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Lesson Plans
Steller Web Spinning Mystery
OverviewProcedure for teachersStudent Resources and Materials
Prep for Teachers

Before teaching this lesson, make sure that all of your Web sites are bookmarked on all of the computers in your classroom, and that all of the necessary links are still valid and running. Make sure that each lab station has all of the necessary components in place for the start of the lesson.

When using media, provide the students with a FOCUS FOR MEDIA INTERACTION, a specific task to complete and/or information to identify during or after viewing of video segments, Web sites, or other multimedia elements.

Introductory Activities: Setting the Stage

Divide the class into groups of 4 to 6 students. Provide each group with a large sheet of newsprint, a stack of 50 index cards (unlined), tape and a magic marker. Have the groups work to accomplish items 1 and 3.

1. Use the index cards and marker to list all of the different types of systems about which you personally know. Write one system on each index card.

2. Are there any similarities between the systems your group has listed? What do they have in common? Write your answer in the space below.

3. Arrange the cards in groups you think are appropriate according to your list of common factors. Place them together on the newsprint with some tape.

Have each group hang their poster on the wall beside their group. Allow each group a few minutes to share their concepts of what a system is with the class.

Have members of each group complete steps 4-6 as shown below.

4. Go to the internet and find a definition of the word "system" which you think best covers the list you have drawn up. Be sure to copy down the URL of the page you take the definition from. Write this definition and URL in the space below.

5. Select one of the systems you have listed in step 1. Use one index card to write the name of each part (component) of the system. Lay the parts out in some pattern that allows you to trace how they are related to each other.

6. Use the space below to explain how the individual components are related to each other in your system.

Have the groups each explain their sample systems to their classmates. Now return to the computer and have the groups come up with an answer to item 7. Then give the students time to individually answer items 8-10.

7. Go to the Internet and find a definition for the term "Feedback". . Be sure to copy down the URL of the page you take the definition from.

8. Give two examples of feedback that you have experienced today.

9. How did each example of feedback affect your actions? Write your answer in the space provided here.

10. Some feedback causes you to keep doing what you were originally. This type of feedback is called positive feedback. Another type of feedback causes change in the way the system is operating. This called negative feedback. Which type of feedback was each of the examples you wrote in item 7?

Learning Activity

Step 1:

Distribute the Learning Activity Questions and Answer form to your students. Place the video in the VCR and CUE it to the start of the tape as the introductory credits say "Viewers like you." Provide students with a FOCUS FOR MEDIA INTERACTION by asking them to write down what they think the "mystery in Alaska" could be. PLAY the tape until you see the anchor dropping in the water as the narrator says,"…and I'm really pleased that we now have the opportunity to try and find some answers." STOP the tape to discuss your students' ideas about what the mystery in Alaska is. ( Steller sea lions and other wildlife are disappearing.)

FAST FORWARD to the visual of the seal surfacing from underwater, with the narrator stating, "so far very little is known about their world below the surface." Provide students with a FOCUS FOR MEDIA INTERACTION by asking them to watch and learn how scientists get accurate counts of the births and deaths of seals. PLAY the tape until the narrator says, "So I joined an expert who has been studying sea lions for over 30 years" while a visual of a large boat on the ocean comes into view. PAUSE the tape to check for student comprehension. (They go and look at the rookeries, which are breeding grounds of the seals.)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking them to find out where in Alaska the seals are disappearing. PAUSE the tape as the scientist points to the map and says, ":from Prince William Sound to the Gulf of Alaska and out to the Aleutian Islands" to visually check the students understanding of the region affected by this problem (from Prince William Sound to the Gulf of Alaska and out to the Aleutian Islands). Place a large clear square of plastic, like Saran Wrap over the TV screen. You will be using a white board dry marker to collect data during the next few minutes. Provide students with a FOCUS FOR MEDIA INTERACTION by asking a volunteer student to circle and count all of the individual seals they can see in the picture from the 1970s, 1980s, and 1990s. They can record the data in the table provided on the worksheet. You will need to PAUSE the picture as each is shown on the video. Change the plastic sheet for each picture. Tape each plastic sheet on the wall to be used for future reference. STOP the tape at the visual of a seal floating up to the surface as the narrator says, "… no bodies means no news.." (There has been an 80% decline in the Steller sea lion population.)


Provide students with a FOCUS FOR MEDIA INTERACTION by asking your class to listen carefully and write down at least 4 possibilities for what is killing the sea lions from the next video clip. PLAY the tape until the narrator says, "Could natural changes in the ocean be causing the sea lion's decline?" as the video shows a water scene with fish. STOP the tape to record the students' answers. (Hump back whales by out competing the sea lions for food; orca - killer whales - for food or sport; people - through pollution; people - through fishing; people - through going into their habitat; and Natural Changes - in the ocean currents)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking the class to try to explain why the food of the sea lions is a suspect and how humans were also affected by this solution to the mystery? PLAY the tape through to the video of the news conference with the man stating, " …on science that is speculative at best and wrong at worst..". STOP the tape to discuss the problem of the sea lions versus the fishermen. (The sea lions principle diet is fish - herring, Pollack, and salmon. The largest industrial fishery came into Alaska at the time of the start of the decline of the sea lions. Industrial fishing was stopped in sea lion habitats.)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking the class to explain why the fishermen feel they have been framed. PLAY the video through to the picture of the killer whales surfacing and swimming in a pod as the narrator states, "scientists aren't sure what role killer whales play in the decline." PAUSE the tape to check for student comprehension. (There are more Pollack than ever and yet the sea lions are dying. Killer whales have been documented killing sea lions. A killer whale was found with more than 30 sea lion bodies in its digestive track.)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking the class to cross hatch the area of Alaska where sea lions are doing well based on the information in the next segment. PLAY the tape until the video shows a smaller beige sea lion squirming on top of its sleeping mother. STOP the video to check that the students have correctly identified the region mentioned in the tape. (1000 miles east of the original location, in the area of fjords around the panhandle region of Alaska-near Juneau)


Provide students with a FOCUS FOR MEDIA INTERACTION by asking the students to list as many parts of the water ecosystem shown in the video as possible on their worksheet. PLAY the video until you see the humpback whales feeding as the narrator says, "The fact that 30 ton whales can survive on these tiny crustaceans is evidence of their abundance." STOP the tape to record the components given by the students.(currents from fjords - bring nutrients from the land to the surface, nutrients feed algae, algal blooms feed copepods and krill, krill feeds humpback whales, Steller sea lions are also in the system, along with herring, pollock, and birds.)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking the class to carefully listen and watch to figure out the relationship between what happened to the whales and what is happening to the Stellers. PLAY the video to the scene of the Pollack swimming and the narrator saying, "You'd think more Pollock would be good news for sea lions." STOP the tape to check for student comprehension. (90% of the whales were slaughtered, leaving their portion of the krill to be eaten by fish. The fish population increased, but not equally. Pollock out-competed the herring and increased more, and pollock also eat herring!)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking your students to find out why more Pollock is bad for seals. PLAY the tape through to the scene in which you see a shoal of herring swimming as the narrator says, "What is the staple food of herring - I'd say its herring…that is their bread and butter." STOP the tape to discuss three ways in which pollock negatively affect sea lions. (take more pollock to get the same calories, pollock is harder for the sea lions to digest, the herring put weight on the sea lions.)

Provide students with a FOCUS FOR MEDIA INTERACTION by asking the class to try to figure out how many different creatures in the Alaska ecosystem might be directly connected to the herring. PLAY the video to the part where the whales are going underwater as the narrator says, "…there's a furnace down there for processing that herring." STOP the tape to make a list on the board or newsprint of the student responses. ( humans, humpback whales, gulls, pollock, bears, eagles, sea lions -- 8 or more)

FAST FORWARD the tape to the visual of the whales blowing puffs through their blow-holes as the narrator says, " …with whales eating so much herring…" Provide students with a FOCUS FOR MEDIA INTERACTION by asking your students to explain why salmon are so vital to sea lions? PLAY the video to the visual of the salmon swimming underwater as the narrator states, "But scientists are reinterpreting the salmon's ancient rituals." STOP the tape. (Sea lions require a mixed diet of fish. Salmon are central to that mixture in the summer.)

Cross-Curricilar Extensions

In this activity you will be creating a model of the Steller sea lion ecosystem as you have seen it in the video.

Materials per student:
Small snack size baggie of colored miniature marshmallows
White glue 1 paper plate
Toothpicks Scissors
Two to three different colors of yarn or string ( about a yard of each)

Learning activity worksheet

In this activity, you will be constructing a web model of the ecosystem involved in the Mystery in Alaska. You will be using the worksheet completed while watching the video to find the components of the ecosystem and their relationship to each other.

You will need to select one color of thread (yarn) to represent a predator (eater) and another color to show the prey ( organism being eaten). To make the connection between a predator and prey, you need to cut the 2 pieces of yarn and tie them together. The end which attaches to the predator should be one color while the end that attaches to the prey will be the other. After making all the connections in your system, you should be able to easily see what the key organisms in your system are.

  1. Place your plate on the desk and select one marshmallow to represent each type of component in the system. Look at the list you made on the worksheet. You should have at least three types of fish, two types of birds, and three types of mammals.
  2. Arrange your component pieces on the paper plate so that they are fairly evenly spaced. You may wish to use multiple marshmallows in a cluster to show relative abundance of this organism in the ecosystem. Use the white glue to secure the component in place on the plate.
  3. Use a pen or colored pencil to label each component on the plate.
  4. Break a toothpick in half and place the toothpick rough side down into the marshmallow. Allow the glue to dry before proceeding.
  5. While the glue in drying, measure and cut your pieces of thread (yarn) for each connection. Starting with the component closest to the center of the plate, tie one end of the thread to the toothpick in that component and then stretch it across to another component and tie the other colored end to that toothpick. See picture below.
  6. Clean up your work area and use your web model to answer the questions shown on the page below the picture.


Cross-Curricilar Extensions

Go to the Habitat-Mediated Predator-Prey Interactions in the Eastern Gulf of Mexico Research Project Internet site at Read through the site and watch the video. How does this research project compare to the one you have been studying. What techniques are common to both projects? Write a one page synopsis of the project comparing it to the Steller sea lion project.

Go online and find pictures of various web- type structures. (Spider webs, jewelry, suspension bridges, etc) Carefully print out the pictures and isolate the points to which the "strings" are attached. Use tracing paper to copy the basic design. Remove one "node" from the web and reconnect the lines to allow for the even dispersal of the stress on the system. What happens to the design? Do you think it will still function as well, better, worse? Explain your answer.

Obtain a set of Jenga building blocks. Build the Jenga tower. Count the number of blocks in the tower as you build it. Be sure to use a regular repeating pattern in building the tower. Now carefully remove the blocks one at a time, recording the position of each piece as you take it out. Use a spreadsheet to keep track of the number of blocks and number of voids with every removal. Continue until the tower collapses. Graph the data collected. Repeat the process using a different pattern of removal. Graph the data. Repeat the process at least one more time. Compare the three graphs to try to discern any pattern in the collapse of the tower. What are the key points in the structures you have built?

How does removal of one component affect the structure? How does this model relate to the Steller sea lion project problem?

Community Connections

Environmental Protection Agency website at Use the site to search for any endangered species which may exist in your region. There is a coloring book with a list of endangered species across the U.S. at Contact local agencies to find out what is being done to preserve the endangered species in your area. Mount an activity to raise public awareness of the situation. You might try a poster contest, an essay contest at the local schools, or some sort of fund-raising activities to help support the protection of the species.

Invite your local environmental center education specialist in to speak to the class.

Take a field trip to a regional environmental center. Choose one organism (plant or animal) to research in depth and present to the class.