Taxis

A taxis (old Greek τάξις "order", " alignment ") is an orienting response of living organisms, ie their orientation to a stimulus or an environmental factor ( eg, temperature, concentration of a substance, illuminance). Taxien occur in motile microorganisms, animals and plants.

In contrast to a triggering stimulus of a final action of directing stimulus must always be present in the taxis, otherwise the action is terminated.

With taxis also directed appetitive behavior of an animal is called within a complex instinct behavior. It is initiated by stimuli, such as noises or movements in animals and is performed only if the state of readiness is present.

Types of taxis

Positive and negative taxis

A distinction for stimulus -related reactions (positive taxis, Topotaxis ) and directed away from the stimulus avoidance or startle response (negative taxis, Phobotaxis ).

Even more accurate classification:

  • Telotaxis: direct it straight from the sense organ to the stimulus.
  • Menotaxis: the alignment at a certain angle to the excitement.
  • Tropotaxis: the symmetrical alignment to the stimulus, for which two spatially separated sensory organs on living organisms are required. The alignment is made from the same angle of two sensory organs.
  • Mnemotaxis: the alignment due to the memory (eg in orientation by the sun or from chemical substances).

Differentiation by stimuli

  • Aerotaxis: Orientation to the oxygen (a special form of chemotaxis and energy taxis)
  • Anemotaxis: orientation to the airflow
  • Chemotaxis: orientation due to chemical stimuli
  • Energy taxis: orientation on the basis of intracellular energy levels
  • Galvanotaxis: focused on electric fields
  • Gravitaxis (formerly geotaxis ): orientation to gravity
  • Hydro Taxis: focused on the bottom or humidity
  • Klinotaxis: orientation by comparing time-shifted information from a receptor / sensory organ
  • Magnetotaxis: orientation in magnetic fields
  • Osmotaxis: orientation to an osmotic gradient
  • Phono Taxis: orientation due to acoustic stimuli (including ultrasound)
  • Phototaxis: Orientation to the brightness and color of light (including infrared and UV radiation)
  • Polarotaxis: Orientation of the polarization of light
  • Rheotaxis: orientation to the water flow
  • Skototaxis: orientation towards the dark
  • Thermotaxis: orientation due to thermal stimuli
  • Thigmotaxis: orientation due to tactile stimuli
  • Traumatotaxis: orientation ( cell organelles ) injured to a cell towards

Examples

  • Turning towards the light (positive phototaxis ) and at the same orientation to gravity ( gravitaxis ) in Euglena viridis, a unicellular photoautotrophic
  • Orientation of bees and ants at the Sun
  • Turn to loot due to chemical substances (chemotaxis ) at the back float
  • Orientation of the body axis on the prey, for example, in toads
  • Phono taxis of crickets: females are based on the song of the male
Animal locomotion Gene Ontology Galvanotaxis#Galvanotaxis .2F electrotaxis Unicellular organism
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