Functional Morphology: Philosophy and Methodology
This activity has benefited from input from faculty educators beyond the author through a review and suggestion process.
This review took place as a part of a faculty professional development workshop where groups of faculty reviewed each others' activities and offered feedback and ideas for improvements. To learn more about the process On the Cutting Edge uses for activity review, see http://serc.carleton.edu/NAGTWorkshops/review.html.
This page first made public: Jun 23, 2009
The exercise is employed at the very beginning of course's section on "functional morphology" and before students have done any background reading on the topic.
Skills and concepts that students must have mastered
How the activity is situated in the course
Content/concepts goals for this activity
2. To appreciate the problems associated with conducting functional analysis.
3. To recognize other, non-functional constraints on morphology (e.g., phylogenetic, ontogenetic).
Higher order thinking skills goals for this activity
- Importance of developing alternative hypotheses in science.
Other skills goals for this activity
- Organization and oral presentation of the group's findings.
Description of the activity/assignment
Materials: Class breaks up into 4 groups of 4 students. Each is presented with a fossil or shell from an invertebrate animal. The shells provided: (1) modern Nautilus, sliced laterally to show the chamber walls; (2) Archimedes bryozoan, just the helically spiraled core of a colony; (3) fossil scaphopod; and (4) fossil gastropod with spines along the apertural lip. Only the group with the gastropod should know the phylogenic affinity of the fossil: tell this group the shell is of a gastropod. The groups with the Archimedes and the scaphopod are asked to interpret the function of the entire shell; they should not be told whether or not the entire skeleton is represented. The Nautilus group is asked to consider the function of the chamber walls. The group with the gastropod is asked to consider the function of just the spines.
1. The groups are asked, based on their intuition, to interpret the function of their shell or structure. (5 mins)
2. Without inquiring about their specific interpretations, the groups are then asked to think about what methodologies, philosophies, or logical approaches were utilized to make functional inferences. (5 mins)
3. Each group reports back.
4. On the board generate a list of the approaches identified. These should reflect many of the formal methods recognized within the discipline. Note how interpretations are tenuous or flawed when based on merely one approach; also note mistaken functions because of wrong assumptions or misapplied methods. (10 mins)
5. Follow this with a short lecture / discussion reviewing the formal methods employed in functional morphology.
The following files are uploaded as supportive teaching materials:
1. Lesson plan with the "conceptual change model" outline.
Determining whether students have met the goals
2. This first application of this relatively simple inquiry-based exercise went very well. Students managed to fall into all the pit-traps I had hoped they would. For example, mechanical analogy was used to interpret the Archimedes skeleton without recognizing that portions of the skeleton were missing and without knowing the phylogenetic affinity of the fossil. Here they interpreted the animal as a burrower. The group with the gastropod wrongly affiliated the fossil with echinoderms and interpreted the spine grooves as part of a tube-feet system.
3. This withstanding, the group did identify many of the methodologies employed in functional morphology, including: a. Comparison against known extant morphologies by analogy (not knowing the phylogenetic affinity); b. Comparison against know extant morphologies by homology (knowing phylogeny); c. Comparison against an engineered structure or feature. In addition, they concluded that morphology can be an unintended consequence of growth and not necessarily have a functional purpose, and that observation and imagination are needed to generate functional hypotheses.
4. The choice of the 4 fossils / shells was perfect. I would repeat the exercise with the same collection.
5. The exercise was time effective. I had hoped to wrap the exercise up in 10 minutes, when it actually consumed 20 minutes. In retrospect, the greater time investment was worthwhile.
Download teaching materials and tips
- Activity Description/Assignment:Lesson Plan (Microsoft Word 57kB Jun23 09)
- Instructors Notes:
- Solution Set: