Lesson Plan #1-Evolutionary Trees
Big Picture: For the students (Ss) to see how scientists collect and organize
data to support the theory of evolution.
Goals:
3.1.10 B. Describe concepts of models as a way to predict and understand
science and technology.
3.1.10 E. Describe patterns of change in nature, physical and man made
systems.
3.3.10 A. Explain the structural and functional similarities and differences found
among living things.
1.5.11 B. Write using well-developed content appropriate for the topic.
1.6.11 A. Listen to others.
1.6.11 D. Contribute to discussions.
Objectives:
1) SWBAT use protein sequences to construct a lineage tree of various
animals.
2) SWBAT map the sequences, identifying areas of overlap (homology).
3) SWBAT establish justification for the tree construction.
4) SWBAT navigate through the NCBI Sequence viewer
Instructional Methods:
Teacher modeling in the use of the program
Cooperative learning between the students
Student production of a product that reflects their
understanding of the lesson
Instructional Materials: pictures of animals (eel, lamprey, nematode,
earthworm, grasshopper, frog, eagle, human, lemur and chimpanzee), plain
paper, computer lab
Reading/Writing Strategies:
Reading the instructions protocol
Written rationale for animal tree based on physical feature
Written report questions
Procedure:
Greeting (3 mins)
“Good morning students. Today we will explore the molecular record of different
animals as evidence of evolution”.
Warm Up (10mins)
Teacher (T)- Take out your animal pictures from yesterday, move next to your
partner, and we’ll continue our discussion on categorizing living organisms. As
the (T) moves about the room, work with your partner to develop an
organizational tree of these animals. When finished, write a paragraph that
explains the rationale you both agreed upon for the placement of your animals.
Activity- (40mins)
(T) moves to the front of the room and asked the class for their attention. “The
focus of today’s lesson is to use the protein sequence of cytochrome c to
construct an evolutionary tree of these animals. I will demonstrate the use of the
Sequence viewer program for you so that you can obtain these sequences”. (T)
will use myoglobin as the protein of interest for a few animals. (T) will also model
the construction of the sequence map. “Are there any questions? Now, lets look
at the instructions for today’s lesson”. (T) reviews handout of instructions. “OK,
lets begin. I will be around to answer any questions may have regarding the
sequence program or with respect to the maps.” As the (T) circulates, she can
observe how the Ss are working together and ask for justification for their
placement of the animals once they have the sequence information.
Wrap Up- (10mins)
The class is brought together for a discussion of their findings. “How many
groups found their first and second trees to be different”? A class discussion
would ensue where the students would share their answers to questions 5b-e on
the instruction hand-out. For homework, bring in comments or questions about
what we did today that you found interesting or puzzling about using protein
sequences as evidence for evolution.
Accomodations/Modifications:
1. For Ss who are opposed to the topic of evolution, the same exercise could
be given with it’s emphasis on the fact that biologist are great organizers
and this would be an exercise in finding how similar or dissimilar these
animals are based on this protein.
2. For learning disabled students, I would provide additional time with
support help to complete the assignment. It may be necessary for this
student(s) to work with the support staff on a computer in the resource
room.
Assesment:
Assessment of their use of the sequence viewer would be obtained as the (T)
circulates the room. Assessment of the use of the molecular record to support
evolution would be evident during the class discussion and their written report.
Rationale:
For Ss to be engaged in their learning they often need to know the usefulness or
value of what it is they are learning (Boaler, 1997; Jonassen, 2003). This lesson
offers particular value as it provides concrete scientific evidence for how and why
biologists support the theory of evolution. This lesson gives them the opportunity
to function as a phylogenist would function providing them with real life
scenarios. Because it actively engages them in the learning process they will be
more likely to understand the relevance of the lesson that was taught. If they
entered this lesson with little understanding of how scientists use the available
information such as DNA and protein sequences, this activity has the potential to
stimulate their thinking on this topic.
Instructions for Establishing an Evolutionary Tree of cytochrome c
(100pts)
Each pair of students will submit a report that includes the following:
1. Construct a phylogenic tree of animals based on physical features and
your written rationale for their placement. (5pts)
2. Access the NCBI Sequence Viewer to obtain cytochrome c protein
sequence for each animal.
3. Construct a map of these sequences so that overlap (or lack of overlap)
can be seen from animal to animal. Label each sequence with the
corresponding animal. (This will be modeled by the T) (20pts)
4. Using the protein sequence data from your map, construct an
evolutionary tree of cytochrome c for these animals. (25pts)
5. Answer the following questions (according to our written assignment
protocol) (50pts):
a. How does your first tree differ from your second tree?
b. How did you decide upon the placement of the animals after you
identified their cytochrome c sequence data?
c. Did both of you agree to their placement? If not, how did your
reasoning differ and how did you come to an agreement?
d. What does this tell you about the evolutionary tract of these
animals?
e. What is the significance of protein sequences to establishing
evolutionary history compared to the fossil record?
Reflective Essay on Lesson Plan #1
Using technology, this lesson will allow the students to collect molecular
data and construct a lineage tree of animals. The purpose is to engage them
in processes of scientists and provide them with concrete evidence that
supports the theory of evolution.
The role of the teacher will be to demonstrate the use of the web site,
NCBI Sequence viewer, and emphasize the importance of obtaining the same
form of cytochrome c for each animal. Additionally, the role as facilitator is
important to allow the students to use the evidence they collect to make a
statement about their findings. It will also be important for the teacher to
circulate the room to question the thought processes of the students as they
analyze the data and organize their tree.
The students will need to work cooperatively with their partner, offering
their own insight into constructing the tree and listening to the analysis their
partner brings to the activity then coming to agreement. This activity also
gives the students the opportunity to think about the implication of their
findings.
I cannot identify a disadvantage to using technology in this lesson. It
provides the student with real world situations and relevance to their learning.
Students are more likely to be engaged in their learning when they see the
value or usefulness of what it is they are learning (Boaler, 1997; Jonassen,
2003). This lesson offers particular value as it provides concrete scientific
evidence for how and why biologists support the theory of evolution. It is my
intention that the students will be able to make an abstract concept more
tangible. For those apposed to this theory, it allows the students to see the
connectedness we have with other animals.
Any internet based activity offers the potential for students not to stay on
task. However, the teacher needs to circulate the room to minimize this. In the
event there would be technical problems, a set of printed sequences could be
made available. This site could be then be visited at a later date and other
features of the site could be explored such as the references for these data;
journal article ,author, email address for the author, publication date, etc.
Their constructed tree and the discussion that follows this exercise will
provide much information about what the students have taken away from this
lesson. It is possible for the students to only come away with the fact that
these animals have similarities but not that the evidence supports the theory
of evolution. This would take us into a deeper discussion and examination of
other tools such as the fossil record, anatomical and embryological records,
and the DNA code.
References
Boaler, J. (1997). Reclaiming School Mathematics: the girls fight back. Gender
and Education, 9(3), 285-305.
Jonassen, D. H., Howland, J., Morre, J., Marra, R.M. (2003). Learning to Solve
Problems with Technology; A Constructivist Perspective. Columbus, Ohio:
Merrill Prentice Hall.