GEL 113 Homework 12 Answer sheet

Study Questions for Chapter 15: Marine Reptiles

Euryapsids)

Part I: True or False:

1.T 2.T 3.F 4.F 5.T

Part II: Multiple Choice:

1.A 2.D 3.C 4.D

Part III: Thought Questions:

1. The Euryapsid skull is derived from the diapsid skull through the loss of the lower fenestra. The bar of bone (primarily jugal) separating the fenestra from the mouth becomes thinner and thinner until it disappears altogether.

2. Locomotion in the water is very efficient - no energy is wasted counteracting gravity. Also, large amounts of food are easily accessible in the ocean.

3. The Lock Ness monster could not be a plesiosaur because:

a) a plesiosaur was an air breathing animal which could not remain submerged all the time (it did not have gills, and could not have simply "evolved them").

b) it would have to come ashore to lay its eggs

c) Loch Ness is not old enough (about 2 million years) to have sheltered a population of plesiosaurs since the Cretaceous (65 million years ago).