Ohio Center for Ecology and Evolutionary Studies





Ohio Center for Ecology and Evolutionary Studies


   One of the goals of the OCEES Undergraduate Research Immersion Program (UGRIP) is to assist students in developing and completing formal research projects in honor theses programs offered in our member departments and the Honors Tutorial College.  We our proud to provide the following listing of our recent UGRIP students who have completed Honor Thesis projects in ecology and evolutionary biology at Ohio University. 




Thesis Title:  
Phylogentic and functional cues in micromammal tarsal bones from 
the late Oligocene Nsungwe Formation of southwestern Tanzania.


Advisor: Dr. Nancy Stevens, Biomedical Sciences
Program:  Biological Sciences Senior Honors Program

Research Summary:
The late Oligocene Nsungwe Formation, situated within the Rukwa Rift Basin in the Western Branch of the East African Rift System in southwestern Tanzania, offers a unique window into Paleogene mammalian evolutionary history. Micromammal fossils are abundant in the fauna, and represented by macroscelidean, rodent, hyracoid, and primate craniodental specimens. Postcranial elements, such as tarsal bones, also preserve well in Nsungwe Formation localities; particularly well-represented by the central element of the tarsal complex, the astragalus, offering important insights into micromammal locomotor behavior and paleoecology. This study used apomorphy-based and morphometric approaches to characterize 19 fossil specimens, placing them within the context of a morphologically and phylogenetically diverse extant sample of small mammals that exhibit a broad range of locomotor modes (generalized terrestrial, arboreal, saltatorial, semi-aquatic, glissant, fossorial). Results document several parameters useful for distinguishing phylogenetic and/or functional groupings among the extant sample. Nearly 70% of fossil specimens were categorized within distinct functional groupings, each with a closely approximated extant morphological representative. Detailed examination of tarsal elements provides an important additional line of evidence for exploring the phylogenetic and ecomorphological affinities of micromammals from the first late Oligocene terrestrial fauna from sub-equatorial Africa.  


Current Work/Future Plans

After graduation, I received a full-time position as a laboratory technician for my thesis advisor, Dr. Nancy Stevens (Biomedical Sciences, HCOM), and this summer, I had the opportunity to travel to Tanzania as a field assistant.  Over the next year, I will continue to refine and build upon my technical skill set, in addition to working with Dr. Stevens on advancing my project, which I will be presenting at the Society of Vertebrate Paleontology Conference this fall. It is my aim to pursue ecology and evolutionary studies at the graduate level, and I look forward to further developing my research interests as I remain in the fostering environment of the OCEES program.




Thesis Title:  
Ontogeny of the Brain Endocasts of Ostriches (Struthio camelus) with
Implications for Interpreting Extinct Dinosaur Endocasts


Advisor: Dr. Larry Witmer, Biomedical Sciences
Program:  Biological Sciences Senior Honors Program
Research Summary:
This project documented the ontogeny of the cranial (brain) endocast of Struthio camelus, the African ostrich. Comparison of size and shape via 3D reconstruction from CT scans provided the data needed to study the ostrich endocast in various stages of life. Endocasts were generated for two embryos, three juveniles of differing ages, and two adults. Comparisons of the shape and size of the endocasts showed changes in nine brain regions from embryo to adult.  The most notable change in surface area is seen in the Wulst region of the cerebrum, implying a prioritization of that region at little expense to the other regions. The Wulst is located dorsally on the telencephalon and is composed of two distinct bumps on either side of the dorsal cerebrum. Additional analysis of one of the specimens with the Lugol’s iodine staining method revealed that the flocculus of the endocast is mainly composed of venous rather than neural tissue. The Lugol’s analysis also revealed that the cerebellar foliation present in the ostrich brain is not detectable in the endocast, because a large venous sinus overlies that area. The inner ear changes mainly in size during development, with a fairly constant shape throughout life. My results suggest that the Wulst is eventually prominent in the ostrich yet is not present at hatching, perhaps reflecting a parallel between ontogeny and phylogeny in that the Wulst also appears later in avian brain evolution. In addition, the fact that the inner ear maintains its shape is indicative of its importance throughout the history of non-avian dinosaurs and its immediate importance after hatching in a precocial species.



-Attending the Biological Sciences PhD program at Auburn University 
in Craig Guyers lab.  
Thesis Title:  NOW PUBLISHED!!!!!   PDF HERE
Herpetofaunal Richness, Density, & Community Composition in 
Plantation Monocultures & Primary Forest of La Selva Biological Station, 
Costa Rica.

Advisor: Dr. Steve Reilly, Biological Sciences
Program:  Biological Sciences Senior Honors Program
Research Summary:
As the rising global human population continues to clear Neotropical forests, tree plantations have emerged not only as a sustainable source of lumber and pulp but also as a means to conserve biodiversity.  To better understand how agroforests might be utilized as conservation tools, I compared amphibian and reptile species richness, density, and community composition in forest plantations of three native tree species (Pentaclethra macroloba, Virola koschnyi, Vochysia guatemalensis) to primary forest at La Selva Biological Station in the Caribbean lowlands of northern Costa Rica.  Richness varied from 9 to 13 species among the plantations, whereas primary forest supported 14 species.  Primary forest and Vochysia supported significantly more species-rich communities than Pentaclethra and Virola (F3,42 = 12.604, P = 0.0001).  Species richness correlated with increases in leaf litter mass (r2 = 0.2663, F1,32 = 11.598, p = 0.002) and moisture (statistics forthcoming).  Herpetofaunal density was significantly higher in primary forest (5.83 ± .59 individuals/100 m2) than in Pentaclethra (2.66 ± 1.68 individuals/100 m2) (U = 11.881, df = 3, p = 0.0078).  Non-metric multidimensional scaling and Analysis of Similarity showed that community composition differed significantly (P = 0.01) with two amphibians, Oophaga pumilio and Craugastor bransfordii, dominating the sample (35.9% and 37.1%, respectively).  Because Vochysia guatemalensis supported a herpetofaunal assemblage most similar to primary forest, my results show that Vochysia plantations were the best planatation type to provide refuges for the native herpetofauna of the Caribbean lowlands of Costa Rica.






- Accepted in to the Biological and Biomedical Sciences PhD 
program at Vanderbilt University
Thesis Title: 
Enzymatic activities and protein levels indicate antioxidant 
capacities are not modulated by acclimation temperature in 
skeletal and cardiac muscles of striped bass, Morone saxatilis.

Advisor: Dr. Lisa Crockett, Biological Sciences
Program:  Biological Sciences Senior Honors Program
Research Summary:
In response to exposure to cold temperatures, fish experience two major physiological adjustments.  The first is an increase in mitochondrial content and as a result, an increase in negative byproducts of oxidative phosphorylation called reactive oxygen species (ROS).  The second is a change in the composition of the cellular membranes, specifically an increase in fatty acids that have more than two double bonds (polyunsaturated fatty acids).  Even though both of these physiological adjustments can have negative effects on the organism, there are antioxidant enzymes that provide a natural defense to protect the cells.  In my study, I looked at three specific antioxidant enzymes and how their activities and quantities increased in skeletal and cardiac muscle of striped bass that were exposed to cold temperatures.



-accepted into the Masters program in Evolution, Ecology, and Organismal Biology at the Ohio State University

Honors Thesis title:

Postcranial skeletal pneumaticity, bone structure, and foraging style in two clades of neognath birds.

Advisor: Dr. Patrick O'Connor, Biomedical Sciences
Program:  Honors Tutorial College, Biological Sciences
Research Summary:

 Postcranial pneumaticity is the invasion of the postcranial skeleton by outgrowths from the air sacs, resulting in the bones being air-filled.  Within birds, there is a large degree of variability in the extent of pneumaticity.  Past research has hypothesized that pneumaticity may have evolved in relation to body mass and foraging styles as a way of reducing energetic cost of locomotion.  I explored these concepts in two orders of birds, Charadriiforms and Pelecaniforms.  I also examined the relationship between pneumaticity/ foraging style and bone structure.



- heading to the Dr. Joe Cook's lab at the University of New Mexico to work on a M.S. degree on small mammal phylogeography and evolutionary genetics.

Honors Thesis title:

Stock structure, management, and phylogeography of muskellunge.

Advisor: Matt White
Program: Honors Tutorial College-Biological Sciences major

Research Summary:
Abstract:  The muskellunge is a commercially important fish species native to Ohio and the surrounding region of the United States.  For the most effective management of the species, we need information about the genetic variation and differentiation among populations.  Distinct genetic groups, or stocks, should be managed as separate management units.  I examined the genetic stock structure and variation of muskellunge at the species level as well as at a the local population level in Ohio.  This was done by analyzing mitochondrial DNA sequence variation and microsatellite variation, respectively.  At the species level, there was no evidence of stock structure, suggesting the current subspecies for muskellunge are invalid.  At the population level, there was considerable genetic diversity and population differentiation, which means the populations should be managed as distinct units.