Why did the
Bald Eagle
Almost Become
Extinct
Glassman, S. J., & Sterling, D. R.
(January 01, 2012). Why Did the Bald
Eagle Almost Become Extinct? A
Guided Inquiry Activity to Investigate
Humans' Impact on the
Environment. Science Scope, 35, 7, 5661.
Day 1
Warm-up: 10 minutes
 Create
a food web for the Bald Eagle
using this information.
 Use the “Construct the Bald Eagle’s Food
Chain” Handout, scissors, glue stick, and
notebook paper.
 Briefly go over the food webs and review
the concept with the students.
 http://www.learner.org/jnorth/tm/eagle/F
oodChainDrawings.html
Bald Eagle Breeding Pairs
- 1963 to 2006
Data Table
Year
Number of Pairs
2006
2005
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
1989
1988
1987
1986
1984
1981
1974
1963
9789
7066
6471
6404
5748
5295
5094
4712
4449
4015
3749
3399
3035
2680
2475
2238
1875
1757
1188
791
487
Day 1:
Create a Graph
Examine the data table.
What observation can you
make?
How could we make this data
more user friendly?
Graph Self Assessment Rubric
Criteria
Novice (1)
Developing (2)
Labels:
X axis
Y axis
Title
Student did not Student labeled
use any labels title but did not
on graph
label both axes.
Standard (3)
Student
accurately and
clearly labeled
title and one
axis or both axis
labeled but no
title
Data
1/4 or fewer
1/2 of data
3/4 of data
Points
data points are points are
points are
accurately
accurately
accurately
plotted.
plotted.
plotted.
Intervals None Expected Student does not Student
accurately use
accurately uses
intervals on
intervals on one
either axis.
axis.
Exemplary (4)
Student accurately
and clearly labeled
title and variable on
horizontal and
vertical axis.
All data points are
accurately plotted.
Student accurately
uses intervals on
both axes.
Day 2: Introduce the Activity

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You are sitting in groups of 4.
Each group member has a specific job to do
during this activity.
1. Leader: Leads group discussion
2. Recorder: Records relevant data and
questions on a Cause & Effect T-chart
3. Reporter: Asks question after analyzing data
4. Materials Manager: Gets and returns
materials correctly to the teacher at the end
of class
Names:
Draw the following data table
on a piece of paper.
Cause
1.
2.
3.
4.
5.
6.
7.
Effect
Procedure for Each Piece of
Evidence

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Each group will see one piece of evidence to help
you answer a specific question.
Your group will have 3 minutes to analyze the data
and formulate a yes or no question to ask the
teacher.
If your group cannot agree on the question in the
amount of time, your group loses its turn.
After you receive all 7 pieces of evidence you will
be able to adequately answer the question and
support your answer with evidence.
Any questions???
Evidence 1 : Picture
3
minutes
 Examine the
evidence.
 Formulate a yes
or no question.
 Ask the teacher.
 Listen to each
group, record
data.
Evidence 2: Graph
Evidence 3: Silent Spring Passage
In the book Silent Spring, Rachel Carson describes how people
throughout the country observed fewer baby bald eagles in the
1950s and late 1940s compared to the 1930s and early 1940s. She
describes these two specific examples in her book: “Observations
at Hawk Mountain are in line with findings elsewhere. One such
report comes from Elton Fawks, an official of the Natural Resources
Council of Illinois. In 1958 Mr. Fawks reported that a recent count of
59 eagles had included only one immature bird.
Similar indications of the dying out of the race come from the
world’s only sanctuary for eagles alone, Mount Johnson Island in
the Susquehanna River…Since 1934 its single eagle nest has been
under observation by Professor Herbert H. Beck…Between 1935 and
1947 use of the nest was regular and uniformly successful. Since
1947, although the adults have occupied the nest and there is
evidence of egg laying, no young eagles have been produced”
(Carson 1962, p. 120).
Evidence 4: DDT Timeline
DDT Timeline
 DDT was introduced as a pesticide in
1947.
 DDT was banned from use in the United
States in 1972.
Evidence 5:
Surface-Runoff Diagram
Evidence 6:
Energy Pyramid
Evidence 7: Bird-Egg Model
 Please
put on your safety goggles before
examining this sample.
 The eggs are very fragile. Please be
careful.
 Record your observations.
Time to Decide
 You
have seen all seven pieces of
evidence.
 Discuss the evidence with your group.
 Then, as a group answer the question,
“Why did the bald eagle almost go
extinct?”
 Be prepared to defend your answer.
Why did the bald eagle
almost become extinct?

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Brief Discussion
Look at the rubric on the next slide to
understand how your paragraphs will be
assessed.
Homework: Write a summary paragraph
explaining why the bald eagle almost
became extinct. Use at least 4 of the 7 pieces
of evidence to support your hypothesis.
We will share the paragraphs in class
tomorrow.
Assessment Rubric
Basic understanding
1. DDT caused the bald eagle to almost become
extinct.
2. Bald eagles eat fish.
3. DDT was in the fish that bald eagles ate.
Additional details
4. DDT was a pesticide sprayed on crops.
5. DDT was in the fish because fish ate smaller
fish, which ate producers.
6. Surface-water runoff carried DDT from crops to
rivers and lakes.
7. DDT caused the eagles to make soft shells.
8. When the eagles sat on the eggs, the eggs
broke.
9. Accurate food chain included showing
producers/aquatic plants, fish, and eagles.
10. Mechanics, grammar, and clarity
Yes
Partial
No