Definition

Noun: A type of non-directional movement or change in activity level of an organism in response to a stimulus. Unlike taxis, which is a directed movement toward or away from a stimulus, kinesis is a random change in speed or rate of turning that increases the chance of the organism encountering a more favorable environment.

Usage

• General Use: Used primarily in biology, ethology, and psychology to describe a simple behavioral response.
• Context: The term is used when discussing how organisms, often simple ones, react to environmental factors like light, humidity, or chemicals without moving in a specific direction relative to the stimulus source.
• Example: "The woodlice exhibited kinesis in response to the dry air, moving more rapidly and turning more frequently until they found a damp area."

Examples

• In a sentence: "Orthokinesis, a form of kinesis, is defined by a change in the organism's speed of movement in response to a stimulus."
• In a sentence: "The study measured the kinesis of the protozoa when exposed to different chemical gradients."

Advanced Usage

• Orthokinesis: A change in the linear speed or frequency of movement in response to a stimulus intensity.
  • Example: "In orthokinesis, the animal's speed increases as the intensity of an unfavorable stimulus increases."
• Klinokinesis: A change in the rate of turning or frequency of directional changes in response to a stimulus intensity.
  • Example: "Klinokinesis involves more frequent random turns when the organism is in an unfavorable condition, helping it to stay in a favorable one."

Variants and Related Words

• Kinetic (adj): Relating to or resulting from motion.
  • Example: "The kinetic energy of the system was calculated."
• -kinesis (suffix): A combining form used in scientific terms to denote movement or activity (e.g., , ).

Synonyms

• Non-directional movement: A more general descriptive term.
• Random locomotor response: Emphasizes the undirected nature of the movement.

Notes on Meaning

• Contrast with Taxis: It is crucial to distinguish kinesis from taxis. Kinesis is a non-directional change in activity, while taxis is a directed movement toward (positive taxis) or away from (negative taxis) a stimulus source.
  • Example of contrast: "Phototaxis is movement toward light, whereas photokinesis is a change in general activity level triggered by light."

Noun

1. a movement that is a response to a stimulus but is not oriented with respect to the source of stimulation