ABSTRACT
The sensory systems that we studied in Chapters 4 and 6 enable animals to know about the world they live in. But sensation is only the first step: to adapt to the world, animals must act upon sensory knowledge. For example, animals have evolved the ability to sense the presence of food-through a combination of olfaction, vision, and taste-so that they can eat the food and obtain energy essential for life. Likewise, animals have evolved the ability to detect danger so that they can fight, hide, or run away from it. In this chapter, we study the output of the nervous system that makes these active responses to sensation possible.
