geotaxis


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Related to geotaxis: thermotaxis

geotaxis

[¦jē·ō¦tak·səs]
(physiology)
Movement of a free-living organism in response to the stimulus of gravity.
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The behavioral basis of larval recruitment in the crab Callinectes sapidus Rathbun: a laboratory investigation of ontogenetic changes in geotaxis and barokinesis.
There were no significant differences between group conditions (sham or carotid) or between treatments (saline, Grx2, or Trx1 administration) for the tasks evaluating surface righting reflex, negative geotaxis, crossed extensor reflex, ear twitching, auditory startle, and ear unfolding (see Supplementary Figure 1 available online at https://doi.org/10.1155/2017/4162465).
However, the impact of interventions on health span is commonly evaluated by means of motor performance test such as spontaneous motor activity and the geotaxis test.
Temperature changes also produce measurable alterations in the directional responses to light (phototaxis) and gravity (geotaxis), and the activity of crustacean larvae in general [10].
The following reflex tests were assessed in all pups from each litter: surface righting reflex (a normal ventral position assumed after the animal is placed on its back, observed for 15 s, postnatal days 2 to 7), negative geotaxis (to turn at least 90, after being placed face-down in a platform inclined at 45; the maximum time allowed for the pup to turn was 30 s, PD 7 to PD 12), and grasping reflex (registering the day of absence of involuntary bending of the fingers in response to tactile stimulation on the palm, PD2 to PD12).
Other model organisms that have been used to demonstrate choice include fruit flies (geotaxis) and crayfish (sand vs.
Very low doses of the chemicals together delayed ear opening, affected geotaxis, and reduced grip strength.
In the pre-weaning stage, control offspring mastered open field assessment and negative geotaxis earlier than growth restricted offspring.
Rats were observed from postnatal day 1 to 25 for the age of the appearance of physiological markers (pinna detachment, inscisor's eruption, eye opening) and acquisition of reflexes (surface righting, visual placing, reflex suspension, negative geotaxis).
To our knowledge, Murphey and Hall (1969) were the first to show that flies selected for negative geotaxis exhibited some physiological adaptation to the dry, plastic environment of a maze, that is, lower locomotor activity and lower mortality in absence of food.
The coastal snail also has a negative geotaxis: it will crawl up, away from the earth, if given the opportunity.