Fossil/modern mole phylogeny
Summary
Students code characters from fossil taxa to add to an existing morphological phylogenetic analysis of moles. This activity is original research; the fossil taxa have never before been included in a phylogenetic analysis.
Context
Audience
Undergraduate/graduate course in vertebrate paleontology.
Skills and concepts that students must have mastered
basic skeletal morphology
basic phylogenetics, including tree generation and tree description and comparison.
basic phylogenetics, including tree generation and tree description and comparison.
How the activity is situated in the course
This is a term project that takes all quarter, culminating in a paper.
Goals
Content/concepts goals for this activity
- phylogenetic analysis, especially the difficulties of character coding and the relationship between characters and the resulting phylogeny
- advanced understanding of some aspect of skeletal morphology.
Higher order thinking skills goals for this activity
- reading and critically evaluating scientific literature
- manipulation and analysis of phylogenetic data
- evaluation and comparison of competing hypotheses
- a priori and a posteriori hypothesis evaluation
- developing hypotheses for future studies from existing results
Other skills goals for this activity
- writing up the results of a scientific study
- coordinating group work
- entering phylogenetic data and running a phylogenetic analysis using current research software
Description of the activity/assignment
This study is introduced at the beginning of class, and runs throughout the quarter. Students are first given a paper describing a morphological phylogeny of modern moles. The first few weeks' labs teach the students basic phylogenetic methods and the aspects of skeletal morphology needed to understand the character descriptions. Students in groups of 2 or 3 are assigned a set of characters from a particular region of the skeleton (i.e. humerus, lower teeth, skull, etc.). Those groups are responsible for learning to distinguish those characters on a representative group of modern specimens (for which the character codings are already available in the paper they have) and then coding those characters for a number of fossil taxa. The fossils are either described in papers posted on the course website or are represented by specimens held in the instructor's research lab. Students are responsible for finding time to come in and work with the specimens. The next to last lab of the quarter is concerned with analyzing data within each group, for the class as a whole, for fossil taxa alone, and for fossil and modern taxa. Students then write up the results of their analyses for their term project due at the end of the quarter.
Determining whether students have met the goals
Evaluation is based on the completeness and consistency of the character matrices (I don't have a right answer a priori, but I can tell by the way they put their data together) as well as their performance in lab and their writeup of the results.
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment:Student handout for Mole Phylogeny Assignment (Microsoft Word 33kB Jun4 09)
- Instructors Notes:
- Solution Set:
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Other Materials
- Trees resulting from analysis of student data (Acrobat (PDF) 250kB Jun4 09)
- Expected tree for mole assignment (Acrobat (PDF) 333kB Jun4 09)
- Character matrix for mole phylogeny assignment (Excel 73kB Jun4 09)