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Malformed Frogs

The Collapse of Aquatic Ecosystems

Michael Lannoo

Publication Year: 2008

The widespread appearance of frogs with deformed bodies has generated much press coverage over the past decade. Frogs with extra limbs or digits, missing limbs or digits, or misaligned appendages raise an alarming question: "Are deformed humans next?" Taking a fresh look at this disturbing environmental problem, this reference provides a balanced overview of the science behind the malformed frog phenomenon. Bringing together data from ecology, parasitology, and other disciplines, Michael Lannoo considers the possible causes of these deformities, tells which frogs have been affected, and addresses questions about what these malformations might mean to human populations. Featuring high-quality radiographic images, Malformed Frogs suggests that our focus should be on finding practical solutions, a key component of which will be controlling chemical, nutrient, and pesticide runoff into wetlands.

Published by: University of California Press


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p. 1-1

Title Page, Copyright, Dedication, Quotes

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pp. 2-9


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pp. ix-x

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pp. xi-xiv

Attending scientific meetings may be the least professional thing that scientists do. Meetings are a lot about personal interactions, and the outcomes of personal interactions are dependent on attributes such as gender (males tend to have an advantage), size (increased height is more influential than increased weight), ...

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pp. xv-xvi

This book wrote itself in a matter of a few months. Given the often demonstrated inverse relationship between time spent and errors generated, and the opposite, direct relationship between eyes observing and perspective achieved (faculty meetings excepted), ...

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pp. 1-6

As a cultural phenomenon it began in the summer of 1995 in south-central Minnesota, with school kids on a field trip.2 While exploring a rural wetland, Cindy Reinitz and her junior high school students discovered a large number of northern leopard frogs (Rana pipiens) that were having trouble jumping. ...

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1. What is an Amphibian Malformation?

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pp. 7-20

The word “malformation” literally means “bad form.” Bad form in most animals means an unintended lack of symmetry, or an imbalance in structure, color, or other quality. A lack of symmetry can arise through one of three mechanisms:2 ...

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2. Malformed Frog Types

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pp. 21-84

In an attempt to organize, and to correlate effect with cause, malformations, whether human, frog, or otherwise, have tended to be divided into types. Malformation types are almost always based on: (1) structures absent or reduced, (2) structures duplicated (or multiplied), and (3) structures present but otherwise abnormal ...

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3. Hotspots

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pp. 85-104

In amphibian conservation biology, the term “hotspot” is used in two contrasting ways. One way, with a good implication, is to denote a site or a region with high amphibian richness. These places are usually located in tropical or subtropical ecosystems and are often the focus of intense conservation efforts. ...

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4. Causes

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pp. 105-110

The year 2006 marked the 300th anniversary of known published observations of malformed frogs. The recognition that malformed frogs preceded the beginning of the Industrial Revolution by about 150 years and preceded modern agricultural techniques (including the application of pesticides) ...

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5. Resolutions

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pp. 111-178

There has been nothing tidy about the malformed frog investigation. Examining the field, some workers have chosen terms like the “complexity of deformed amphibians”2 or an “eco-devo riddle”3 as descriptors. At face value this is true, but I gently disagree that we need more data. ...

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6. Human Malformations and Causes

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pp. 179-188

The fear that what was happening to frogs could happen to humans is the major reason why the malformed frog problem tipped in 1996. As with many ways of thinking about malformed frogs, the logic behind this concern is sound. Something in the water is causing frog malformations; ...

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7. Solutions

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pp. 189-202

Why is it that when human congenital malformations are addressed, the full suite of abnormalities and the full range of causes are considered, but when addressing malformations in frogs, the focus is typically only on single causes and their effects on hindlimbs, and then often only on hindlimb polymely? ...

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Species Affected

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pp. 203-216

Amphibian malformations are not evenly distributed across taxa. As mentioned in Chapter 1, amphibian malformations tend to be frog malformations. A quick count shows that 52 of 105 U.S. frog species (50%) had documented malformations compared with 19 of 188 U.S. salamander species (10%). ...


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pp. 234-237


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pp. 217-264


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pp. 265-270

Production Notes, Back Cover

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pp. 292-294

E-ISBN-13: 9780520942530
Print-ISBN-13: 9780520255883

Page Count: 288
Publication Year: 2008