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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 fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manaus
Manaus () is the capital and largest city of the Brazilian state of Amazonas. It is the seventh-largest city in Brazil, with an estimated 2020 population of 2,219,580 distributed over a land area of about . Located at the east center of the state, the city is the center of the Manaus metropolitan area and the largest metropolitan area in the North Region of Brazil by urban landmass. It is situated near the confluence of the Negro and Solimões rivers. It is the only city in the Amazon Rainforest with a population over 1 million people. The city was founded in 1669 as the Fort of São José do Rio Negro. It was elevated to a town in 1832 with the name of "Manaus", an altered spelling of the indigenous Manaós peoples, and legally transformed into a city on October 24, 1848, with the name of ''Cidade da Barra do Rio Negro'', Portuguese for "The City of the Margins of the Black River". On September 4, 1856, it returned to its original name. Manaus is located in the center of ... [...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 unit of p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monte Cevedale
Monte Cevedale is a mountain at the border of the Lombardy and Trentino-Alto Adige/Südtirol regions in Italy. The southern summit (3769 m) is the highest mountain of Trentino province, while three provinces, Sondrio, South Tyrol it, Provincia Autonoma di Bolzano – Alto Adige lld, Provinzia Autonoma de Balsan/Bulsan – Südtirol , settlement_type = Autonomous province , image_skyline = , image_alt ..., and Trentino meet on the northern summit (3757 m), known as Cima Cevedale or Zufallspitze. Mountains of the Alps Alpine three-thousanders Mountains of Italy Mountains of Lombardy {{Lombardy-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnotus
''Gymnotus'' is a genus of Neotropical freshwater fish in the family Gymnotidae found widely in South America, Central America and southern Mexico (36th parallel south to 18th parallel north). The greatest species richness is found in the Amazon basin. They are sometimes referred to by the English name banded knifefish, although this typically is reserved for the most widespread species, ''Banded knifefish, G. carapo''. Overall ''Gymnotus'' is the most widespread genus in the order Gymnotiformes. Although not commonly eaten by humans, some members of this genus are used locally as fishing bait, and occasionally kept in aquariums. Habitat ''Gymnotus'' occur in virtually any freshwater habitat in their range, even those with little oxygen (survives by breathing air directly from the water surface), areas affected by pollution, and for a period on land if their aquatic habitat dries out. Large species tend to live near floating vegetation along the edges of large rivers or floodplai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ports Of Bremen
The Ports of Bremen, Bremen Ports or Bremish Ports, in German "Bremische Häfen" consist of the commercial ports in Bremen and Bremerhaven. They are managed by ''bremenports GmbH & Co. KG'', a company of private status in public property. In 2011, in the Ports of Bremen more than 60 million tons of goods were transported, including 6 million containers and 2.1 million cars. Bremerhaven Harbour is the world's busiest port transporting cars. History Medieval harbours The first port of Bremen was the Balge, a narrow branch of the Weser river. In the mid-13th century, on Bremen city's riverside of the main river, a quay was built, called the Schlachte. For about three centuries, both ports were used in parallel, before Balge harbour stopped being used. Outer Harbours Like in many other European regions, the medieval extension of agriculture increased erosion of soil in the Weser basin. Since about 1400, the bed of the lower Weser was choked with sand, dramatically. Laden sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomy
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function (biology), function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic research, basic sciences that are applied in medicine. The discipline of anatomy is divided into macroscopic scale, macroscopic and microscopic scale, microscopic. Gross anatomy, Macroscopic anatomy, or gross anatomy, is the examination of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Organ (fish)
file:Elektroplax_Rochen.png, An 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 Elasmobranchii, elasmobranchs and teleosts. These fish use their electric discharges for animal navigation, navigation, communication, mating, defence in animals, defence, and in strongly electric fish also for the incapacitation of Predation, prey. The electric organs of two strongly electric fish, the Electric ray, torpedo ray and the electric eel were first studied in the 1770s by John Walsh (scientist), John Walsh, Hugh Williamson, and John Hunter (surgeon), John Hunter. Charles Darwin used them as an instance of convergent evolution in his 1859 ''On the Origin of Species''. Modern study began with Hans L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curare
Curare ( /kʊˈrɑːri/ or /kjʊˈrɑːri/; ''koo-rah-ree'' or ''kyoo-rah-ree'') is a common name for various alkaloid arrow poisons originating from plant extracts. Used as a paralyzing agent by indigenous peoples in Central and South America for hunting and for therapeutic purposes, curare only becomes active when it contaminates a wound. These poisons cause weakness of the skeletal muscles and, when administered in a sufficient dose, eventual death by asphyxiation due to paralysis of the diaphragm. Curare is prepared by boiling the bark of one of the dozens of plant sources, leaving a dark, heavy paste that can be applied to arrow or dart heads. In medicine, curare has been used as a treatment for tetanus or strychnine poisoning and as a paralyzing agent for surgical procedures. History The word 'curare' is derived from ''wurari'', from the Carib language of the Macusi of Guyana. It has its origins in the Carib phrase "mawa cure" meaning of the Mawa vine, scienti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nysa, Poland
Nysa (german: Neisse or ''Neiße'', szl, Nysa) is a town in southwestern Poland on the Eastern Neisse (Polish language, Polish: ''Nysa Kłodzka'') river, situated in the Opole Voivodeship. With 43,849 inhabitants (2019), it is the capital of Nysa County. It comprises the urban portion of the surrounding Gmina Nysa. Historically the town was part of Upper Silesia. History Nysa, one of the oldest towns in Silesia, was probably founded in the 10th century. The name of the Nysa Kłodzka , Nysa river, from which the town takes its name, was mentioned in 991, when the region formed part of the Duchy of Poland (966–1025) , Duchy of Poland under Mieszko I of Poland. A Polish stronghold was built in Nysa in the 11th and 12th century due to the proximity of the border with the Duchy of Bohemia , Czech Duchy. As a result of the fragmentation of Poland, it became part of the Duchy of Silesia, and from the 14th century it functioned as the capital of the Duchy of Nysa, administered by t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrow Poison
Arrow poisons are used to poison arrow heads or darts for the purposes of hunting and warfare. They have been used by indigenous peoples worldwide and are still in use in areas of South America, Africa and Asia. Notable examples are the poisons secreted from the skin of the poison dart frog, and curare (or 'ampi'), a general term for a range of plant-derived arrow poisons used by the indigenous peoples of South America. Poisoned arrows have featured in mythology, notably the Greek story of Heracles slaying the centaur Nessus using arrows poisoned with the blood of the Lernaean Hydra. The Greek hero Odysseus poisons his arrows with hellebore in Homer's ''Odyssey''. Poisoned arrows also figure in Homer's epic about the Trojan War, the ''Iliad'', in which both Achaeans and Trojans used toxic arrows and spears. Poisoned arrows are referred to in the Book of Job in the Bible, descriptive of the sufferings experienced by the just man, Job. The modern terms "toxic" and "toxin" derive f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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