High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! A taxis (plural taxes, pronounced / tæksi z/) is an innate behavioral response by an organism to a directional stimulus or gradient of stimulus intensity. 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 that results in the migration toward or away from a stimulus.