BIOL 204 Study Guide - Midterm Guide: Lungless Salamander, Alligator Gar, Swim Bladder
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Note: for some of these sample solutions, i have provided more than one possible solution to give examples of a range of acceptable answers. For example, for the fourth bullet of practice problem 5, the solutions provided are: The hypoblast cells are lost during gastrulation / once the hypoblast is fully formed these cells do not need to continue dividing meaning that either one of these two options would be an acceptable answer for this point. Consider the alligator gar (actinopterygii) and the lungless salamander (amphibia). The alligator gar has gills for breathing water, but can also breathe air using a gas bladder, a pouch that forms from the lining of part of the pharynx (the pharynx is part of the digestive tract). The adult lungless salamander breathes air using its skin. Explain your answer based on the embryonic origins of these two structures.
