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Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are(More)
BACKGROUND Polar bears (Ursus maritimus) are among those species most susceptible to the rapidly changing arctic climate, and their survival is of global concern. Despite this, little is known about polar bear species history. Future conservation strategies would significantly benefit from an understanding of basic evolutionary information, such as the(More)
After a decade with nine of the lowest arctic sea-ice minima on record, including the historically low minimum in 2012, we synthesize recent developments in the study of ecological responses to sea-ice decline. Sea-ice loss emerges as an important driver of marine and terrestrial ecological dynamics, influencing productivity, species interactions,(More)
Collared lemmings (genus Dicrostonyx) are circumpolar Arctic arvicoline rodents associated with tundra. However, during the last glacial maximum (LGM), Dicrostonyx lived along the southern ice margin of the Laurentide ice sheet in communities comprising both temperate and boreal species. To better understand these communities and the fate of these southern(More)
Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty,(More)
Steamer ducks (Tachyeres) comprise four species, three of which are flightless. The flightless species are believed to have diverged from a flying common ancestor during the Late Pleistocene; however, their taxonomy remains contentious. Of particular interest is the previously unstudied population of flying steamer ducks in the Falkland Islands. We present(More)
Passenger Pigeons (Ectopistes migratorius) were once the most abundant bird in North America, with flock sizes estimated in the billions. However, by the turn of the 20th century, this previously abundant species had been driven to extinction. Morphological analyses linked the Passenger Pigeon with the New World mourning doves of the genus Zenaida. However,(More)
Keywords: Northern pike Esox lucius Stable isotopes Beringia Biogeography Ancient DNA Paleolimnology Holocene Alaska a b s t r a c t The biogeography of freshwater fish species during and after late-Pleistocene glaciations relate to how these species are genetically organized today, and the management of these often disjunct populations. Debate exists(More)
A scimitar-toothed cat (Homotherium serum) and stag moose (Cervalces sp.) are described from Tyson Spring Cave, Fillmore County, Minnesota. These specimens represent the first records of both species in the state, and the first record for H. serum in the Great Lakes region. Although the Cervalces specimen remains undated, it shares features with(More)
Position responsibilities  Provide leadership to a team of one department head, 20-25 library faculty members, 5-7 lecturers, and 25-30 professional and clerical staff. Ensure a working environment that fosters excellent customer service, innovation, and teamwork. Handle collective bargaining contractual responsibilities for six distinct unions.  Evolve(More)