Browsing Biology Faculty Research, Publications and Presentations by Submit Date
Now showing items 61-80 of 185
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Development of the blood and muscle oxygen stores in gray seals (Halichoerus grypus): Implications for juvenile diving capacity and the necessity of a terrestrial postweaning fast
To successfully transition from nursing to foraging, phocid seal pups must develop adequate diving physiology within the limited time between birth and their first independent foraging trip to sea. We studied the postpartum ... -
Body condition at weaning affects the duration of the postweaning fast in gray seal pups (Halichoerus grypus)
Gray seals (Halichoerus grypus) undergo a terrestrial postweaning fast (PWF) that depletes energy reserves acquired during the suckling interval. Plasticity in PWF duration may ensure that pups of variable body condition ... -
Polar Bear Diets and Arctic Marine Food Webs: Insights from Fatty Acid Analysis
We used quantitative fatty acid signature analysis (QFASA) to examine the diets of 1738 individual polar bears (Ursus maritimus) sampled across the Canadian Arctic over a 30-year span. Polar bear foraging varied over ... -
Pollen limitation of plant reproduction: Ecological and evolutionary causes and consequences
Determining whether seed production is pollen limited has been an area of intensive empirical study over the last two decades. Yet current evidence does not allow satisfactory assessment of the causes or consequences of ... -
Male and female pollination success in a deceptive orchid, a selection study
We carried out phenotypic selection analyses to assess the relative importance of several Horal traits, as well as microhabitat, in determining both male and female pollination success in a nonrewarding orchid (Cypripedium ... -
Correlations among Fertility Components Can Maintain Mixed Mating in Plants
Classical models studying the evolution of self-fertilization in plants conclude that only complete selfing and complete outcrossing are evolutionarily stable. In contrast with this prediction, 42% of seed-plant species ... -
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Symmetry, change, perturbation, and observing mode in natural communities
Like a kaleidoscope, nature presents continuously fleeting images of natural communities. It has been difficult to discern patterns of community structure in these elusive images. For both theoretical and applied considerations, ... -
Diazotrophic bacteria respond to Saharan dust additions
Three bioassay experiments were performed to study the effects of nutrient and Saharan dust additions on natural diazotrophic communities in the tropical North Atlantic Ocean. Samples for nucleic acid analysis were collected ... -
Compartmental models of nitrogen cycling in tropical and temperate marine environments
Time-course measurements of super(15)N tracer kinetics in particulate organic and in NH super(+) sub(4) pools from tropical and temperate regions were used to test several compartmental models describing the exchange of ... -
Natural Selection, Variation, Adaptation, and Evolution: a Primer of Interrelated Concepts
Natural selection is an elegantly simple concept but one that can manifest in complex ways. I review how the basic model of single-trait viability selection has been extended to more complex forms of selection on multiple ... -
Conservation genetics as applied evolution: from genetic pattern to evolutionary process
Conservation genetics can be seen as the effort to influence the evolutionary process in ways that enhance the persistence of populations. Much published research in the field applies genetic sampling techniques to infer ... -
Adaptive Value and Costs of Physiological Plasticity to Soil Moisture Limitation in Recombinant Inbred Lines of Avena barbata
Costs are hypothesized to constrain the evolution of adaptive phenotypic plasticity, but they have been difficult to quantify because strong selection should eliminate costly genotypes from natural populations. However, ... -
Observer Effects and Avian-Call-Count Survey Quality: Rare-Species Biases and Overconfidence
Wildlife monitoring surveys are prone to nondetection errors and false positives. To determine factors that affect the incidence of these errors, we built an Internet-based survey that simulated avian point counts, and ... -
Sex-specific, seasonal foraging tactics of adult grey seals (Halichoerus grypus) revealed by state-space analysis
In many large pelagic animals, observing behavior is limited to observation by radio or satellite telemetry. In many cases, discriminating different behaviors from telemetry data has been a key, but often elusive, goal. ... -
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The role of development, parental behavior, and nestmate competition in fledging of nestling Tree Swallows
Fledging (i.e. leaving the nest) in altricial birds is a major step toward independence. The timing of this important event may be influenced by nestling development, parental behavior, and sibling interactions. In this ... -
Spatiotemporal Patterns in Nest Box Occupancy by Tree Swallows Across North America
Data from the North American Breeding Bird Survey (BBS) suggest that populations of aerial insectivorous birds are declining, particularly in northeastern regions of the continent, and particularly since the mid-1980s. ... -
Seasonal and Age-Dependent Dietary Partitioning between the Great Black-Backed and Herring Gulls
Studies of seabird diets may reveal subtle ways in which sympatric species partition resources to facilitate co-existence. We studied the variability and partitioning of diets between the Herring (Larus argentatus) and ...
