Chapter 41, Problem 9TYU

EVOLUTION CONNECTION Lizards and snakes cannot breathe while chewing food because the connection between their external nostrils and their esophagus is in the mouth. In contrast, mammals can continue breathing through the nostrils while chewing food in the mouth. However, choking sometimes occurs when the paths of air and food cross each other. Thinking about the high oxygen demand of active endotherms, explain how the concept of descent with modification explains this "imperfect" anatomy of some amniotes (see Figure 34.2 to review vertebrate phylogeny).