7.5: Part 3- Making Caminalcule Cladograms
The evolutionary biologist Joseph Caminal created Caminalcules as an example model system to understand phylogenetics. He imagined 29 living species and 48 fossils of these fictitious animals which were published by Robert R. Sokal (1983a) in the journal Systematic Zoology. They were used to conduct detailed research on evolutionary classification. (Sokal, R. R. (June 1983). "A phylogenetic analysis of the Caminalcules. I. The data base". Systematic Zoology . 32 (2): 159–184. doi:10.2307/2413279. JSTOR 2413279)
As an alternative, your instructor may ask you to construct a cladogram for the specimens that you used for the dichotomous key.
Caminalcule Procedure
- As an example, list the similarities and differences among the following individuals.
- Draw the simplest possible evolutionary tree that contains these 4 living critters and 3 fossil critters.
- Include at least one trait that distinguishes each living critter.
- Use each fossil as an ancestor .
- Remember—cladograms are hypotheses that must be tested. Your hypothesis might be different from someone else’s!
The Caminalcules
Using the provided sheet of paper with illustrated Caminalcules, cut out each individual using a pair of scissors. Next, working in groups of 2 or 3, categorize individuals into subgroupings based on shared morphological features that distinguish them from other subgroupings (known as a shared derived feature ). Also, pay attention to traits that all Caminalcules share regardless if they are living or extinct. These are known as ancestral traits. Once you have categorized the species into four or five major groups, paste the animals onto a piece of paper and indicate branches delineated by a shared derived feature. The instructor will illustrate an example of a completed cladogram.
Remember! Cladograms are hypotheses that must be tested! Your hypothesis might be different from someone else’s. Be prepared to defend your decision with evidence to someone whose hypothesis is different.