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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.
1

The biology and systematics of frogs : contributions submitted to The University of Adelaide

Tyler, Michael J., 1937- January 1958 (has links) (PDF)
Vol. [2] comprises 6 reprints of published monographs in box folder; but numbered within the publications submitted listing (90 items), and within the 3 categories identified; at the beginning of vol. 1. Includes bibliographical references. [1]. Publications: The biology of frogs ; Systematics and nomenclature ; The fossil record of frogs -- [2]. Monographs Comprises 90 contributions to the biology and systematics of frogs, with particular emphasis upon those concerning the fauna of Australia and New Guinea. Provides an understanding of the state of knowledge when the author commenced his studies; permitting the extent of his work, an the nature of its significance, to be evaluated.
2

The biology and systematics of frogs : contributions submitted to The University of Adelaide / by Michael J. Tyler. / M. J. Tyler.: publications (1958-2002) submitted for the degree / Publications (1958-2002) submitted for the degree of Doctor of Science

Tyler, Michael J., 1937- January 2002 (has links)
Vol. [2] comprises 6 reprints of published monographs in box folder; but numbered within the publications submitted listing (90 items), and within the 3 categories identified; at the beginning of vol. 1. / Includes bibliographical references. / 2 v. (various pagings) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Comprises 90 contributions to the biology and systematics of frogs, with particular emphasis upon those concerning the fauna of Australia and New Guinea. Provides an understanding of the state of knowledge when the author commenced his studies; permitting the extent of his work, an the nature of its significance, to be evaluated. / Thesis (D.Sc.)--University of Adelaide, Dept. of Environmental Biology, 2002
3

Ecophysiology of Australian cocooning and non-cocooning, burrowing, desert frogs

McMaster, Kellie Anne January 2007 (has links)
[Truncated abstract] This thesis explores the ecophysiology of cocooning and non-cocooning Australian burrowing desert frogs in order to specify the details of these two alternative survival strategies. Many details of these life-history strategies have not previously been determined for Australian frogs. In this study the detailed method of function and formation of the cocoon itself was investigated for the first time, as were the moulting cycles, which drive cocoon formation. Cocooning species had consistently shorter inter-moult-periods than non-cocooning species, which is presumably adaptive, allowing production of cocoon layers at a faster rate. Transmission electron microscopy revealed cocoon formation in Cyclorana platycephala to be a plastic, rather than static adaptation. The initial stages of cocoon formation appear to be the most critical. Cocoon layer formation is fastest in the first month and the initial layers produced are thicker than subsequent layers. Also, only in this initial stage does layer thickness appear to be influenced by soil moisture. Scanning electron microscopy confirmed the lips, eyelids and cloaca of cocooned frogs to be sealed by continuous layers of cocoon. However, it remains unclear precisely how the continuous junctions between cells from discreet sources, such as the upper and lower lip, are formed. Measurements of evaporative water loss and resistance over various relative humidity gradients suggested that water content within the cocoon structure is very low unless the external RH is > 93%. Therefore, anuran cocoon is confirmed to function as a specialised and highly effective barrier to water diffusion in arid-zone frogs. ... Within a dune swale, N. aquilonius burrows were an average depth of 1.13 m in loamy sand (clay = 6%, silt = 7%). Neobatrachus aquilonius excavated from the claypan had well formed cocoons, while those found in the dune swale had only one or two thin layers, indicating cocoon formation had only just commenced, although the last rainfall had been over six months prior. This suggests that N. aquilonius is able to switch between the cocooning and non-cocooning strategy in different soil types and different conditions. In summary, cocoon formation was found not to be an entirely passive accumulation of layers. Cocoon formation involved specialisation in the rate and thickness of epithelial layer production and the sealing of layers over lips, eyes and cloaca. Moreover, the cocoon was confirmed to operate effectively as a diffusion barrier at all except the highest external relative humidity. Like cocoon-forming species, Notaden nichollsi was found to metabolically depress to survive for longer periods underground. However, they cannot survive for the entire period

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