A taxis (plural taxes, pronounced [ˈtæksiːz]) is an innate behavioural response by an organism to a directional stimulus. A taxis differs from a tropism (turning response, often growth towards or away from a stimulus) in that the organism has motility and demonstrates guided movement towards or away from the stimulus ^[1]. Articles with similar titles include the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... Look up innate in Wiktionary, the free dictionary. ... Behavior or behaviour refers to the actions or reactions of an object or organism, usually in relation to the environment. ... This article needs additional references or sources for verification. ... In physiology, a stimulus is a detectable change in the internal or external environment. ... It has been suggested that chemotropism be merged into this article or section. ... Motility is a biological term which refers to the ability to move spontaneously and independently. ...

Examples

For example, flagellate protozoans of the genus Euglena move towards a light source. Here the directional stimulus is light, and the orientation movement is towards the light. This reaction or behaviour is a positive one to light and specifically termed "positive phototaxis", since phototaxis is a response to a light stimulus, and the organism is moving towards the stimulus. If the organism moves away from the stimulus, then the taxis is negative. Many types of taxis have been identified and named using prefices to specify the stimulus that elicits the response. These include anemotaxis (stimulation by wind), barotaxis (pressure), chemotaxis (chemicals), galvanotaxis (electrical current), geotaxis (gravity), hydrotaxis (moisture), phototaxis (light), rheotaxis (fluid flow), thermotaxis (temperature changes) and thigmotaxis (physical contact). Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ... Hey Euglena is a common Euglenophyte protist, typical of the euglenids, and commonly found in nutrient-rich freshwater, with a few marine species. ... This article or section does not cite any references or sources. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin in Canberra, Australia. ... A chemical substance is any material substance used in or obtained by a process in chemistry: A chemical compound is a substance consisting of two or more chemical elements that are chemically combined in fixed proportions. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... Gravity is a force of attraction that acts between bodies that have mass. ... Dew on a spider web Moldy bread Moisture generally refers to the presence of water, often in trace amounts. ... Phototaxis is an organisms automatic movement toward or away from light. ... This article does not cite any references or sources. ... (Positive) Rheotaxis is a behavior in fish whereby they will (generally) turn to face into an oncoming current. ... A current is fluid flow, especially of water or air. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... The somatosensory system is the sensory system of somatic sensation. ...

Depending on the type of sensory organs present, taxes can be classified as klinotaxes, where an organism continuously samples the environment to determine the direction of a stimulus, tropotaxes, where bilateral sense organs are used to determine the stimulus direction, and telotaxes, which are similar to tropotaxes but where a single organ suffices to establish the orientation movement. (See also sense) A sensory system is a part of the nervous system that consists of sensory receptors, neural pathways, and those parts of the brain responsible for processing the information. ...

Geotaxis

Geotaxis is a response to the attraction due to gravity. The planktonic larvae of the king crab Lithodes aequispinus use a combination of positive phototaxis (movement towards the light) and negative geotaxis (upward movement) ^[2]. Both positive and negative geotaxes are found in a variety of protozoans ^[3]. Gravity is a force of attraction that acts between bodies that have mass. ... Photomontage of plankton organisms Plankton are any drifting organism that inhabits the water column of oceans, seas, and bodies of fresh water. ... Genera Acantholithodes Cryptolithodes Dermaturus Glyptolithodes Hapalogaster Lithodes Lopholithodes Neolithodes Oedignathus Paralithodes Paralomis Phyllolithodes Placetron Rhinolithodes King crabs, also called stone crabs, are a family of crab-like decapod crustaceans chiefly found in cold seas. ... Wikisource has an original article from the 1911 Encyclopædia Britannica about: Protozoa Protozoa (in Greek proto = first and zoa = animals) are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. ...

Phototaxis

Main article: phototaxis

Phototaxis is the movement of an organism in response to light. This is advantageous for phototrophic organisms as they can orientate themselves most efficiently to receive light for photosynthesis. Two types of positive phototaxis are observed in prokaryotes. Scotophototaxis is observable as the movement of a bacterium out of the area illuminated by a microscope. Entering darkness signals the cell to reverse direction and reenter the light. A second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. Phototaxis is an organisms automatic movement toward or away from light. ... This article does not cite any references or sources. ...

Chemotaxis

Main article: chemotaxis

Chemotaxis is a migratory response elicited by chemicals. Unicellular (e.g. protozoa) or multicellular (e.g. worms) organisms are targets of the substances. A concentration gradient of chemicals developed in a fluid phase guides the vectorial movement of responder cells or organisms. Inducers of locomotion towards increasing steps of concentrations are considered as chemoattractants, while chemorepellents result moving off the chemical. However, chemotaxis is described in prokaryotic and eukaryotic cells, signalling mechanisms (receptors, intracellular signaling) and effectors are significantly different. Chemotaxis is a kind of taxis, in which bodily cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment. ... Inorganic or organic substances possessing chemotaxis inducer effect in motile cells. ... Inorganic or organic substances possessing chemotaxis modulator, negative effect in motile cells. ... Prokaryotes are unicellular (in rare cases, multicellular) organisms without a nucleus. ... Kingdoms Eukaryotes are organisms with complex cells, in which the genetic material is organized into membrane-bound nuclei. ...

Rheotaxis

Main article: rheotaxis

Rheotaxis is a response to a current in a fluid. Positive rheotaxis is shown by fish turning to face against the current. In a flowing stream, this behavior leads them to hold their position in a stream rather than being swept downstream. Some fish will exhibit negative rheotaxis where they will avoid currents. (Positive) Rheotaxis is a behavior in fish whereby they will (generally) turn to face into an oncoming current. ... A current is fluid flow, especially of water or air. ...

Magnetotaxis

Main article: magnetotaxis

Magnetotaxis is the ability of certain motile, aquatic bacteria to sense a magnetic field and coordinate their movement in response. It has been suggested that by orientating themselves toward the Earth's poles, marine bacteria are able to direct their movement downwards, towards the sediment. Furthermore, bacteria that are able to metabolise metal compounds may also use magnetosomes to detect deposits of ferrous compounds. Magnetotaxis is the ability of certain cells to sense the polarity or the inclination of the earths magnetic field, as an aid to navigation. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Magnetic field lines shown by iron filings In physics, a magnetic field is a solenoidal vector field in the space surrounding moving electric charges, such as those in electric currents and bar magnets. ...

See also

• Haptotaxis
• Mechanotaxis
• Kinesis

This page is a candidate to be moved to Wiktionary. ... Mechanotaxis is the directed movement of cell motility or outgrowth, e. ... // Biology Kinesis is a movement or activity of a cell or an organism in response to a stimulus such as light. ...

References