A
taxis (plural
taxes , from the
Ancient Greek , meaning "arrangement") is the
movement of an
organism in response to a
stimulus such as light or the presence of food. Taxes are
innate behavioral responses. A taxis differs from a
tropism (turning response, often growth towards or away from a stimulus) in that the organism has
motility and demonstrates guided movement towards or away from the stimulus source. It is sometimes distinguished from a
kinesis, a non-directional change in activity in response to a stimulus.