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Title: Does Structured Intellectual Playtime With Phylogenetic Trees Help Students Understand Biodiversity and Evolution?

Problem:  Students need to understand the evolutionary connections between different organismal groups

We wiped out many aspects of organismal biodiversity and natural history when we moved to an inquiry-based lab format in Introductory Organismal Biology.

We wondered if we could use phylogenetic trees to reincorporate the study of organismal biodiversity into our course, thus providing an inquiry-based framework.  We also wondered if using phylogenies would help students understand organismal diversity in an evolutionary context, which was sorely lacking in our traditional taxonomic "march through the phyla".

Our rationale for using phylogenies in this endeavor is twofold: 1) classical systematics and the historical component of evolutionary theory seems to be disappearing from Introductory Biology courses.  This could lead to further movement of students away from evolution as an organizing concept in biology; and 2) phylogenies are hypotheses and, as such, provide the students with a way to study evolution in a hypothesis-testing framework, thus establishing evolution in their minds as a biology discipline on a par with physiology and molecular biology.

Learning Goals:

1. Students are able to map the hypothesized evolutionary history of character-state transitions on a phylogeny.

2. Students can apply the principle of parsimony to choose one of two competing hypotheses.

3. Students can explain a phylogenetic tree as a depiction of ancestor-descendent relationships.

Question:  Does the ability to work with phylogenetic trees mechanistically correlate with an ability to interpret phylogenetic trees in the abstract?

Assumptions: Being able to understand phylogenetic trees in the abstract is correlated with students' acceptance of evolution as an organizing principle. 

What evidence do I need to get:

Evidence of students' ability to read and interpret phylogenetic trees.

Evidence that ability to interpret phylogenetic trees is correlated with the ability to work with the mechanics of phylogenetic trees.

(Evidence that the ability to interpret phylogenetic trees is correlated with acceptance of evolution.)

Design to Collect Data: 

Pre-test/Post Test Design

Administered the first day of class and then as a summative assessment. 

Three-part Phylogeny Assessment 

Map Evolution of Characters onto Two Trees (alternative hypotheses) [Quantitative Literacy]

Apply the Principle of Parsimony to Choose the Preferred Hypothesis [Scientific Method]

Demonstrate an understanding of trees as a representation of ancestor-descendent relationships [Tree-thinking]

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 phylogeny_assessment.pdf
Assessment Tool for Phylogenies Project
37.8 kB15:09, 18 Jul 2008jsmithActions
Viewing 4 of 4 comments: view all
looks really sharp. What do you think might be the difference between them creating their own trees from the data as opposed to having to chose between two prepared trees. The issue of using the exercise for assessment versus instruction was still unclear to me. Will the students be doing a similar phylogenetic analysis that you described in class as a learning exercise? Or will this sort of phylogenetic analysis only show up as the pre/post test? An item for future clarification.
Posted 12:10, 18 Jul 2008
I think it would be very useful and important to really outline all the activities that will go into the "structural play time" so that it is clear what activit(ies) you are focusing on as having an impact on their understanding of biodiversity and evolution

Also I think it will be very important if you can proactively try to think about all the other things that might impact their understanding of biodiversity and evolution other than the structural playtime during the course of the unit. Perhaps you might consider having some self assessment tool for the students to ask smth like: What three things helped you the most in understanding biodiversity? Rank them in the order of usefulness, etc. to give you a sense..
Posted 12:11, 18 Jul 2008
Research question: Does the ability to play with trees correlate with the ability to understand trees?

First, bravo for bringing trees back into biology in a creative way that encourages (requires!) inquiry. Second, I liked how you clearly defined your learning goals and tied your research question and methods back to those learning goals.

For future presentations/papers/grant applications: Who are your students? Bring that out a little more. What is there background? Their goals/majors? Their purpose for taking your class?

Love this exercise! It uses animals they can visualize unlike some exercises like this that use cartoon-like characters. I do have one material question about your assessment tool. On Question B, why couldn't the answer be tree 1 because of the trait lost/gained in tree 2? Consider adding an interview or think-aloud as students go through this process -- it may give you vision into how they are thinking and if their understanding is developing.

Networking: Talk to Chris Pires at U of Mo -- He has done some research on "tree thinking" in botany with similar exercises. He would love to see what you are doing!
Posted 12:12, 18 Jul 2008
your question is well focused
can you use PHYLOGENY to understand Biodiversity and Evolution-
or do increases in phylogeny understanding correlate with increases in Biodiversity understanding.

2.You will not know if your lab exercise (inquiry) is the source of these changes- but such is life.
3. I think the pre and post test is a very good assessment and you will be able to compare changes in scores for each part of the question.
part a addresses the skill of mapping
part b addresses - do students understand concept of parsimony
part d- addresses do students see connection between trees and evolution
Posted 12:13, 18 Jul 2008
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