Information about electrolocation

Electroreceptors (Ampullae of Lorenzini) and lateral line canals in the head of a shark.

Electroreception, sometimes written as electroception, is the biological ability to receive and make use of electrical impulses. It is much more common among aquatic creatures, as water is a far superior conductor than air. Electroreception is primarily used for electrolocation: the ability to use electric fields to locate objects (compare with animal echolocation).

Mechanism

Active electrolocation. Conductive objects concentrate the field and resistant objects spread the field.

Many fish have an electroreception sense, believed to be associated with the lateral line system. This sense operates in two main modalities; active and passive.

Active

In "active" electroreception, the animal senses its surrounding environment by generating electric fields and detecting distortions in these fields using electroreceptor organs. This ability is especially important in murky water, where visibility is low.

Animals that use active electroreception include the weakly electric fish, which generate small (typically less than one volt) electrical pulses using an organ in the tail consisting of two to five rows of modified muscle cells (electrocytes).

Weakly electric fish can discriminate between objects with different resistance and capacitance values, which may help in identifying the object. They can also communicate by modulating the electrical waveform they generate; an ability known as electrocommunication.^[1]

Active electroreception typically has a range of about one body length, though objects with an electrical resistance similar to that of water are nearly undetectable.

Passive

In "passive" electroreception the animal senses the weak bioelectric fields generated by other animals. Animals that use passive electroreception include sharks and rays.

Occurrence

Elasmobranchii

Sharks and rays (members of the subclass Elasmobranchii) rely heavily on electrolocation in the final stages of their attacks, as can be demonstrated by the robust feeding response elicited by electric fields similar to those of their prey. Sharks are the most electrically sensitive animals known; responding to DC fields as low as 5 nV/cm.

The electric field sensors of sharks are called the ampullae of Lorenzini. They consist of electroreceptor cells connected to the seawater by pores on their snouts and other zones of the head. A problem with the early submarine telegraph cables was the damage caused by sharks who sensed the electric fields produced by these cables. It is possible that sharks may use Earth's magnetic field to navigate the oceans using this sense.

A recent study has suggested that the same genes that contribute to a shark's sense of electroreception may also be responsible at least in part to the development of facial structures in humans.^[2]

Other vertebrates

The platypus also uses electroreception.

The electric eel (a strongly electric fish), besides its ability to generate high voltage electric shocks, uses lower voltage pulses for navigation and prey detection in its turbid habitat. This ability is shared with other Gymnotiformes.

Monotremes are the most prevelent mammals that use electroception. Among these, the platypus has the most acute sense.^[3]^[4] The platypus may use electroreception in conjunction with tactile (pressure) sensors in order to determine the distance to prey, by using the delay between the arrival of electrical signals and pressure changes in the water.<ref name="Electro1" />

There are no known cases of mimicry involving electroreception, though it is theoretically possible.^[5]

References

1. ^ Hopkins, CD (May 1999). "Design features for electric communication". J Exp Biol 202: 1217-1228.
2. ^ Cohn, Martin J.; Freitas, Renata, Zhang, GuangJun, Albert, James S. & Evans, David H. (January 2006). "Developmental origin of shark electrosensory organs". Evolution & Development 8: 74.
3. ^ H, Scheich; Langner G, Tidemann C, Coles RB, Guppy A. (1986 January 30-February 5). "Electroreception and electrolocation in platypus". Nature 319(6052): 401-2.
4. ^ Pettigrew, John D. (1999). "Electroreception in Monotremes". The Journal of Experimental Biology (202): 1447–1454. Retrieved on 19 September, 2006.
5. ^ Szabo, T. (1980) Elektrische Fische und Elektrorezeption. Leopoldina. 22:131-151.

External links

• • [ e] Nervous system: Sensory systems/sense
Special senses	Visual system/Visual perception • Auditory system/Hearing • Chemoreception (Olfactory system/Olfaction • Gustatory system/Taste)
Somatosensory system	Nociception • Thermoreception • Vestibular system • Mechanoreception (Pressure, Vibration, Proprioception)
Other	Sensory receptor

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In science and engineering, conductors, such as copper or aluminum, are materials with atoms have loosely held valence electrons. See electrical conduction.

Conductors in context

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Senses are the physiological methods of perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology (or cognitive science), and philosophy of perception.
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lateral line is a sense organ used to detect movement and vibration in the surrounding water. Lateral lines are usually visible as faint lines running lengthwise down each side, from the vicinity of the gill covers to the base of the tail.
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An electric fish is a fish that can generate electric fields. It is said to be electrogenic; a fish that has the ability to detect electric fields is said to be electroreceptive. Most fish that are electrogenic are also electroreceptive.
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volt (symbol: V) is the SI derived unit of electric potential difference or electromotive force.^[1]^[2] It is named in honor of the Italian physicist Alessandro Volta (1745–1827), who invented the voltaic pile, the first modern chemical battery.
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For the musical instrument, see Electronic organ.

The electric organ is a myogenic organ common to all electric fish used for the purposes of creating an electric field, a behavior used for navigation as well as communication in natural
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Electrical resistance is a measure of the degree to which an object opposes an electric current through it. The SI unit of electrical resistance is the ohm. Its reciprocal quantity is electrical conductance measured in siemens.
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Capacitance is a measure of the amount of electric charge stored (or separated) for a given electric potential. The most common form of charge storage device is a two-plate capacitor.
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SHARK

General
Vincent Rijmen, Joan Daemen, Bart Preneel, Antoon Bosselaers, Erik De Win
1996

KHAZAD, Rijndael

Cipher detail
Key size(s):| 128 bits

Block size(s):| 64 bits
Substitution-permutation network
6

In cryptography,
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Batoidea

Orders

Rajiformes - common rays and skates
Pristiformes - sawfishes
Torpediniformes - electric rays
See text for families.

Batoidea
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Elasmobranchii
Bonaparte, 1838

Superorders

Batoidea (rays and skates)
Selachimorpha (sharks)

Elasmobranchii is the subclass of cartilaginous fish that includes skates, rays (batoidea), and sharks (selachii).
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predation describes a biological interaction where a predator organism feeds on another living organism or organisms known as prey.^[1] Predators may or may not kill their prey prior to feeding on them.
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Direct current (DC or "continuous current") is the constant flow of electric charge. This is typically in a conductor such as a wire, but can also be through semiconductors, insulators, or even through a vacuum as in electron or ion beams.
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ampullae of Lorenzini are special sensing organs, forming a network of jelly-filled canals found on elasmobranchs (sharks and rays) and Chimaera. Each ampulla consists of a jelly-filled canal opening to the surface by a pore in the skin and ending blindly in a cluster of
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submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries.

The first submarine communications cables carried telegraphy traffic.
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magnetic field is a field that permeates space and which exerts a magnetic force on moving electric charges and magnetic dipoles. Magnetic fields surround electric currents, magnetic dipoles, and changing electric fields.
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Earth's oceans
(World Ocean)

Arctic Ocean
Atlantic Ocean
Indian Ocean
Pacific Ocean
Southern Ocean

An ocean (from Ωκεανός, Okeanos
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