Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors.

At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10-30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0-2.5 °C, during daily fluctuations that often exceeded 15°-20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on 'habitat-level' measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature.

Graduate students' teaching experiences improve their methodological research skills.

Science, technology, engineering, and mathematics (STEM) graduate students are often encouraged to maximize their engagement with supervised research and minimize teaching obligations. However, the process of teaching students engaged in inquiry provides practice in the application of important research skills. Using a performance rubric, we compared the quality of methodological skills demonstrated in written research proposals for two groups of early career graduate students (those with both teaching and research responsibilities and those with only research responsibilities) at the beginning and end of an academic year. After statistically controlling for preexisting differences between groups, students who both taught and conducted research demonstrate significantly greater improvement in their abilities to generate testable hypotheses and design valid experiments. These results indicate that teaching experience can contribute substantially to the improvement of essential research skills.

Curricular reform and inquiry teaching in biology: where are our efforts most fruitfully invested?

University faculty often express frustration with the accuracy of students' understanding of science in general and of evolution in particular. A rich research literature suggests that inquiry-based pedagogies are more effective in producing meaningful learning than are traditional, didactic approaches. A pragmatic investigation into the efficacy of inquiry-based curricular reforms compared to traditional laboratory activities was undertaken in the introductory biology course for majors at a large state university in the southeastern United States. The topics of the course focused on biodiversity, evolution, and plant and animal anatomy and physiology. Students' learning in the inquiry versus traditional units was compared using both a test of pre-post content knowledge as well as open-ended written responses in which students described events in which there was meaningful learning and conceptual changes. The pre-post tests were replicated over five semesters of the same course (n = 1493 students). Students' misconceptions as well as examples of meaningful learning were gathered for two semesters in the same course (n = 518 students). Results consistently revealed that descriptive, concrete topics such as anatomy can be taught effectively using traditional didactic methods; average effect sizes (a measure of the difference between pretest scores and posttest scores) range from 1.8 to 2.1. The inquiry units also increased knowledge of content on the topics of evolution and biodiversity by a significant degree (average effect sizes range from 1.0 to 1.1), despite the fact that students spent less than half the instructional time on these units compared to the didactic units. In addition, a literature review indicated that highly abstract or mathematical concepts such as evolution or geologic time require greater formal reasoning ability and that students often show lesser gains in these areas compared to more concrete topics. It was therefore especially notable that the frequency of meaningful learning events was significantly higher in the units on evolution compared to the traditional units (χ(2) P < 0.5 to 0.001). A catalog of students' misconceptions (some of which were quite unexpected) was also generated and found useful for future teaching. Therefore, we feel that when time and resources for curricular reform are limited, those efforts should prioritize abstract and foundational topics such as evolution. Didactic teaching appears sufficient for more concrete topics such as anatomy.

Microsatellite DNA analyses support an east-west phylogeographic split of American alligator populations.

We examined the population genetic structure of American alligators (Alligator mississippiensis) sampled from 12 localities across the southeastern United States. The primary goal of this study was to determine the extent of population differentiation among alligators from four Florida lakes using eight microsatellite loci and compare the results to additional sites located at varying distances from them. Analyses of population structure revealed little differentiation (F(ST)=0.039; Rho=0.012) among the four Florida lakes, Apopka, Griffin, Orange and Woodruff, which are all located in the St. John&'s River watershed in north-central Florida. Further, there was little differentiation among these samples and samples collected from the Everglades National Park (F(ST)=0.044; Rho=0.009) and south Georgia (F(ST)=0.045; Rho=0.032). Therefore, these six samples were pooled together as a "FL/sGA group." Similarly, samples collected in the western extent of the range, Anahuac National Wildlife Refuge in Texas and Salvador Wildlife Management Area, Marsh Island Wildlife Refuge and Rockefeller Wildlife Refuge in Louisiana, also lacked population structure (F(ST)=0.024; R(ST)=0.040). These four populations were pooled into the "TX/LA group." Comparisons of these two groups with samples taken from the Santee Coastal Reserve in South Carolina and Mobile, Alabama yielded three to four times more differentiation among groups (F(ST)=0.131; Rho=0.187). These and other analyses support the hypothesis of an east-west phylogeographic split in American alligator populations and are consistent with studies of many freshwater fish and aquatic and terrestrial turtles distributed throughout this same geographic region.