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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

The Analysis of Palaeobotanical Remains from Native American Sites in the Tennessee Region of the Upper Cumberland Plateau.

Beck, Chase W. 13 August 2010 (has links)
Sediment samples were collected from 3 rock shelter sites and one natural pond on the Upper Cumberland Plateau. Samples were processed to quantitatively and qualitatively evaluate pollen and charcoal abundance as well as other palaeobotanicals. The analysis was to determine when prehistoric Native Americans began controlled burns to enhance resources acquisition. Samples were also analyzed for the presence of pollen to determine vegetation changes that may accompany the use of controlled burns and to determine the onset of horticulture. The Upper Cumberland Plateau is often considered a marginal area used only seasonally by Native Americans; however, management practices may have been highly refined to maximize resources acquisition. Results show evidence of overt land management and usage of the area by Native Americans over several thousand years. Remains indicate reliance upon nut producing trees. This reliance led to land management practices designed to maximize availability of said resources.
92

Black Bears (Ursus americanus) versus Brown Bears (U. arctos): Combining Morphometrics and Niche Modeling to Differentiate Species and Predict Distributions Through Time

Kantelis, Theron Michael 01 May 2017 (has links)
Late Pleistocene American black bears (Ursus americanus) often overlap in size with Pleistocene brown bears (U. arctos), occasionally making them difficult to diagnose. Large U. americanus have previously been distinguished from U. arctos by the length of the upper second molar (M2). However, the teeth of fossil U. americanus sometimes overlap size with U. arctos. As such, there is need for a more accurate tool to distinguish the two species. Here, 2D geometric morphometrics is applied to the occlusal surface of the M2 to further assess the utility of this tooth for distinguishing U. americanus and U. arctos specimens. When combined with an Ecological Niche Model of U. americanus and U. arctos in North America from the Last Glacial Maximum, this morphometric technique can be applied to key regions. A case of two Pleistocene specimens previously identified as U. arctos from eastern North America exemplifies the utility of this combination.
93

Etudes anatomiques et phylogénétiques des structures endocrâniennes des stégocéphales (tétrapodes anciens) / Phylogenetic and anatomical studies based on endocranial structures in stegocephals (ancient tetrapods)

Arbez, Thomas 06 November 2018 (has links)
L’anatomie interne des crânes des stégocéphales Stanocephalosaurus (Temnospondyli), Laosuchus (Chroniosuchia) et Diplocaulus (Lepospondyli) a pu être révélée par l’utilisation de la tomographie à rayons X et a permis de mieux comprendre leur paléobiologie : 1) l’oreille moyenne de Stanocephalosaurus serait adaptée à la perception de sons dans le milieu subaquatique ; 2) des canaux sensoriels intra-osseux ont été identifiés chez Laosuchus. La morphologie endocrânienne a ensuite été utilisée dans une analyse phylogénétique portant sur les relations de parentés controversées entre stégocéphales et lissamphibiens. Cette analyse montre que la monophylie des lissamphibiens serait due à un phénomène d’attraction des longues branches, résultant de l’optimisation de la simplification crânienne, identifiée comme une convergence. Les morphologies de la boite crânienne, du stapes et du palais favorisent une origine diphylétique des lissamphibiens parmi les temnospondyles. / The intracranial anatomy of the stegocephals Stanocephalosaurus (Temnospondyli), Laosuchus (Chroniosuchia) and Diplocaulus (Lepospondyli) has been revealed by X-rays tomography and allowed to better understand their paleobiology: 1) the middle ear of Stanocephalosaurus would be an underwater adapted hearing system; 2) intraosseous sensorial canals have been identified in Laosuchus. The endocranial morphology have been included in a phylogenetic analysis on the debated relationships between stegocephals and lissamphibians. This analysis shows that the monophyly of Lissamphibia may result from a long-branch attraction, due to the optimisation of the cranial simplification, here as identified convergent. The morphologies of braincase, stapes and palate favour a biphyletic origin of lissamphibians among temnospondyls.
94

A morphometric analysis of the phalanges and a fragmentary first metatarsal from the Drimolen hominin site, South Africa.

Vernon, Danielle Sarah 18 July 2013 (has links)
M.Phil. (Anthropology) / The primary aim of this study was to undertake the description and analysis of the manual and pedal hominin phalanges from Drimolen, South Africa. The specimens were contextualized by examining their counterparts in a series of extant and extinct specimens. As Drimolen preserves the remains of both Paranthropus robustus and early Homo, it provides an opportunity to contribute to our understanding of morphological variation and differences between these taxa, as well as providing an important first step in conceptualizing their evolutionary history and palaeobiology. The first section focused on the manual and pedal phalanges, while the second focused exclusively on the first metatarsal. Numerous studies have analyzed Plio-Pleistocene manual and pedal phalanges to evaluate tool-related behaviours and locomotion in early hominins. In this dissertation nine phalanges were described and analyzed for the first time. The manual specimens consist of one proximal (DNH 9), two proximal pollical (DNH 116 and DNH 119), four intermediates (DNH 48, DNH 63, DNH 65 and DNH 66) and one distal pollical phalanx (DNH 13). There is currently only one pedal proximal phalanx (DNH 117). As at Swartkrans, assignment of postcranial elements was hampered by the fact that two hominin species have been found at the site, namely Paranthropus robustus and early Homo. To analyze the specimens, multivariate statistics (PCA and CVA) were conducted on the specimens using raw and size-adjusted data. This was done within the context of a large extinct and extant dataset to compare size and shape data. In general, PCA and CVA yielded similar results but only the raw data was useful in discriminating between taxa. There was poor discrimination in the analyses based upon size-adjusted data because of the huge degree of overlap between fossil and extant taxa. Consequently, results were not diagnostic and it wasn’t possible to assign specimens confidently to either Paranthropus or Homo. This was exacerbated by the isolated nature of the remains, the presence of two hominin taxa and taxonomic uncertainties of several Swartkrans phalanges. Despite these difficulties, these specimens do provide insight into the degree of morphological variation present in the phalanges from the Plio-Pleistocene of South Africa. The second section described the fragmentary first metatarsal and quantified it by using laser scanning and calculating the curvature of the proximal articular surface. Univariate statistics were then calculated in order to examine the degree of curvature between each of the extant taxa and whether these differences were statistically significant. Finally, a simple bivariate plot was generated using the curvature results which showed that this joint surface was most curved in chimpanzees and western gorillas, moderately curved in eastern gorillas, and flattened in modern humans and baboons. Highly curved joint surfaces in this region suggest a more mobile hallux, whereas flattened surfaces suggest reduced joint mobility. The fossil specimens SK 1813, STW 573, STW 595 and OH-8 all grouped closely with modern humans; A.L. 333-54 and SKX 5017 grouped with chimpanzees, while DNH 115 grouped with eastern gorillas. Overall, these results indicate that SKX 5017 was the most curved of the South African specimens and is attributed to Paranthropus (Susman, 1988). It grouped closely with DNH 115 which suggested that climbing activities may have continued to play an important role in the behavioral repertoire of these individuals during the Plio-Pleistocene.
95

Paleoenvironmental Reconstruction of Quaternary Saltville, Virginia, using Ostracode Autecology

Gause, Austin 01 August 2020 (has links)
The Saltville valley in southwestern Virginia is home to Quaternary localities containing paleontological and archaeological remains. Historically the valley has been mined for salt and the small lakes, ponds and springs along the valley floor have a brackish signature. A preliminary report on the site’s ostracode fauna suggested that the site’s water was not always saline. This study analyzed modern and Quaternary ostracodes to understand the valley’s hydrologic and chemical evolution. Sediments contained primarily freshwater species, including the environmentally sensitive Candona crogmaniana. The presence of Pelocypris tuberculatum and a new Fabaeformiscandona species throughout a vertical section spanning the latest Pleistocene and Holocene suggests that ephemeral pools were being fed by freshwater springs throughout the latest Quaternary. Climate ranges, estimated through species autecology and MOTR, reveal that the site’s mean annual temperature was between 0 - 19.1℃. Ostracode salinity tolerances suggest that the site was fresh during the sampled record.
96

Encephalization in Commensal Raccoons: A Unique Test of the Cognitive Buffer Hypothesis

Anderson, Peter M 01 May 2020 (has links)
This study investigated selective pressures associated with encephalization in mammals and discussed broader implications. Relative brain size as measured by EQ (Encephalization Quotient) was compared between ecological categories. Omnivores had higher average EQ than ecological specialists. Since specialists are disproportionately affected by extinction events, selection for ecological generalism is proposed as encephalization mechanism. This mechanism may reinforce the more widely known Cognitive Buffer Hypothesis (CBH)—the idea that possessing relatively large brains has buffered lineages against environmental change. CBH is tested here by comparing EQs in Procyon lotor (raccoon) in urban and rural environments. CBH predicts that raccoons in the most radically altered environment, the city, experience the strongest selection for encephalization. Urban raccoons studied here exhibit a higher EQ. Although results are preliminary, data suggest that encephalization is accelerated during abrupt periods of environmental change. Finally, implications for the evolution of biological complexity more generally are discussed.
97

A Phylogenetic Analysis of Species Relationships in Hemlocks, the Genus <em>Tsuga</em> (Pinaceae).

Baker, Jordan David 19 August 2009 (has links) (PDF)
The genus Tsuga is comprised of eight extant species found in North America and East Asia and four species represented by fossils from Europe and Japan. This study presents the first phylogenetic analysis based on structural, biochemical, and molecular sequence data. Characters obtained from published and unpublished literature were combined with new morphological characters from seeds, seedlings, and leaf cuticle material. Results from parsimony analyses of these characters differed from the published molecular based phylogeny. The non-molecular based phylogeny resolves two separate clades, a North American and an Asian, but did not group the western North American species, as in the molecular based analysis. Character states were traced on the trees to interpret character evolution. The combined analysis resulted in a phylogeny that differed from the previously published molecular tree by resolving a clade between T. caroliniana and T. diversifolia and placing T. dumosa outside of the Asian clade.
98

Phylogenetic Paleobiology: Phenotypic Diversification and Evolutionary Radiation in Paleozoic Crinoids

Wright, David F. January 2016 (has links)
No description available.
99

Descriptions of Interglacial Mastodons from Snowmass, Colorado

White, Connor 01 May 2024 (has links) (PDF)
The Ziegler Reservoir fossil site (ZRFS) in Colorado contains over 4000 mastodon bones that date from 140,000 to 100,000 years ago. At an elevation of ~2705 meters above sea level, ZRFS represents an alpine ecosystem dated to Marine Isotope Stage (MIS) 5. Formal descriptions of cheek teeth, mandibles, crania, and femora were completed. Statistical analyses of the upper and lower third molars, including a novel measurement of interloph(id) distances, indicate significant differences between ZRFS mastodons and Mammut pacificus, while falling within the ranges for Mammut americanum. This study agrees with the taxonomic assignment of ZRFS mastodons to Mammut americanum and not Mammut pacificus. Body mass estimates of ZRFS mastodons are between 3451 and 6244 kg, and a niche model indicates elevation and water availability influenced Mammut distribution during MIS 5. Incorporating ZRFS mastodons into large comparative datasets will contribute to ongoing research into Late Pleistocene Mammut.
100

Archaeomalacological Data and Paleoenvironmental Reconstruction at the Jupiter Inlet I Site (8PB34a), Southeast Florida

Unknown Date (has links)
The Jupiter Inlet I site is situated between the Atlantic coast and the Loxahatchee River in southeast Florida. Although excavations were previously conducted, faunal remains were not systematically collected until recently. Molluscan remains recovered in 2010 are examined to reconstruct past ecological habitats, identify which water bodies were used for extracting resources, and document changes in molluscan species over time. Based upon identifications, only brackish and marine species are represented, indicating that the Loxahatchee River was brackish rather than freshwater during the time of occupation and that the site inhabitants were collecting mollusks from both the lagoon and coastal waters. / Includes bibliography. / Thesis (M.A.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

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