Biology

Title: Visiting Assistant Professor
Department: Biology
Degrees: B.S., University of Illinois at Urbana Champaign; Ph.D., University of South Florida.

Contact Info

Email: lwhitena@allegheny.edu
Phone: (814) 332-2888
Website: Click here

Office Info

Office Location: Steffee Hall B200
Office Hours: MW 2-4; Th 9:30-11:30

Research Interests

My general research interest is on the evolution of shape. My main focus is on functional morphology, the relationship between form and function, in extinct and extant organisms, especially in predator-prey systems. My primary tool for this is biomechanics, the application of quantitative engineering techniques to determine how organisms perform mechanical functions, the design of morphological systems, and the relationship of these to the organism’s environment. I also use shape as a diagnostic tool for species delimitation in the fossil record via geometric morphometrics.

My research has historically concerned chondrichthyans (sharks and other cartilagenous fishes). These fishes have been in existence for 400 million years, and typically only leave behind teeth. Despite the fact that extant and fossil shark teeth encompass a wide variety of shapes and perform a variety of biological functions, relatively little biomechanically is known about them. Studying the functional morphology of shark teeth not only elucidates the biological role that teeth play in feeding, but also provides insight specifically into the evolution of shark feeding. My research in this arena included performance testing to determine how shark teeth differed in puncturing and draw, material testing of shark tooth materials, and finite element analysis (FEA) to examine the structural mechanics of shark teeth. So far, I have only scratched the surface of testing the wide variety of shark tooth shapes that have existed. Current research includes expanding this biomechanical research on shark teeth, as well as utilizing fossil and extant shark teeth in amino-specific stable isotope analysis to elucidate how trophic levels have changed through recent shark evolution.

I am also currently employing similar biomechanical techniques, as well as prey handling experiments, to study the evolution of the Florida fighting conchs, Strombus, and one of their predators, the stone crab Menippe. Through the fossil record of Florida, Strombus begins spineless then adds spines one by one through time. The current hypothesis is that this is a response to increased predation pressure by fishes and crabs. In addition to biomechanical testing with both the crabs and snails, we are currently addressing species delimitation in the snails with geometric morphometrics.

Most recently, my research has taken a turn into the realm of tetrapod locomotion, under the direction of my students. Several of my seniors are working on salamander locomotion and regneration of limbs and tails. Automy, or the loss of a limb or tail, is a defensive strategy used by some salamanders in the face of predation. However, losing a limb or tail may have immediate effects on locomotion, as well as long term effects if the regrown part is not as effective as the original. My students are working on investigating these questions, and you can read more about them here.