KEY CONCEPT Behavior lets organisms respond rapidly and adaptively to their environment.

1. KEY CONCEPT Behavior lets organisms respond rapidly and adaptively to their environment.

2. Behavioral responses to stimuli may be adaptive. • Detecting and responding to stimuli is key to an individual’s survival. • Internal stimuli tell an animal what is occurring in its own body. • hunger • thirst • pain

3. External stimuli give an animal information about its surroundings. • sound • sight • changes in day length or temperature

4. Specialized cells that are sensitive to stimuli detect sensory information. • information is transferred to the nervous system • nervous system may activate other systems in response • Animal behaviors help to maintain homeostasis.

5. Kinesis and taxis are two types of movement-related behaviors. • Kinesis is an increase in random movement. • Taxis is movement in a particular direction.

6. Internal and external stimuli usually interact to trigger specific behaviors. • Most behaviors are a response to both internal and external stimuli. • External stimuli may trigger internal stimuli. • Green anole reproductive behavior is triggered by internal and external stimuli.

7. Some behaviors occur in cycles. • A circadian rhythm is the daily cycle of activity. • occurs over 24-hour period • run by a biological clock

8. Behaviors may occur daily, monthly, seasonally, or annually. • During hibernation, an animal enters a seasonal dormant state.

9. Behaviors may occur daily, monthly, seasonally, or annually. • During hibernation, an animal enters a seasonal dormant state. • During migration, animals move seasonally from one portion of their range to another.