A recent paper by Kraft, Comita, Chase, EEB faculty member Nate Sanders, Swenson, Crist, Stegen, Vellend, Boyle, Anderson, Cornell, Davies, Freestone, Inouye, Harrison, and Meyers on “Disentangling the Drivers of ? Diversity Along Latitudinal and Elevational Gradients” appeared in today’s Science. This was work done as part of an NCEAS working group.
Abstract:
Understanding spatial variation in biodiversity along environmental gradients is a central theme in ecology. Differences in species compositional turnover among sites (? diversity) occurring along gradients are often used to infer variation in the processes structuring communities. Here, we show that sampling alone predicts changes in ? diversity caused simply by changes in the sizes of species pools. For example, forest inventories sampled along latitudinal and elevational gradients show the well-documented pattern that ? diversity is higher in the tropics and at low elevations. However, after correcting for variation in pooled species richness (? diversity), these differences in ? diversity disappear. Therefore, there is no need to invoke differences in the mechanisms of community assembly in temperate versus tropical systems to explain these global-scale patterns of ? diversity.
Jaime Call, a staff member in the EEB main office, has been named as UTK’s most courteous employee for Sept. 2011. Note that UTK has roughly 15,000 employees, so the competition is fierce.
Below is some of the information used in her nomination:
Jaime Call, a staff member in the EEB main office, has been named as UTK’s most courteous employee for Sept. 2011. Note that UTK has roughly 15,000 employees, so the competition is fierce.
Below is some of the information used in her nomination:
A recent paper in the Proceedings of the National Academy of Sciences by Michael Bode, Lance Bode, and UTK EEB assistant professor Paul Armsworth examines a novel mechanism that maintains diversity in patchy habitats. Abstract is below. See the full paper here.
Abstract: The coexistence of multiple species on a smaller number of limiting resources is an enduring ecological paradox. The mechanisms that maintain such biodiversity are of great interest to ecology and of central importance to conservation. We describe and prove a unique and robust mechanism for coexistence: Species that differ only in their dispersal abilities can coexist, if habitat patches are distributed at irregular distances. This mechanism is straightforward and ecologically intuitive, but can nevertheless create complex coexistence patterns that are robust to substantial environmental stochasticity. The Great Barrier Reef (GBR) is noted for its diversity of reef fish species and its complex arrangement of reef habitat. We demonstrate that this mechanism can allow fish species with different pelagic larval durations to stably coexist in the GBR. Further, coexisting species on the GBR often dominate different subregions, defined primarily by cross-shelf position. Interspecific differences in dispersal ability generate similar coexistence patterns when dispersal is influenced by larval behavior and variable oceanographic conditions. Many marine and terrestrial ecosystems are characterized by patchy habitat distributions and contain coexisting species that have different dispersal abilities. This coexistence mechanism is therefore likely to have ecological relevance beyond reef fish.
The Knoxville News-Sentinel newspaper recently covered the establishment of a UT/ORNL site as one of 20 ecological observatories funded as part of a new $434M national program. Members of EEB will be heavily involved in this research.
Famed ecologist Paul Ehrlich addressed an audience at UT as part of the Baker Center Interdisciplinary Group on Energy and Environmental Policy series.
EEB grad student Premal Shah (now a postdoc in the Plotkin lab at the U. of Pennsylvania) and his adviser, Associate Prof. Mike Gilchrist, recently published a paper in the Proceedings of the National Academy of Sciences on “Explaining complex codon usage patterns with selection for translational efficiency, mutation bias, and genetic drift.”
Abstract: The genetic code is redundant with most amino acids using multiple codons. In many organisms, codon usage is biased toward particular codons. Understanding the adaptive and nonadaptive forces driving the evolution of codon usage bias (CUB) has been an area of intense focus and debate in the fields of molecular and evolutionary biology. However, their relative importance in shaping genomic patterns of CUB remains unsolved. Using a nested model of protein translation and population genetics, we show that observed gene level variation of CUB in Saccharomyces cerevisiae can be explained almost entirely by selection for efficient ribosomal usage, genetic drift, and biased mutation. The correlation between observed codon counts within individual genes and our model predictions is 0.96. Although a variety of factors shape patterns of CUB at the level of individual sites within genes, our results suggest that selection for efficient ribosome usage is a central force in shaping codon usage at the genomic scale. In addition, our model allows direct estimation of codon-specific mutation rates and elongation times and can be readily applied to any organism with high-throughput expression datasets. More generally, we have developed a natural framework for integrating models of molecular processes to population genetics models to quantitatively estimate parameters underlying fundamental biological processes, such a protein translation.
Brandon Matheny and Neale Bougher (Department of Conservation, Western Australia) have received a grant from the Australian Biological Resources Study, in conjunction with matching funds from the Western Australia Naturalists’ Club, Inc., to add a systematic volume to the Fungi of Australia series. The subject of the volume will be the Inocybaceae of Australia, a family of ectomycorrhizal fungi particularly diverse in temperate regions of Australia.