Digital Commons Network^™

Biogeography Of Microorganisms Inhabiting Marine Sponges, Suzy C. Szumowski

Macalester Reviews in Biogeography

Sponge-associated microorganisms are an intriguing system for the consideration of biogeographic patterns due to complications arising from their small size and their symbiotic relationship with sponges. Whether or not microorganisms are capable of exhibiting biogeographic patterns is a topic of heated debate in the literature. Recent studies utilizing new identification techniques have revealed an astonishing amount of diversity and spatiotemporal stability in microorganism communities. Case studies outlined in this paper suggest that some sponge-associated microorganisms represent monophyletic groups that have evolved speciesspecific associations with their hosts. The biogeography of these organisms is receiving increasing attention because they are one of …

Controls On Microbial Community Structure In Thermal Environments : Exploring Bacterial Diversity And The Relative Influence Of Geochemistry And Geography, Kendra Renee Mitchell

Biology ETDs

Community wide molecular surveys have revealed incredible hidden phylogenetic and metabolic diversity in microbial habitats. We have conducted the first microbial survey of Yellowstone National Park thermal environments, sampling 103 communities from across the park and across the range of conditions found. Yellowstone is particularly suited for this type of research because of the large number and wide variety of thermal springs, which are naturally occurring chemostats enabling examination of the factors that control microbes and drive community structure. In addition to samples for molecular microbial analysis, we collected water for extensive geochemical analysis in order to begin to deduce …

From Cells To Coastlines: How Can We Use Physiology To Forecast The Impacts Of Climate Change?, Brian Helmuth

Faculty Publications

The interdisciplinary fields of conservation physiology, macrophysiology, and mechanistic ecological forecasting have recently emerged as means of integrating detailed physiological responses to the broader questions of ecological and evolutionary responses to global climate change. Bridging the gap between large-scale records of weather and climate (as measured by remote sensing platforms, buoys and ground-based weather stations) and the physical world as experienced by organisms (niche-level measurements) requires a mechanistic understanding of how ‘environmental signals’ (parameters such as air, surface and water temperature, food availability, water flow) are translated into signals at the scale of the organism or cell (e.g. body temperature, …

Parallel Shifts In Ecology And Natural Selection In An Island Lizard, Ryan Calsbeek, Wolfgang Buermann, Thomas B. Smith

Dartmouth Scholarship

Natural selection is a potent evolutionary force that shapes phenotypic variation to match ecological conditions. However, we know little about the year-to-year consistency of selection, or how inter-annual variation in ecology shapes adaptive landscapes and ultimately adaptive radiations. Here we combine remote sensing data, field experiments, and a four-year study of natural selection to show that changes in vegetation structure associated with a severe drought altered both habitat use and natural selection in the brown anole, Anolis sagrei.

Results: In natural populations, lizards increased their use of vegetation in wet years and this was correlated with selection on limb length …