directed movement of a motile cell or organism in response to an external stimulus
(Redirected from Chemotaxis)

A taxis (plural taxes) is an innate behavioral response by an organism to a directional stimulus. This means the organism automatically moves towards or away from the stimulus.

A taxis differs from a tropism (turning response, often plant growth towards or away from a stimulus) in that the organism has motility and shows movement towards or away from the stimulus source.[1][2]

  • Phototaxis: movement, usually towards light. Shown by many organisms, such as many flying insects.
  • Chemotaxis: movement towards desirable chemicals, and away from unpleasant ones.

Even single-celled organisms can show taxis.


  1. Kendeigh S.C (1961). Animal ecology. Prentice-Hall, Englewood Cliffs N.J.
  2. Dusenbery, David B. 2009. Living at micro scale, Ch. 14. Harvard University Press, Cambridge, Mass. ISBN 978-0-674-03116-6