1.
Conservation status
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The conservation status of a group of organisms indicates whether the group still exists and how likely the group is to become extinct in the near future. Various systems of conservation status exist and are in use at international, multi-country, the IUCN Red List of Threatened Species is the best known worldwide conservation status listing and ranking system. Also included are species that have gone extinct since 500 AD, when discussing the IUCN Red List, the official term threatened is a grouping of three categories, critically endangered, endangered, and vulnerable. Widespread and abundant taxa are included in this category, Data deficient – Not enough data to make an assessment of its risk of extinction Not evaluated – Has not yet been evaluated against the criteria. The Convention on International Trade in Endangered Species of Wild Fauna and Flora aims to ensure that trade in specimens of wild animals. Many countries require CITES permits when importing plants and animals listed on CITES, in the European Union, the Birds and Habitats Directives are the legal instruments that evaluate the conservation status within the EU of species and habitats. NatureServe conservation status focuses on Latin America, United States, Canada, and it has been developed by scientists from NatureServe, The Nature Conservancy, and the network of natural heritage programs and data centers. It is increasingly integrated with the IUCN Red List system and its categories for species include, presumed extinct, possibly extinct, critically imperiled, imperiled, vulnerable, apparently secure, and secure. The system also allows ambiguous or uncertain ranks including inexact numeric ranks, NatureServe adds a qualifier for captive or cultivated only, which has a similar meaning to the IUCN Red List extinct in the wild status. The Red Data Book of the Russian Federation is used within the Russian Federation, in Australia, the Environment Protection and Biodiversity Conservation Act 1999 describes lists of threatened species, ecological communities and threatening processes. The categories resemble those of the 1994 IUCN Red List Categories & Criteria, prior to the EPBC Act, a simpler classification system was used by the Endangered Species Protection Act 1992. Some state and territory governments also have their own systems for conservation status, in Belgium, the Flemish Research Institute for Nature and Forest publishes an online set of more than 150 nature indicators in Dutch. In Canada, the Committee on the Status of Endangered Wildlife in Canada is a group of experts that assesses and designates which wild species are in danger of disappearing from Canada. Under the Species at Risk Act, it is up to the federal government, in China, the State, provinces and some counties have determined their key protected wildlife species. There is the China red data book, in Finland, a large number of species are protected under the Nature Conservation Act, and through the EU Habitats Directive and EU Birds Directive. In Germany, the Federal Agency for Nature Conservation publishes red lists of endangered species, india has the Wild Life Protection Act,1972, Amended 2003 and the Biological Diversity Act,2002. In Japan, the Ministry of Environment publishes a Threatened Wildlife of Japan Red Data Book, in the Netherlands, the Dutch Ministry of Agriculture, Nature and Food Quality publishes a list of threatened species, and conservation is enforced by the Nature Conservation Act 1998. Species are also protected through the Wild Birds and Habitats Directives, in New Zealand, the Department of Conservation publishes the New Zealand Threat Classification System lists
2.
Least Concern
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A least concern species is one which has been categorized by the International Union for Conservation of Nature as evaluated but not qualified for any other category. As such they do not qualify as threatened, near threatened, species cannot be assigned the Least Concern category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, since 2001 the category has had the abbreviation LC, following the IUCN2001 Categories & Criteria. However, around 20% of least concern taxa in the IUCN database use the code LR/lc, prior to 2001 least concern was a subcategory of the Lower Risk category and assigned the code LR/lc or. While least concern is not considered a red listed category by the IUCN, the number of animal species listed in this category totals 14033. There are also 101 animal subspecies listed and 1500 plant taxa, there are also two animal subpopulations listed, the Australasian and Southern African subpopulations of spiny dogfish. No fungi or protista have the classification, though only four species in those kingdoms have been evaluated by the IUCN, humans qualify for this category, and in 2008 were formally assessed as such by the IUCN
3.
IUCN Red List
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The IUCN Red List of Threatened Species, founded in 1964, is the worlds most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the main authority on the conservation status of species. A series of Regional Red Lists are produced by countries or organizations, the IUCN Red List is set upon precise criteria to evaluate the extinction risk of thousands of species and subspecies. These criteria are relevant to all species and all regions of the world, the aim is to convey the urgency of conservation issues to the public and policy makers, as well as help the international community to try to reduce species extinction. Major species assessors include BirdLife International, the Institute of Zoology, the World Conservation Monitoring Centre, collectively, assessments by these organizations and groups account for nearly half the species on the Red List. The IUCN aims to have the category of every species re-evaluated every five years if possible, the 1964 IUCN Red List of Threatened Plants used the older pre-criteria Red List assessment system. Plants listed may not, therefore, appear in the current Red List, IUCN advise that is best to check both the online Red List and the 1997 plants Red List publication. The 2006 Red List, released on 4 May 2006 evaluated 40,168 species as a whole, plus an additional 2,160 subspecies, varieties, aquatic stocks, on 12 September 2007, the World Conservation Union released the 2007 IUCN Red List of Threatened Species. Russ Mittermeier, chief of Swiss-based IUCNs Primate Specialist Group, stated that 16,306 species are endangered with extinction,188 more than in 2006, the Red List includes the Sumatran orangutan in the Critically Endangered category and the Bornean orangutan in the Endangered category. The study shows at least 1,141 of the 5,487 mammals on Earth are known to be threatened with extinction, and 836 are listed as Data Deficient. The Red List of 2012 was released 19 July 2012 at Rio+20 Earth Summit, nearly 2,000 species were added, the IUCN assessed a total of 63,837 species which revealed 19,817 are threatened with extinction. With 3,947 described as endangered and 5,766 as endangered. At threat are 41% of amphibian species, 33% of reef-building corals, 30% of conifers, 25% of mammals, the IUCN Red List has listed 132 species of plants and animals from India as Critically Endangered. Extinct – No known individuals remaining, extinct in the wild – Known only to survive in captivity, or as a naturalized population outside its historic range. Critically endangered – Extremely high risk of extinction in the wild, Endangered – High risk of extinction in the wild. Vulnerable – High risk of endangerment in the wild, near threatened – Likely to become endangered in the near future. Does not qualify for a more at-risk category, widespread and abundant taxa are included in this category. Data deficient – Not enough data to make an assessment of its risk of extinction, Not evaluated – Has not yet been evaluated against the criteria
4.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
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Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
6.
Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
7.
Actinopterygii
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Actinopterygii /ˌæktᵻnˌɒptəˈrɪdʒi. aɪ/, or the ray-finned fishes, constitute a class or subclass of the bony fishes. These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm, to the ocean sunfish, at 2,300 kg. Ray-finned fishes occur in variant forms. The main features of a typical ray-finned fish are shown in the diagram at the left. In nearly all ray-finned fish, the sexes are separate, development then proceeds with a free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism, in most cases this involves protogyny, fish starting life as females and converting to males at some stage, triggered by some internal or external factor. This may be advantageous as females become less prolific as they age while male fecundity increases with age, protandry, where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization, of the oviparous teleosts, most do not provide parental care. Viviparity is relatively rare and is found in about 6% of teleost species, male territoriality preadapts a species for evolving male parental care. There are a few examples of fish that self-fertilise, the mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to the habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C and can fertilise eggs that are spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred, the earliest known fossil actinopterygiian is Andreolepis hedei, dating back 420 million years. Remains have been found in Russia, Sweden, and Estonia, actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii, in turn, are divided into the infraclasses Holostei and Teleostei, during the Mesozoic and Cenozoic the teleosts in particular diversified widely, and as a result, 96% of all known fish species are teleosts. The cladogram shows the groups of actinopterygians and their relationship to the terrestrial vertebrates that evolved from a related group of fish
8.
Anglerfish
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Anglerfishes are fish of the teleost order Lophiiformes /ˌlɒfiːəˈfɔːrmiːz/. They are bony fish named for their mode of predation. Some anglerfish are also notable for sexual dimorphism and sexual parasitism of the small male on the much larger female. In these species, males may be several orders of magnitude smaller than females, some are pelagic, while others are benthic, some live in the deep sea, while others on the continental shelf. Pelagic forms are most laterally compressed, whereas the benthic forms are often extremely dorsoventrally compressed, a mitochondrial genome phylogenetic study suggested the anglerfishes diversified in a short period of the early to mid-Cretaceous, between 130 and 100 million years ago. Their length can vary from 20 cm to over 1 m with weights up to 45 kg, fishBase, Nelson, and Pietsch list 18 families, but ITIS lists only 16. The following taxa have been arranged to show their evolutionary relationships, the organ has been hypothesized to serve the obvious purpose of luring prey in dark, deep-sea environments, but also serves to call males attention to the females to facilitate mating. The source of luminescence is symbiotic bacteria that dwell in and around the esca and they depend on the fish to make up the difference. Electron microscopy of these bacteria in some species reveals they are Gram-negative rods that lack capsules, spores and they have double-layered cell walls and mesosomes. A pore connects the esca with the seawater, which enables the removal of bacteria and cellular waste. This, as well as the constant temperature of the bathypelagic zone inhabited by fish, is crucial for the long-term viability of bacterial cultures. In most species, a wide mouth extends all around the circumference of the head. The teeth can be depressed so as to offer no impediment to an object gliding towards the stomach, but prevent its escape from the mouth. The anglerfish is able to both its jaw and its stomach, since its bones are thin and flexible, to enormous size. In 2005, near Monterey, California, at 1474 metres depth, when approached, the fish retreated rapidly, but in 74% of the video footage, it drifted passively, oriented at any angle. When advancing, it swam intermittently at a speed of 0.24 body lengths per second, the lethargic behaviour of this ambush predator is suited to the energy-poor environment of the deep sea. Another in situ observation of three different whipnose anglerfish showed unusual upside-down swimming behavior, fish were observed floating upside-down completely motionless with the illicium hanging down stiffly in a slight arch in front of the fish. The illicium was hanging over small visible burrows and it was suggested this is an effort to entice prey and an example of low-energy opportunistic foraging and predation
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Goosefish
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Like most other anglerfishes, they have a very large head with a large mouth that bears long, sharp, recurved teeth. Also like other anglerfishes, the first spine of the dorsal fin has been modified as an angling apparatus that bears a bulb-like or fleshy lure. The angling apparatus is located at the tip of the snout just above the mouth and is used to attract prey, in the more primitive anglerfish genera, the gill opening extends partially in front of the elongated pectoral fin base. In the derived genera, and all other anglerfishes, the gill opening does not extend in front of the pectoral fin base. The largest monkfish may exceed 1.5 m in length, several of the large species in the genus Lophius, commonly known as monkfishes in northern Europe, are important commercially fished species. The liver of monkfish, known as ankimo, is considered a delicacy in Japan, Genus Eosladenia Eosladenia caucasica Bannikov,2004 Genus Sharfia Sharfia mirabilis Pietsch & Carnevale,2011
10.
Lophius
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Members of the genus Lophius, also sometimes called monkfish, fishing-frogs, frog-fish and sea-devils, are well known off the coasts of Europe. To the North Sea fishermen, this fish is known as the monk, or monkfish, a name also belongs to Squatina squatina, the angelshark. The north European species is Lophius piscatorius, the Mediterranean species Lophius budegassa, the seven recognized extant species in this genus are, Lophius americanus Valenciennes,1837 Lophius budegassa Spinola,1807 Lophius gastrophysus A. Miranda-Ribeiro,1915 Lophius litulon D. S. All around its head and also along the body, the skin bears fringed appendages resembling short fronds of seaweed, species of Lophius have three long filaments sprouting from the middle of their heads, these are the detached and modified three first spines of the anterior dorsal fin. Whether the prey has been attracted to the lure or not is not strictly relevant, monkfish, like most anglerfish, are also characterised by an enormously distensible stomach, which allows an individual monkfish to swallow prey fully as large as itself. Monkfish grow to a length of more than 150 cm, specimens of 100 cm are common, the spawn of this genus consists of a thin sheet of transparent gelatinous material 60–100 cm wide and 8–10 m in length. The eggs in this sheet are in a layer, each in its own little cavity. The spawn is free in the sea, the larvae are free-swimming and have the pelvic fins with elongated filaments. The East Atlantic species is found along the coasts of Europe, the species caught on the North American side of the Atlantic is usually Lophius americanus. A third species, inhabits the Mediterranean, and a fourth the coasts of China, the black and white anglerfish both live in shallow, inshore waters from 800 m to deeper waters. These two species are similar to one another with only a few distinctions between them. These include, the colour of the peritoneum and the number of rays in the dorsal fin. Also, minor differences in their distribution occur, black anglerfish tend to have a more southern distribution whereas the white anglerfish are distributed further north. Despite these differences, the distribution of the black and white anglerfish tend to overlap greatly. A map of the distribution of anglerfish in the waters surrounding Europe, both species of Lophius are important because they are commercially valuable species usually caught by trawl and gillnetting fleets. Concern is expressed over the sustainability of monkfish fishing, the method most commonly used to catch monkfish, beam trawling, has been described as damaging to seafloor habitats. In February 2007, the British supermarket chain Asda banned monkfish from their stores
11.
Binomial nomenclature
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Such a name is called a binomial name, a binomen, binominal name or a scientific name, more informally it is also called a Latin name. The first part of the name identifies the genus to which the species belongs, for example, humans belong to the genus Homo and within this genus to the species Homo sapiens. The formal introduction of system of naming species is credited to Carl Linnaeus. But Gaspard Bauhin, in as early as 1623, had introduced in his book Pinax theatri botanici many names of genera that were adopted by Linnaeus. Although the general principles underlying binomial nomenclature are common to these two codes, there are differences, both in the terminology they use and in their precise rules. Similarly, both parts are italicized when a binomial name occurs in normal text, thus the binomial name of the annual phlox is now written as Phlox drummondii. In scientific works, the authority for a name is usually given, at least when it is first mentioned. In zoology Patella vulgata Linnaeus,1758, the original name given by Linnaeus was Fringilla domestica, the parentheses indicate that the species is now considered to belong in a different genus. The ICZN does not require that the name of the person who changed the genus be given, nor the date on which the change was made, in botany Amaranthus retroflexus L. – L. is the standard abbreviation used in botany for Linnaeus. – Linnaeus first named this bluebell species Scilla italica, Rothmaler transferred it to the genus Hyacinthoides, the ICN does not require that the dates of either publication be specified. Prior to the adoption of the binomial system of naming species. Together they formed a system of polynomial nomenclature and these names had two separate functions. First, to designate or label the species, and second, to be a diagnosis or description, such polynomial names may sometimes look like binomials, but are significantly different. For example, Gerards herbal describes various kinds of spiderwort, The first is called Phalangium ramosum, Branched Spiderwort, is aptly termed Phalangium Ephemerum Virginianum, Soon-Fading Spiderwort of Virginia. The Latin phrases are short descriptions, rather than identifying labels, the Bauhins, in particular Caspar Bauhin, took some important steps towards the binomial system, by pruning the Latin descriptions, in many cases to two words. The adoption by biologists of a system of binomial nomenclature is due to Swedish botanist and physician Carl von Linné. It was in his 1753 Species Plantarum that he first began using a one-word trivial name together with a generic name in a system of binomial nomenclature. This trivial name is what is now known as an epithet or specific name
12.
Carl Linnaeus
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Carl Linnaeus, also known after his ennoblement as Carl von Linné, was a Swedish botanist, physician, and zoologist, who formalised the modern system of naming organisms called binomial nomenclature. He is known by the father of modern taxonomy. Many of his writings were in Latin, and his name is rendered in Latin as Carolus Linnæus, Linnaeus was born in the countryside of Småland, in southern Sweden. He received most of his education at Uppsala University. He lived abroad between 1735 and 1738, where he studied and also published a first edition of his Systema Naturae in the Netherlands and he then returned to Sweden, where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on journeys through Sweden to find and classify plants. In the 1750s and 1760s, he continued to collect and classify animals, plants, and minerals, at the time of his death, he was one of the most acclaimed scientists in Europe. The philosopher Jean-Jacques Rousseau sent him the message, Tell him I know no man on earth. The German writer Johann Wolfgang von Goethe wrote, With the exception of Shakespeare and Spinoza, Swedish author August Strindberg wrote, Linnaeus was in reality a poet who happened to become a naturalist. Among other compliments, Linnaeus has been called Princeps botanicorum, The Pliny of the North and he is also considered as one of the founders of modern ecology. In botany, the abbreviation used to indicate Linnaeus as the authority for species names is L. In older publications, sometimes the abbreviation Linn. is found, Linnæus was born in the village of Råshult in Småland, Sweden, on 23 May 1707. He was the first child of Nicolaus Ingemarsson and Christina Brodersonia and his siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, and Emerentia Linnæa. One of a line of peasants and priests, Nils was an amateur botanist, a Lutheran minister. Christina was the daughter of the rector of Stenbrohult, Samuel Brodersonius, a year after Linnæus birth, his grandfather Samuel Brodersonius died, and his father Nils became the rector of Stenbrohult. The family moved into the rectory from the curates house, even in his early years, Linnæus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and often showed flowers to Linnaeus, soon Linnæus was given his own patch of earth where he could grow plants
13.
10th edition of Systema Naturae
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The 10th edition of Systema Naturae is a book written by Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature. In it, Linnaeus introduced binomial nomenclature for animals, something he had already done for plants in his 1753 publication of Species Plantarum, before 1758, most biological catalogues had used polynomial names for the taxa included, including earlier editions of Systema Naturae. The first work to consistently apply binomial nomenclature across the kingdom was the 10th edition of Systema Naturae. Names published before that date are unavailable, even if they would otherwise satisfy the rules, during Linnaeus lifetime, Systema Naturae was under continuous revision. The Animal Kingdom, Animals enjoy sensation by means of an organization, animated by a medullary substance, perception by nerves. They have members for the different purposes of life, organs for their different senses and they all originate from an egg. Their external and internal structure, their anatomy, habits, instincts. The list has been broken down into the six classes Linnaeus described for animals, Mammalia, Aves, Amphibia, Pisces, Insecta. These classes were created by studying the internal anatomy, as seen in his key. Warm, red blood Viviparous, Mammalia Oviparous, Aves Heart with 1 auricle,1 ventricle, cold, red blood Lungs voluntary, Amphibia External gills, Pisces Heart with 1 auricle,0 ventricles. Linnaeus described mammals as, Animals that suckle their young by means of lactiferous teats, in external and internal structure they resemble man, most of them are quadrupeds, and with man, their natural enemy, inhabit the surface of the Earth. The largest, though fewest in number, inhabit the ocean and they are areal, vocal, swift and light, and destitute of external ears, lips, teeth, scrotum, womb, bladder, epiglottis, corpus callosum and its arch, and diaphragm. They breathe by means of gills, which are united by a bony arch, swim by means of radiate fins. Many of them are without a head, and most of them without feet. They are principally distinguished by their tentacles, by the Ancients they were not improperly called imperfect animals, as being destitute of ears, nose, head, eyes and legs, and are therefore totally distinct from Insects. In addition to repeating the species he had listed in his Species Plantarum. The species from Species Plantarum were numbered sequentially, while the new species were labelled with letters, new plant species described in the 10th edition of Systema Naturae include, The original 1758 Systema Naturae Linnaeus 1758 Classification of Animals on the Taxonomicon
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Synonym (taxonomy)
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For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies. This name is no longer in use, it is now a synonym of the current scientific name which is Picea abies, unlike synonyms in other contexts, in taxonomy a synonym is not interchangeable with the name of which it is a synonym. In taxonomy, synonyms are not equals, but have a different status, for any taxon with a particular circumscription, position, and rank, only one scientific name is considered to be the correct one at any given time. A synonym cannot exist in isolation, it is always an alternative to a different scientific name, given that the correct name of a taxon depends on the taxonomic viewpoint used a name that is one taxonomists synonym may be another taxonomists correct name. Synonyms may arise whenever the same taxon is described and named more than once, independently. They may also arise when existing taxa are changed, as when two taxa are joined to one, a species is moved to a different genus. To the general user of scientific names, in such as agriculture, horticulture, ecology, general science. A synonym is a name that was used as the correct scientific name but which has been displaced by another scientific name. Thus Oxford Dictionaries Online defines the term as a name which has the same application as another. In handbooks and general texts, it is useful to have mentioned as such after the current scientific name. Synonyms used in this way may not always meet the strict definitions of the synonym in the formal rules of nomenclature which govern scientific names. Changes of scientific name have two causes, they may be taxonomic or nomenclatural, a name change may be caused by changes in the circumscription, position or rank of a taxon, representing a change in taxonomic, scientific insight. A name change may be due to purely nomenclatural reasons, that is, based on the rules of nomenclature, the earliest such name is called the senior synonym, while the later name is the junior synonym. One basic principle of zoological nomenclature is that the earliest correctly published name, synonyms are important because if the earliest name cannot be used, then the next available junior synonym must be used for the taxon. Objective synonyms refer to taxa with the type and same rank. For example, John Edward Gray published the name Antilocapra anteflexa in 1855 for a species of pronghorn, however, it is now commonly accepted that his specimen was an unusual individual of the species Antilocapra americana published by George Ord in 1815. Ords name thus takes precedence, with Antilocapra anteflexa being a subjective synonym. Objective synonyms are common at the level of genera, because for various reasons two genera may contain the type species, these are objective synonyms
15.
Atlantic Ocean
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The Atlantic Ocean is the second largest of the worlds oceans with a total area of about 106,460,000 square kilometres. It covers approximately 20 percent of the Earths surface and about 29 percent of its surface area. It separates the Old World from the New World, the Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Eurasia and Africa to the east, and the Americas to the west. The Equatorial Counter Current subdivides it into the North Atlantic Ocean, in contrast, the term Atlantic originally referred specifically to the Atlas Mountains in Morocco and the sea off the Strait of Gibraltar and the North African coast. The Greek word thalassa has been reused by scientists for the huge Panthalassa ocean that surrounded the supercontinent Pangaea hundreds of years ago. The term Aethiopian Ocean, derived from Ancient Ethiopia, was applied to the Southern Atlantic as late as the mid-19th century, many Irish or British people refer to the United States and Canada as across the pond, and vice versa. The Black Atlantic refers to the role of ocean in shaping black peoples history. Irish migration to the US is meant when the term The Green Atlantic is used, the term Red Atlantic has been used in reference to the Marxian concept of an Atlantic working class, as well as to the Atlantic experience of indigenous Americans. Correspondingly, the extent and number of oceans and seas varies, the Atlantic Ocean is bounded on the west by North and South America. It connects to the Arctic Ocean through the Denmark Strait, Greenland Sea, Norwegian Sea, to the east, the boundaries of the ocean proper are Europe, the Strait of Gibraltar and Africa. In the southeast, the Atlantic merges into the Indian Ocean, the 20° East meridian, running south from Cape Agulhas to Antarctica defines its border. In the 1953 definition it extends south to Antarctica, while in later maps it is bounded at the 60° parallel by the Southern Ocean, the Atlantic has irregular coasts indented by numerous bays, gulfs, and seas. Including these marginal seas the coast line of the Atlantic measures 111,866 km compared to 135,663 km for the Pacific. Including its marginal seas, the Atlantic covers an area of 106,460,000 km2 or 23. 5% of the ocean and has a volume of 310,410,900 km3 or 23. 3%. Excluding its marginal seas, the Atlantic covers 81,760,000 km2 and has a volume of 305,811,900 km3, the North Atlantic covers 41,490,000 km2 and the South Atlantic 40,270,000 km2. The average depth is 3,646 m and the maximum depth, the bathymetry of the Atlantic is dominated by a submarine mountain range called the Mid-Atlantic Ridge. It runs from 87°N or 300 km south of the North Pole to the subantarctic Bouvet Island at 42°S, the MAR divides the Atlantic longitudinally into two halves, in each of which a series of basins are delimited by secondary, transverse ridges. The MAR reaches above 2000 m along most of its length, the MAR is a barrier for bottom water, but at these two transform faults deep water currents can pass from one side to the other
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Barents Sea
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The Barents Sea is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia divided between Norwegian and Russian territorial waters. Known among Russians in the Middle Ages as the Murman Sea and it is a rather shallow shelf sea, with an average depth of 230 metres, and is an important site for both fishing and hydrocarbon exploration. Novaya Zemlya, an extension of the part of the Ural Mountains. The southern half of the Barents Sea, including the ports of Murmansk, in September, the entire Barents Sea is more or less completely ice-free. Until the Winter War, Finlands territory also reached to the Barents Sea, with the harbor at Petsamo being Finlands only ice-free winter harbor. There are three types of water masses in the Barents Sea, Warm, salty Atlantic water from the North Atlantic drift, cold Arctic water from the north, and warm. Between the Atlantic and Polar waters, a front called the Polar Front is formed, the lands of Novaya Zemlya attained most of their early Holocene coastal deglaciation approximately 10,000 years before present. The International Hydrographic Organization defines the limits of the Barentsz Sea as follows, On the west, on the northwest, The eastern shore of West Spitzbergen, Hinlopen Strait up to 80° latitude north, south and east coasts of North-East Land to Cape Leigh Smith. On the north, Cape Leigh Smith across the Islands Bolshoy Ostrov, Gilles and Victoria, on the east, Cape Kohlsaat to Cape Zhelaniya, west and southwest coast of Novaya Zemlya to Cape Kussov Noss and thence to western entrance Cape, Dolgaya Bay on Vaigach Island. Through Vaigach Island to Cape Greben, thence to Cape Belyi Noss on the mainland, on the south, The northern limit of the White Sea. Other islands in the Barents Sea include Chaichy and Timanets, most of its geological history is dominated by extensional tectonics, caused by the collapse of the Caledonian and Uralian orogenic belts and the break-up of Pangaea. These events created the rift basins that dominate the Barents Shelf, along with various platforms. Due to the North Atlantic drift, the Barents Sea has a high biological production compared to other oceans of similar latitude. The spring bloom of phytoplankton can start quite early close to the ice edge, the phytoplankton bloom feeds zooplankton such as Calanus finmarchicus, Calanus glacialis, Calanus hyperboreus, Oithona spp. and krill. The zooplankton feeders include young cod, capelin, polar cod, whales, the capelin is a key food for top predators such as the north-east Arctic cod, harp seals, and seabirds such as common guillemot and Brunnichs guillemot. The fisheries of the Barents Sea, in particular the cod fisheries, are of importance for both Norway and Russia. There is a genetically distinct polar bear population associated with the Barents Sea and its eastern corner, in the region of the Pechora Rivers estuary, has been known as Pechorskoye Morye, that is, Pechora Sea. This sea was given its present name in honor of Willem Barentsz, Barentsz was the leader of early expeditions to the far north, at the end of the sixteenth century
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Strait of Gibraltar
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The Strait of Gibraltar is a narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Gibraltar and Peninsular Spain in Europe from Morocco and Ceuta in Africa. The name comes from the Rock of Gibraltar, which in turn originates from the Arabic Jebel Tariq named after Tariq ibn Ziyad. It is also known as the Straits of Gibraltar, the Gut of Gibraltar, the STROG in naval use, and Bab Al Maghrib, Gate of the West. In the Middle Ages, Muslims called it Al-Zuqaq, The Passage, the Romans called it Fretum Gatitanum, Europe and Africa are separated by 7.7 nautical miles of ocean at the straits narrowest point. Ferries cross between the two every day in as little as 35 minutes. The Spanish side of the Strait is protected under El Estrecho Natural Park, on the northern side of the Strait are Spain and Gibraltar, while on the southern side are Morocco and Ceuta. Its boundaries were known in antiquity as the Pillars of Hercules, there are several islets, such as the disputed Isla Perejil, that are claimed by both Morocco and Spain. Due to its location, the Strait is commonly used for illegal immigration from Africa to Europe, the International Hydrographic Organization defines the limits of the Strait of Gibraltar as follows, On the West. A line joining Cape Trafalgar to Cape Spartel, a line joining Europa Point to P. Almina. The seabed of the Strait is composed of synorogenic Betic-Rif clayey flysch covered by Pliocene and/or Quaternary calcareous sediments, exposed bedrock surfaces, coarse sediments and local sand dunes attest to the strong bottom current conditions at the present time. The resultant accumulation of huge salt and mineral deposits about the Mediterranean basin are directly linked to this era. It is believed that this took a short time, by geological standards. The erosion produced by the incoming waters seems to be the cause for the present depth of the strait. The strait is expected to close again as the African Plate moves northward relative to the Eurasian Plate, for full articles on the history of the north Gibraltar shore, see History of Gibraltar or History of Spain. For the full article on the history of the south Gibraltar shore, evidence of the first human habitation of the area by Neanderthals dates back to 125,000 years ago. Archaeological evidence of Homo sapiens habitation of the dates back c.40,000 years. In that year, the last Muslim government north of the straits was overthrown by a Spanish force, the small British enclave of the city of Gibraltar presents a third cultural group found in the straits. This enclave was first established in 1704 and has since used by Britain to act as a surety for control of the sea lanes into
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Mediterranean Sea
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The sea is sometimes considered a part of the Atlantic Ocean, although it is usually identified as a separate body of water. The name Mediterranean is derived from the Latin mediterraneus, meaning inland or in the middle of land and it covers an approximate area of 2.5 million km2, but its connection to the Atlantic is only 14 km wide. The Strait of Gibraltar is a strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Gibraltar. In oceanography, it is called the Eurafrican Mediterranean Sea or the European Mediterranean Sea to distinguish it from mediterranean seas elsewhere. The Mediterranean Sea has a depth of 1,500 m. The sea is bordered on the north by Europe, the east by Asia and it is located between latitudes 30° and 46° N and longitudes 6° W and 36° E. Its west-east length, from the Strait of Gibraltar to the Gulf of Iskenderun, the seas average north-south length, from Croatia’s southern shore to Libya, is approximately 800 km. The Mediterranean Sea, including the Sea of Marmara, has an area of approximately 2,510,000 square km. The sea was an important route for merchants and travelers of ancient times that allowed for trade, the history of the Mediterranean region is crucial to understanding the origins and development of many modern societies. In addition, the Gaza Strip and the British Overseas Territories of Gibraltar and Akrotiri, the term Mediterranean derives from the Latin word mediterraneus, meaning amid the earth or between land, as it is between the continents of Africa, Asia and Europe. The Ancient Greek name Mesogeios, is similarly from μέσο, between + γη, land, earth) and it can be compared with the Ancient Greek name Mesopotamia, meaning between rivers. The Mediterranean Sea has historically had several names, for example, the Carthaginians called it the Syrian Sea and latter Romans commonly called it Mare Nostrum, and occasionally Mare Internum. Another name was the Sea of the Philistines, from the people inhabiting a large portion of its shores near the Israelites, the sea is also called the Great Sea in the General Prologue by Geoffrey Chaucer. In Ottoman Turkish, it has also been called Bahr-i Sefid, in Modern Hebrew, it has been called HaYam HaTikhon, the Middle Sea, reflecting the Seas name in ancient Greek, Latin, and modern languages in both Europe and the Middle East. Similarly, in Modern Arabic, it is known as al-Baḥr al-Mutawassiṭ, in Turkish, it is known as Akdeniz, the White Sea since among Turks the white colour represents the west. Several ancient civilisations were located around the Mediterranean shores, and were influenced by their proximity to the sea. It provided routes for trade, colonisation, and war, as well as food for numerous communities throughout the ages, due to the shared climate, geology, and access to the sea, cultures centered on the Mediterranean tended to have some extent of intertwined culture and history. Two of the most notable Mediterranean civilisations in classical antiquity were the Greek city states, later, when Augustus founded the Roman Empire, the Romans referred to the Mediterranean as Mare Nostrum
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Black Sea
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The Black Sea is a body of water between Eastern Europe and Western Asia, bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. It is supplied by a number of rivers, such as the Danube, Dnieper, Rioni, Southern Bug. The Black Sea has an area of 436,400 km2, a depth of 2,212 m. It is constrained by the Pontic Mountains to the south and by the Caucasus Mountains to the east, the longest east-west extent is about 1,175 km. The Black Sea has a water balance, that is, a net outflow of water 300 km3 per year through the Bosphorus. Mediterranean water flows into the Black Sea as part of a two-way hydrological exchange, the Black Sea drains into the Mediterranean Sea and then the Atlantic Ocean, via the Aegean Sea and various straits. The Bosphorus Strait connects it to the Sea of Marmara, and these waters separate Eastern Europe and Western Asia. The Black Sea is also connected to the Sea of Azov by the Strait of Kerch, the water level has varied significantly. Due to these variations in the level in the basin. At certain critical water levels it is possible for connections with surrounding water bodies to become established and it is through the most active of these connective routes, the Turkish Straits, that the Black Sea joins the world ocean. When this hydrological link is not present, the Black Sea is a basin, operating independently of the global ocean system. Currently the Black Sea water level is high, thus water is being exchanged with the Mediterranean. The Turkish Straits connect the Black Sea with the Aegean Sea, and comprise the Bosphorus, the Sea of Marmara, the International Hydrographic Organization defines the limits of the Black Sea as follows, On the Southwest. The Northeastern limit of the Sea of Marmara, a line joining Cape Takil and Cape Panaghia. Strabos Geographica reports that in antiquity, the Black Sea was often just called the Sea, for the most part, Graeco-Roman tradition refers to the Black Sea as the Hospitable sea, Εὔξεινος Πόντος Eúxeinos Póntos. This is a euphemism replacing an earlier Inhospitable Sea, Πόντος Ἄξεινος Póntos Áxeinos, strabo thinks that the Black Sea was called inhospitable before Greek colonization because it was difficult to navigate, and because its shores were inhabited by savage tribes. The name was changed to hospitable after the Milesians had colonized the southern shoreline and it is also possible that the epithet Áxeinos arose by popular etymology from a Scythian word axšaina- unlit, dark, the designation Black Sea may thus date from antiquity. A map of Asia dating to 1570, entitled Asiae Nova Descriptio, from Abraham Orteliuss Theatrum Orbis Terrarum, english-language writers of the 18th century often used the name Euxine Sea to refer to the Black Sea
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Irish Sea
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The Irish Sea, separates the islands of Ireland and Great Britain. It is connected to the Celtic Sea in the south by St Georges Channel, anglesey is the largest island within the Irish Sea, followed by the Isle of Man. The sea is occasionally, but rarely, referred to as the Manx Sea, the sea is of significant economic importance to regional trade, shipping and transport, fishing, and power generation in the form of wind power and nuclear power plants. Annual traffic between Great Britain and Ireland amounts to over 12 million passengers and 17 million tonnes of traded goods, the Irish Sea has undergone a series of dramatic changes over the last 20,000 years as the last glacial period ended and was replaced by warmer conditions. At the height of the glaciation the central part of the sea was probably a long freshwater lake. As the ice retreated 10,000 years ago the lake reconnected to the sea, becoming brackish, the International Hydrographic Organization defines the limits of the Irish Sea as follows, On the North. The Southern limit of the Scottish Seas, a line joining St. Davids Head to Carnsore Point. It is connected to the North Atlantic at both its northern and southern ends, to the north, the connection is through the North Channel between Scotland and Northern Ireland and the Malin Sea. The southern end is linked to the Atlantic through the St Georges Channel between south eastern Ireland and Pembrokeshire in Wales, and the Celtic Sea. The Irish Sea is composed of a channel about 300 km long and 30–50 km wide on its western side. The western channels depth ranges from 80 metres up to 275 m in the Beauforts Dyke in the North Channel, the main embayments – Cardigan Bay in the south and the waters to the east of the Isle of Man – are less than 50 m deep. The Sea has a water volume of 2,430 km3, 80% of which is to the west of the Isle of Man. The largest sandbanks are the Bahama and King William Banks to the east and north of the Isle of Man, the Irish Sea, at its greatest width, is 200 km and narrows to 75 km. Unlike Great Britain, Ireland has no tunnel or bridge connection to continental Europe, thus the vast majority of heavy goods trade is done by sea. The Port of Liverpool handles 32 million tonnes of cargo and 734 thousand passengers a year, Holyhead port handles most of the passenger traffic from Dublin and Dún Laoghaire ports, as well as 3.3 million tonnes of freight. Ports in the Republic handle 3,600,000 travellers crossing the sea each year and this has been steadily dropping for a number of years, probably as a result of low cost airlines. There is also a connection between Liverpool and Belfast via the Isle of Man or direct from Birkenhead, the worlds largest car ferry, Ulysses, is operated by Irish Ferries on the Dublin Port–Holyhead route, Stena Line also operates between Britain and Ireland. The Port of Barrow-in-Furness, despite being one of Britains largest shipbuilding centres, a ferry crossing used to run between Swansea and Cork, but given the geographical limits defined above, this route crosses the Celtic Sea rather than the Irish Sea
21.
Tooth
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A tooth is a hard, calcified structure found in the jaws of many vertebrates and used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes, the roots of teeth are covered by gums. Teeth are not made of bone, but rather of tissues of varying density. The cellular tissues that ultimately become teeth originate from the germ layer. The general structure of teeth is similar across the vertebrates, although there is variation in their form. The teeth of mammals have deep roots, and this pattern is found in some fish. In most teleost fish, however, the teeth are attached to the surface of the bone. In cartilaginous fish, such as sharks, the teeth are attached by tough ligaments to the hoops of cartilage that form the jaw, some animals develop only one set of teeth while others develop many sets. Sharks, for example, grow a new set of every two weeks to replace worn teeth. Rodent incisors grow and wear away continually through gnawing, which helps maintain relatively constant length, the industry of the beaver is due in part to this qualification. Many rodents such as voles and guinea pigs, but not mice, Teeth are not always attached to the jaw, as they are in mammals. In many reptiles and fish, teeth are attached to the palate or to the floor of the mouth, some teleosts even have teeth in the pharynx. While not true teeth in the sense, the dermal denticles of sharks are almost identical in structure and are likely to have the same evolutionary origin. Though modern teeth-like structures with dentine and enamel have been found in late conodonts, living amphibians typically have small teeth, or none at all, since they commonly feed only on soft foods. In reptiles, teeth are simple and conical in shape. The pattern of incisors, canines, premolars and molars is found only in mammals, the numbers of these types of teeth vary greatly between species, zoologists use a standardised dental formula to describe the precise pattern in any given group. The genes governing tooth development in mammals are homologous to these involved in the development of fish scales, Teeth are among the most distinctive features of mammal species. Paleontologists use teeth to identify species and determine their relationships
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Fish fin
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Fins are usually the most distinctive features of a fish. Apart from the tail or caudal fin, fish fins have no connection with the spine and are supported only by muscles. Their principal function is to help the fish swim, Fins located in different places on the fish serve different purposes such as moving forward, turning, keeping an upright position or stopping. Most fish use fins when swimming, flying fish use pectoral fins for gliding, for every type of fin, there are a number of fish species in which this particular fin has been lost during evolution. Bony fishes form a group called Osteichthyes. They have skeletons made of bone, and can be contrasted with cartilaginous fishes which have made of cartilage. Bony fishes are divided into ray-finned and lobe-finned fish, most fish are ray-finned, an extremely diverse and abundant group consisting of over 30,000 species. It is the largest class of vertebrates in existence today, in the distant past, lobe-finned fish were abundant. Nowadays they are extinct, with only eight living species. Bony fish have fin spines and rays called lepidotrichia and they typically have swim bladders, which allows the fish to create a neutral balance between sinking and floating without having to use its fins. However, these are absent in species, and have developed into primitive lungs in the lungfishes. Bony fishes also have an operculum, which helps them breathe without having to use fins to swim, lobe-finned fishes are a class of bony fishes called Sarcopterygii. They have fleshy, lobed, paired fins, which are joined to the body by a single bone, the fins of lobe-finned fish differ from those of all other fish in that each is borne on a fleshy, lobelike, scaly stalk extending from the body. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs and these fins evolved into legs of the first tetrapod land vertebrates, amphibians. They also possess two dorsal fins with separate bases, as opposed to the dorsal fin of ray-finned fish. The coelacanth is another lobe-finned fish which is still extant and it is thought to have evolved into roughly its current form about 408 million years ago, during the early Devonian. Locomotion of the coelacanths is unique to their kind, to move around, coelacanths most commonly take advantage of up or downwellings of the current and drift. They use their fins to stabilize their movement through the water
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Sand
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Sand is a naturally occurring granular material composed of finely divided rock and mineral particles. It is defined by size, being finer than gravel and coarser than silt, Sand can also refer to a textural class of soil or soil type, i. e. a soil containing more than 85% sand-sized particles by mass. The second most common type of sand is calcium carbonate, for example aragonite, for example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Sand is a non renewable resource over human timescales, and sand suitable for making concrete is in high demand, in terms of particle size as used by geologists, sand particles range in diameter from 0.0625 mm to 2 mm. An individual particle in this size is termed a sand grain. Sand grains are between gravel and silt, a 1953 engineering standard published by the American Association of State Highway and Transportation Officials set the minimum sand size at 0.074 mm. A1938 specification of the United States Department of Agriculture was 0.05 mm. Sand feels gritty when rubbed between the fingers. ISO14688 grades sands as fine, medium and coarse with ranges 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is commonly divided into five sub-categories based on size, very fine sand, fine sand, medium sand, coarse sand, and very coarse sand. These sizes are based on the Krumbein phi scale, where size in Φ = -log2D, on this scale, for sand the value of Φ varies from −1 to +4, with the divisions between sub-categories at whole numbers. The composition of sand is highly variable, depending on the local rock sources. The gypsum sand dunes of the White Sands National Monument in New Mexico are famous for their bright, arkose is a sand or sandstone with considerable feldspar content, derived from weathering and erosion of a granitic rock outcrop. Some sands contain magnetite, chlorite, glauconite or gypsum, Sands rich in magnetite are dark to black in color, as are sands derived from volcanic basalts and obsidian. Chlorite-glauconite bearing sands are typically green in color, as are sands derived from basaltic with a high olivine content, many sands, especially those found extensively in Southern Europe, have iron impurities within the quartz crystals of the sand, giving a deep yellow color. Sand deposits in some areas contain garnets and other resistant minerals, the study of individual grains can reveal much historical information as to the origin and kind of transport of the grain. Quartz sand that is weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in the trade where it is preferred for concrete. Sand that is transported long distances by water or wind will be rounded, people who collect sand as a hobby are known as arenophiles
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Seaweed
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Seaweed refers to several species of macroscopic, multicellular, marine algae. The term includes some types of red, brown, and green algae, seaweed can also be classified by use. Seaweed is a term and lacks a formal definition. A seaweed may belong to one of groups of multicellular algae, the red algae, green algae. As these three groups do not have a common ancestor, the seaweed are in a polyphyletic group. In addition, some tuft-forming bluegreen algae are sometimes considered to be seaweed, seaweeds appearance somewhat resembles non-arboreal terrestrial plants. Two specific environmental requirements dominate seaweed ecology and these are the presence of seawater and the presence of light sufficient to drive photosynthesis. Another common requirement is an attachment point, although some genera such as Sargassum. As a result, seaweed most commonly inhabit the part of a sea that is close to the shore, seaweed occupy a wide range of ecological niches. The highest elevation is only wetted by the tops of sea spray, in some areas, littoral seaweed can extend several miles out to sea. The limiting factor in such cases is sunlight availability, the deepest living seaweed are some species of red algae. Others have adapted to live in rock pools. In this habitat seaweed must withstand rapidly changing temperature and salinity, seaweed has a variety of purposes, for which it is farmed or foraged from the wild. At the beginning of 2011, Indonesia produced 3 million tonnes of seaweed and surpassed the Philippines as the worlds largest seaweed producer, by 2011, the production was estimated to have reached 10 million tonnes. Seaweed is consumed by people, particularly in East Asia, e. g. Japan, China, Korea, Taiwan. In Asia, Gim, nori, zicai are sheets of dried Porphyra used in soups, chondrus crispus is another red alga used in producing food additives, along with Kappaphycus and gigartinoid seaweed. Porphyra is a red alga used in Wales to make laver, laverbread, made from oats and the laver, is a popular dish there. In northern Belize, edible seaweed are mixed with milk, nutmeg, cinnamon, seaweed are also harvested or cultivated for the extraction of alginate, agar and carrageenan, gelatinous substances collectively known as hydrocolloids or phycocolloids
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Camouflage
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Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the spotted coat, the battledress of a modern soldier. A third approach, motion dazzle, confuses the observer with a pattern, making the object visible. The majority of camouflage methods aim for crypsis, often through a general resemblance to the background, high contrast disruptive coloration, eliminating shadow, and countershading. Some animals, such as chameleons and octopuses, are capable of changing their skin pattern and colours. Military camouflage was spurred by the range and accuracy of firearms in the 19th century. In particular the replacement of the inaccurate musket with the rifle made personal concealment in battle a survival skill, in the 20th century, military camouflage developed rapidly, especially during the First World War. On land, artists such as André Mare designed camouflage schemes, at sea, merchant ships and troop carriers were painted in dazzle patterns that were highly visible, but designed to confuse enemy submarines as to the targets speed, range, and heading. During and after the Second World War, a variety of schemes were used for aircraft. The use of radar since the century has largely made camouflage for fixed-wing military aircraft obsolete. Non-military use of camouflage includes making cell telephone towers less obtrusive, patterns derived from military camouflage are frequently used in fashion clothing, exploiting their strong designs and sometimes their symbolism. Camouflage themes recur in modern art, and both figuratively and literally in science fiction and works of literature, in ancient Greece, Aristotle commented on the colour-changing abilities, both for camouflage and for signalling, of cephalopods including the octopus, in his Historia animalium, The octopus. Seeks its prey by so changing its colour as to render it like the colour of the adjacent to it, it does so also when alarmed. Camouflage has been a topic of interest and research in zoology for well over a century, the English zoologist Edward Bagnall Poulton studied animal coloration, especially camouflage. In his 1890 book The Colours of Animals, he classified different types such as special protective resemblance and his experiments showed that swallowtailed moth pupae were camouflaged to match the backgrounds on which they were reared as larvae. Among vertebrates numerous species of parrots, iguanas, tree-frogs, beddard did however briefly mention other methods, including the alluring coloration of the flower mantis and the possibility of a different mechanism in the orange tip butterfly. He wrote that the scattered green spots upon the surface of the wings might have been intended for a rough sketch of the small flowerets of the plant. The artist Abbott Handerson Thayer formulated what is sometimes called Thayers Law, Thayer was roundly mocked for these views by critics including Teddy Roosevelt
26.
Scale (anatomy)
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In most biological nomenclature, a scale is a small rigid plate that grows out of an animals skin to provide protection. In lepidopteran species, scales are plates on the surface of the insect wing, scales are quite common and have evolved multiple times through convergent evolution, with varying structure and function. Scales are generally classified as part of an organisms integumentary system, there are various types of scales according to shape and to class of animal. Fish scales are derived, specifically in the mesoderm. This fact distinguishes them from reptile scales paleontologically, genetically, the same genes involved in tooth and hair development in mammals are also involved in scale development. True cosmoid scales can only be found on the extinct Crossopterygians, the inner layer of the scale is made of lamellar bone. On top of this lies a layer of spongy or vascular bone, the coelacanth has modified cosmoid scales that lack cosmine and are thinner than true cosmoid scales. Ganoid scales can be found on gars, bichirs, and reedfishes, ganoid scales are similar to cosmoid scales, but a layer of ganoin lies over the cosmine layer and under the enamel. Ganoin scales are diamond shaped, shiny, and hard, within the ganoin are guanine compounds, iridescent derivatives of guanine found in a DNA molecule. The iridescent property of these provide the ganoin its shine. Placoid scales are found on cartilaginous fish including sharks and these scales, also called denticles, are similar in structure to teeth, and have one median spine and two lateral spines. Leptoid scales are found on higher-order bony fish, as they grow they add concentric layers. They are arranged so as to overlap in a direction, like roof tiles, allowing a smoother flow of water over the body. They come in two forms, Cycloid scales have an outer edge, and are most common on fish with soft fin rays, such as salmon. Ctenoid scales have an outer edge, and are usually found on fish with spiny fin rays, such as bass. Reptile scale types include, cycloid, granular, and keeled, scales usually vary in size, the stouter, larger scales cover parts that are often exposed to physical stress, while scales are small around the joints for flexibility. Most snakes have extra broad scales on the belly, each covering the belly from side to side. The scales of all reptiles have a component, but many reptiles, such as crocodilians
27.
Dorsal fin
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A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fish, cetaceans, and the ichthyosaurs. Depending on the species, an animal may have one or two of them, wildlife biologists often use the distinctive nicks and wear patterns which develop on the dorsal fins of large cetaceans to identify individuals in the field. The bony or cartilaginous bones that support the base of the fin in fish are called pterygiophores. The main purpose of the fin is to stabilize the animal against rolling. Some species have adapted their dorsal fins to other uses. The sunfish uses the dorsal fin for propulsion, in anglerfish, the anterior of the dorsal fin is modified into a biological equivalent to a fishing pole and a lure known as illicium or esca. Many catfish can lock the leading ray of the fin in an extended position to discourage predation or to wedge themselves into a crevice. Some animals have developed dorsal fins with protective functions, such as spines or venom, for example, both the spiny dogfish and the Port Jackson shark have spines in their dorsal fins which are capable of secreting venom. Like tuna, mackerel and other scombroids, billfish streamline themselves by retracting their fins into a groove in their body when they swim. The shape, size, position and colour of the dorsal fin varies with the type of billfish, for example, the white marlin has a dorsal fin with a curved front edge and is covered with black spots. The huge dorsal fin, or sail, of the sailfish is kept retracted most of the time, sailfish raise them if they want to herd a school of small fish, and also after periods of high activity, presumably to cool down. Fish fin Submarine sail Vertical stabilizer
28.
Fishing lure
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A fishing lure is a type of artificial fishing bait which is designed to attract a fishs attention. The lure uses movement, vibration, flash and color to bait fish, many lures are equipped with one or more hooks that are used to catch fish when they strike the lure. Some lures are placed to attract fish so a spear can be impaled into the fish or so the fish can be captured by hand. Most lures are attached to the end of a line and have various styles of hooks attached to the body and are designed to elicit a strike resulting in a hookset. Many lures are made but some are hand made such as fishing flies. Hand tying fly lures to match the hatch is considered a challenge by many amateur entomologists, modern commercial lures usually are often used with a fishing rod and fishing reel but there are some who use a technique where they hold the line in their hands. Handlining is a technique in which the line is directly in the hands versus being fed through the guides of a fishing rod. Longlining also can employ lures to catch fish, when a lure is used for casting, it is continually cast out and retrieved, the retrieve making the lure swim or produce a popping action. A skilled angler can explore many possible hiding places for fish through lure casting such as under logs, in early time, fishing lures were made from bone or bronze. The Chinese and Egyptians used fishing rods, hooks, and lines as early as 2,000 B. C. though most of the first fishermen used handlines. The first hooks were made out of bronze, which was strong but still very thin, the Chinese were the first to make fishing line, spun from fine silk. The modern fishing lure was made commercially in the United States in the early 1900s by the firm of Heddon, before this time most fishing lures were made by individual craftsman. Commercial-made lures were based on the ideas that the individual craftsmen were making. The reel is attached to a rod, the motion of the lure is made by winding line back on to the reel, by sweeping the fishing rod, jigging movements with the fishing rod, or by being pulled behind a moving boat. Exceptions included are artificial flies, commonly called flies by fly fishers, which float on the water surface, slowly sink or float underwater. There are many types of fishing lures, in most cases they are manufactured to resemble prey for the fish, but they are sometimes engineered to appeal to a fishes sense of territory, curiosity or aggression. Most lures are made to look like dying, injured, or fast moving fish and they include the following types, A jig is a weighted hook with a lead head opposite the sharp tip. They usually have a minnow or crawfish or even a plastic worm on it to get the fishs attention, some jigs can be fished in water depths down to 300 metres
29.
Spawn (biology)
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Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to refers to the process of releasing the eggs and sperm. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning, spawn consists of the reproductive cells of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova into the water, often in large quantities, fungi, such as mushrooms, are also said to spawn a white, fibrous matter that forms the matrix from which they grow. Marine animals, and particularly fish, commonly reproduce by broadcast spawning. This is a method of reproduction where the female releases many unfertilised eggs into the water. At the same time, a male or many males release a lot of sperm into the water which fertilises some of these eggs, the eggs contain a drop of nutrient oil to sustain the embryo as it develops inside the egg case. The oil also provides buoyancy, so the float and drift with the current. The strategy for survival of broadcast spawning is to disperse the fertilised eggs, there the larvae develop as they consume their fat stores, and eventually hatch from the egg capsule into miniature versions of their parents. To survive, they must then become miniature predators themselves, feeding on plankton, fish eventually encounter others of their own kind, where they form aggregations and learn to school. Internally, the sexes of most marine animals can be determined by looking at the gonads, male lampreys, hagfish and salmon discharge their sperm into the body cavity where it is expelled through pores in the abdomen. Male sharks and rays can pass sperm along a duct into a seminal vesicle, externally, many marine animals, even when spawning, show little sexual dimorphism or little difference in colouration. Where species are dimorphic, such as sharks or guppies, the males often have penis-like intromittent organs in the form of a modified fin, a species is semelparous if its individuals spawn only once in their lifetime, and iteroparous if its individuals spawn more than once. The term semelparity comes from the Latin semel, once, and pario, to beget, while iteroparity comes from itero, to repeat, semelparity is sometimes called big bang reproduction, since the single reproductive event of semelparous organisms is usually large and fatal to the spawners. The classic example of an animal is the Pacific salmon, which lives for many years in the ocean before swimming to the freshwater stream of its birth, spawning. Other spawning animals which are semelparous include mayflies, squid, octopus, smelt, capelin, semelparity is often associated with r-strategists. However, most fish and other spawning animals are iteroparous, when the internal ovaries or egg masses of fish and certain marine animals are ripe for spawning they are called roe. Roe from certain species, such as shrimp, scallop, crab, caviar is a name for the processed, salted roe of non-fertilized sturgeon
30.
Larva
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A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a phase of their life cycle. The larvas appearance is very different from the adult form. A larva often has unique structures and organs that do not occur in the adult form and their diet may also be considerably different. Larvae are frequently adapted to separate from adults. For example, some such as tadpoles live almost exclusively in aquatic environments. By living in an environment, larvae may be given shelter from predators. Animals in the stage will consume food to fuel their transition into the adult form. In some species like barnacles, adults are immobile but their larvae are mobile, some larvae are dependent on adults to feed them. In many eusocial Hymenoptera species, the larvae are fed by female workers, in Ropalidia marginata the males are also capable of feeding larvae but they are much less efficient, spending more time and getting less food to the larvae. The larvae of species can become pubescent and do not develop further into the adult form. This is a type of neoteny and it is a misunderstanding that the larval form always reflects the groups evolutionary history. This could be the case, but often the stage has evolved secondarily. In these cases the form may differ more than the adult form from the groups common origin. Within Insects, only Endopterygotes show different types of larvae, several classifications have been suggested by many entomologists, and following classification is based on Antonio Berlese classification in 1913. There are four types of endopterygote larvae types, Apodous larvae - no legs at all and are poorly sclerotized. Based on sclerotization, three forms are recognized. Eucephalous - with well sclerotized head capsule, found in Nematocera, Buprestidae and Cerambycidae families
31.
International Union for Conservation of Nature
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The International Union for Conservation of Nature is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in gathering and analysis, research, field projects, advocacy, lobbying. IUCNs mission is to influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of resources is equitable. Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to equality, poverty alleviation. Unlike other international NGOs, IUCN does not itself aim to mobilize the public in support of nature conservation and it tries to influence the actions of governments, business and other stakeholders by providing information and advice, and through lobbying and partnerships. The organization is best known to the public for compiling and publishing the IUCN Red List. IUCN has a membership of over 1200 governmental and non-governmental organizations, some 11,000 scientists and experts participate in the work of IUCN commissions on a voluntary basis. It employs approximately 1000 full-time staff in more than 60 countries and its headquarters are in Gland, Switzerland. IUCN has observer and consultative status at the United Nations, and plays a role in the implementation of several conventions on nature conservation. It was involved in establishing the World Wide Fund for Nature, in the past, IUCN has been criticized for placing the interests of nature over those of indigenous peoples. In recent years, its relations with the business sector have caused controversy. It was previously called the International Union for Protection of Nature, establishment In 1947, the Swiss League for the Protection of Nature organised an international conference on the protection of nature in Brunnen. It is considered to be the first government-organized non-governmental organization, the initiative to set up the new organisation came from UNESCO and especially from its first Director General, the British biologist Julian Huxley. At the time of its founding IUPN was the international organisation focusing on the entire spectrum of nature conservation Early years. Its secretariat was located in Brussels and its first work program focused on saving species and habitats, increasing and applying knowledge, advancing education, promoting international agreements and promoting conservation. Providing a solid base for conservation action was the heart of all activities. IUPN and UNESCO were closely associated and they jointly organized the 1949 Conference on Protection of Nature. In preparation for this conference a list of endangered species was drawn up for the first time
32.
Public domain
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The term public domain has two senses of meaning. Anything published is out in the domain in the sense that it is available to the public. Once published, news and information in books is in the public domain, in the sense of intellectual property, works in the public domain are those whose exclusive intellectual property rights have expired, have been forfeited, or are inapplicable. Examples for works not covered by copyright which are therefore in the domain, are the formulae of Newtonian physics, cooking recipes. Examples for works actively dedicated into public domain by their authors are reference implementations of algorithms, NIHs ImageJ. The term is not normally applied to situations where the creator of a work retains residual rights, as rights are country-based and vary, a work may be subject to rights in one country and be in the public domain in another. Some rights depend on registrations on a basis, and the absence of registration in a particular country, if required. Although the term public domain did not come into use until the mid-18th century, the Romans had a large proprietary rights system where they defined many things that cannot be privately owned as res nullius, res communes, res publicae and res universitatis. The term res nullius was defined as not yet appropriated. The term res communes was defined as things that could be enjoyed by mankind, such as air, sunlight. The term res publicae referred to things that were shared by all citizens, when the first early copyright law was first established in Britain with the Statute of Anne in 1710, public domain did not appear. However, similar concepts were developed by British and French jurists in the eighteenth century, instead of public domain they used terms such as publici juris or propriété publique to describe works that were not covered by copyright law. The phrase fall in the domain can be traced to mid-nineteenth century France to describe the end of copyright term. In this historical context Paul Torremans describes copyright as a coral reef of private right jutting up from the ocean of the public domain. Because copyright law is different from country to country, Pamela Samuelson has described the public domain as being different sizes at different times in different countries. According to James Boyle this definition underlines common usage of the public domain and equates the public domain to public property. However, the usage of the public domain can be more granular. Such a definition regards work in copyright as private property subject to fair use rights, the materials that compose our cultural heritage must be free for all living to use no less than matter necessary for biological survival
33.
Wikispecies
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Wikispecies is a wiki-based online project supported by the Wikimedia Foundation. Its aim is to create a free content catalogue of all species. Jimmy Wales stated that editors are not required to fax in their degrees, Wikispecies is available under the GNU Free Documentation License and CC BY-SA3.0. Benedikt Mandl co-ordinated the efforts of people who are interested in getting involved with the project. Databases were evaluated and the administrators contacted, some of them have agreed on providing their data for Wikispecies, the board of directors of the Wikimedia Foundation voted by 4 to 0 in favor of the establishment of a Wikispecies. The project was launched in August 2004 and is hosted at species. wikimedia. org and it was officially merged to a sister project of Wikimedia Foundation on September 14,2004. On October 10,2006, the project exceeded 75,000 articles, on May 20,2007, the project exceeded 100,000 articles with a total of 5,495 registered users. On September 8,2008, the project exceeded 150,000 articles with a total of 9,224 registered users, on October 23,2011, the project reached 300,000 articles. On June 16,2014, the project reached 400,000 articles, on January 7,2017, the project reached 500,000 articles. Wikispecies has disabled local upload and asks users to use images from Wikimedia Commons, Wikispecies does not allow the use of content that does not conform to a free license
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Integrated Taxonomic Information System
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The Integrated Taxonomic Information System is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. The database draws from a community of taxonomic experts. Primary content staff are housed at the Smithsonian National Museum of Natural History, the primary focus of ITIS is North American species, but many groups are worldwide and ITIS continues to collaborate with other international agencies to increase its global coverage. ITIS provides a reference database of scientific and common names for species. As of May 2016, it contains over 839,000 scientific names, synonyms, and common names for terrestrial, marine, data presented in ITIS are considered public information, and may be freely distributed and copied, though appropriate citation is requested. ITIS is frequently used as the de facto source of data in biodiversity informatics projects. It presents the names in a classification that contains author, date, distributional. In addition, common names are available through ITIS in the official languages of the Americas. ITIS and its partner, Species 2000, cooperate to annually produce the Catalogue of Life. The Catalogue of Lifes goal was to complete the global checklist of 1.9 million species by 2011. As of May 2012, the Catalogue of Life has reached 1.4 million species—a major milestone in its quest to complete the first up-to-date comprehensive catalogue of all living organisms, ITIS and the Catalogue of Life are core to the Encyclopedia of Life initiative announced May 2007. EOL will be largely on various Creative Commons licenses. The newer material has been checked to higher standards of taxonomic credibility, biological taxonomy is not fixed, and opinions about the correct status of taxa at all levels, and their correct placement, are constantly revised as a result of new research. Many aspects of classification remain a matter of scientific judgment, the ITIS database is updated to take account of new research as it becomes available, and the information it yields is likely to represent a fair consensus of modern taxonomic opinion. Records within ITIS include information about how far it has been possible to check and its information should be checked against other sources where these are available, and against the primary research scientific literature where possible
35.
FishBase
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FishBase is a global species database of fish species. It is the largest and most extensively accessed online database on adult finfish on the web, over time it has evolved into a dynamic and versatile ecological tool that is widely cited in scholarly publications. The site has about 700,000 unique visitors per month, hypotheses, such as this one, could be tested only if large amounts of empirical data were available. At the time, fisheries management used analytical models which required estimates for fish growth and it can be particularly difficult for people in developing countries who need such information. Such a database would be useful if the data has also been standardised and validated. Pauly recruited Rainer Froese, and the beginnings of a software database along these lines was encoded in 1988 and this database, initially confined to tropical fish, became the prototype for FishBase. FishBase was subsequently extended to cover all finfish, and was launched on the Web in August 1996 and it is now the largest and most accessed online database for fish in the world. In 1995 the first CD-ROM was released as FishBase 100, subsequent CDs have been released annually. The software runs on Microsoft Access which operates only on Microsoft Windows, FishBase covers adult finfish, but does not detail the early and juvenile stages of fish. In 1999 a complimentary database, called LarvalBase, went online under the supervision of Bernd Ueberschär. It covers ichthyoplankton and the stage of fishes, with detailed data on fish eggs and larvae, fish identification. Given FishBases success, there was a demand for a database covering forms of life other than finfish. This resulted, in 2006, in the birth of SeaLifeBase, altogether, there are about 300,000 known species in this category. As awareness of FishBase has grown among fish specialists, it has attracted over 1,700 contributors and collaborators, since 2000 FishBase has been supervised by a consortium consisting of nine international institutions. The Leibniz Institute of Marine Sciences in Kiel, Germany, functions as the coordinating body, Catalog of Fishes List of online encyclopedias Bailly N Why there may be discrepancies in the assessment of scientific names between the Catalog of Fishes and FishBase Version 2,6 May 2010. Bailly N, Reyes Jr R, Atanacio R and Froese R Simple Identification Tools in FishBase In, Nimis PL and Vignes Lebbe R. Tools for Identifying Biodiversity, Progress and Problems, pages 31–36. Froese R The science in Fishbase In, Villy Christensen and Jay Maclean Ecosystem Approaches to Fisheries, A Global Perspective, Cambridge University Press, Froese R and Pauly D FishBase 2000, concepts, design and data sources ICLARM, Philippines. Froese R and Pauly D Fishbase as a tool for comparing the life patterns of flatfish Netherlands Journal of Sea Research,32
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Fish
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A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. They form a group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous, tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods, because in this manner the term fish is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces is considered a typological, but not a phylogenetic classification, the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts, fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators, the first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Fish are abundant in most bodies of water and they can be found in nearly all aquatic environments, from high mountain streams to the abyssal and even hadal depths of the deepest oceans. With 33,100 described species, fish exhibit greater species diversity than any group of vertebrates. Fish are an important resource for humans worldwide, especially as food, commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by fishers, kept as pets, raised by fishkeepers. Fish have had a role in culture through the ages, serving as deities, religious symbols, fish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event. Early fish from the record are represented by a group of small, jawless. Jawless fish lineages are mostly extinct, an extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils, the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may have kept the form into adulthood. Fish are a group, that is, any clade containing all fish also contains the tetrapods
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Diversity of fish
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Fish are very diverse animals and can be categorised in many ways. This article is an overview of some of ways in which fish are categorised, although most fish species have probably been discovered and described, about 250 new ones are still discovered every year. According to FishBase,33,100 species of fish had been described by April 2015 and that is more than the combined total of all other vertebrate species, mammals, amphibians, reptiles and birds. Fish species diversity is roughly divided equally between marine and freshwater ecosystems, more than 5,600 fish species inhabit Neotropical freshwaters alone, such that Neotropical fishes represent about 10% of all vertebrate species on the Earth. Exceptionally rich sites in the Amazon basin, such as Cantão State Park, Fish systematics is the formal description and organisation of fish taxa into systems. It is complex and still evolving, controversies over arcane, but important, details of classification are still quietly raging. The term fish describes any non-tetrapod chordate, that has gills throughout life and has limbs, if any, unlike groupings such as birds or mammals, fish are not a single clade but a paraphyletic collection of taxa, including jawless, cartilaginous and skeletal types. Jawless fish were the earliest fish to evolve, there is current debate over whether these are really fish at all. They have no jaw, no scales, no paired fins and their skin is smooth and soft to the touch, and they are very flexible. Instead of a jaw, they possess an oral sucker and they use this to fasten onto other fish, and then use their rasp-like teeth to grind through their hosts skin into the viscera. Jawless fish inhabit both fresh and salt water environments, some are anadromous, moving between both fresh and salt water habitats. Extant jawless fish are either lamprey or hagfish, juvenile lamprey feed by sucking up mud containing micro-organisms and organic debris. The lamprey has well-developed eyes, while the hagfish has only primitive eyespots, the hagfish coats itself and carcasses it finds with noxious slime to deter predators, and periodically ties itself into a knot to scrape the slime off. It is the only fish and the only animal which has a skull. It has four hearts, two brains, and a paddle-like tail, cartilaginous fish have a cartilaginous skeleton. However, their ancestors were bony animals, and were the first fish to develop paired fins, cartilaginous fish dont have swim bladders. Their skin is covered in scales that are as rough as sandpaper. Because cartilaginous fish do not have bone marrow, the spleen and their tails can be asymmetric, with the upper lobe longer than the lower lobe
38.
Ethnoichthyology
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Ethnoichthyology is an area in anthropology that examines human knowledge of fish, the uses of fish, and importance of fish in different human societies. It draws on knowledge from different areas including ichthyology, economics, oceanography. This area of study seeks to understand the details of the interactions of humans with fish, a knowledge of fish and their life strategies is extremely important to fishermen. In order to fish species, it is also important to be aware of other cultures knowledge of fish. Ignorance of the effects of human activity on fish populations may endanger fish species, knowledge of fish can be gained through experience, scientific research, or information passed down through generations. The term was first used in the literature by W. T. Morrill. He justified the origin and use of term by stating that it arose from the model of ethnobotany. Ethnoichthyological knowledge can be used to environmental conservation strategies. With a sound knowledge of ecology, informed decisions with respect to fishing practices can be made. Ethnoichthyological knowledge can be the difference between conserving a species of fish, or placing a moratorium on fishing, the collapse of the cod fishery in Newfoundland and Labrador was due to a lack of ethnoichthyological knowledge and conservation efforts. The waters of Newfoundland were once teeming with cod. John Cabots crew reported that The sea there is full of fish that can be not only with nets. Until John Cabots crew arrived in Newfoundland, those who caught cod were mostly subsistence fishermen and they generally used techniques like jigging, longlining, and small trawler use. These methods were not stressful on the cod population, however, the invasion of European superpowers put a great deal of pressure on the environment. At one point, the French, English, Spanish and Portuguese would anchor as nearby as 12 miles off the Newfoundland shore with large trawlers in order to maximize their catch and this was extremely detrimental to the population. The catch of cod reached its peak in 1968 at 80,000 tons, foreign ships were forced to fish two hundred miles offshore. Despite good intentions, the results were not favourable and this was because Canadian and American fishermen were then freed of competition and able to increase their catch. By the 1980s the amount of fish taken had increased from a safe 139,000 tons to an unsustainable 250,000 tons, the use of draggers was found to be extremely detrimental to the cod population in several ways. Not only did it decimate the number of cod
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Evolution of fish
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The evolution of fish began about 530 million years ago during the Cambrian explosion. It was during this time that the early chordates developed the skull, the first fish lineages belong to the Agnatha, or jawless fish. During the late Cambrian, eel-like jawless fish called the conodonts, most jawless fish are now extinct, but the extant lampreys may approximate ancient pre-jawed fish. Lamphreys belong to the Cyclostomata, which includes the extant hagfish, the first jawed vertebrates probably developed during the late Ordovician period. They are first represented in the record from the Silurian by two groups of fish, the armoured fish known as placoderms, which evolved from the ostracoderms. The jawed fish that are extant in modern days also appeared in late Silurian, the Chondrichthyes. The bony fish evolved into two groups, the Actinopterygii and Sarcopterygii. During the Devonian period a great increase in fish variety occurred, especially that of the ostracoderms and placoderms, as well as lobe-finned fish and this has led to the Devonian being known as the age of fishes. It was from the fish that the tetrapods evolved, the non-fish four-limbed vertebrates, represented today by amphibians, mammals, reptiles. Transitional tetrapods first appeared during the early Devonian, and by the late Devonian the first tetrapods appeared, Fish do not represent a monophyletic group, but a paraphyletic one, as they exclude the tetrapods. Fish, like other organisms, have been greatly affected by extinction events throughout natural history. The Ordovician–Silurian extinction events led to the loss of many species, the late Devonian extinction led to the extinction of the ostracoderms and placoderms by the end of the Devonian, as well as other fish. The spiny sharks became extinct at the Permian–Triassic extinction event, the conodonts became extinct at the Triassic–Jurassic extinction event, the Cretaceous–Paleogene extinction event, and the present day Holocene extinction, have also affected fish variety and fish stocks. Fish may have evolved from a similar to a coral-like sea squirt. The first ancestors of fish, or animals that were closely related to fish, were Pikaia, Haikouichthys. These three genera all appeared around 530 Ma, Pikaia had a primitive notochord, a structure that could have developed into a vertebral column later. Unlike the other fauna that dominated the Cambrian, these groups had the basic body plan, a notochord, rudimentary vertebrae. All of these early vertebrates lacked jaws in the common sense and these were followed by indisputable fossil vertebrates in the form of heavily armoured fishes discovered in rocks from the Ordovician Period 500–430 Ma
40.
Fish diseases and parasites
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Like humans and other animals, fish suffer from diseases and parasites. Fish defences against disease are specific and non-specific, non-specific defences include skin and scales, as well as the mucus layer secreted by the epidermis that traps microorganisms and inhibits their growth. If pathogens breach these defences, fish can develop inflammatory responses that increase the flow of blood to infected areas, specific defences are specialised responses to particular pathogens recognised by the fishs body, that is adaptative immune responses. In recent years, vaccines have become used in aquaculture and ornamental fish, for example vaccines for furunculosis in farmed salmon. Some commercially important fish diseases are VHS, ich and whirling disease, all fish carry pathogens and parasites. Usually this is at some cost to the fish, if the cost is sufficiently high, then the impacts can be characterised as a disease. However disease in fish is not understood well, what is known about fish disease often relates to aquaria fish, and more recently, to farmed fish. Disease is a prime agent affecting fish mortality, especially when fish are young, Fish can limit the impacts of pathogens and parasites with behavioural or biochemical means, and such fish have reproductive advantages. Interacting factors result in low grade infection becoming fatal diseases, in particular, things that causes stress, such as natural droughts or pollution or predators, can precipitate outbreak of disease. Disease can also be problematic when pathogens and parasites carried by introduced species affect native species. An introduced species may find invading easier if potential predators and competitors have been decimated by disease, Parasites can provide information about host population ecology. In fisheries biology, for example, parasite communities can be used to distinguish distinct populations of the fish species co-inhabiting a region. Additionally, parasites possess a variety of specialized traits and life-history strategies that enable them to colonize hosts, understanding these aspects of parasite ecology, of interest in their own right, can illuminate parasite-avoidance strategies employed by hosts. Usually parasites need to avoid killing their hosts, since extinct hosts can mean extinct parasites, evolutionary constraints may operate so parasites avoid killing their hosts, or the natural variability in host defensive strategies may suffice to keep host populations viable. Parasite infections can impair the courtship dance of male threespine sticklebacks, when that happens, the females reject them, suggesting a strong mechanism for the selection of parasite resistance. However, not all parasites want to keep their hosts alive, for example, some tapeworms make some fish behave in such a way that a predatory bird can catch it. The predatory bird is the next host for the parasite in the stage of its life cycle. Parasites can be internal or external.6 millimetre, the males are tiny, various protists and Myxosporea are also parasitic on gills, where they form cysts
41.
Fishery
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Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. The definition often includes a combination of fish and fishers in a region, a fishery may involve the capture of wild fish or raising fish through fish farming or aquaculture. Directly or indirectly, the livelihood of over 500 million people in developing countries depends on fisheries, overfishing, including the taking of fish beyond sustainable levels, is reducing fish stocks and employment in many world regions. In biology – the term fish is most strictly used to any animal with a backbone that has gills throughout life and has limbs, if any. Many types of animals commonly referred to as fish are not fish in this strict sense. In fisheries – the term fish is used as a collective term, true fish – The strict biological definition of a fish, above, is sometimes called a true fish. True fish are referred to as finfish or fin fish to distinguish them from other aquatic life harvested in fisheries or aquaculture. Fisheries are harvested for their value and they can be saltwater or freshwater, wild or farmed. Examples are the salmon fishery of Alaska, the cod fishery off the Lofoten islands, capture fisheries can be broadly classified as industrial scale, small-scale or artisanal, and recreational. Close to 90% of the fishery catches come from oceans. These marine catches have remained stable since the mid-nineties. Most marine fisheries are based near the coast, however, productive wild fisheries also exist in open oceans, particularly by seamounts, and inland in lakes and rivers. Most fisheries are fisheries, but farmed fisheries are increasing. Farming can occur in areas, such as with oyster farms. There are species fisheries worldwide for finfish, mollusks, crustaceans and echinoderms, however, a very small number of species support the majority of the world’s fisheries. Some of these species are herring, cod, anchovy, tuna, flounder, mullet, squid, shrimp, salmon, crab, lobster, oyster and scallops. All except these last four provided a catch of well over a million tonnes in 1999, with herring. Many other species are harvested in smaller numbers, cullis-Suzuki S and Pauly D Failing the high seas, A global evaluation of regional fisheries management organizations Marine Policy,34 pp 1036–1042
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Fishing
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Fishing is the activity of trying to catch fish. Fish are normally caught in the wild, techniques for catching fish include hand gathering, spearing, netting, angling and trapping. Fishing may include catching aquatic animals other than fish, such as molluscs, cephalopods, crustaceans, the term is not normally applied to catching farmed fish, or to aquatic mammals, such as whales where the term whaling is more appropriate. According to United Nations FAO statistics, the number of commercial fishermen. Fisheries and aquaculture provide direct and indirect employment to over 500 million people in developing countries, in 2005, the worldwide per capita consumption of fish captured from wild fisheries was 14.4 kilograms, with an additional 7.4 kilograms harvested from fish farms. In addition to providing food, modern fishing is also a recreational pastime, Fishing is an ancient practice that dates back to at least the beginning of the Upper Paleolithic period about 40,000 years ago. Isotopic analysis of the remains of Tianyuan man, a 40. Archaeology features such as middens, discarded fish bones, and cave paintings show that sea foods were important for survival. During this period, most people lived a lifestyle and were, of necessity. However, where there are examples of permanent settlements such as those at Lepenski Vir. The British dogger was a type of sailing trawler from the 17th century. The Brixham trawler that evolved there was of a build and had a tall gaff rig. They were also sufficiently robust to be able to tow large trawls in deep water, the great trawling fleet that built up at Brixham, earned the village the title of Mother of Deep-Sea Fisheries. The small village of Grimsby grew to become the largest fishing port in the world by the mid 19th century, an Act of Parliament was first obtained in 1796, which authorised the construction of new quays and dredging of the Haven to make it deeper. It was only in the 1846, with the expansion in the fishing industry. The foundation stone for the Royal Dock was laid by Albert the Prince consort in 1849, the dock covered 25 acres and was formally opened by Queen Victoria in 1854 as the first modern fishing port. The elegant Brixham trawler spread across the world, influencing fishing fleets everywhere, by the end of the 19th century, there were over 3,000 fishing trawlers in commission in Britain, with almost 1,000 at Grimsby. These trawlers were sold to fishermen around Europe, including from the Netherlands, twelve trawlers went on to form the nucleus of the German fishing fleet
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Fish as food
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Fish are consumed as food by many species, including humans. It has been an important source of protein and other nutrients for humans throughout recorded history, in culinary and fishery contexts, the term fish can also include shellfish, such as molluscs, crustaceans and echinoderms. English does not distinguish between fish as an animal and the food prepared from it, as it does with pig vs. pork or cow vs. beef, some other languages do, as in the Spanish peces versus pescado. The modern English word for fish comes from the Old English word fisc which was pronounced as it is today, English also has the term seafood, which covers fish found in the seas and oceans as well as other marine life used as food. Over 32,000 species of fish have been described, making them the most diverse group of vertebrates, in addition, there are many species of shellfish. However, only a number of species are commonly eaten by humans. Fish can be prepared in a variety of ways and it can be cured by marinating, pickling, or smoking. Or it can be cooked by baking, frying, grilling, poaching, many of the preservation techniques used in different cultures have since become unnecessary but are still performed for their resulting taste and texture when consumed. Intermediate Technology Publications wrote in 1992 that Fish provides a source of high quality protein and contains many vitamins. It may be classed as either whitefish, oily fish, or shellfish, whitefish, such as haddock and seer, contain very little fat whereas oily fish, such as sardines, contain between 10-25%. The latter, as a result of its fat content, contain a range of fat-soluble vitamins and essential fatty acids. This has highlighted the role for fish in the functionality of the human body, Fish is the most common food to obstruct the airway and cause choking. Choking on fish was responsible for about 4,500 reported accidents in the UK in 1998, a seafood allergy is a hypersensitivity to an allergen which can be present in fish, and particularly in shellfish. This can result in an overreaction of the system and lead to severe physical symptoms. Most people who have a food allergy also have a seafood allergy, allergic reactions can result from ingesting seafood, or by breathing in vapours from preparing or cooking seafood. The most severe seafood allergy reaction is anaphylaxis, an emergency requiring immediate attention, some species of fish, notably the puffer fugu used for sushi, and some kinds of shellfish, can result in serious poisoning if not prepared properly. These fish always contain these poisons as a defense against predators, particularly, fugu has a lethal dose of tetrodotoxin in its internal organs and must be prepared by a licensed fugu chef who has passed the national examination in Japan. Ciguatera poisoning can occur from eating fish from warm tropical waters, such as sea bass, grouper
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Fear of fish
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Fear of fish or ichthyophobia ranges from cultural phenomena such as fear of eating fish, fear of touching raw fish, or fear of dead fish, up to irrational fear. Galeophobia is the fear specifically of sharks, ichthyophobia is described in Psychology, An International Perspective as an unusual specific phobia. Both symptoms and remedies of ichthyophobia are common to most specific phobias, let his brother, aged four, who has no fear of fish, come up to the bowl and put his hands in the bowl and catch the fish. No amount of watching a child play with these harmless animals will remove the fear from the toddler. Try shaming him, making a scapegoat of him, let us try, however, this simple method. Place the child at meal time at one end of a ten or twelve feet long. Just as soon as the meal is placed before him remove the cover from the bowl, if disturbance occurs, extend your table and place the bowl still farther off, so far away that no disturbance occurs. Eating takes place normally, nor is digestion interfered with, repeat the procedure on the next day, but move the bowl a little nearer. In four or five days the bowl can be right up to the food tray without causing the slightest disturbance. Then take a glass dish, fill it with water and move the dish back. Again in three or four days the small glass dish can be put on the tray alongside of his milk, the old fear has been driven out by training, unconditioning has taken place, and this unconditioning is permanent. In contrast, radical exposure therapy was used successfully to cure a man with a life affecting fish phobia on the 2007 documentary series, historically, the Navajo people were described as being ichthyophobic, due to their aversion to fish. However, this was recognised as a cultural or mythic aversion to aquatic animals. The Journal of the American Medical Association have published a paper addressing the fears of eating fish because contaminants. In his autobiography, Italian footballer Paolo Di Canio describes finding that his then team-mate, during a practical joke, Di Canio describes Grants fearful reaction after finding a salmon head in his bed. Grant told The Independent that item in his bed was in fact a sharks head, the term ichthyophobia comes from the Greek ἰχθῦς - ichthus, meaning fish and φόβος - phobos, fear. Galeophobia comes from the Greek γαλεός - galeos, small shark, list of phobias How I overcame my fish phobia
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Fish kill
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The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life. The most common cause is reduced oxygen in the water, which in turn may be due to such as drought, algae bloom, overpopulation. Infectious diseases and parasites can also lead to fish kill, toxicity is a real but far less common cause of fish kill. Fish kills are often the first visible signs of stress and are usually investigated as a matter of urgency by environmental agencies to determine the cause of the kill. Pollution events may affect fish species and fish age classes in different ways, if it is a cold-related fish kill, juvenile fish or species that are not cold-tolerant may be selectively affected. If toxicity is the cause, species are more generally affected, a reduction in dissolved oxygen may affect larger specimens more than smaller fish as these may be able to access oxygen richer water at the surface, at least for a short time. Fish kills may result from a variety of causes, of known causes, fish kills are most frequently caused by pollution from agricultural runoff or biotoxins. Ecological hypoxia is one of the most common causes of fish kills. The hypoxic event may be brought on by such as algae blooms, droughts, high temperatures. Because of the difficulty and lack of standard protocol to investigate fish kills, oxygen enters the water through diffusion. The amount of oxygen that can be dissolved in water depends on the atmospheric pressure, the water temperature and whether the water is salty. For example, at 20 °C and one atmosphere of pressure, the amount of oxygen that can be dissolved in the water decreases by about 1 mg/l for each 10 °C increase in water temperature above 20 °C. Many cold water fish live in clean cold waters become stressed when oxygen concentrations fall below 8 mg/l while warm water fish generally need at least 5 ppm of dissolved oxygen. Fish can endure periods of reduced oxygen. Depleted oxygen levels are the most common cause of fish kills, associated with these photosynthetic rhythms there is a matching pH rhythm as bicarbonate ion is metabolised by plant cells. This can lead to pH stress even when oxygen levels are high and these are naturally occurring in many bodies of water, and fish that are stressed for other reasons, such as spawning or suboptimal water quality, are more susceptible. For example, since 2004 fish kills have been observed in the Shenandoah River basin in the spring, so far, investigators suspect certain bacteria, along with environmental and contaminant factors that may cause immune suppression. In fish farming, where populations are optimized for the resources, parasites or disease can spread quickly
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Hypoxia in fish
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Fish are exposed to large oxygen fluctuations in their aquatic environment since the inherent properties of water can result in marked spatial and temporal differences in the concentration of oxygen. Fish respond to hypoxia with varied behavioral, physiological, and cellular responses in order to maintain homeostasis and this article is a review of the effects of hypoxia on all aspects of fish, ranging from behavior down to genes. Hypoxia tolerance in fish can often be determined by assessing the value of critical O2 tension, Pcrit is a point where an oxy-regulator becomes an oxy-conformer. Individuals with low Pcrit values are associated with high hypoxia tolerance while individuals with high Pcrit values tend to be more hypoxia sensitive. However, some species or individuals can be complete oxy-conformers and may not show distinctive Pcrit points, therefore, experimentally defining hypoxia in such species can be difficult. These structures include the type I cells of the carotid body, in fish, the neuroepithelial cells have been implicated as the major oxygen sensing cells. NEC have been found in all teleost fish studied to date, NEC are also found in all four gill arches within several different structures, such as along the filaments, at the ends of the gill rakers and throughout the lamellae. Two separate neural pathways have been identified within the gill arches both the motor and sensory nerve fibre pathways. Since neuroepithelial cells are distributed throughout the gills, they are ideally situated to detect both arterial as well as environmental oxygen. Neuroepithelial cells are thought to be neuron-like chemoreceptor cells because they rely on membrane potential changes for the release of neurotransmitters, once NEC of the zebrafish gills come in contact with either environmental or aortic hypoxia, an outward K+ leak channel is inhibited. K+ leak channels are two-pore-domain ion channels that are open at the membrane potential of the cell. Once this leak channel is closed, the K+ is no longer able to flow out of the cell, and the membrane potential of the NEC increases. If the post-synaptic cell is a neuron, then an increased firing rate in that neuron will transmit the signal to the central nervous system for integration. In fish, the signal is carried up to the brain for processing by the glossopharyngeal. The first branchial arch is innervated by the nerve, however all four arches are innervated by the vagus nerve. Both the glossopharyngeal and vagus nerves carry sensory nerve fibres into the brain, through studies using mammalian model organisms, there are two main hypotheses for the location of oxygen sensing in chemoreceptor cells, the membrane hypothesis and the mitochondrial hypothesis. The membrane hypothesis was proposed for the body in mice. The mitochondrial hypothesis was proposed for the carotid body of mice
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Ichthyology
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Ichthyology, also known as fish science, is the branch of zoology devoted to the study of fish. This includes bony fish, cartilaginous fish, and jawless fish, while a large number of species have been discovered, approximately 250 new species are officially described by science each year. According to FishBase,33,400 species of fish had been described by October 2016, the study of fish dates from the Upper Paleolithic Revolution. The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements, the study of fish receives its origins from humans desire to feed, clothe, and equip themselves with useful implements. Early cultures manifested these insights in abstract and identifiable artistic expressions, informal, scientific descriptions of fish are represented within the Judeo-Christian tradition. The Old Testament laws of kashrut forbade the consumption of fish scales or appendages. These fish include cyprinids of the genera Barbus and Mirogrex, cichlids of the genus Sarotherodon, Aristotle incorporated ichthyology into formal scientific study. Between 335 BC–322 BC, he provided the earliest taxonomic classification of fish, furthermore, Aristotle documented anatomical and behavioral differences between fish and marine mammals. After his death, some of his pupils continued his ichthyological research, theophrastus, for example, composed a treatise on amphibious fish. The Romans, although devoted to science, wrote extensively about fish. Pliny the Elder, a notable Roman naturalist, compiled the works of indigenous Greeks, including verifiable and ambiguous peculiarities such as the sawfish. Plinys documentation was the last significant contribution to ichthyology until the European Renaissance, the writings of three sixteenth century scholars, Hippolito Salviani, Pierre Belon, and Guillaume Rondelet, signify the conception of modern ichthyology. The investigations of individuals were based upon actual research in comparison to ancient recitations. This property popularized and emphasized these discoveries, despite their prominence, Rondelets De Piscibus Marinis is regarded as the most influential, identifying 244 species of fish. The incremental alterations in navigation and shipbuilding throughout the Renaissance marked the commencement of a new epoch in ichthyology, the Renaissance culminated with the era of exploration and colonization, and upon the cosmopolitan interest in navigation came the specialization in naturalism. Georg Marcgrave of Saxony composed the Naturalis Brasilae in 1648 and this document contained a description of 100 species of fish indigenous to the Brazilian coastline. In 1686, John Ray and Francis Willughby collaboratively published Historia Piscium, the fish contained within this informative literature were arranged in a provisional system of classification. The classification used within the Historia Piscium was further developed by Carl Linnaeus and his taxonomic approach became the systematic approach to the study of organisms, including fish
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Fish anatomy
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Fish anatomy is the study of the form or morphology of fishes. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish, the anatomy of fish is often shaped by the physical characteristics of water, the medium in which fish live. Water is much denser than air, holds a small amount of dissolved oxygen. The body of a fish is divided into a head, trunk and tail, the skeleton, which forms the support structure inside the fish, is either made of cartilage, in cartilaginous fish, or bone in bony fish. The main skeletal element is the column, composed of articulating vertebrae which are lightweight yet strong. The ribs attach to the spine and there are no limbs or limb girdles. The main external features of the fish, the fins, are composed of bony or soft spines called rays which. They are supported by the muscles which compose the main part of the trunk, the heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision, there is an inner ear but no external or middle ear. Sharks and rays are basal fish with numerous primitive anatomical features similar to those of ancient fish and their bodies tend to be dorso-ventrally flattened, they usually have five pairs of gill slits and a large mouth set on the underside of the head. The dermis is covered with separate dermal placoid scales and they have a cloaca into which the urinary and genital passages open, but not a swim bladder. Cartilaginous fish produce a number of large, yolky eggs. Some species are ovoviviparous and the young develop internally but others are oviparous, the bony fish lineage shows more derived anatomical traits, often with major evolutionary changes from the features of ancient fish. They have a skeleton, are generally laterally flattened, have five pairs of gills protected by an operculum. The dermis is covered with overlapping scales, bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca. They mostly spawn a number of small eggs with little yolk which they broadcast into the water column. Fish have a variety of different body plans, at the broadest level their body is divided into head, trunk, and tail, although the divisions are not always externally visible. The body is fusiform, a streamlined body plan often found in fast-moving fish
One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Angler". Encyclopædia Britannica. 2 (11th ed.). Cambridge University Press. p. 15.
