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Electric Organ (anatomy)
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' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On The Origin Of Species
''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''),The book's full original title was ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''. In the 1872 sixth edition, "On" was omitted, so the full title is ''The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.'' This edition is usually known as ''The Origin of Species.'' The 6th is Darwin's final edition; there were minor modifications in the text of certain subsequent issues. See Freeman, R. B. In Van Wyhe, John, ed. ''Darwin Online: On the Origin of Species'', 2002. published on 24 November 1859, is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. Darwin's book introduced the scientific theory that populatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torpedo Californica
''Tetronarce californica'' also known as the Pacific electric ray is a species of electric ray in the family Torpedinidae, endemic to the coastal waters of the northeastern Pacific Ocean from Baja California to British Columbia. It generally inhabits sandy flats, rocky reefs, and kelp forests from the surface to a depth of , but has also been known to make forays into the open ocean. Measuring up to long, this species has smooth-rimmed spiracles (paired respiratory openings behind the eyes) and a dark gray, slate, or brown dorsal coloration, sometimes with dark spots. Its body form is typical of the genus, with a rounded pectoral fin disc wider than long and a thick tail bearing two dorsal fins of unequal size and a well-developed caudal fin. Solitary and nocturnal, the Pacific electric ray can generate up to 45 volts of electricity for the purposes of subduing prey or self-defense. It feeds mainly on bony fishes, ambushing them from the substrate during the day ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl Sachs
Carl Sachs (19 September 1853–18 August 1878) was a German zoologist, known for his discovery of what is now called Sachs' organ in the electric eel. Biography Carl Sachs was born in Neisse (now in Poland). He was sent to Latin America by the physiologist Emil du Bois-Reymond, to study the electric eel (''Electrophorus'') in the same Llanos region where Humboldt had made his observations; he took with him a galvanometer and electrodes to measure the fish's electric organ discharge, and used rubber gloves ("") to enable him to catch the fish without being shocked, to the surprise of the local people. He published his research on the fish, including his discovery of what is now called Sachs' organ, in 1877. While in the Llanos, he used giant toads instead of the frogs that du Bois-Reymond's laboratory normally employed to detect electrical activity from electric fish. Sachs studied the electric eel's seeming immunity to its own shocks, and to electricity applied to it. He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which in his view is intentional, whereas natural selection is not. Genetic diversity, Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the Cell (biology), cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alessandro Volta
Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist and lay Catholic who was a pioneer of electricity and power who is credited as the inventor of the electric battery and the discoverer of methane. He invented the voltaic pile in 1799, and reported the results of his experiments in 1800 in a two-part letter to the president of the Royal Society. With this invention Volta proved that electricity could be generated chemically and debunked the prevalent theory that electricity was generated solely by living beings. Volta's invention sparked a great amount of scientific excitement and led others to conduct similar experiments, which eventually led to the development of the field of electrochemistry. Volta also drew admiration from Napoleon Bonaparte for his invention, and was invited to the Institute of France to demonstrate his invention to the members of the institute. Volta enjoyed a certain amount of closeness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Luigi Galvani
Luigi Galvani (, also ; ; la, Aloysius Galvanus; 9 September 1737 – 4 December 1798) was an Italian physician, physicist, biologist and philosopher, who studied animal electricity. In 1780, he discovered that the muscles of dead frogs' legs twitched when struck by an electrical spark. This was an early study of bioelectricity, following experiments by John Walsh and Hugh Williamson. Early life Luigi Galvani was born to Domenico Galvani and Barbara Caterina Foschi, in Bologna, then part of the Papal States. Domenico was a goldsmith. Galvani then began taking an interest in the field of "medical electricity". This field emerged in the middle of the 18th century, following electrical researches and the discovery of the effects of electricity on the human body by scientists including Bertrand Bajon and Ramón M. Termeyer in the 1760s, and by John Walsh and Hugh Williamson in the 1770s. Galvani vs. Volta Alessandro Volta, a professor of experimental physics in the Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugh Williamson
Hugh Williamson (December 5, 1735 – May 22, 1819) was an American Founding Fathers of the United States, Founding Father, physician, and politician. He is best known as a signatory to the U.S. Constitution, and for representing North Carolina at the Philadelphia Convention, Constitutional Convention. Williamson was a scholar of international renown. His erudition had brought him into contact with some of the leading intellectuals of the Patriot (American Revolution), Patriot cause and, in turn, with the ferment of political ideas that eventually found expression in the Constitution. During the American Revolution, Williamson contributed his talents as physician and natural scientist to the American war effort. His experiences in that preeminent event of his generation transformed the genial scholar into an adroit politician and a determined leader in the campaign for effective national government. This leadership was evident not only at the Convention in Philadelphia but also, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Eel's Electric Organs
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwell's equations. Various common phenomena are related to electricity, including lightning, static electricity, electric heating, electric discharges and many others. The presence of an electric charge, which can be either positive or negative, produces an electric field. The movement of electric charges is an electric current and produces a magnetic field. When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by Coulomb's law. If the charge moves, the electric field would be doing work on the electric charge. Thus we can speak of electric potential at a certain point in space, which is equal to the work done by an external agent in carrying a u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
