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Full-Text Articles in Education
Field Investigations Of Malformed Frogs In Minnesota 1993-97, Judy C. Helgen, Mark C. Gernes, Susan M. Kersten, Joel W. Chirhart, Jeff T. Canfield, Dorothy Bowers, Jon Haferman, Robert G. Mckinnell, David M. Hoppe
Field Investigations Of Malformed Frogs In Minnesota 1993-97, Judy C. Helgen, Mark C. Gernes, Susan M. Kersten, Joel W. Chirhart, Jeff T. Canfield, Dorothy Bowers, Jon Haferman, Robert G. Mckinnell, David M. Hoppe
Journal of the Iowa Academy of Science: JIAS
Reports of malformed frogs were made to the Minnesota Pollution Control Agency (MPCA) from different parts of Minnesota in 1993, 1995, 1996, and 1997 and one, nine, 190, and 172 reports were received, respectively. MPCA field crews and Drs. Hoppe and McKinnell documented malformed frog locations starting in 1993. By 1997, MPCA field crews documented malformed frogs at 62 locations in Minnesota, in 29 of 87 counties. Most malformations were in young metamorphs of Rana pipiens but they were observed also in R. clamitans, R. septentrionalis, R. sylvatica, Bufo americanus, and Hyla spp. Frequencies of malformations varied by time of …
The North American Reporting Center For Amphibian Malformations, Douglas H. Johnson, Suzanne C. Fowle, Jeffrey A. Jundt
The North American Reporting Center For Amphibian Malformations, Douglas H. Johnson, Suzanne C. Fowle, Jeffrey A. Jundt
Journal of the Iowa Academy of Science: JIAS
The North American Reporting Center for Amphibian Malformations was established to provide a conduit of information about, and a systematic data base on, malformed amphibians. This article describes the Reporting Center and the variety of features available at its Web site, presents an example of a summary analysis that can be conducted with its data, discusses caveats about the data, and makes recommendations about systematic surveys to better understand patterns and trends in the incidence of malformed amphibians.
Interactive Effects Of Anthropogenic, Environmental, And Biotic Stressors On Multiple Endpoints In Hyla Chrysoscelis, Carol A. Britson, Stephen T. Threlkeld
Interactive Effects Of Anthropogenic, Environmental, And Biotic Stressors On Multiple Endpoints In Hyla Chrysoscelis, Carol A. Britson, Stephen T. Threlkeld
Journal of the Iowa Academy of Science: JIAS
Multiple stressors have been proposed as causative agents for declining populations and increased incidence of malformations in amphibians although few studies have examined possible interactions among these stressors. We measured interactive effects of UV radiation, three chemicals, and interspecific competition (with Rana 1phenocephala) on multiple endpoints in Hyla chrysoscelis using a center point- and chemical-free control-enhanced 24 factorial design. UV radiation was transmitted or filtered using OP-4 or OP-3 acrylite filters installed above 72, 500-liter mesocosms on 16 May 1997. Methyl mercury, chlorpyrifos, and atrazine were applied at levels of 0, 10, 50, and 100 % of 400 ppb, …
History Of Minnesota Frog Abnormalities: Do Recent Findings Represent A New Phenomenon?, David M. Hoppe
History Of Minnesota Frog Abnormalities: Do Recent Findings Represent A New Phenomenon?, David M. Hoppe
Journal of the Iowa Academy of Science: JIAS
Two lines of investigation were used to determine whether recent Minnesota reports of frog abnormalities differ from historical reports: (1) museum collection studies paired with follow-up field surveys, and (2) comparison of recent and earlier field surveys in west-central Minnesota. For the museum study I examined 2433 northern leopard frogs (Rana pipiens) in the Bell Museum of Natural History collections of the University of Minnesota, collected during 1958-63. 0.7% of frogs were found to have abnormalities, consisting of 0.5% predator amputations and 0.2% malformations. Three types of malformation were found: missing hindlimbs, vestigial feet, and fused digits. Conspicuously absent from …
Defining Anuran Malformations In The Context Of A Developmental Problem, Carol U. Meteyer, Rebecca A. Cole, Kathryn A. Converse, Douglas E. Docherty, Mark Wolcott, Judy C. Helgen, Richard Levey, Laura Eaton-Poole, James G. Burkhart
Defining Anuran Malformations In The Context Of A Developmental Problem, Carol U. Meteyer, Rebecca A. Cole, Kathryn A. Converse, Douglas E. Docherty, Mark Wolcott, Judy C. Helgen, Richard Levey, Laura Eaton-Poole, James G. Burkhart
Journal of the Iowa Academy of Science: JIAS
This paper summarizes terminology and general concepts involved in animal development for the purpose of providing background for the study and understanding of frog malformations. The results of our radiographic investigation of rear limb malformations in Rana pipiens provide evidence that frog malformations are the product of early developmental errors. Although bacteria, parasites and viruses were identified in these metamorphosed frogs, the relevant window to look for the teratogenic affect of these agents is in the early tadpole stage during limb development. As a result, our microbiological findings must be regarded as inconclusive relative to determining their contribution to malformations …