geotaxis


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Related to geotaxis: thermotaxis

geotaxis

 [je″o-tak´sis]
taxis in response to gravity; movement influenced by gravity.

ge·o·tax·is

(jē'ō-tak'sis),
A form of positive barotaxis in which there is a tendency to growth or movement toward or into the earth.
Synonym(s): geotropism
[geo- + G. taxis, orderly arrangement]

geotaxis

(jē′ō-tăk′sĭs)
n.
Movement of a motile organism using the earth's gravity for orientation.

ge′o·tac′tic (-tĭk) adj.
ge′o·tac′ti·cal·ly adv.

geotaxis

a type of animal movement (not growth) in which the body becomes orientated in relation to the force of gravity. For example, fruit flies exhibit negative geotaxis, moving upwards in the culture bottle, away from the gravitational force.
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References in periodicals archive ?
hexandrum treated mother rats were more efficient in negative geotaxis than control on 6th day, but on later days the efficiency was comparable to control (Table 3).
A total of 51 individuals that were infected by Polymorphus minutus and 59 uninfected animals from the Veze River were used for geotaxis tests.
melanogaster to coconut oil concentrations (10% and 20%) revealed a decrease in locomotor capacityby changes in geotaxis negative, a commonly used behavior addressed to assess neurolocomotor function in Drosophila melanogaster [44].
We observed a significant change in the negative geotaxis behavior of flies treated with P.
As an example of a study that compared the development of prezygotic isolation as a correlated response with divergent selection with and without gene flow, consider the experiments of Hurd and Eisenberg (1975) who selected divergently (95% of flies removed by selection each generation) for geotaxis in allopatric (0% gene flow) and sympatric (50% gene flow) populations.
The lower comb rows beat faster than the upper rows, with ciliary power strokes directed aborally, when the animal turns to swim mouth upward (negative geotaxis).
Unlike other invertebrate statocysts, the ctenophore statocyst does not require neural or muscular responses to mediate geotaxis (Tamm, 1982, 2014a, b).
In contrast, fiddler crab megalopae have an endogenous circatidal rhythm where swimming activity is increased during times of flood tides; this, combined with negative geotaxis, results in upward swimming in the water column (Tankersley & Forward 1994).
Alternatively, orientation may be an active directional response to a gradient in another exogenous cue such as gravity or pressure (i.e., geotaxis, barotaxis) (Fraenkel and Gunn, 1961).
However, the involvement of negative geotaxis that was found for crab larvae (e.g., Forward, 1985) needs to be tested.
The Zoea I were characterized by a lack of spines (Campodonico, 1971), positive geotaxis (Paschke et al., 2006), a maximum swimming velocity of 2.1 cm [s.sup.-1] (Escobar, 2005), carapace length 2.4 mm, carapace width 1.61 mm, (Surot, 2006), dry weight 1040 to 878 [micro]g [larvae.sup.-1] (Kattner et al., 2003; Surot, 2006), and protein content 41% of the dry weight; triacylglycerols accounted for about 75% of the lipid fraction, and mono-unsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were 48.3% and 29.8% of the total fatty acid content, respectively (Kattner et al., 2003).