Talking Teaching

February 27, 2012

what is the caminalcule lab supposed to teach?

Filed under: science teaching — Tags: , , — alison @ 9:37 pm

It’s quite interesting (& post-provoking) to read the search terms for this blog every now & then. Today’s examination gave me the title of this post :-)

I was first introduced to the Caminalcules way back in the dim dark past when I was a brand new undergraduate student. They were the basis of a lab exercise on evolution & evolutionary relationships, & were invented by the taxonomist Joseph Camin to aid learning about taxonomy & classification. Here’s what they look like (these are just the ‘living’ species):

The idea was to sort them – both ‘living’ and ‘fossil’ species – into groups on the basis of various similarities, & then to work out a possible family tree (a phylogeny) that reflected their possible evolutionary history. Camin used made-up ‘animals’ rather than actual organisms because he wanted to avoid students’ preconceptions about relationships affecting the development of their phylogenetic trees.

I must have found this rather fun because, when I was in the position of redeveloping a paper on the evolution & diversity of life, I remembered the Caminalcules & decided to use them as the basis of a lab class myself. As you do, I did a little googling & found not only the images of fond memory, but also a lab exercise developed by Rob Gendron, of Indiana University of Pennsylvania. Rather than reinvent the wheel, I e-mailed Rob & he very kindly allowed me to use his lab exercises in our BIOL201 paper. (And I’m extremely grateful that he was so generous with his resource – if you read this, Rob, thank you again!)

I must admit, I did wonder what today’s computer-savvy generation of students would think of a paper-&-scissors exercise, but apart from one or two who felt it a bit kindergarten-ish, everyone seemed to enjoy identifying the features that would (& wouldn’t) be useful in working out relationships & in building up what turns out to be quite a complex family tree. Along the way they learn about synapomorphies (features shared by a particular group that derive from a common ancestor for that group); how to recognise convergent evolution; and the taxonomic significance of vestigial characteristics (among other concepts). They’re also challenged to think about how environmental conditions might drive the diversity seen in some lineages of Caminalcules, and similarly, why other lineages appear to be in evolutionary stasis.

You can see that there’s a lot of concept development, & good hard thinking, going on in this lab. Because it’s such a good introduction to thinking about evolutionary history, I used it as the first lab in our 12-week semester, to give the students the framework into which to fit the concepts & ideas they’d be gaining as we worked through the rest of the paper. Camin’s original concept has turned out to be one useful, & long-lived, idea :-)

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When I went looking for the image I’ve used here, I was enchanted to also find the “Snouters“, another family of imaginary creatures. (I actually have the book about them, thanks to one of my brothers.) So nice to be reminded that science doesn’t always match the popular image, but is also about creativity, imagination, & downright fun!

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1 Comment »

  1. All phylogenetic trees are theories. They are hard to test because there is no true tree to compare with. Caminalcules, being artificial actually have a true ancestor and tree that we can test algorithms against.

    Comment by Athanasios Seliotis (@seliotis) — February 12, 2013 @ 6:59 am


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