Chapter 4: Teeth Everywhere

Reading this chapter helped me learn the significant roles of our teeth; "Teeth are a powerful window into an animal's lifestyle" (69). It was interesting to learn that the teeth are the hardest parts of our bodies, allowing paleontologists to observe an animal's diet. The teeth differentiate the mammals from the reptiles, reptiles lacking precise occlusion. Mammals, having precise jaw lines, replace their teeth once whereas reptiles replace their teeth continually as they shatter from the mismatch between upper and lower teeth. What surprised me was that Shubin was able to identify the creature Bill had found, tritheledont- half mammal, half reptile- just by observing the tooth-to-tooth occlusion of its jaw. The purpose of the teeth, the interactions of skin layers, was to make other important skin structures, such as feathers, breasts, and hairs, from occurring. "In a very real sense organs as different as teeth, feathers, and breasts are inextricably linked by history" (89).