Caminalcule Phylogenetic Exercise
Summary
Imaginary creatures (caminalcues) are used as an introduction to the methods, assumptions, and conclusions of phylogenetic analysis.
Collapse
Context
Audience
I have used this exercise at several levels, from an undergraduate paleontology course for majors to graduate courses in paleontology
Skills and concepts that students must have mastered
None
How the activity is situated in the course
This exercise is completed prior to any detailed discussion of phylogenetic methods and interpretations.
Goals
Content/concepts goals for this activity
The goal is to have students think about the practical questions, decisions, and limitations of interpretations that are part of a phylogenetic analysis
Higher order thinking skills goals for this activity
analysis of data, formulation of phylogenetic hypotheses and evaluation of alternative phylogenies, etc.
Other skills goals for this activity
Description of the activity/assignment
To prepare students to think about the data, assumptions, and interpretations that are part of a phylogenetic analysis. This exercise comes in five parts. The first part is all of the data -- all specimens and age dates for all specimens. This simulates the impossible -- a complete fossil record. The second part has 10% of the specimens randomly removed (an imperfect fossil record), but all age information is provided for the 90% given. Similarly, the third and fourth parts have 20% (different 20%s) of the data randomly removed, and all information is provided for the 80% of remaining specimens (a more imperfect fossil record). The fifth part has dates only for the modern forms -- all other dates are removed. This simulates the situation for a group lacking a fossil record or a situation where the fossil record is ignored.
Depending on the class size, students either individually or in groups develop a phylogeny from their data prior to class time. In class we lay everything out on tables and compare and contrast the various phylogenies and in the process discuss many of the basic assumptions, practices, biases, etc. of phylogenetic reconstruction.
You could make this more complex and have students code things into MacClade, Paup, etc.; however, I use this for the concepts of phylogenetic reconstruction only.
Depending on the class size, students either individually or in groups develop a phylogeny from their data prior to class time. In class we lay everything out on tables and compare and contrast the various phylogenies and in the process discuss many of the basic assumptions, practices, biases, etc. of phylogenetic reconstruction.
You could make this more complex and have students code things into MacClade, Paup, etc.; however, I use this for the concepts of phylogenetic reconstruction only.
Determining whether students have met the goals
Evaluation is based on a lively discussion by all students
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment:Caminalcule Phylogenetic Exercise (Acrobat (PDF) 16.8MB Jun4 09)
- Instructors Notes:
- Solution Set:
Share your modifications and improvements to this activity through the Community Contribution Tool »
Other Materials
Supporting references/URLs
Sokal, R.R. 1983a. A phylogenetic analysis of the caminalcules. I. The data base. Systematic Zoology, 32:159-184.
Sokal, R.R. 1983b. A phylogenetic analysis of the caminalcules. II. Estimating the true cladogram. Systematic Zoology, 32:185-201.
Sokal, R.R. 1983c. A phylogenetic analysis of the caminalcules. III. Fossils and classification. Systematic Zoology, 32:248-258.
Sokal, R.R. 1983b. A phylogenetic analysis of the caminalcules. II. Estimating the true cladogram. Systematic Zoology, 32:185-201.
Sokal, R.R. 1983c. A phylogenetic analysis of the caminalcules. III. Fossils and classification. Systematic Zoology, 32:248-258.