Alaska Sea Grant

Investigation 1 - The Missing Sea Otters

Class Time Required 4 - 5 class periods
Materials Needed
  • Science notebooks
  • Student handouts and items for group display
  • Butcher paper, art materials
  • Internet access
  • LCD or overhead projector.
Teacher Preparation

60 minutes to read, view web sites, copy and prepare materials

Prior Student Knowledge
  • Experience with reading graphs
  • Basic knowledge of tides
Vocabulary Algae, Baleen, Blubber, Consumer, Copepod, Decompose, Ecosystem, Food Chain, Holdfast, Intertidal , Invertebrates, Kelp, Microbe, Organism, Pelt, Phytoplankton, Predator, Producer, Recolonize, Scavenger, Subtidal, Tally, Transient, Underfur, Urchin, Zooplankton
Science GLEs Addressed

3rd grade: SA3.1, SC3.1, SC3.2

4th grade: SC2.2, SC3.1, SC3.2

5th grade:  SA3.1, SC3.1, SC3.2

Other GLEs Addressed

Reading, Writing, Math

Investigation 1Overview: 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.”

An ecosystem is made up of plants, animals (including humans), microbes, and physical environmental features (e.g. rocks, currents, precipitation) that depend on each other in some way. Interactions between plants, animals, and physical features make an ecosystem an interconnected unit. (See Teacher Background.)

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.

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.
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?


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

Teacher Preparation:

Tips from Teachers

Ask students to draw sea otters using oil pastels!


  • 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


Materials Needed:

Student Handouts

Sea Otter Story Part 1

Science notebooks

Readings 1, 2, 3, and 4

Food Chain Cards PDF

Items for Group Display

Map of Aleutians

Sea Otter Data Graphs

Large Diagram of Beach PDF

Food Chain Diagram PDF

Material Items

Butcher paper

Tagboard and felt-tip pens (if clue cards are used)

Art materials for making murals, if time permits

Facility/Equipment Requirements Internet access on LCD projector OR
Student computers and overhead projector

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:

[4] SC2.2 describing the basic  characteristics and requirements of living things.

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:

[4] SC3.1 identifying examples of living and non-living things and the relationship between them (e.g., living things need water, herbivores need plants).
[4] SC3.2 Identifying a simple food chain and diagramming how energy flows through it and describing the effects of removing one link.

Essential Question:

In what ways are organisms in aquatic environments connected to each other?

Enduring Understandings:

  • Organisms in aquatic habitats interact with and depend on one another in various ways.
  • An ecosystem is a community of living things with its physical environment, functioning as a unit.
  • Science is a way to help us study the many connections in our world.
Alaska Sea Grant University of Alaska Fairbanks Alaska Department of Education and Early Development NOAA