The Living Edens -- South Georgia Island -- Classroom Resources

Lesson 2 -Food Web

Grade Level: 5 through 8

Subject Area: Science

Estimated time of Completion: Activity and discussion can take up to 2 90-minute blocks depending on the amount of research

Food webs show the interaction of different producers and consumers in an ecosystem. They are a good visual organizer to show the different flows of energy among the organisms. They can also be used to demonstrate how each organism is important to the survival of the ecosystem.

The Living Edens: South Georgia Island shows examples of organisms that live on South Georgia Island and how they get their energy. After watching the video, students can construct a food web showing the interactions among the organisms on the island and in the ocean.

Instructional Objectives:

By the end of this activity, students will be able to:

Identify the producers and consumers in an ecosystem.
Make a model of a food web.
Explain how changes in the population of one organism can affect the entire food web.

National Science Standards:

This lesson addresses the following national science standards for grades 5 through 8 as established in the National Science Education Standards at http://www.nap.edu/readingroom/books/nses/html/:

Life Science: Populations and Ecosystems
Science in Personal and Social Perspectives: Populations, resources and environments

Procedures and Activities:

Warm Up:

Ask students to list several organisms found in the region. These should include animals and plants. (Students might begin by listing things they've eaten in the past 24 hours.) List these organisms in different places on a blackboard. Ask students to draw lines representing "who eats what" among the organisms listed. Afterwards, fill in any blanks or clear up any confusing relationships. Explain that organisms in every environment are part of a food web; students will be looking for such a web in the South Georgia Island video. (*The teacher may show the entire video so students can see the complete variety of organisms represented; however, teachers may want to screen the program first due to a few graphic scenes of seals fighting.)

Procedure:

Students should list the organisms discussed in the video. They include: albatrosses, King penguins, Gentoo penguins, Macaroni penguins, leopard seals, krill, elephant seals, snow petrels, skuas, fur seals, squid, various insects, and grass.
Have students research the various organisms to find out what they eat. You may want to divide the organisms among groups to save time and resources.
After the research is complete, create a chart showing the organism and what they eat. For example:

Organism What It Eats

King penguins Krill, squid, fish

This can be done as a class discussion with students reporting on their research and filling out the chart.
After the chart is complete, students could either work individually or in groups and use the information to complete a food web.
Have the students write down the organisms on index cards or scraps of paper. This way they can practice different arrangements to find one that is the easiest to organize.
Once they have an arrangement that works, they should then create their food web by writing the organisms on a clean piece of paper. Draw arrows from each organism to all the other organisms that eat it.
When the food webs are complete, discuss with students the following:
- What are the producers and consumers in the food web? ( students could chart this)
- Which organism would you consider to be the most important in the food web and why?
- If you were to remove one of your organisms from the food web, how would other organisms be affected? Explain.
- Why would a scientist study an ecosystem and develop a food web for it?

Assessment Recommendations:

Completed food webs could be used to measure the students understand of how energy flows in the ecosystem.

Student participation in discussion could be observed. Students could also individually answer the discussion questions on paper.

Extensions:

Have students research various ways Antarctica and surrounding islands have been affected by humans (egg harvesting, oil spills, hunting, over fishing, and loss of habitat). How have these actions changed the populations of organisms of the ecosystem/food web? What can be done to prevent humans from destroying the South Georgia ecosystem?

Students could examine an organism in the food web and determine how it is adapted to hunt and eat its food. They could also examine how they camouflage and protect themselves from predators.

Web Resources: (Note: these links will take you away from PBS Online.)

Pete and Barb's Penguin Page
http://ourworld.compuserve.com/homepages/Peter_and_Barbara_Barham/frame_ndx.html

Seal Conservation Society: Antarctic Fur Seal
http://www.pinnipeds.org/species/antfursl.htm

Life in Antarctica: British Antarctic Survey
http://www.antarctica.ac.uk/Employment/locations/antarctica/index.php

USA Today: Work and Daily Life in Antarctica
http://www.usatoday.com/news/science/cold-science/life-work/antarctic-life.htm

Antarctica Online
http://www.antdiv.gov.au/index.html

About the Author:

Kathleen Taylor is a 6th grade Science and Computer Science Teacher at George Mason Middle School in Falls Church, VA. She graduated from the University of Mississippi with a Bachelor of Arts degree in Elementary Education.

Her current interest is developing curriculum that allows her to students to explore the earth sciences in creative ways. She has the most fun teaching oceanography, meteorology, and geology because she feels kids are naturally fascinated by understanding the physical world around them.