Download Beak of the Finch Student Activity Guide

HS-LS4-2.
Construct an explanation based on evidence that the process of evolution primarily results from four factors: (1) the potential
for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual
reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive
and reproduce in the environment. [Clarification Statement: Emphasis is on using evidence to explain the influence each of the
four factors has on number of organisms, behaviors, morphology, or physiology in terms of ability to compete for limited resources
and subsequent survival of individuals and adaptation of species. Examples of evidence could include mathematical models such as
simple distribution graphs and proportional reasoning.] [Assessment Boundary: Assessment does not include other mechanisms of
evolution, such as genetic drift, gene flow through migration, and co-evolution.]
Activity Guide: Beak of the Finch
Indicators (how will YOU know you understand?)
 You will be able to construct an argument using evidence from discussion and the short film regarding
the evolution of the Galapagos finches.
 You will be able use data to make a prediction about the trend of natural selection in the finch
population.
Outcomes (how will I know you understand?)
 Your prediction for natural selection is correctly based on the data provided.
 You use multiple pieces of evidence in your argument, and they all support your claim.
Part 1: What do you already know?
1. With your group, looking at the finch cards,
put them into groups based on observations. Give
each group a title based on your observations.
2. On a large piece of butcher paper (using blue
tape, or something else that is easily moved) OR
on your table, you will display your groups, and
provide EVIDENCE for why you put those birds
in the same group (on index cards or on paper).
Pause for a gallery walk.
3. During your gallery walk, look for the
following things:
 How did other groups’ categories look the
same as yours? How were they different?
 What were the pieces of evidence that
your classmates used to justify their groupings?
Do you agree or disagree with their arguments?
4. Revision: based on what you saw during your
gallery walk, are there any changes you want to
make? What additional evidence do you need to
better justify your claims? You need to make
these changes in your written evidence.
5. Make a prediction: if these birds were moved
to San Lorenzo and therefore had to survive on
acorns from the oak trees, which birds would
survive the best? Provide a rationale for your
prediction using the picture, as well as any prior
knowledge you have.
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Part 2: Beak of the Finch Video Segment 1
Keep in mind your indicators and outcomes for this task when you watch the first segment of the video, and
listen for the following things:
 Why do all the finches have different beaks?
 What kinds of evidence could scientists use to determine that all 13 species of finches on the Galapagos
have one common ancestor?
o What was the alternate theory, and how did scientists discount that?
o WHY was this an important idea in terms of determining the natural selection of the birds?
PAUSE for class discussion
1. Using what you heard in the video, go BACK to your finch groupings from Part 1; re-group if necessary,
and revise your explanations using any new evidence from the video.
a. What did you change?
b. What new evidence did you add from the video?
Part 3: Beak of the Finch Video Segment 2 (5:37 – 9:00)
As you watch the next segment, listen for evidence that could answer the following question:
 How did the population of medium ground finches on the island of Daphne Major change as the result of
environmental changes?
When you finish with the first chunk of the segment, make a prediction ON YOUR OWN using a bar graph
about the population sizes of the following finches both before AND after the drought in the Galapagos (Hint:
That means you will need two bars for each bird, one representing the populations before the drought,
and one representing the populations after the drought):
 Cactus finch (feeds on cactus flowers)
 Sharp-beaked ground finch (feeds on small seeds)
 Medium ground finch (feeds on medium seeds)
 Large ground finch (can feed on larger seeds)
Pause. Share your graph with your partner, and provide feedback by asking your partner two or more
questions about their graph. Be ready to explain your graph.
Now, finish watching the segment.
1. How close was your graph to the actual graph? Who in your group had a graph that was the closest?
Make sure to use evidence from the video to support your answer.
a. If no one in your group was close, what pieces of evidence did you not consider, that the
researchers might have?
b. If your graphs WERE close, what part of your thinking was the same as the scientists’ in the
video?
2. Why did the drought have such an impact on the finch populations?
Pause. Class prediction: if the drought had continued longer, what would you expect your beak graph to
look like?
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Part 4: Beak of the Finch Video Segment 3
As the video wraps up, be listening for the following:
 How did one ancestral population give rise to many species, each with different characteristics?
1. With your partner (or group), create one graphic representation of the process that led to 13 different
finch species (you do not have to draw all 13 finches!). This will be like a museum exhibit, which means
it will have to stand alone WITHOUT you explaining it. However, you can have a caption (like they do
in museums).
Pause for gallery walk. During the gallery walk, you must offer CONSTRUCTIVE feedback in the form
of questions to at least three other groups’ exhibits.
2. Revision: what do you need to add to your representation? What do you need to take out? Make sure
your representation can stand up to peer review.
Part 5 Summary: Construct an explanation based on evidence that the process of evolution primarily
results from competition for limited resources (environmental factors necessary for survival e.g. water,
shelter etc.), and the multiplying of those organisms that are better able to survive and reproduce in the
environment.
Use the evidence below, as well as any evidence from the video or the class’ graphic representations, to
construct your explanation.
Figure 1. Beak sizes of a sample of 200 medium ground finches
living in Daphne Major in 1976
Figure 3. Beak sizes of the offspring of the medium ground finches
that survived the drought of 1977.
Next Gen Science Innovations DRAFT 1/2015
Figure 2. Beak sizes of medium ground finches living in Daphne
Major in 1976 (grey bars) and of the finches that survived the
drought of 1977 (black bars).
Part 6: Application of Knowledge
Imagine you are studying a population of finches on one of the Galápagos Islands. You have been recording
many of the birds’ physical traits, including the length of both wings. You observe that for 80% of individuals
measured, the length of the left wing is not significantly different from the length of the right wing (in other
words, they are symmetrical). But for about 20% of birds measured the wing lengths are asymmetrical. This
distribution is true from generation to generation. Suddenly, a rare 5-day windstorm takes over the island. After
the storm, you spend the next several days netting each bird on the island that survived the storm. You discover
that 85% of the birds with symmetrical wings survived the storm, whereas only 5% of the birds with
asymmetrical wings did.
Construct an explanation, INCLUDING graphs and links back to the video, for what the next generation of
birds on the islands would look like.
Next Gen Science Innovations DRAFT 1/2015