How species will respond to ongoing and future climate change is one of the most important questions facing biodiversity scientists today. The fossil record provides unparalleled insight into past ecological and evolutionary responses to climate change, but the resource remains virtually untapped for many organisms. We use geometric morphometrics and a 25,000 year fossil record to quantify changes in body size and mandible shape through time and across climate regimes for two bat species present in Quaternary paleontological deposits of central Texas: Myotis velifer, a bat distributed throughout the Southwestern US and Mexico that is still found in central Texas today, and Eptesicus fuscus, a bat widely distributed throughout North America that has been extirpated in central Texas. Because of ecogeographic rules like Bergmann’s rule, which posits that endotherms are larger in colder environments, we hypothesized that both species were larger during cooler time intervals. Additionally, we hypothesized that both species would show variation in dental morphology across the studied sequence as a response to climate change. While we found a decrease in centroid size–a proxy for body size–through time for both species, we could not establish a clear relationship between centroid size and temperature alone. However, we did find that specimens from drier environments were significantly larger than those from wetter ones. Furthermore, we found significant dental shape variation between environments reflecting different temperature levels for both species. Yet only M. velifer exhibited significant variation between environments of varying precipitation levels. This result was surprising because present-day populations of E. fuscus are highly variable across both temperature and precipitation gradients. We determined that the morphological change experienced by M. velifer through time, and between warmer and cooler temperatures, was associated with the coronoid process, condylar process, and the mandibular symphysis. These parts play a pivotal role in bite force, so changes in these features might relate to changes in diet. We show that long-term datasets derived from fossil material provide invaluable insight not only into the validity of ecogeographic rules, but also into the adaptive capacities of extant taxa when faced with environmental changes. Our results highlight diverging responses to a variety of climate factors that are relevant to consider in biodiversity research given ongoing global change.
The purpose of this study was to demonstrate the desire and need for peer-to-peer tutoring programs at Division 1 Dell Medical School at the University of Texas. Materials and Methods. Two sets of surveys were created and sent to students at the Dell Medical School, University of Texas, USA. One survey asking about the need or desire to engage with a peer tutor was sent to first-year students, and another one asking about the desire to provide these services to underclassmen as a potential leadership course option was sent to third-year students. Results. For the first-year student survey, 52.9% of respondents disagreed or strongly disagreed of being aware of near-peer tutoring and 70.5% of respondents either agreed or strongly agreed that it would be an option utilized by students. For the third-year student survey, 75% of students either disagreed or felt neutral in being aware of near-peer tutoring as an option to serve underclassmen, whereas 65% of upperclassmen either agreed or strongly agreed that if near-peer tutoring had been offered, they would have chosen this leadership course option in the effort to teach their underclassmen peers. Conclusions. Numerous studies have demonstrated peer-to-peer tutorial options to be of high utility to students in the medical education space. This particular paper obtained results demonstrating students’ desire to engage in peer tutoring voluntarily for their own course success goals and upperclassmen’s desire to participate as near-peer tutors for the benefit of underclassmen.
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