Kinesis

Definition

Kinesis is a movement or activity of an organism in response to a stimulus, where the direction of the movement is random and not oriented toward or away from the source of stimulation. It contrasts with taxis, which involves movement toward or away from a specific stimulus.

5 Must Know Facts For Your Next Test

1. Kinesis can be influenced by factors such as light intensity, humidity, temperature, or chemical concentration.
2. Unlike taxis, kinesis does not result in directed movement toward or away from a stimulus; it is nondirectional.
3. There are two main types of kinesis: orthokinesis (change in speed) and klinokinesis (change in turning rate).
4. An increased rate of movement in response to an unfavorable stimulus may help the organism find a more favorable environment.
5. Examples of kinesis include woodlice moving faster in dry areas and slower in humid ones to avoid desiccation.

Review Questions

• What distinguishes kinesis from taxis?
• What are the two main types of kinesis and how do they differ?
• How does kinesis help organisms survive in varying environmental conditions?

Related terms

Taxis: Directed movement towards or away from a stimulus.

Orthokinesis: A type of kinesis where the speed of movement changes relative to the intensity of the stimulus.

Klinokinesis: A type of kinesis where the frequency or amount of turning behavior changes relative to the intensity of the stimulus.