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Dorsal Fins
A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found in most fish, in mammals such as whales, and in extinct ancient marine reptiles such as ichthyosaurs. Most have only one dorsal fin, but some have two or three. Wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of whales to identify individuals in the field. The bones or cartilages that support the dorsal fin in fish are called pterygiophores. Functions The main purpose of the dorsal fin is usually to stabilize the animal against rolling and to assist in sudden turns. Some species have further adapted their dorsal fins to other uses. The sunfish uses the dorsal fin (and the anal fin) for propulsion. In anglerfish, the anterior of the dorsal fin is modified into a biological equival ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aileron De Requin
An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in Flight dynamics, roll (or movement around the aircraft's Flight control surfaces#Longitudinal axis, longitudinal axis), which normally results in a change in flight path due to the tilting of the Lift (force), lift vector. Movement around this axis is called rolling or banking. Considerable controversy exists over credit for the invention of the aileron. The Wright brothers and Glenn Curtiss fought a years-long Wright brothers patent war, legal battle over the Wright patent of 1906, which described a method of wing-warping to achieve lateral control. The brothers prevailed in several court decisions which found that Curtiss's use of ailerons violated the Wright patent. Ultimately, the World War I, First World War compelled the U.S. Government to legislate a legal r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australian Museum
The Australian Museum, originally known as the Colonial Museum or Sydney Museum. is a heritage-listed museum at 1 William Street, Sydney, William Street, Sydney central business district, Sydney CBD, New South Wales. It is the oldest natural history museum in Australia and the fifth oldest natural history museum in the world, with an international reputation in the fields of natural history and anthropology. It was first conceived and developed along the contemporary European model of an encyclopedic warehouse of cultural and natural history, and features collections of vertebrate and invertebrate zoology, as well as mineralogy, palaeontology and anthropology. The scientific stature of the museum was established under the curatorship of scientist Gerard Krefft in the 1860s. Apart from permanent displays in its galleries, permanent and temporary exhibitions, the museum also undertakes research and is involved in community programs. Since 1973 it has operated the Lizard Island ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyosaur
Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago ( Ma) and at least one species survived until about 90 million years ago, into the Late Cretaceous. During the Early Triassic epoch, ichthyosaurs and other ichthyosauromorphs evolved from a group of unidentified land reptiles that returned to the sea, in a development similar to how the mammalian land-dwelling ancestors of modern-day dolphins and whales returned to the sea millions of years later, which they gradually came to resemble in a case of convergent evolution. Ichthyosaurians were particularly abundant in the Late Triassic and Early Jurassic periods, until they were replaced as the top aquatic predators by another marine reptilian group, the Plesiosauria, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orca
The orca (''Orcinus orca''), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. The only extant species in the genus '' Orcinus'', it is recognizable by its black-and-white-patterned body. A cosmopolitan species, it inhabits a wide range of marine environments, from Arctic to Antarctic regions to tropical seas. Orcas are apex predators with a diverse diet. Individual populations often specialize in particular types of prey, including fish, sharks, rays, and marine mammals such as seals, dolphins, and whales. They are highly social, with some populations forming stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often unique to specific groups and passed down from generation to generation, are considered to be manifestations of animal culture. The International Union for Conservation of Nature (IUCN) lists the orca's conservation status as data deficient as multiple orca types ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indo-Pacific Sailfish
The Indo-Pacific sailfish (''Istiophorus platypterus'') is a sailfish native to the Indian and Pacific Oceans and is naturalized in the Atlantic where it has entered the Mediterranean Sea via the Suez Canal as a Lessepsian migrant. It is dark blue on top, brown-blue laterally, silvery white underbelly; upper jaw elongated in the form of a spear; first dorsal fin greatly enlarged in the form of a sail, with many black cones, its front squared off, highest at its midpoint; pelvic fins very narrow, reaching almost to the anus; body covered with embedded scales, blunt at end; lateral line curved above pectoral fin, then straight to base of tail. They have a large and sharp bill, which they use for hunting. They feed on tuna and mackerel, some of the fastest fish in the ocean. Most authorities only recognise a single species of sailfish, ''I. platypterus''. It is theorized by marine biologists that the 'sail' (dorsal fin array) of the sailfish may serve the purpose of a cooling and ... [...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, such as the electric eel, to stun prey. The capabilities are found almost exclusively in aquatic or amphibious animals, since water is a much better Conductor (material), 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 order Gymnotiformes (knifefishes) and family Mormyridae (elephantfishes), and by the monotypic genus ''Gymnarchus'' (African knifefish). An electric fish generates an electric field using an Elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
African Knifefish
The African knifefish, ''Gymnarchus niloticus'' – also called the ''aba aba'' – is an electric fish, living at the bottoms of rivers and lakes. It is the only species in the genus ''Gymnarchus'' and the family Gymnarchidae, within the order Osteoglossiformes. It is a long slender fish with no pelvic or anal fins, and a tail fin shaped like a rat's tail. It swims using its elongated dorsal fin, allowing it to keep its body straight while it moves. This in turn enables it to produce a steady but weak electric field, which it uses to locate its prey. It is large for a river fish; adults can reach 1.6 m (5.2 ft) in length and 19 kg (42 lb) in weight. In 1950, Hans Lissmann noticed that the fish could swim equally well forwards or backwards, clearly relying on a sense other than vision. He demonstrated that it could locate prey by electroreception, making it the first fish known to have this ability. The fish is considered good to eat in West Africa, wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermal
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided into two layers, the superficial area adjacent to the epidermis called the papillary region and a deep thicker area known as the reticular dermis.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology'' (10th ed.). Saunders. Pages 1, 11–12. . The dermis is tightly connected to the epidermis through a basement membrane. Structural components of the dermis are collagen, elastic fibers, and extrafibrillar matrix.Marks, James G; Miller, Jeffery (2006). ''Lookingbill and Marks' Principles of Dermatology'' (4th ed.). Elsevier Inc. Page 8–9. . It also contains mechanoreceptors that provide the sense of touch and thermoreceptors that provide the sense of heat. In addition, hair follicles, s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great White Shark
The great white shark (''Carcharodon carcharias''), also known as the white shark, white pointer, or simply great white, is a species of large Lamniformes, mackerel shark which can be found in the coastal surface waters of all the major oceans. It is the only known surviving species of its genus ''Carcharodon''. The great white shark is notable for its size, with the largest preserved female specimen measuring in length and around in weight at maturity. However, most are smaller; males measure , and females measure on average. According to a 2014 study, the lifespan of great white sharks is estimated to be as long as 70 years or more, well above previous estimates, making it one of the longest lived Chondrichthyes, cartilaginous fishes currently known. According to the same study, male great white sharks take 26 years to reach sexual maturity, while the females take 33 years to be ready to produce offspring. Great white sharks can swim at speeds of 25 km/h (16 mph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sailfish
The sailfish is one or two species of marine fish in the genus ''Istiophorus'', which belong to the family Istiophoridae ( marlins). They are predominantly blue to gray in colour and have a characteristically large dorsal fin known as the sail, which often stretches the entire length of the back. Another notable characteristic is the elongated rostrum (bill) consistent with that of other marlins and the swordfish, which together constitute what are known as billfish in sport fishing circles. Sailfish live in colder pelagic waters of all Earth's oceans, and hold the record for the highest speed of any marine animal. Species There is a dispute based on the taxonomy of the sailfish, and either one or two species have been recognized.McGrouther, M. (2013). Sailfish, Istiophorus platypterus.' Australian Museum. Retrieved 26 April 2013. No differences have been found in mtDNA, morphometrics or meristics between the two supposed species and most authorities now only recogni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Billfish
The billfish are a group (Xiphioidea) of saltwater fish, saltwater predatory fish characterised by prominent pointed beak, bills (rostrum (anatomy), rostra), and by their large size; some are longer than . Extant billfish include sailfish and marlin, which make up the family Istiophoridae; and swordfish, sole member of the family Xiphiidae. They are often apex predators which feed on a wide variety of smaller fish, crustaceans and cephalopods. These two families are sometimes classified as belonging to the order (biology), order Istiophoriformes, a group which originated around 71 million years ago in the Late Cretaceous, with the two families divergent evolution, diverging around 15 million years ago in the Late Miocene. However, they are also classified as being closely related to the mackerels and tuna within the suborder Scombroidei of the order Perciformes. However, the 5th edition of the ''Fishes of the World'' does recognise the Istiophoriformes as a valid order, albeit in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haddock
The haddock (''Melanogrammus aeglefinus'') is a saltwater ray-finned fish from the Family (biology), family Gadidae, the true cods. It is the only species in the Monotypy, monotypic genus ''Melanogrammus''. It is found in the North Atlantic Ocean and associated seas, where it is an important species for fisheries, especially in northern Europe, where it is marketed fresh, frozen and Smoked fish, smoked; smoked varieties include the Finnan haddie and the Arbroath smokie. Other smoked versions include long boneless, the fileted side of larger haddock smoked in oak chips with the skin left on the fillet. Description The haddock has the elongated, tapering body shape typical of members of the cod family. It has a relatively small mouth which does not extend to below the eye; with the lower profile of the face being straight and the upper profile slightly rounded, this gives its snout a characteristic wedge-shaped profile. The upper jaw projects beyond the lower more so than in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
