Gravitaxis (or geotaxis[1]) is a form of taxis characterized by the directional movement of an organism in response to gravity.[2]
There are a few different causes for gravitaxis. Many microorganisms have receptors like statocysts that allow them to sense the direction of gravity and to adjust their orientation accordingly. However, gravitaxis can result also from a purely physical mechanism so that organs for sensing the direction of gravity are not necessary. An example is given by microorganisms with a center of mass that is shifted to one end of the organism. Similar to a buoy, such mass-anisotropic microorganisms orient upwards under gravity. It has been shown that even an asymmetry in the shape of microorganisms can be sufficient to cause gravitaxis.[3]
Gravitaxis is different from gravitropism in a way that the latter is more about the growth response of an organism to gravity.
^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.
^"Gravitaxis - Biology-Online Dictionary". Retrieved 25 March 2018.
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(see galvanotaxis) along the direction of the gravitational force (see gravitaxis) along a rigidity gradient (see durotaxis) along a gradient of cell adhesion...
dumerilii. The first c-opsin mediates in the larva UV induced gravitaxis. The gravitaxis forms with phototaxis a ratio-chromatic depth-gauge. In different...
react on UV-light and make the larvae swimming down gravitactically. The gravitaxis here is countered by phototaxis, which makes the larvae swimming up to...
foraging for resources involves changes in patchiness, which combines gravitaxis, movement in response to changes in gravity, and chemoreception to identify...
to avoid getting trapped in certain flow structures by learning smart gravitaxis. Deep reinforcement learning has been used to explore microswimmer navigation...
its Müller's vesicle to distinguish between up and down (geotaxis or gravitaxis), which it uses as a stimulus in addition to the oxygen concentration...
non-directional UV-light. This behavior is a UV-induced positive gravitaxis. This gravitaxis and negative phototaxis induced by light coming from the water...
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