Chapter 51: Animal Behavior Overview 1. How is behavior defined? ?A behavior is the nervous system?s response to a stimulus and is carried out by the muscular or the hormonal system ?Animal behavior is based on physiological systems and processes Concept 51.1 Discrete sensory inputs can stimulate both simple and complex behaviors 2. What is ethology? ?Ethology is the scientific study of animal behavior, particularly in natural environments 3. What is the difference between proximate and ultimate causation? ?Proximate causation, or the ?how? explains or focuses on: ?Environmental stimuli triggering a behavior, and ?Genetic, physiological, and anatomical mechanisms underlying a behavior ?Ultimate causation, or ?why? explains or focuses on the: