Salmon Ups and Downs

Subject: Science

Grades: 9-12
Ages: 14-18

Lesson Objective

This lesson can be taught during a unit on ecosystems and population growth. Students will investigate fluctuations in salmon populations. The database contains population data for six varieties of salmon and was collected at the Bonneville Dam (located 40 miles east of Portland, Oregon) from 1938-2002. Depending on the number of available computers, students can work individually or in pairs. Ideally, students should have access to the Internet to conduct further research on their hypotheses.

  Teacher Instructions  

1. Begin the lesson by asking individual students to brainstorm a list of reasons why the population of an animal might fluctuate. After brainstorming, discuss as a class students’ ideas.
2. Open the InspireData database Fish Counts at: InspireData Starter Screen> Databases> Science. Click on the Yearly Count of Salmon tab and while in the Table View, delete records from 1938-1987 from the table. Save file under a different name to isolate the last two decades of data. The database that was saved now contains records from 1988-2002. Switch to Plot View, and select Axis Plot, set the X axis to Year and the Y axis to Yearly Count.
   Click the Series Display controls to play the Animated Time Series Plot of Year vs. Yearly Count. For information on using the Series Display controls refer to InspireData Starter Screen> Learn to Use> Documentation> Handouts> Learn to Use Time Series. Direct students to record the answer to the following questions in the Notes Area and then capture a Slide with their responses. Refer to InspireData Starter Screen> Learn to Use> Documentation>Handouts>Learn to Use Slide Show for information on creating slides.

   a.  Which year had the largest fluctuation in total number of salmon?
   b.  Calculate the actual difference in total number of salmon for the year with the largest fluctuation.
   c.  What three species of salmon had the largest fluctuations in population?

3. Have students switch to the Bonneville Dam Data 1938-2002 table in the Fish Counts database, again delete records from 1938-1987. Examine its contents. Direct the students to make an Axis Plot for each of the species identified in Question 2c. For each species, students should use the Notes Area to record their answers to the directions or questions below and then capture a Slide.

   a.  Identify the year with the largest fluctuation in number of salmon.
   b.  Calculate the actual difference in the number of salmon for the year with the largest fluctuation.

4. Ask students to close InspireData, take out a piece of paper and write answers to the following:

   a.  What factors do you think contributed to the fluctuations in the salmon population?
   b.  List three hypotheses of possible causes for these fluctuations.

Assessment

• Assess students’ slides for completeness and accuracy of information.
• Check students’ answers to completed questions for completeness and accuracy.

Lesson Adaptations

• Have each student share one of their hypotheses with a peer/team and investigate the validity of the hypothesis using the Internet, textbooks or other education-specific resources.
• Students can use Inspiration to create an observation and conclusion document to record their findings.