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Electrolocation
Electroreception and electrogenesis are the closely-related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes to stun prey. The capabilities are found almost exclusively in aquatic or amphibious animals, since water is a much better conductor of electricity than air. In passive electrolocation, objects such as prey are detected by sensing the electric fields they create. In active electrolocation, fish generate a weak electric field and sense the different distortions of that field created by objects that conduct or resist electricity. Active electrolocation is practised by two groups of weakly electric fish, the Gymnotiformes (knifefishes) and the Mormyridae (elephantfishes), and by ''Gymnarchus niloticus'', the African knifefish. An electric fish generates an electric field using an electric organ, modified from muscles in its tail. The field is ca ...
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Electroreception System In Elephantfish
Electroreception and electrogenesis are the closely-related biological abilities to perceive electrical stimuli and to generate electric fields. Both are used to locate prey; stronger electric discharges are used in a few groups of fishes to stun prey. The capabilities are found almost exclusively in aquatic or amphibious animals, since water is a much better conductor of electricity than air. In passive electrolocation, objects such as prey are detected by sensing the electric fields they create. In active electrolocation, fish generate a weak electric field and sense the different distortions of that field created by objects that conduct or resist electricity. Active electrolocation is practised by two groups of weakly electric fish, the Gymnotiformes (knifefishes) and the Mormyridae (elephantfishes), and by ''Gymnarchus niloticus'', the African knifefish. An electric fish generates an electric field using an electric organ, modified from muscles in its tail. The field is call ...
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Electric Fish
An electric fish is any fish that can generate electric fields. Most electric fish are also electroreceptive, meaning that they can sense electric fields. The only exception is the stargazer family. Electric fish, although a small minority, include both oceanic and freshwater species, and both cartilaginous and bony fishes. Electric fish produce their electrical fields from an electric organ. This is made up of electrocytes, modified muscle or nerve cells, specialized for producing strong electric fields, used to locate prey, for defence against predators, and for signalling, such as in courtship. Electric organ discharges are two types, pulse and wave, and vary both by species and by function. Electric fish have evolved many specialised behaviours. The predatory African sharptooth catfish eavesdrops on its weakly electric mormyrid prey to locate it when hunting, driving the prey fish to develop electric signals that are harder to detect. Bluntnose knifefishes produce an el ...
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Electric Eel
The electric eels are a genus, ''Electrophorus'', of neotropical freshwater fish from South America in the family Gymnotidae. They are known for their ability to stun their prey by generating electricity, delivering shocks at up to 860 volts. Their electrical capabilities were first studied in 1775, contributing to the invention in 1800 of the electric battery. Despite their name, electric eels are not closely related to the true eels (Anguilliformes) but are members of the electroreceptive knifefish order, Gymnotiformes. This order is more closely related to catfish. In 2019, electric eels were split into three species: for more than two centuries before that, the genus was believed to be monotypic, containing only ''Electrophorus electricus.'' They are nocturnal, air-breathing animals, with poor vision complemented by electrolocation; they mainly eat fish. Electric eels grow for as long as they live, adding more vertebrae to their spinal column. Males are larger than fem ...
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Electric Organ (biology)
An electric ray (Torpediniformes) showing location of paired electric organs in the head, and electrocytes stacked within it">Torpediniformes.html" ;"title="electric ray (Torpediniformes">electric ray (Torpediniformes) showing location of paired electric organs in the head, and electrocytes stacked within it In biology, the electric organ is an organ that an electric fish uses to create an electric field. Electric organs are derived from modified muscle or in some cases nerve tissue, and have evolved at least six times among the elasmobranchs and teleosts. These fish use their electric discharges for navigation, communication, mating, defence, and in strongly electric fish also for the incapacitation of prey. The electric organs of two strongly electric fish, the torpedo ray and the electric eel were first studied in the 1770s by John Walsh, Hugh Williamson, and John Hunter. Charles Darwin used them as an instance of convergent evolution in his 1859 ''On the Origin of Species ...
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Platypus
The platypus (''Ornithorhynchus anatinus''), sometimes referred to as the duck-billed platypus, is a semiaquatic, egg-laying mammal Endemic (ecology), endemic to Eastern states of Australia, eastern Australia, including Tasmania. The platypus is the sole living representative or monotypic taxon of its Family (biology), family (Ornithorhynchidae) and genus (''Ornithorhynchus''), though a number of Fossil Monotremes, related species appear in the fossil record. Together with the four species of echidna, it is one of the five wikt:extant, extant species of monotremes, mammals that lay Egg (biology), eggs instead of giving birth to live young. Like other monotremes, it senses prey through electroreception, electrolocation. It is one of the few species of venomous mammals, as the male platypus has a spur (zoology), spur on the hind foot that delivers a Platypus venom, venom, capable of causing severe pain to humans. The unusual appearance of this egg-laying, duck-billed, beaver-t ...
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Gymnotiformes
The Gymnotiformes are an order of teleost bony fishes commonly known as Neotropical knifefish or South American knifefish. They have long bodies and swim using undulations of their elongated anal fin. Found almost exclusively in fresh water (the only exceptions are species that occasionally may visit brackish water to feed), these mostly nocturnal fish are capable of producing electric fields to detect prey, for navigation, communication, and, in the case of the electric eel (''Electrophorus electricus''), attack and defense. A few species are familiar to the aquarium trade, such as the black ghost knifefish (''Apteronotus albifrons''), the glass knifefish (''Eigenmannia virescens''), and the banded knifefish (''Gymnotus carapo''). Description Anatomy and locomotion Aside from the electric eel (''Electrophorus electricus''), Gymnotiformes are slender fish with narrow bodies and tapering tails, hence the common name of "knifefishes". They have neither pelvic fins nor dorsal ...
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Monotreme
Monotremes () are prototherian mammals of the order Monotremata. They are one of the three groups of living mammals, along with placentals (Eutheria), and marsupials (Metatheria). Monotremes are typified by structural differences in their brains, jaws, digestive tract, reproductive tract, and other body parts, compared to the more common mammalian types. In addition, they lay eggs rather than bearing live young, but, like all mammals, the female monotremes nurse their young with milk. Monotremes have been considered members of Australosphenida, a clade that contains extinct mammals from the Jurassic and Cretaceous of Madagascar, South America, and Australia, though this is disputed. The only surviving examples of monotremes are all indigenous to Australia and New Guinea, although there is evidence that they were once more widespread, as ''Monotrematum'' is known from the Paleocene of South America. The extant monotreme species are the platypus and four species of echidnas. The ...
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Hans Lissmann (zoologist)
Hans Lissmann FRS (30 April 1909 – 21 April 1995) was a British zoologist of Ukrainian provenance, specialising in animal behaviour. He was elected a Fellow of the Royal Society in 1954, following breakthrough research with his assistant Kenneth E. Machin identifying the electric field generated by the African Knife fish (''Gymnarchus''), and the uses which the fish makes of it. He was Reader, Department of Zoology, University of Cambridge, 1966–1977, then Reader Emeritus, and Director, Sub-Department of Animal Behaviour, 1969–1977. Life Early years Hans Werner Lissmann was born into a wealthy German family in Mykolaiv, Ukraine, which was then part of Russia. As members of the ethnic German minority the family fell under suspicion when war broke out in 1914. Lissmann and his elder brother were sent into "internal exile" in Siberia, separated from their parents, Robert and Ebba Lissmann. At the end of the war they were permitted to return home, but by 1922 the family ...
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Gymnarchus
''Gymnarchus niloticus'' – commonly known as the ''aba'', ''aba aba'', frankfish, freshwater rat-tail, ''poisson-cheval'', or African knifefish – is an electric fish, and the only species in the genus ''Gymnarchus'' and the family Gymnarchidae within the order Osteoglossiformes. It is found in swamps, lakes and rivers in the Nile, Turkana, Chad, Niger, Volta, Senegal, and Gambia basins. Description and biology ''G. niloticus'' has a long and slender body, with no caudal, pelvic, or anal fins. The dorsal fin is elongated, running along the back of the fish towards the blunt, finless tail, and is the main source of propulsion. It grows up to in length and in weight. ''G. niloticus'' is nocturnal and has a poor vision. Instead, it navigates and hunts smaller fish using a weak electric field, as demonstrated by the zoologist Hans Lissmann in 1950, when he noticed that it could swim equally well forwards or backwards, clearly relying on a sense other than vision. This ope ...
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Conductor (material)
In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge ( electric current) in one or more directions. Materials made of metal are common electrical conductors. Electric current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases. In order for current to flow within a closed electrical circuit, it is not necessary for one charged particle to travel from the component producing the current (the current source) to those consuming it (the loads). Instead, the charged particle simply needs to nudge its neighbor a finite amount, who will nudge ''its'' neighbor, and on and on until a particle is nudged into the consumer, thus powering it. Essentially what is occurring is a long chain of momentum transfer between mobile charge carriers; the Drude model of conduction describes this process more rigorously. This momentum transfer model makes metal ...
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Knollenorgan
A Knollenorgan is an electroreceptor in the skin of weakly electric fish of the family Mormyridae (Elephantfish) from Africa. The structure was first described by Viktor Franz (1921), a German anatomist unaware of its function. They are named after "Knolle", German for "tuberous root" which describes their structure. Structure and function Knollenorgans contain modified epithelial cells that act as sensory transducers for electric fields. Besides these, there are supporting cells and a sensory neuron. The neuron projects to the fish's brain, specifically to the nucleus of the electrosensory lateral line lobe (nELL) of the medulla via the posterior branch of the lateral line nerve. The organs are embedded in the thickened epidermis. The receptor cells lie buried in the deeper layers of the epidermis, where they expand into a pocket in the superficial layers of the corium. The sense organ is surrounded by a basement membrane which separates corium from epidermis. Epithelial cel ...
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Journal Of Experimental Biology
''Journal of Experimental Biology'' (formerly ''The British Journal of Experimental Biology)'' is a peer-reviewed scientific journal in the field of comparative physiology and integrative biology. It is published by The Company of Biologists. The journal is partnered with Publons and has two-way integration with bioRxiv. ''Journal of Experimental Biology'' is now a hybrid journal and publishes 24 issues a year. Content over six months old is free to read. History ''The'' ''British Journal of Experimental Biology'' was established in Edinburgh in 1923 (''Br. J. Exp. Biol.'': ). It was published by Oliver and Boyd and edited by F. A. E. Crew with an Editorial Board of nine members, including Julian Huxley. When the journal ran into financial trouble, George Parker Bidder II, the founder of The Company of Biologists, rescued it in 1925. Sir James Gray was appointed as the journal's first Editor-in-Chief in 1925 and the journal was renamed ''The Journal of Experimental Biology' ...
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