most profoundly affected in your specific ecosystem?
Possible Topics
Tropical rainforest
Temperate rainforest (Olympic National Park)
Coniferous forest (Crater Lake National Park)
Salt marsh
Fresh water wetlands
Large Natural Lake e.g. Lake Superior
Human created fresh water reservoir
SW U.S. Desert
Sahara Desert
Temperate, deciduous forest e.g. Virginia
Florida Everglades
Tide pool on the Oregon Coast
Alpine environment (highest mountain tops)
North Pole Ice
South Pole Ice
Abyssal zone of ocean
U.S./Canadian Prairie
African savannah
Open ocean (not deepest part, but photic and pelagic zones)
Coral reefs
Urban park
Tropical dry forest
River