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

Behavioral responses to stimuli may be adaptive. A stimulus is a type of information that can make an animal change its behavior. 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 pain thirst

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

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.

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

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.

Some behaviors occur in cycles. A circadian rhythm is the daily cycle of activity. occurs over 24-hour period run by a biological clock An internal mechanism that controls an organism’s activity patterns.

Behaviors may occur daily, monthly, seasonally, or annually. During hibernation, an animal enters a seasonal dormant state. Estivation: dormancy during hot times

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.