The electrosensory and visual adaptations of elasmobranchs to the environment have been more studied than most other senses, however, work on these senses is mostly limited to descriptive analyses of sensitivity, morphology, and behavior. The goal of this work was to explore electrosensory and visual capabilities in a more ecological context. To gain an understanding of the content of bioelectric signals, the magnitude and frequency of these stimuli were recorded from a broad survey of elasmobranch prey items... Color vision adaptations also correlated to the photic environment of each species; cownose rays inhabit turbid, green-dominated waters and had two cone visual pigments that maximize contrast of objects against the green background... Yellow stingrays were trichromatic and likely possess the ability to discriminate colors in their clear, reef and seagrass habitats, which are spectrally rich. Both species showed evidence of ultraviolet sensitivity, which may aid in predator and conspecific detection as an enhanced communication channel. Future studies should investigate the integration of sensory input and sensory involvement in intraspecific communication to gain more insight into ecological adaptations. / by Christine N. Bedore. / Thesis (Ph.D.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

The brain is inherently bisexual, differentiating during development so that in adulthood, males mount receptive females. Yet, vestiges of this bisexuality persist in adults, with heterotypical behaviors (females mounting and males being receptive) observed in some species. Consequently, differences in sexual behavior between the sexes, and between individuals of the same sex, are reflective of the predisposition and degree to which these behaviors are exhibited. How one behavior is facilitated and its complement simultaneously suppressed during a reproductive encounter suggests that behavioral expression is gated in some manner. Because male and female vertebrates typically display behavior characteristic of their own sex, simultaneous study of neural circuits gating homotypical and heterotypical behaviors in conventional animal models has received scant attention. The whiptail lizard species, Cnemidophorus uniparens, comprises individuals that are genetically and hormonally female, and that naturally display both types of behavior. Using High Pressure Liquid Chromatography (HPLC), immunocytochemistry, in situ hybridization, intracranial surgeries, as well as pharmacological and behavioral analyses, I report that serotonin levels, and signaling via distinct serotonergic receptors at behaviorally relevant brain nuclei might allow the system to switch between either behavioral repertoire. The use of the same molecule to mediate the reciprocal inhibition of complementary behavioral repertories within the same sex is evidence of a phenomenon of molecular parsimony underlying a striking form of behavioral plasticity. This dissertation also illustrates that sexually differentiated traits such as male and female-typical sexual behaviors are sculpted by neurochemical signaling at neural substrates present in both sexes. / text

published_or_final_version / Zoology / Master / Master of Philosophy

No description available.

Natural ecosystems are dynamic and complex, with many being threatened by human activity. However, humans can also be at the root of a solution to this problem by developing ecosystem engineering which can be used to design, construct, modify, upgrade, repair, remediate, and maintain ecosystems. The aim of this project was to improve virtual ecosystems that can be used to increase the knowledge base for ecological engineering by studying adaptability as a factor for the success of species. This was done by analysing adaptive species in a virtual ecosystem, a computer application with which various configurations can be designed and studied in a closed environment. The virtual ecosystems used in this project represent ecosystems in general rather than any specific ecosystem, and allow for repeatable test cases to be run so that ecosystem dynamics can be studied. Adaptability was defined as the ability of an individual to adjust to a short term environmental pressure according to two factors: the adaptation speed, which is how fast an individual can respond to a change in environment, and the adaptive capacity, which is a quantitative indicator of how much the individual is able to adapt. In this project, experiments were performed to determine the effects of adaptability when applied to one aspect of individuals in an ecosystem. From the results of the experiments it was seen that the adaptation speed value could affect the success of a producer species in an ecosystem both positively and negatively. It was also found that ecosystems with both a consumer and producer species could persist longer when adaptability was incorporated into the individuals of the consumer species.

No description available.

Thesis (Ph. D.)--Carleton University, 2002. / Includes bibliographical references (p. 166-178). Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 147-165). Also available in electronic format on the Internet.

Thesis (M. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 119-132). Also available in electronic format on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.