Lab Report: Vertebrates II—Amniotes
Lab day and time: ____________ Name ________________________
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The vertebrates we will study this week are all amniotes. That is, amniotic vertebrates all
surround the developing embryo with layers of membranes (amnion surrounds the embryo, the
allantois collects wastes, the yolk sac contains nutrients, and the chorion protects all the other
membranes and embryo); sometimes an additional layer is added, a hard, waterproof shell.
A second trait that has evolved in some amniotes is endothermy. Mammals and birds, and few
reptiles, are endothermic, keeping their body temperatures relatively constant. This strategy is
costly; mammals and birds have metabolic rates (consumption of Oxygen) that are 7 to 10 times
that of a reptile. To keep their internal body temperatures constant requires a great deal of energy
to meet these high metabolic demands. Many ectothermic reptiles, on the other hand, can go
without food for long periods of time, given their low demands for consuming Oxygen.
Questions about the Video segments
Video segment: Shape of Life-bones, brawn and brains
What evidence is the video saying supports that dinosaur bone grew relatively fast?
How would the graduate student know what patterns to look for in the bone to indicate
fast growth? In other words, how could she know that the organization of bone that she
sees provides her with an answer to growth rate of dinosaurs?
Which hypothesis is suggested for the demise of the dinosaurs?
Video: The Reptiles
What types of behaviors attract a crocodile hunting response?
What are the two parts that make up the turtle shell, and from which skeletal parts are
they derived?
Bi102 Vertebrates II: Amniotes 1
