The Experiment

Geometric morphometrics is the quantitative analysis of shape, whereby the multidimensional geometric information of an object is translated into Cartesian coordinates (Klingenberg and Monteiro, 2005). Discernable, repeatable points on bone act as landmarks that can then be compared both within and between specimens. Fluctuating asymmetry concerns the 'directionally random' deviations from pairwise symmetry between bodily elements of an organism (Leung and Forbes, 1997). While pairwise elements, like two hands, or two wings, or two halves of a mandible, within a single body should be mirror images of each other, slight deviations from this ideal state can be measured using geometric morphometrics. While no one organism is perfectly symmetrical because of the inherent messiness of becoming a breathing, moving, eating entity from a ball of cells, the idiosyncratic changes from one pairwise element to another can be indicative of developmental stressors within a single individual. If an entire population of individuals is randomly asymmetrical (without a directional bias for either left or right asymmetry), it can be an indicator of some larger problem that is powerful enough to cause a population-wide disruption in development (Klingenberg, 2015).

Question: Is there a difference in the fluctuating asymmetry between two populations of Icelandic arctic foxes due to difference developmental pressures, namely biopollutants?

Hypothesis: The costal arctic fox will have higher FA than coeval inland arctic foxes as a consequence of being an apex predator of the mercury cycle.

Methods: Photograph left and right mandibles of X arctic foxes belonging to both the coastal and inland populations in high resolution to collect 2D shape data. The photographs will be digitized using TPSdig software using XX landmarks. The landmark definitions are included as an appendix of this report, and are defined in alignment with accepted scientific literature.

The digitized shape coordinates will be subsequently analyzed using MophoJ software (Klingenberg, 2011).

Literature cited

Klingenberg, C. P., & Monteiro, L. R. (2005). Distances and directions in multidimensional shape spaces: implications for morphometric applications. Systematic Biology, 54(4), 678-688.

Klingenberg, C. P (2011). MorphoJ: an integrated software package for geometric morphometrics. Molecular ecology resources, 11(2), 353-357.

Klingenberg, C. P. (2015). Analyzing fluctuating asymmetry with geometric morphometrics: concepts, methods, and applications. Symmetry, 7(2), 843-934.

Leung, B., & Forbes, M. R. (1997). Modelling fluctuating asymmetry in relation to stress and fitness. Oikos, 397-405.

Report Abuse

If you feel that this video content violates the Adobe Terms of Use, you may report this content by filling out this quick form.

To report a Copyright Violation, please follow Section 17 in the Terms of Use.