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Biology

Morphology

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Full-Text Articles in Life Sciences

Assessing Morphology Of Iprgcs After Traumatic Brain Injury, Brian Foresi, Matt Smith Jan 2020

Assessing Morphology Of Iprgcs After Traumatic Brain Injury, Brian Foresi, Matt Smith

Williams Honors College, Honors Research Projects

ipRGCs are retinal ganglion cells that project to visual processing centers of the brain for nonimage forming visual functions. The relation of ipRGCs to tramatic brain injury (TBI) is emerging as data has been published describing ipRGC functional changes in TBI affected military veterans. Major symptomologies of concussions, a mild form of TBI, also overlap with the function governed by sites in the brain with major ipRGC projection percentages. Assesing if a morphological change is occuring in the ipRGCs after a TBI could support the idea of a pathological mechanism of the injury. This study could also indicate further relevance ...


Survival, Growth, And Radula Morphology Of Postlarval Pinto Abalone (Haliotis Kamtschatkana) When Fed Six Species Of Benthic Diatoms, Lillian Miller Kuehl Jan 2020

Survival, Growth, And Radula Morphology Of Postlarval Pinto Abalone (Haliotis Kamtschatkana) When Fed Six Species Of Benthic Diatoms, Lillian Miller Kuehl

WWU Graduate School Collection

Haliotis kamtschatkana Jonas (pinto or northern abalone) is the only abalone native to the Pacific Northwest of North America. Haliotis kamtschatkana populations are in decline, and current restoration efforts in Washington State rely on out-planting hatchery-produced juveniles. Although several other abalone species are cultured extensively, little information exists on the cultivation of H. kamtschatkana, and hatchery production of this species has largely been a matter of trial and error. Hatcheries report highest mortalities in the postlarval stage, especially the first 3 to 6 months. Postlarvae feed on films of benthic diatoms, and the purpose of this study was to test ...


The Functional, Ecological, And Evolutionary Morphology Of Sea Lampreys (Petromyzon Marinus), Bradley Morgan Wood Nov 2019

The Functional, Ecological, And Evolutionary Morphology Of Sea Lampreys (Petromyzon Marinus), Bradley Morgan Wood

LSU Doctoral Dissertations

Lampreys (Petromyzontiformes) are jawless vertebrates with an evolutionary history lasting at least 360 million years and are often used in comparisons with jawed vertebrates because some of their morphological aspects, such as the segmented trunk musculature with curved myosepta and a non-mineralized skeleton fibrous skeleton, are thought to resemble the condition of early vertebrates before the evolution of jaws. Although earlier authors studied the morphology of the skeleto-muscular system of the trunk of lampreys, their studies are not detailed and complete enough to allow a functional and biomechanical analysis that is needed as a basis for modeling the mechanics of ...


How The Egg Rolls: A Morphological Analysis Of Egg Shape In The Context Of Displacement Dynamics, Ian R. Hays Jan 2018

How The Egg Rolls: A Morphological Analysis Of Egg Shape In The Context Of Displacement Dynamics, Ian R. Hays

School of Arts & Sciences Theses

Very little is known about how morphology effects the motion, stability and the resulting viability of avian eggs. The limited research that exists focuses on the pyriform or ‘pointed’ egg shapes found in the Alcidea family. This unusual shell form is thought to suppress displacement and prevents egg loss on the cliffside nesting habitat of the Uria genera. Unfortunately, these studies never isolated or quantify the specific morphological features (elongation, asymmetry and conicality) of these pyriform eggs, which limits their applicability to other taxa and hampers a robust proof of concept. We isolated each feature as a variable, produced models ...


A Characterization Of West Virginia Coyotes (Canis Latrans) Utilizing Skull Morphology, Katharina E. Scholer Jan 2018

A Characterization Of West Virginia Coyotes (Canis Latrans) Utilizing Skull Morphology, Katharina E. Scholer

Theses, Dissertations and Capstones

Coyotes (Canis latrans) are now found throughout North and Central America, but before European colonization were restricted to west of the Mississippi. Migration occurred in two major paths to the East; north over the Great Lakes (through Canada) and south below the Great Lakes. The location of these routes is significant because those migrating north interbred with the wolves that reside there. These hybrid animals are larger and behaviorally different from their western counterparts. It is possible to differentiate these hybrids morphologically and genetically. Hybrids are known to be located in Maine, New York, and Pennsylvania, but the interest of ...


The Integration Of Morphology, Variation, And Phylogenetics To Better Understand Fossil Taxa And Their Modern Relatives, Steven E. Jasinski Jan 2018

The Integration Of Morphology, Variation, And Phylogenetics To Better Understand Fossil Taxa And Their Modern Relatives, Steven E. Jasinski

Publicly Accessible Penn Dissertations

Morphology, or shapes, particularly of bones, is important for understanding how animals vary and, therefore, for understanding diversity. Comparison of morphology in animals can be used to make inferences on fossil organisms. At its base, fossil specimens are described and compared with other fossil and modern specimens, often to determine if they represent a new and distinct species, thereby increasing observed biodiversity through time. Dromaeosaurids (family Dromaeosauridae) are a group of dynamic, swift predatory dinosaurs, that have a sparse fossil record, particularly at the time of their extinction near the Cretaceous-Paleogene boundary. A recently recovered specimen from the latest Cretaceous ...


Morphological And Behavioral Traits Associated With Locomotion In Lizards, Chase T. Kinsey Jan 2018

Morphological And Behavioral Traits Associated With Locomotion In Lizards, Chase T. Kinsey

Electronic Theses and Dissertations

Morphology, locomotion, and behavior are co-adapted to optimize performance and ultimately fitness. Successfully navigating a complex environment is dictated by an animal’s locomotor behavior, and for some behaviors, its locomotor performance. The locomotor performance of an organism is directly related to the form and function of the structures involved in locomotion such that movement is efficient – that is, minimal loss of energy. The first chapter of this thesis focuses on the effects of obstacle placement and forelimb position on facultative bipedalism. Placing an obstacle beyond a lizard’s acceleration threshold did not affect the frequency of bipedal posture. Furthermore ...


The Role Of Phenotypic Integration In Mammalian Tooth Function And Jaw Morphological Diversity, Andrew Conith Jul 2017

The Role Of Phenotypic Integration In Mammalian Tooth Function And Jaw Morphological Diversity, Andrew Conith

Doctoral Dissertations

Here I investigate how two major components of the mammalian feeding system, teeth and jaws, are influenced by functional, environment, and developmental factors. First, I build physical models of the molars from two early mammals, Morganucodon and Kuehneotherium, and compare their ability to process a proxy food item. Early mammals were under strong selection to reduce metabolic costs, so any savings in energy during feeding would be advantageous. I tested the ability of both mammals to process a hard and soft food item with material properties similar to that of the insects they would have likely consumed. Morganucodon was better ...


Functional Trade-Offs In Feeding Performance In Salamanders Of The Family Salamandridae, Charlotte M. Stinson Jun 2017

Functional Trade-Offs In Feeding Performance In Salamanders Of The Family Salamandridae, Charlotte M. Stinson

Graduate Theses and Dissertations

Performance is an organism’s ability to accomplish a particular task or behavior, and morphology can have a major impact on the performance of an organism. Salamanders are ecologically diverse and can feed using a variety of behaviors depending on the environment in which feeding occurs. Feeding is accomplished through the use of the hyobranchial apparatus, which lies along the oropharynx, and this structure can have competing roles; in aquatic environments the apparatus is used for suction feeding and works to depress the floor of the mouth, but during terrestrial feeding this structure projects the tongue forward out of the ...


Spider Brain Morphology & Behavior, Skye M. Long Jul 2016

Spider Brain Morphology & Behavior, Skye M. Long

Doctoral Dissertations

Spiders are ideal model animals for experimental and comparative studies of behavior, learning and perception. They display many complex behaviors, such as the multimodal mating dances of lycosid spiders, the stealthy hunting strategies of the jumping spider Portia sp., to the labile sociality of theridiids. Spiders also demonstrate a wide range of cognitive capabilities. Spiders perceive their environment using multiple sensory modalities including: chemosensory organs; lyriform and slit-sense organs and specialized hairs that detect vibration and air movement; and up to eight eyes that vary in function, some able to detect polarization and a broad spectrum of light, including ultraviolet ...


The Utilization Of Morphological And Genetic Diagnostic Techniques For The Description Of Trematode Species Collected From Waterbirds From Lake Winnibigoshish, Minnesota, Usa, Tyler Joseph Achatz Jan 2016

The Utilization Of Morphological And Genetic Diagnostic Techniques For The Description Of Trematode Species Collected From Waterbirds From Lake Winnibigoshish, Minnesota, Usa, Tyler Joseph Achatz

All Theses, Dissertations, and Other Capstone Projects

Historically, morphological techniques for species identification were the leading diagnostic methodology, however, the increased usage of genetic techniques has led to a decrease in reports of morphometrics. The decrease in morphological reports increases the chance of missing diagnostic morphometrics. The three studies described herein used morphological and genetic diagnostic methods to identify trematodes from five families in order to improve genetic and morphological information for trematode species identification.

The first study identified ten species of trematodes from intestines of waterbirds previously collected from Lake Winnibigoshish, Minnesota. Nine of the species were sequenced for 28S ribosomal DNA (rDNA). Two species were ...


The Reproductive Biology Of The Finetooth Shark, Carcharhinus Isodon, In The Northwest Atlantic Ocean, Amanda Brown Jan 2015

The Reproductive Biology Of The Finetooth Shark, Carcharhinus Isodon, In The Northwest Atlantic Ocean, Amanda Brown

UNF Graduate Theses and Dissertations

Shark fisheries are a multimillion dollar industry in the United States and have significant contributions both recreationally and commercially. In order to maintain this industry, fisheries must be properly managed. An understanding of life history and reproduction is crucial in order to adequately manage shark fisheries. The finetooth shark, Carcharhinus isodon, is a member of the small coastal shark (SCS) fishery complex. It is found in Atlantic waters from South Carolina to Florida and throughout the Gulf of Mexico. This species has recently come under increased fishing pressure and has previously been overfished. New data is needed in order to ...


Phylogeny, Taxonomy And Morphological Evolution In Conostegia (Melastomataceae: Miconieae), Ricardo Kriebel Feb 2014

Phylogeny, Taxonomy And Morphological Evolution In Conostegia (Melastomataceae: Miconieae), Ricardo Kriebel

All Dissertations, Theses, and Capstone Projects

The genus Conostegia comprises 77 species of shrubs and trees ranging from Central America to northern South America and the Caribbean. They are ecologically important as they provide pollen for native bees and fruits for birds. One of the main questions of this study is if the genus Conostegia is actually monophyletic. I address this question for the first time by gathering genetic data from four chloroplast regions and two nuclear ribosomal regions of DNA. Phylogenetic analyses of these data revealed that Conostegia is not monophyletic and that a group of species in the genera Clidemia and Miconia fall within ...


A Morphological And Genetic Analysis Of Forensically Important Blow Flies, From Georgia: The Genus Lucilia, Katie S. Googe Jan 2014

A Morphological And Genetic Analysis Of Forensically Important Blow Flies, From Georgia: The Genus Lucilia, Katie S. Googe

University Honors Program Theses

Identification of Blow flies (Diptera: Calliphoridae) to species is important for estimating postmortem intervals, because insect species develop at different rates. Three Blow fly species in Georgia; Lucilia coeruleiviridis, L. cuprina, and L. sericata are similar morphologically, making identification difficult. Furthermore, the status of L. cuprina is in doubt; this species may be a complex of true L. cuprina, and L. cuprina x L. sericata hybrids. The objective of this study was to survey the Georgia Blow fly community and validate the statuses of L. coeruleiviridis, L. cuprina, and L. sericata, through morphological and genetic analyses. For a representative sample ...


Testing Subspecies Limits In Monardella Villosa, Taylor Mclaughlin Crow Mr. Jun 2013

Testing Subspecies Limits In Monardella Villosa, Taylor Mclaughlin Crow Mr.

Master's Theses and Project Reports

Several subspecies of Monardella villosa (California Coyote Mint) have been distinguished on the basis of leaf thickness, shape, and trichome characteristics, yet many intermediates are known. We investigated morphological differences in natural populations of two subspecies (M. v. subsp. villosa and M. v. subsp. franciscana) in the Scott Creek watershed, north of Davenport, in Santa Cruz County, CA. Monardella villosa subsp. franciscana grows in coastal scrub in gulches and ocean terraces whereas subsp. villosa grows at more protected inland sites. Morphological difference between subspecies may be adaptations to these different habitats. I grew plants in a common garden at Cal ...


Fossil Trachemys (Testudines: Emydidae) From The Late Hemphillian Of Eastern Tennessee And Its Implications For The Evolution Of The Emydidae, Steven E. Jasinski May 2013

Fossil Trachemys (Testudines: Emydidae) From The Late Hemphillian Of Eastern Tennessee And Its Implications For The Evolution Of The Emydidae, Steven E. Jasinski

Electronic Theses and Dissertations

Trachemys (Testudines: Emydidae) represents one of the most well-known turtles today. The evolution of Trachemys, while being heavily documented with various fossil representatives, is not well understood. Numerous fossils from the Gray Fossil Site in northeastern Tennessee are helping to elucidate the taxon’s evolution. The fossil Trachemys at the Gray Fossil Site represent a new species. A review of previously named Trachemys taxa reveals that a huge majority of them are not valid or have been previously misinterpreted. A phylogenetic analysis preformed on modern emydids and supposed fossil representatives of those genera also shows the evolution of a portion ...


Understanding Biodiversity: The Importance Of Sexual Dimorphism In The Micro- And Macroevolution Of Hummingbirds, Chelsea Marie Berns Jan 2013

Understanding Biodiversity: The Importance Of Sexual Dimorphism In The Micro- And Macroevolution Of Hummingbirds, Chelsea Marie Berns

Graduate Theses and Dissertations

ABSTRACT

For centuries, biologists have asked "why are there so many species, and why do we see such magnificent biological diversity?" This dissertation addresses this question by examining sexual size and shape dimorphism hummingbird bills at both a micro and macroevolutionary scale. Specifically, I quantify sexual size and shape dimorphism of bill morphology of 269 species of hummingbirds and begin with a species-level study to find that community structure might be a driving factor in the evolution of sexual size dimorphism in 2 sister species of hummingbirds, and the presence of sexual shape dimorphism in one of those species.

I ...


Nutrient Availability Affects Flowering Rate But Has Limited Influence On Morphology Of The Hooded Pitcher Plant, Sarracenia Minor., Justin M. Lemmons Jan 2013

Nutrient Availability Affects Flowering Rate But Has Limited Influence On Morphology Of The Hooded Pitcher Plant, Sarracenia Minor., Justin M. Lemmons

UNF Graduate Theses and Dissertations

Carnivorous plants perform as both producers and consumers. Botanical carnivory has evolved in sunny, moist, nutrient-poor environments, and the primary nutrient supplied by prey is proposed to be nitrogen. There is a trade-off between carnivorous and photosynthetic structures which corresponds to degree of carnivory expression and available nutrients. This study was conducted on the hooded pitcher plant, Sarracenia minor, which is a facultative wetland plant and Florida-threatened species. Sarracenia minor is considered a specialist myrmecophage and ants characterize the majority of attracted and captured prey. Ants not only provide nutritional benefit, but also protection against herbivory. A natural population of ...


The Effects Of Locomotor Posture On Kinematics, Performance And Behavior During Obstacle Negotiation In Lizards, Jessica Self Oct 2012

The Effects Of Locomotor Posture On Kinematics, Performance And Behavior During Obstacle Negotiation In Lizards, Jessica Self

Electronic Theses and Dissertations

The ability to efficiently move over uneven terrain is critical for most terrestrial animals. Bipedal running is common in lizard species, however the biological advantage of a bipedal running posture remains uncertain. I examined the hypothesis that a bipedal posture is advantageous when crossing obstacles. Particularly, I determined whether kinematic adjustments differ among four focal species with contrasting body forms and ecology. I also examined how sprint speed changed when crossing obstacles with a quadrupedal versus a bipedal posture. I quantified kinematics from high-speed video (300 frames/second) of lizards running down a 3m runway both with and without the ...


The Role Of Kitlb On Development Of Coordinated Muscular Contractions In The Zebrafish Gastrointestinal Tract, Brittany A. Heatherington Aug 2012

The Role Of Kitlb On Development Of Coordinated Muscular Contractions In The Zebrafish Gastrointestinal Tract, Brittany A. Heatherington

Biology Master’s Theses

Gastrointestinal (GI) motility is the spontaneous rhythmic contractions of smooth muscles that mix and propel the contents of the GI tract. Regulation of the complex muscular contractions is controlled by smooth muscles, interstitial cells of the Cajal (ICC) and enteric neurons. ICC act as pacemaker cells in the GI tract and set the frequency of spontaneous contractions. Altering ICC density results in uncoordinated GI muscular contractions. Our lab examines the role of

ICC in GI motility and is focused on mechanisms that regulate ICC growth and development. Expression of the Kit receptor tyrosine kinase is used to identify ICC. Kit ...


Influence Of Substrate And Hydraulic Variables On Habitat Preferences Of A Sculptured And An Unsculptured Freshwater Mussel, Daniel Goodding Apr 2012

Influence Of Substrate And Hydraulic Variables On Habitat Preferences Of A Sculptured And An Unsculptured Freshwater Mussel, Daniel Goodding

Biology Theses

Freshwater mussels of the family Unionidae in North America have been in decline for at least the past 150 years. Major causes behind the decline are thought to be related to alteration or loss of habitat. Recent efforts by researchers have focused on understanding habitat associations of mussels so that more effective conservation efforts can be applied. Recent studies have identified variables that limit mussel community distributions. These variables are a combination of substrate and hydraulic variables that are associated with substrate stability. Furthermore, recent studies have suggested mussel studies are most informative at larger spatial scales and at high ...


Ontogeny Of Postcranial Morphology And Locomotor Behavior In Propithecus Verreauxi Coquereli And Lemur Catta, Stephanie Ann Wolf May 2011

Ontogeny Of Postcranial Morphology And Locomotor Behavior In Propithecus Verreauxi Coquereli And Lemur Catta, Stephanie Ann Wolf

Masters Theses, 2010-2019

Despite living under the same environmental pressures and sympatrically in many cases, Propithecus verreauxi and Lemur catta have evolved very different strategies for survival in stochastic environmental conditions. P. verreauxi show slow somatic growth, low maternal investment, and rapid dental growth while L. catta show faster somatic growth, high maternal investment, and slower dental growth. P. v. coquereli are highly specialized for vertical clinging and leaping (VCL) among lemurs, while L. catta, the most terrestrial of lemurs, use a wider variety of locomotor types including quadrupedalism, climbing, and leaping. P. v. coquereli have unusually long legs and muscular thighs while ...


Sponges Of The Caribbean: Linking Sponge Morphology And Associated Bacterial Communities, Ericka Ann Poppell May 2011

Sponges Of The Caribbean: Linking Sponge Morphology And Associated Bacterial Communities, Ericka Ann Poppell

Master's Theses

The ecological and evolutionary relationship between sponges and their symbiotic microflora remains poorly understood, which limits our ability to understand broad scale patterns in benthic-pelagic coupling on coral reefs. Previous research classified sponges into two different categories of sponge microbial associations: High Microbial Abundance (HMA) and Low Microbial Abundance (LMA) sponges. Choanocyte chamber morphology and density was characterized in representatives of HMA and LMA sponges using scanning electron microscopy from freeze-fractured tissue. Denaturing Gradient Gel Elextrophoresis was used to examine taxonomic differences among the bacterial communities present in a variety of tropical sponges. The results supported the hypothesis that choanocyte ...


Adaptive Responses Of Branchial Morphology To Hypoxia In The Neotropical Electric Fish Genus Brachyhypopomus, Leilani B. Pathak Jan 2011

Adaptive Responses Of Branchial Morphology To Hypoxia In The Neotropical Electric Fish Genus Brachyhypopomus, Leilani B. Pathak

Electronic Theses and Dissertations, 2004-2019

Many tropical aquatic environments worldwide are characterized by intermittent or prolonged hypoxia (low dissolved oxygen). Nevertheless, many tropical freshwater fishes are able to inhabit these challenging environments via a range of morphological, physiological and behavioral adaptations. Brachyhypopomus is a diverse genus of weakly electric fishes represented by 28 known species distributed from Panama to Argentina. 17 species are restricted to permanently normoxic habitats (blackwater rivers and terra firme streams), eight species are restricted to seasonally or perennially hypoxic habitats (whitewater floodplains of large tropical rivers or permanent swampy habitats), and three species are eurytopic (occur in both seasonally hypoxic and ...


The Status Of Dwarfed Populations Of Short-Horned Lizards (Phrynosoma Hernandesi) And Great Plains Toads (Anaxyrus Cognatus) In The San Luis Valley, Colorado, Megan E. Lahti Dec 2010

The Status Of Dwarfed Populations Of Short-Horned Lizards (Phrynosoma Hernandesi) And Great Plains Toads (Anaxyrus Cognatus) In The San Luis Valley, Colorado, Megan E. Lahti

All Graduate Theses and Dissertations

The San Luis Valley is a large valley formation in Colorado surrounded on either side by mountain ranges exceeding 4,267 m. Within the Valley, two of the 14 amphibian and reptile species are dwarfed: the short-horned lizard (Phrynosoma hernandesi) and the Great Plains toad (Anaxyrus cognatus). Since its initial reporting in 1968 and confirmation in 1981, no research further investigating this dwarfism has been conducted. I collected morphological measurements to determine the extent and patterns of dwarfism of both species. I then investigated the genetics of both species using mitochondrial DNA to determine whether they are genetically distinct, their ...


Assessing Traditional Morphology- And Chemistry-Based Species Circumspections In Lichenized Ascomycetes: Character Evolution And Molecular Species Delimitation In Common Western North American Lichens, Steven Leavitt Jul 2010

Assessing Traditional Morphology- And Chemistry-Based Species Circumspections In Lichenized Ascomycetes: Character Evolution And Molecular Species Delimitation In Common Western North American Lichens, Steven Leavitt

Theses and Dissertations

Accurate species delimitation has critical implications for ecological and conservation studies; and for understanding factors driving diversification. However, a growing body of evidence indicates that morphology-based species circumspection in lichenized ascomycetes often fails to accurately represent the number of fungal species. The use of molecular data in lichen systematics provides an important alternative to traditional morphological characters for identifying natural groups and assessing evolutionary histories in challenging lichen taxa. In this work, I examined two common lichen-forming genera in western North America, Rhizoplaca and Xanthoparmelia, as models for investigating character evolution, species delimitation in morphologically and chemically diverse species, and ...


Utilization Of Phylogenetic Systematics, Molecular Evolution, And Comparative Transcriptomics To Address Aspects Of Nematode And Bacterial Evolution, Scott M. Peat Jun 2010

Utilization Of Phylogenetic Systematics, Molecular Evolution, And Comparative Transcriptomics To Address Aspects Of Nematode And Bacterial Evolution, Scott M. Peat

Theses and Dissertations

Both insect parasitic/entomopathogenic nematodes and plant parasitic nematodes are of great economic importance. Insect parasitic/entomopathogenic nematodes provide an environmentally safe and effective method to control numerous insect pests worldwide. Alternatively, plant parasitic nematodes cause billions of dollars in crop loss worldwide. Because of these impacts, it is important to understand how these nematodes evolve, and, in the case of entomopathogenic nematodes, how their bacterial symbionts evolve. This dissertation contains six chapters. Chapter one is a review of DNA markers and their use in the phylogenetic systematics of entomopathogenic and insect-parasitic nematodes as well as a review of phylogenetic ...


Development Of Representative Species-Level Molecular Markers And Morphological Character Analysis Of Leucothoid Amphipods (Crustacea: Amphipoda), Kristine Nicolle White May 2010

Development Of Representative Species-Level Molecular Markers And Morphological Character Analysis Of Leucothoid Amphipods (Crustacea: Amphipoda), Kristine Nicolle White

Dissertations

Leucothoid amphipods were investigated using morphology and molecular rDNA gene sequence fragments. The morphological diagnostic characters for traditional taxonomy have been clarified, a molecular marker for representative species has been developed, and one of the current anamorph-leucomorph connections has been confirmed with molecular sequence data. Ultimately this study has combined traditional morphological and modern molecular methods to clarify the taxonomy and to propose a preliminary phylogeny of the Leucothoidae. Analysis of 18S rDNA gene fragments from 13 species in two genera supported the current morphological species designations and the separation of the family into two clades. Combined analysis of 18S ...


Type Of Muscle Present In Adult Amphibian Lymphatic Heart Based On The Dna Sequence Of The Myosin Heavy Chain, Maribeth Morral Jan 2004

Type Of Muscle Present In Adult Amphibian Lymphatic Heart Based On The Dna Sequence Of The Myosin Heavy Chain, Maribeth Morral

Honors Theses

Water and plasma are forced from the capillaries into the interstitial fluid. This fluid is useful l as it moves materials between cells. Most of this fluid is collected in the capillarie of a second circulatory system, the lymphatic system. The first function of such a system is returning the excess blood plasma, now o as lymph, that has accumulated in the tissue spaces. Lymph flows from small lymph capillaries into lymph vessels that are similar to veins in having valves that prevent back flow. Lymph vessels collect to lymph nodes, lymph organs, or to the cardiovascular system at the ...


The Status Of Leptodactylus Validus As A Single Taxon And Its Relationship To Letptodactylus Pallidirostris, Kenneth Christopher Yanek Jan 2004

The Status Of Leptodactylus Validus As A Single Taxon And Its Relationship To Letptodactylus Pallidirostris, Kenneth Christopher Yanek

Master's Theses

Leptodactylus validus exhibits an unusual distribution inhabiting Trinidad, Tobago, and the Lesser Antilles, but not the mainland of South America. This distribution is inconsistent with other distribution patterns observed for these islands. Although slight variation in adult morphology has been observed among the island populations, call data suggest the presence of a single species. Calls of Leptodactylus pallidirostris from Venezuela suggested that this taxon might be conspecific with L. validus. Herein sequence data from the 12S and 16S mt rRNA genes were collected and analyzed in order to address: 1.) whether more than one species is represented within L. validus ...