Today's osteology lecture introduced us to the dentition! As we've spent a little time already this term going over some sex estimation methods, and emphasizing how sexual dimorphism exists on a contiuum, I saw today as a perfect opportunity to not only talk about teeth and dental morphology, but also hammer home some of the concepts about sex.
This activity was inspired by a cusp-morphology activity suggested in Kristina Killgrove's Human Osteology Lab Workbook
A handout for my activity can be found at this link: Link to activity guidelines
Because it was Halloween last week, I was able to get my hands on a few big bags of Dubble Bubble gum. I gave a piece of gum to each student and had them flatten it slightly. I then instructed them to make an impression of their left maxillary and mandibular first molars by biting into the gum firmly, but not completely. (I had some volunteers practice this the day before and we decided that impressions had to be made in unchewed gum, otherwise it became too soft to accurately hold cusp details!).
Once each student had made their impression, I taught them how to use the non-digital Vernier calipers, and they took the maximum mesio-distal and bucco-lingual measurements for their first molars.
They made a chart on our dry-erase boards and recorded these measurements along with their gender (if disclosed), and their stature (in cm).
Each group of students then plotted their mesio-distal (x-axis) vs. bucco-lingual (y-axis) measurements against each other and coded them based on gender to observe if molar size varied based on this factor. I collected data from each dry-erase board and made a master plot for the students:
It worked! There was a trend for men to have larger molars than women, but there was considerable overlap between the groupings, which served as a wonderful teachable point regarding the non-binary nature of sex/gender and how human sexual dimorphism exists on a continuum. We coded things based on gender in this exercise because we're living humans with known identities, but if this exercise were to be applied to a skeletal population, sex may be a better attribute to consider here.
We didn't have time to get to it in class, but in future iterations of this activity I hope to have students correct their tooth measures by body size (represented by stature). It will be good to get students thinking about the effect that our size has on the quanitification of these attributes, and considering how we can control our observations based on other variables.
- (no comments)