Thesis (M.S.)--Georgia Southern University, 2007. / "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." In Biology, under the direction of David Rostal. ETD. Electronic version approved: December 2007. Includes bibliographical references (p. 54-59) and appendices.

Thesis (M.S.)--Georgia Southern University, 2004. / ETD. "A thesis submitted to the Graduate Faculty of Georgia Southern University in partial fulfillment of the requirements for the degree Master of Science." Includes bibliographical references.

Thesis (M.Sc.)--Acadia University, 2000. / Includes bibliographical references (leaves 66-71). Also available on the Internet via the World Wide Web.

Thesis (B.S.) Magna Cum Laude--Butler University, 2008. / Includes bibliographical references (38-42).

The aim of the present study was to investigate the potential for children to use the turtle methaphor to develop understandings of intrinsic, euclidean and cartesian geometrical ideas. Four aspects of the problem were investigated. a) the nature of the schema children form when they identify with the turtle in order to change its state on the screen; b) whether it is possible for them to use the schema to gain insights into certain basic geometrical principles of the cartesian geometrical system; c) how they might use the schema to form understandings of euclidean geometry developed inductively from specific experiences; d) the criteria they develop for choosing between intrinsic and euclidean ideas. Ten 11 to 12 year - old children participated in the research, previously having had 40 to 50 hours of experience with Turtle geometry. The research involved three case - studies of pairs of children engaging in cooperative activities, each case - study within a geometrical Logo microworld. The data included hard copies of everything that was said, typed and written. Issues a) and b) were investigated by means of the first case - study which involved three pairs of children and a microworld embedding intrinsic and coordinate ideas. A model of the children's intrinsic schema and a model of the coordinate schema which they formed during the study were devised. The analysis shows that the two schemas remained separate in the children's minds with the exception of a limited number of occasions of context specific links between the two. Issue c) was investigated in the second case - study involving one pair of children and a microworld where the turtle was equipped with distance and turn measuring instruments and a facility to mark positions. The analysis illustrates how a turtle geometric environment of a dynamic mathematical nature was generated by the children, who used their intrinsic schema and predominantly engaged in inductive thinking. The geometrical content available to the children within this environment was extended from intrinsic to both intrinsic and euclidean geometry. Issue d) was investigated by means of the third case - study involving a pair of children and a microworld where the children could choose among circle procedures embedding intrinsic and/or euclidean notions in order to construct figures of circle compositions. The analysis shows that the children employed their turtle schema in using both kinds of notions and did not seem to perceive qualitative differences between them. Their decisions on which type of notion to use were influenced by certain broader aspects of the mathematical situations generated in the study.

Hatchling loggerhead turtles emerge from subsurface nests on the beach at night, crawl down the beach and enter the sea. Recently, increases in a floating algae (Sargassum) has been reported in the mid-Atlantic and the Caribbean, resulting in large algal wrack on Florida beaches. The purpose of my study was to determine if these accumulations acted as a barrier, preventing hatchlings from completing their crawl to the sea. To address this issue I recorded seasonal changes in Sargassum density and directly observed when, and under what circumstances, hatchlings could cross the wrack. There was a significant overlap between when Sargassum accumulation peaked and when the turtles emerged, with the result that hatchling recruitment was significantly reduced (by~22%) during the 2020 nesting season. I conclude that algal accumulations represent a significant threat that may impede the recovery of loggerhead populations, that are currently threatened or endangered worldwide. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2021. / FAU Electronic Theses and Dissertations Collection

<p>Maintaining high genetic diversity within and among wildlife populations is an important component to the management of threatened species. Population genomics utilizes recent advancements in high-throughput next-generation sequencing to obtain genome-wide data that can yield deeper perspectives on intraspecific genetic variation and elucidate evolutionary significant units that may require conservation management or augmentation. The semi-aquatic Blanding’s Turtle (<i>Emydoidea blandingii</i>) has experienced drastic population declines in North America due in large part to anthropogenic activities. This species is listed as threatened or endangered across most of its range. A population genomic study can help to understand the status of this species and guide future management practices. Hence, a population genomic analysis was conducted using 3RAD to discover and analyze SNPs across the range using samples from Nebraska, Indiana, Michigan, Ohio, and Nova Scotia,. Range-wide analysis used 8,602 SNPs while analysis within the Great Lakes region used 7,893 SNPs. High amounts of missing data were found across all individuals and loci. Low levels of genetic variation relative to other turtle species were detected both across the range and within the Great Lakes region. Minimal population structure was detected range-wide via clustering and admixture analyses; however, a signal of population differentiation was detected among Nebraska, Nova Scotia, and the Great Lakes. Clustering and differentiation analyses focused on the Great Lakes region found a signal of population structure and differences between the Lake Michigan and Lake Erie watershed. These results may prove useful for conservation management of Blanding’s Turtle populations, particularly related to efforts using translocation or head-starting practices.</p>

No description available.

The diets of green turtles from five dissimilar aggregations of juvenile C. mydas on the East Coast of Florida were analyzed. C. mydas were captured by tangle net from four of the study sites and a dietary sample was collected by an esophageal flushing technique. The gut content of stranded individuals was collected for the fifth site. The vegetation in these study areas differs in varying degrees of abundance and diversity. Analysis of the samples revealed the alga types preferred by green turtles from each population and provided the basis for examination of similarities and differences in their diets. Large numbers of the juvenile C. mydas worldwide are infected with a disease called Fibropapillomatosis (FP). The herpes-type virus that appears to cause the disease manifests as tumors normally on the fleshy parts of the body. The placement and size of the tumors can eventually impede the green turtle’s ability to swim and forage. Severe conditions of the disease lead to death either by starvation or the inability to evade predators. While the herpesvirus initiates FP, there are other environmental cofactors that may play a role in promoting the disease. Some toxic microalgae (dinoflagellates) of the genus Prorocentrum produces a known tumor promoter called okadaic acid. The acid has been shown to promote cutaneous tumors in laboratory mice. These Prorocentrum species live primarily as epiphytes, forming a mucilaginous attachment to seagrasses and macroalgae. Chelonia mydas may be consuming the toxic microalgae when they forage on vegetation. Samples of available vegetation at each study area were collected and examined to determine if C. mydas were potentially consuming Prorocentrum. Prorocentrum were quantified for diet items by counting the number of cells per wet weight of macroalgae. In most cases, the diet analysis and microalgae quantification results showed an association between the consumption of substrates utilized by Prorocentrum spp and a high prevalence of FP in that population.

The seasonal and diel movements of fourteen immature green turtles (Chelonia mydas) in Mosquito, Lagoon, Florida were monitored using sonic telemetry. The feeding ecology of this turtle population was also studied using dissection and stomach flushing techniques. An attempt was made to relate the movement patterns of the turtles to their feeding habits. The immature green turtles were found to make seemingly random, long distance movements (X̄km moved/day=7.79) and to remain in deeper waters (X̄depth=1.63m), apparently not feeding, when water temperatures fell below 19°C. When average water temperatures ranged between 19-25°C, the turtles were found primarily in shallow waters (X̄depth=1.1m) and demonstrated a decrease in agility (X̄km moved/day=3.14). At water temperatures above 25°C, the animals became even less agile (2.58 km moved per day) and adopted a home range area that included a "center of activity" and a "home site." A "shuttling" behavior was observed when water temperatures averaged 31°C and higher. In the early mornings, turtles were found feeding on the grass flats. When shallow water temperatures rose above 30°C at midday, the turtles would relocate to deeper water. In late afternoon, they would return to the grass flats for a short period of time. Sea grasses made up 88% of the lagoonal turtle diet, with manatee grass (Syringodium filirorme) alone constituting 77%. No significant difference was found in per cent composition of stomach contents obtained in January via dissection and August via pumping.