A study was done on the zoogeography of species of oceanic
shrimp in the North Pacific from 22°N to 56°N and from 124°W to
145°E, using samples of shrimp collected from 1954 to 1969. These
collections were made during the following cruises: John R. Manning
Cruise 22, and the Hugh...
With continual and worldwide human population growth, our impact on the natural environment expands and intensifies every day. We consume natural resources, burn fossil fuels, and release toxic compounds into the air, water, and earth. We build roads that fragment the landscape, construct new settlements, and develop agricultural lands in...
Eggs, larvae and adults of the four subspecies of Hy la regilla
occurring in Oregon as given by Jameson, Mackey and Richmond
(1966) were collected and subjected to salt stress in a series of
graded seawaters.
It was found that in all cases adults were more tolerant than
larvae and...
My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male...
My thesis explored the effects of and potential mediating mechanisms for an important environmental stressor, ultraviolet-B (UVB) radiation. UVB radiation has negative effects on organisms in both terrestrial and aquatic systems. I used meta-analysis to quantify the effects of UVB radiation on a diversity of aquatic organisms (Chapter 2). UVB...
The presence of the etiologic agent of "salmon poisoning"
disease, Neorickettsia helminthoeca, was demonstrated in eggs of
the trematode vector, Nanophyetus salmincola. Three dogs were
given 100,000 and one dog 82,000 ground fluke eggs by intraperitoneal
injection. The four animals developed "salmon poisoning"
disease and died. One of these dogs...
Primary monolayer cultures of chick renal epithelial cells
grown on plastic coverslips were reversibly dissociated with the
chelating agent ethylenediaminetetraacetic acid (EDTA). The cellular
responses during dissociation and reaggregation in Hank's balanced
salt solution (BSS) were observed with phase optics and recorded
by time-lapse cinemicrography.
The epithelial cells grow as...
Coral reefs have become vulnerable to climate change, with mass bleaching events, the loss of symbiotic algae (Symbiodiniaceae), increasing in both frequency and severity. As climate change continues to threaten the persistence and existence of coral reefs around the world, the biggest question posed for coral reefs is “can they...
In recent years, studies dealing with temperature regulation,
temperature sensitivity, and physiological responses to temperature
in lizards and other reptiles have increased tremendously. It is
notable that snakes have been largely ignored in such studies. This
no doubt is due to their less direct relationship to ancestral endotherms.
However, problems...
This study investigated several physiological aspects of the
water economy of the Sage Sparrow, Amphispiza belli nevadensis,as
they relate to the ability of this species to inhabit xeric desert environments.
When maintained in captivity on a dry diet without
drinking water, Sage Sparrows gradually lost weight and died. During the...
An investigation was undertaken to determine the role that temperature might play in limiting the distribution of the mountain beaver, Aplodontia rufa. A field study was carried on from August, 1965, through August, 1966, in the coast mountains of Benton County, Oregon, and consisted of measuring the annual temperature cycle...
Biological invasions pose one of the greatest threats to global biodiversity, but many naturalized invaders coexist with the native community. Community ecology theory provides a framework for understanding the mechanisms by which invaders might coexist with native species or exclude them from the community, thus informing management practices to maximize...
The influence of the physical environment on organisms has long been a subject of ecological research. But, the complex drivers of environmental variation, and the multiple scales at which this can occur, make studying this topic a difficult challenge. In rocky intertidal habitats, oceanographic- and climate-scale variability influence benthic communities...
Little, if any, quantifications have been made on the contribution of the vertebral column during jumping in quadrupedal mammals. Previous studies of jumpers have focused on the morphological and physiological specializations of the hindlimbs. In this study, such specialization was measured during the supramaximal jumps of the Pacific jumping mouse...
These studies examined the role of perinatal androgen
in the development of neuroendocrine and behavioral
characteristics of gray-tailed voles, Microtus
canicaudus. When mature, females exhibited alternating
vaginal smear patterns or persistent vaginal
cornification; estrogen and progesterone concentrations
were not correlated with vaginal smear patterns. Corpora
lutea were not observed in...
The high productivity of Eastern Boundary Upwelling Ecosystems (EBUE), some of the most productive ecosystems in the globe, is attributed to the nutrient rich waters brought up through upwelling. Climate change scenarios for coastal upwelling systems, predict an intensification of coastal upwelling winds. Associated with intensification in upwelling are biogeochemical...
One hypothesis proposed to explain how the endocrine
system controls reproductive cycles in seasonally breeding
animals is that the hypothalamus undergoes seasonal
changes in sensitivity to negative feedback by gonadal
steroids. The result is seasonal changes in the secretion
of luteinizing hormone-releasing hormone (LHRH) and
gonadotropin secretion. The present experiments...
Cnidarians, such as corals and sea anemones serve as hosts to a variety of organisms including symbiotic dinoflagellates, bacteria, virus, and apicomplexans. As corals are vital to the health and productivity of the reef ecosystem it is important to understand how these organisms interact with each component of the holobiont....
Ecosystems are facing increasing threats from human related activities, such as overfishing, pollution, habitat destruction, species invasions, and diseases, among others. While oceanic islands provide natural laboratories to understand ecological and evolutionary process, they are also particularly vulnerable to these impacts, given their usual isolation from the mainland and the...
Birds affected the community structure of an Oregon rocky shore by
preying upon mussels (Mytilus spp.) and limpets (Collisella spp.). The
impact of such predation is potentially great, as mussels are the
competitively dominant mid-intertidal space-occupiers, and limpets are
important herbivores in this community.
Prey selection by birds reflects differences...
An investigation was undertaken to determine if respiratory
changes might occur in conjunction with migrations of the rough-skinned
newt, Taricha granulosa (Skilton) in and out of ponds in the
Willamette Valley. A field study was carried on from December
1964 through October 1965 to investigate certain physical and
chemical parameters...
This is a neuroanatomical and ethological study of the pectines, the primary
chemosensory organs of scorpions (Arachnida: Scorpiones). The pectines are
paired, ventromedial appendages that brush the substrate as the scorpion walks.
This comb-like organ consists of a supportive spine and an array of teeth. Each
tooth supports hundreds of...
The 13 species of shrimps studied for this thesis were collected
off the Oregon coast. The family Oplophoridae is well represented
in this area. Five of the seven known genera were identified.
Hymenodora frontalis, H. glacialis, and H. gracilis were described
and further differentiating characters were illustrated. Other members
of...
The gastrula of the sea urchin Strongylocentrotus purpuratus
was dissociated into single cells. In culture these cells appeared
apolar, but reassembled into quasi-normal embryos composed of
structures with polarized cells. In this study emphasis was placed on
those morphological events coincident with the reestablishment of a
polar orientation within the...
Thais (Nucella) emarginata is a common predatory gastropod of the
rocky intertidal system of western North America. It is usually found at
low tide on top of its sedentary prey, barnacles and mussels. Thais
is also highly polymorphic for shell color, and breeding of isolated
females has shown that the...
The stages in the life history of the parasitic copepod Nectobrachia
indivisa Fraser, 1920, have been described.
The adult female lives permanently attached to the gills of the
starry flounder, Platichthys stellatus (Pallas, 1811) Girard, 1854.
The adult male is a dwarf, which usually lives attached to the genital
process...
The fish Cymatogaster aggregata, Embiotoca lateralis and
Phanerodon furcatus served as definitive hosts for the trematode
Telolecithus pugetensis Lloyd and Guberlet. Eggs that were collected
from the terminal part of the uterus of mature worms were found to
have undergone several cleavages, but complete development was
observed only in some...
Biological invasions provide a unique opportunity to study the mechanisms that regulate community composition and ecosystem function. Invasive species that are also ecosystem engineers can substantially alter physical features in an environment, and this can lead to cascading effects on the biological community. Aquatic-terrestrial interface ecosystems are excellent systems to...
(Brandt) were surveyed for the presence of polyploid cells.
Large polyploid cells were found in the hepatic cecum, gut
and sheath of the testis.
The relative DNA content of the polyploid nuclei was
measured by means of two wavelength cytophotometry. Histograms
plotted from the data provide information on the level...
The histopathological and histochemical effects on the snail
Oxytrema siliqua, caused by the larvae of Nanophyetus salmincola,
have been studied. The parasite causes damage to the organ by increased
pressure, active ingestion of the hepatic tubules, and by
the increased burden placed upon the snail in disposing of the waste...
The patterns of cell proliferation in the choroid plexuses of
embryonic and post-natal hamsters were studied by means of auto-radiography
(H³-thymidine). In addition, the PAS technique was
used to determine the times of first appearance, relative amounts,
location, and times of disappearance of glycogen free the plexuses.
Many mitotic figures...
Prior to the present work, no detailed study had been made of
the amphibians and reptiles inhabiting Benton County, Oregon. Very
little has been published on the precise ranges, the habitat preferences,
and the mode of life history of these animals as they are
found in Benton County and adjacent...
This study deals with the autoradiographic analysis, using a
DNA precursor (tritiated thymidine), of the trophoblastic giant cells
in the placentae of the golden hamster (Mesocricetus auratus Waterhouse),
beginning with the sixth day of gestation and extending to term
on day sixteen. Both the percent of labelled cells in the...
The gills of an Oregon crayfish, Pacifastacus leniusculus Dana,
were examined with histological and histochemical techniques and
their fine structure was investigated by electron microscopy. Special
attention was given to the structural basis of active ion uptake.
The histology of these gills was the same as that of other crayfish...
The spermiogenesis of Mytilus edulis (a marine mussel) has
been studied, employing techniques of light and electron microscopy
and cytochemical preparations. The observations trace the development
of the acrosomal complex, the nucleus, the mitochondrial
middle-piece, and the flagellum.
In early spermatids numerous membrane-bounded proacrosomal
vesicles arise from several Golgi complexes...
Investigations about the feeding ecology of a consumer
can facilitate prediction of its effects on prey populations
and the biological community. The aspects of feeding
ecology that are important to predicting consumer effects
include foraging movements, feeding preference and
selectivity, and the effects of physical factors on foraging
behavior and...
Developing sea urchin eggs (Strongylocentrotus purpuratus),
reared at 15° C, were subjected to single 15-minute treatments with
disodium versenate in calcium-free sea water, applied at 10-minute
intervals, from 4 minutes after insemination to the second cleavage.
These versene pulses produced specific degrees of retardation in
the mitotic process and delayed...
During karyokinesis in the ciliate, Tetrahymena pyriformis, strain GL-I, an extranuclear chromatin body (ECB) is frequently formed as an excluded mass between the two dividing daughter macronuclei. The formation and fate of ECB's were followed by means of Feu lgen, toluidine blue 0, and euchrysine staining and autoradiography (³H-thymidine). The...
I examined two amphibian communities to assess factors
that may impact amphibian biodiversity. The results suggest
that the potential factors which influence the maintenance
of amphibian biodiversity are multi-faceted and thus,
attempts to understand these factors must reflect these
complexities.
I investigated factors that influenced the susceptibility
of western toad...
Some parasites may modify the behavior of their
hosts. Altered behaviors may: 1) benefit the host in
that they defend against the pathogen, 2) benefit the
pathogen and represent manipulations of the host
response, and 3) benefit neither the host or the
pathogen and simply be a product of the...