Population genetic structure is widespread in many organisms and can be found at small spatial scales. Fine-scale differentiation is the result of ecological and evolutionary processes working together to produce an overall pattern, but the relative importance of these factors in population differentiation is poorly understood. The goals of my...
An increased understanding of secondary metabolism in fungi is important for both biological and societal reasons. The ascomycete genus, Tolypocladium, is an ideal system to explore secondary metabolism characterization, ecology, evolution and regulation. The genus produces and has the genomic potential to produce a wide array of metabolites. Paired with...
Question: Are there general life-history rules for exploitation-caused extinction of mammal populations?
Mathematical methods: A population of size N faced with the added mortality of human exploitation will deterministically go extinct if its per-capita birth rate can no longer match its per-capita mortality rate as N approaches zero. We develop...
Long-term data sets that quantitatively confirm basic ecological theory are rare for field
populations. Highly variable recruitment often causes wide temporal variation in population
age distribution and basic theory for adaptive sex ratio often predicts ‘sex ratio tracking’ to
match the fluctuating age distribution. Using sex-changing shrimp as a model...
The evolutionary relationship between Frankia and actinorhizal plants was evaluated
by reconstructing molecular phylogenetic trees from nifH, 16S rDNA, and rbcL
nucleotide sequences. Subgroupings in Frankia phylogenetic trees reconstructed from
nifH and from 16S rDNA sequences were consistent in terms of plant origins of Frankia
strains. Although the branching order...
Kelso's theory of Biocultural Evolution states that as culture evolves, the variation between groups diminishes while the variation within groups increases. The theory is tested with stature, cephalic index and nasal index. Means and standard deviations for these traits are examined for 237 ethnic groups. The groups are organized according...
Determination of the Vertebrate pedigree was a
particularly enigmatic problem for evolutionary morphologists
of the early post-Darwinian period. At that time,
practically no characteristics were known by which the
Vertebrates could be linked to any of the other animal
groups. Up to the 1850's, most research in embryology
and anatomy...
Caenorhabditis elegans is arguably the best understood animal on the planet.
Used for over 50 years to study development, we have a vast amount of knowledge of
the inner workings of this worm. Our knowledge is incomplete, however, without
placing this organism in its evolutionary and ecological context. In this...
Rhizopogon vesiculosus is a common ectomycorrhizal (EM) symbiont of Pseudotusga menziesii (Douglas-fir) in the coast range of the Pacific Northwest. The species has been studied for its systematics, genet size, population structure, and competitive ability in several field and experimental studies. This thesis seeks to provide a more thorough characterization...
DRAFT REPORT. In 2013 – 2015, reconnaissance observations were made across non-forest habitats on FS and BLM land in the Coast Range and Cascade foothills within the Salem and Eugene BLM district areas for plant communities that did not fit the USFS Northwest Oregon Non-forest Plant Community guide. Surveys were...
Forest fires contribute a significant amount of CO₂ to the atmosphere each year, and CO₂ emissions from fires are likely to increase under projected conditions of global climate change. In addition to volatilizing aboveground biomass and litter layers, forest fires have a profound effect on belowground carbon (C) pools and...
Hypotheses of phylogenetic and historical zoogeographic relationships of glyptocephalines (Glyptocephalus cynoglossus, G. zachirus, G. stelleri, Microstomus kitt, H. pacificus, H. achne,
Embassichthys bathybius, and Tanakius kitaharae) were constructed based on comparative anatomy and external morphology. The phylogenetic approach was cladistic and character polarity was
determined by using out-group comparison. One...
Background: The owl limpet (Lottia gigantea) is an ectothermic invertebrate that inhabits
the rocky intertidal zone where it territorially defends home ranges and grazes algae growing
on the rocks. Among endothermic species, home range scales isometrically with body mass.
Hypothesis: Home range area scales isometrically (scaling exponent ∼1.0) across individuals...
The term "interaction" in evolutionary biology and ecology
describes the relationships among variables in two classes of causal
models. In the first, "interaction" refers to the influence of a
single putatively causal variable on a variable of interest. In the
second class of models, the term applies when a third...
A fossil-calibrated phylogenetic framework based on exemplars from each of the four taxonomic sections within Pinus was created using multiple nuclear and chloroplast loci. Calibration at the well-defined subgeneric split within Pinus with either fossil leaves and cones (ca. 45 million years ago) or fossil wood (ca. 85 million years...
Measurements of physical tree crown dimensions were of subjective character in the past, even though they can be considered important for the management of many silvicultural operations, such as timing of thinning operations. In our study we investigated if and how measures of physical crown dimensions of trees differed when...
The quantity and characteristics of coarse woody debris (CWD) were examined in four distinct pine ecosystems of north-western (NW) Spain, NW Russia and the NW USA. The average CWD volume and biomass ranged from 3.76 m³ ha⁻¹, 1.55 Mg ha⁻¹ in pine plantations in NW Spain to 24.86 m3 ha⁻¹,...