May 18 2010

12:00 BSRB 154

EcoLunch Series

Graduate Student Presentations by Abbie Curtis and Jim Holmquist


Abbie Curtis

"Cats are such Airheads! Variation and Allometry in Felid Frontal Sinuses"

Abstract:Within mammal skulls are numerous hollow cavities, called paranasal sinuses, that form when the nasal epithelium invades surrounding bones including the maxillary, sphenoid, ethmoid, and frontal. Proposed functions include shock absorption, reduction of skull mass, mucus secretion, but no single hypothesis for their function has achieved widespread acceptance. Studies of paranasal sinuses have been limited by the fact that they were inaccessible without use of destructive methods. Advanced imaging technologies, such as x-ray computed tomography (CT) scanning, now allow researchers to non-destructively examine the interior of skulls, even in fossils, and have prompted development of novel methods to quantify morphology. Here I utilize CT technology to conduct a comparative study of frontal sinuses in felids, a clade for which no detailed study of sinus morphology exists. Of the paranasal sinuses, the frontal sinuses are often the best preserved, exhibit marked interspecific variation and are located in close proximity to major attachment sites for the feeding musculature. I explore which felid species have sinuses, quantify sinus diversity using spherical harmonics, examine scaling, and test their potential use in taxonomic identification. Results indicate that frontal sinus size is positively correlated with body size, but sinus shape is independent of body size.


“The effect of temperature, hydrology and ecology on post-glacial carbon accumulation in the James Bay Lowlands”

Northern peatlands sequester 270-450 Pg of carbon, over 30% of global soil carbon in both living and dead submerged plant material. The rates of carbon accumulation may be perturbed by changes in temperature, hydrology and ecology resulting in possible positive or negative feedback to future warming. Peat stratigraphies contain records of long-term apparent carbon accumulation rate, climate and ecology. However, the James Bay Lowlands in Canada, the second largest continuous peatland complex in the world, have been under represented in the paleo-record until very recently. In this presentation I will briefly outline four proposed studies that will describe geographic and temporal patterns of carbon accumulation in the James Bay Lowlands, develop a testate amoeba transfer-function for a paleo-reconstruction of water-table depth, compare long-term carbon accumulation in three peat cores to reconstructions of water-table depth and dominant plant ecology, and determine the variability of carbon accumulation, hydrology and ecology over the history of a single bog.















































































































































































































































































































































































































































































































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