Gravitaxis

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Gravitaxis is a form of taxis characterized by the directional movement of an organism in response to gravity.[1] Gravitaxis is one of the many forms of taxis. It is characterized by the movement of an organism in response to gravitational forces. It is sometimes called geotaxis.[2]

Gravitaxis is different from gravitropism in a way that the latter is more about the growth response of an organism to gravity.

Taxis[edit]

Taxis is a behavioral response of a cell or an organism to an external stimulus. The movement is characteristically directional. The movement may be positive or negative. A positive taxis is one in which the organism or a cell moves towards the source of stimulation (attraction). A negative taxis is when the organism or a cell moves away from the source of stimulation (repulsion).

Examples[edit]

It can be seen in many microorganisms including Euglena.[3] The response of planktonic larvae of Lithodes aequispinus (king crab) to gravity is another example of gravitaxis.[2] They show both positive and negative gravitaxes in a way that they move either upward (negative) or downward (positive). Gravitaxis can also be observed in Drosophila.[4]

Etymology[edit]

The term is coined from gravi- meaning gravity, and taxis or the movement of an organism in response to a stimulus.

See also[edit]

References[edit]

  1. ^ "Gravitaxis - Biology-Online Dictionary". Retrieved 25 March 2018.
  2. ^ a b Adams, C. F.; Paul, A. J. (February 1999). "Phototaxis and Geotaxis of Light-Adapted Zoeae of the Golden King Crab Lithodes aequispinus (Anomura: Lithodidae) in the Laboratory". Journal of Crustacean Biology. 19 (1): 106. doi:10.2307/1549552. JSTOR 1549552.
  3. ^ Häder, DP; Hemmersbach, R (2017). "Gravitaxis in Euglena". Advances in Experimental Medicine and Biology. 979: 237–266. doi:10.1007/978-3-319-54910-1_12. PMID 28429325.
  4. ^ Armstrong, JD; Texada, MJ; Munjaal, R; Baker, DA; Beckingham, KM (April 2006). "Gravitaxis in Drosophila melanogaster: a forward genetic screen". Genes, brain, and behavior. 5 (3): 222–39. doi:10.1111/j.1601-183X.2005.00154.x. PMID 16594976.