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A Plague of Frogs--Study Questions
Chapter 7 – “Rumors, Theories, Rules of Engagement”
1. What was Joe Tietge’s purpose in contacting Cindy Reinitz?
Joe Tietge was a research biologist with the U.S. EPA study team on fish and amphibians and wanted to find out more information to study.(80)
2. Why did Tietge need to find a new problem to solve?
Tietge’s lab had to continually reinvent itself by finding new problems to solve which would ensure future funding for the scientists to continue their studies.(81)
3. Explain why chemical influence on frog development would be a promising area of research.
Answers will vary.
4. Why did Ankley and Tietge pursue developing a bioassay of amphibians?
Bioassays provide an organism’s history and little toxicological work had been done on frogs.(81)
5. What agent did Ankley and Tietge think was causing the disruption of limb
outgrowth?
A xenobiotic chemical was thought to be the cause of the disruption of growth.(83)
6. Why are complex mixtures considered to be stubbornly unyielding for scientists?
These mixtures are difficult to separate and name.(84)
7. What are “effects-based” approaches according to the EPA?
These were used to set up lab models of toxic scenarios by inducing an effect on organisms seen in the field.(84)
8. Explain how science is analogous to a great city.
Answers will vary.(87)
9. Based upon what study did Tietge seek out Ken Muneoka?
Muneoka, Chairman of Tulane’s biology department, had published a work with his mentor, Bryant, on the genetic chemical direction of body development.(88)
Explain the stages of development in frog embryos.
Answers will vary.
10. Explain the analogy of the development of the limbs to the half time card show.
Whole limb development occurs when individual cells perform to their designed form and function at an exact location just as a football audience views a full picture when individual people
operate placards. The placards alone do not mean anything until they are joined together and seen from an external point of view. Answers will vary.(89)
11. What is the significance of intercalation ?
Intercalation demonstrates the ability of cells to communicate with one another and share information regarding their location and what type of tissue they are supposed to be in the overall
organism.(91)
12. Why does retinoic acid play a critical role in limb development?
Derived from vitamin A, retinoic acid has been found to play a critical role in bud development at the appropriate axes.
13. Distinguish receptors as “biological hair triggers” from other hormones.
Nuclear receptors must be present in very specific units(hairlike) in order to work properly.(92)
14. Hypothesize how limb induction occurs through cell to cell communication.
Answers will vary.
15. What hypothesis did Sessions provide as explaination for the deformities occurring in frog population.
Sessions asserted that parasites were a natural cause of limb deformities as they had been throughout history.(94)
16. How would a visible frog be created in the lab?
Frogs should skinned, enviscerated, stained and chemically treated to be transparent. (94)
17. By what method could parasites enter a frog?
Parasites could enter the frog through the cloaca or by boring directly through the skin. (96)
18. Summarize the experiment Sessions carried out with the resin beads in the limb buds in order to demonstrate the plausibility of his hypothesis of parasites scrambling the blueprint of limb development.
Answers will vary. (98)
19. Why did the cysts not cause deformities in all the frogs in which they were found ?
Sessions hypothesized that parasites had a specific window of time to infect their host and cause limb malformation.
20. What is a coevolved system?
Answers will vary. (99)
21. Given that Sessions had seemingly proved that parasites were the culprit causing the malformed limbs, why was the case not discontinued?
Answers will vary.(100)
22. Explain the relationship between frogs and humans that would impose concern for environmental degradation.
Frogs and humans belong to the phylum Chordata.(105)
22. What is meant by “phylogeny recapitulates ontogeny” with reference to the published article in Genetics.
Answers will vary.
23. What are bioactive chemicals and how are they different from toxins?
Bioactive chemicals interfere with developmental processes in living organisms whereas toxins.(81)
24. Why would the farmers be hesitant to report frog deformities occurring on their land?
Answers will vary.
25. Why might Minnesota want to change the slogan on their state license plates?
Answers will vary.
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