To complete this assignment successfully, you should:
1. Using figure 28-3, what was the stem ancestor for amphibians? When did frogs have an explosion of speciation? What happened to the numbers of salamanders during the Mesozoic? Speculate why. 3 points.
2. Where would a zoologist look for salamanders that use their skin for respiration? 1 point.
3. What does caudata mean? In what context have you seen the affix "cauda" before? 1 point.
4. What possible advantages does paedomorphosis provide for certain salamanders? 1 point.
5.Using the www, do research on labs that use anurans and note the procedures used. Name three areas of research in which anurans play a part. 3 points.
6. Why would anyone lick a frog or toad? 1 point.
7. Can you find animals other than tadpoles and frogs that start as herbivores and become carnivores? Think of the ability to change a digestive tract and the enzymes associated with that tract from one mode to another. Describe the general shape of an herbivore's intestinal tract to that of a carnivore. Why is there a great difference? 2 points.
8. Why would the pressure-sensitive lateral line not be of benefit for terrestrial animals? 1 point.
9. Why are amphibian species declining? 1 point.
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E-mail Sylvester Allred at Syl.Allred@nau.edu
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