Elakha. Phtot courtesy of the Elakha Alliance.
Overview
Lesson 1: Introduction to Relationships between Humans and the Environment
Lesson 2: Sea Otters and the Food Web
Lesson 3: Sea Otters, A Keystone Species
Lesson 4: Native Americans and the Sea Otter
Lesson 5: Dangers to Sea Otter and Responsibility of People
Extending the lessons/References
Standards
ENGLISH LANGUAGE ARTS
EL.03.RE.08—Demonstrate listening comprehension of more complex text through discussions.
EL.03.RE.34—Take part in creative response to text, such as dramatizations and oral presentations.
EL.03.SL.09—Answer questions completely and with appropriate elaboration.
EL.03.WR.02—Discuss ideas for writing, use diagrams and charts to develop ideas, and make a list or notebook of ideas.
CD Segments to Play
Background
The sea otter is considered a keystone species. A keystone species is a species that is so important to an ecosystem (one kind of ecosystem is a kelp forest) that when it is gone the entire ecosystem is at risk.
In the 1700s and 1800s fur trappers killed most all of the sea otters.
As the sea otters died, the number of sea urchin grew and grew because there was nothing in the ecosystem that ate sea urchins.
As a result, the kelp forests were eaten up by the sea urchins.
When kelp forests disappear, there is no place for the fish and other sea animals that need the kelp forest to survive.
Just like in the food web game, the sea urchins kept eating until there was no kelp left.
The ban on killing sea otters saved some of the sea otters that lived in Alaska, but the sea otters that once lived up and down the coast of the Pacific Ocean were gone. In 1938 a small group of sea otters were seen in California. The sea otters began eating the sea urchins and the kelp forests began coming back. Along with the kelp forests came fish and other sea animals that need kelp forests to live in.
There are many groups of people—Native American tribes, scientists, universities and others interested in bringing back the sea otter—that work together trying to help the sea otter populations come back. Recently a few sea otters were seen off the Oregon coast. This was great news! Scientists and other interested people are all working together to try to help the sea otters re-populate areas where they once lived so abundantly.
Activities
1. Review
Remind the students of what happened in the Food Web game, and how all the sea urchins ate the kelp forests.
2. Discuss
Ask: How many sea otters do you think are in California?
The answer is approximately 2,000 sea otters. Much of the research scientists do on sea otters is focused on the kelp forests. As we learned yesterday, without sea otters, the sea urchins often eat away the kelp forests. One of the things scientists do is take pictures from airplanes to see whether the kelp forests are growing, staying the same, or getting smaller. There are also scientists who dive into the water and count all of the living organisms; this is done by video recording and then later counting all organisms in the video.
Besides scientists, Native American Tribes and other interested people work together to try to help the sea otters come back to the oceans.
3. Draw
Have the students draw a picture of sea otters and kelp forests. Allow them to draw sea otters eating all the sea urchins; sea urchins eating all the kelp, or how happy the people were to see the sea otters in California, or any other thing they would like to illustrate.
