Investigation 1 - The Missing Sea Otters

Overview: In this 4-5 day investigation, students begin by reading a mystery story about sea otters in the Aleutian Islands, and examining an accompanying population graph. They identify information that they will need to help them solve the missing sea otter mystery, and explore ecological relationships in the sea otter environment using Web sites, video clips, and readings. Information is shared with the class and/or summarized on clue cards, and students then create murals showing the sea otter/kelp bed ecosystem.

Focus Questions:

• What is an ecosystem?
• How are things in an ecosystem connected?

Engagement: (30 minutes)

Locate Aleutians on a map, and/or take a look at the study area using Google Earth.

With the whole class, read the Sea Otter Story Part 1 about sea otters in the Aleutian Islands while displaying the sea otter data graphs.

Discuss with the students:

• What do the graphs tell you?
• As a scientist, what questions do the data prompt?
• What do you think happened to the otters?

Exploration: (2-3 class periods of 30-45 minutes)

Post a large diagram showing a cross-section of a beach with intertidal and subtidal zones depicted. Explain what those terms mean. You can draw or write in the plants and animals in the appropriate zones as they are mentioned and discussed during this investigation. Ask students to write a definition of "ecosystem" in their science notebooks. Since they may not have an understanding of the term, the definitions may be quite brief or incorrect. They will continue to develop their understanding throughout the unit.

With the whole class together, share and discuss the definition of “ecosystem.”

Show internet video clips of sea otters and kelp beds from some of these sites and/or have students investigate some of the sites to see visual images.

• Photos of Sea Otters from Otternet
• Kelp Forest Photographs by Phillip Colla
• Monterey Bay Kelp Forest Virtual Dive
• Monterey Bay Aquarium Sea Otter Live Cam and “Surrogate Sea Otter Moms” Video
• US Fish and Wildlife Service Sea Otter Photos
• US Fish and Wildlife Service Sea Otter Video Clip 1
• US Fish and Wildlife Service Sea Otter Video Clip 2
• Waves of Change Sea Otter Video
• Jean-Michel Cousteau: Ocean Adventures Kelp Forest Video

Do a “KWL” (K-W-L explanation) activity with students:

After looking at the visual images, ask the students what they know about sea otters and their ecosystem.THis information will be added to the "K" section of the chart. Students can create their own version of the chart in their science notebooks, and fill in the sections as you go.

As a whole group, brainstorm what would have to be understood in an otter’s ecosystem in order to understand the otter population decline: (food needs, need for shelter, adaptations to their environment, what dangers are in their environment—predators, pollution, how they are used by people). This information will be added to the "W" section of the chart - What do they want to learn, or what do they think they will need to learn to understand the otter's ecosystem.

Assign readings to small groups of 4-6 students as research to discover the ecological relationships that will help solve the eco-mystery. Ask students to take notes and make illustrations in their science notebooks as they read.

Reading 1: Sea Otter Biology and History in the Aleutian Islands
Reading 2: The Producers in the Ecosystem
Reading 3: Consumers: Marine Invertebrates and Fish in the Kelp Forest
Reading 4: Consumers: Marine Mammals

Explanation: (30 minutes)

Students groups report their research to the class as pieces of the mystery to be solved.
OR
Students summarize their research on clue cards with illustrations on one side and facts on the other side.

Extension (Application): (45 minutes-1 hour)

Discuss the sea otter’s food web using a food chain diagram and cards. As a class, have students create a mural of the otter/kelp/urchin ecosystem, showing the relationships between organisms. Have students use the cards to create their mural, or if time allows, have them create representations of the organisms themselves using a variety of art and craft materials. Be sure to include humans as part of the ecosystem. Discuss the mural as you work on it.

Ask students to reflect in their science journals:

• What questions do you have?

• Is there an idea you don’t understand?
• What do you know now that you didn’t know before?

Evaluation:

Formal Evaluation will be done at the end of the unit.

Teacher Preparation:

• Read the background information and the lesson materials.
• Investigate Web sites to choose images and video clips.
• Copy student handouts.
• Cut apart Food Chain Cards.
• Make and post a large diagram (3D) of a beach showing intertidal and subtidal zones.
• Make overhead transparencies and/or prepare for showing digital images.
• Teacher's Background and Resources

Curricular Connections:

Social Studies/Alaska History/Fur Trade

Alaska Science Grade Level Expectations Addressed:

The student demonstrates an understanding of the structure, function, behavior, development, life cycles, and diversity of living organisms by:

The student demonstrates an understanding that all organisms are linked to each other and their physical environments through the transfer and transformation of matter and energy by: