Students learn about taxonomic classification by categorizing fictional animal-like forms into species based on their physical features.
- to illustrate the process of taxonomic classification
- to demonstrate that historical approaches to classification were based on morphology alone and illuminate the difficulties with this approach
- to clarify the importance of holotypes and paratypes as museum specimens
Class: SLS 12: Understanding Darwinism
Introduction/Background: This interdisciplinary course discusses Darwin’s theories and their impact on society and modern evolutionary biology. Historically, biological specimens were classified into species based on morphology (form and structure) alone, as early scientists did not have access to techniques like the examination of DNA. In this activity, students experience the difficulty of taxonomic classification by categorizing fictional animal-like forms, known as caminalcules, into species using their physical features.
Before Class: Students were already introduced to the concept of natural history collections and their purpose (cataloging biological diversity) in previous classes.
- Instructions are included on a handout as well as written on the board. The activity began with a discussion of how to catalog a biological specimen that was new to science.
- The instructor shows students an illustration of a single caminalcule (attached) – a fictitious animal-like form used to understand taxonomy and evolution. Students are told to imagine they just came across this unique specimen that was new to science. The instructor asked how students would approach cataloging such a specimen. Through this discussion, they were introduced to the concepts of holotypes (the original specimen used when a new species is first described) and paratypes (a specimen other than the holotype used to define the species).
- Next, students were split into groups of four and given the handout containing illustrations of 29 caminalcules (attached) and told to organize the 29 specimens into 5 species. Students had 10 minutes to identify the defining features that differentiated one species from another.
- During the discussion, the instructor drew a large table on the chalkboard with 10 columns and one row per group. After the discussion, students then wrote the numbers of the caminalcules for a single species in one column and the identifying features in the next, doing this for all 5 species they distinguished.
- After all the information was documented on the board, students discussed the similarities and differences in their approaches to classification, and the challenges they faced in classifying the species.
Students used a handout containing illustrations of 29 'Caminalcules' (animal-like forms invented by Joseph Camin to understand phylogenetics).
2 Sokal, R. R. (June 1983). "A phylogenetic analysis of the Caminalcules. I. The data base". Systematic Zoology 32 (2): 159–184
- One suggestion from the instructor: “Because the students tend to go over time with this exercise, make sure the expected outputs are clear (the numbers of the specimens for each species and identifying features) so that the transition from their group work to the class discussion is smooth.”
- According to Loo, the benefit of this exercise is that “this activity actively engages the students in attempting to classify a set of animals taxonomically, leading to productive discussions on natural history and taxonomy, both in a historical context and in relation to current methods.”
Submitted by Wesley Loo, Teaching Fellow, Organismic and Evolutionary Biology