1.
Hagfish (band)
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After officially disbanding in 2001, Hagfish have reunited occasionally for live performances. Hagfish was formed in Dallas, Texas when brothers, guitarist Zach Blair and their collective chemistry lead the trio to pursue frontman James Newhouse, formerly of the band Terminal Rot, who would fill the position. During this time period, Hagfish began performing locally, opening for bands as All. A demo tape was released following the contrasting sensibility of punk band the Descendents, with tracks like Tallman, about the middle finger and Maybe, a love song composed by Lyon. Tensions between Lyon and the Blair brothers culminated in Lyon leaving the band and John Frum took over on drums and this lineup pushed the quintet into new territory, and although popular with fans, the band was collapsing due to internal conflict. Newhouse was fired from the group and later died in a car accident in October 1994, the Blair brothers severed ties with Frum and Brown after an attempted recording project, bringing with them the Hagfish moniker. The pair briefly reunited with Lyon and began searching for a singer, after Lyon departed for the second time, drummer Scott Carter joined Hagfish in 1993, who along with the Blair brothers and Reagan, began work on Buick Men, the groups debut studio album. During the recording sessions Carter was replaced with drummer Tony Barsotti, the album was released later that year on Dragon Street Records, who had issued the debut album by local companions Tripping Daisy, the previous year. Buick Men was followed up with a four song 7 vinyl EP on BYO Records in 1994, in addition to six brand new tracks, many songs from Buick Men were re-recorded with much sleeker production to create the album Rocks Your Lame Ass, released June 27,1995. To promote the release, Hagfish embarked on their first major tour with Bad Brains, Rocks Your Lame Ass would go on to become the most successful Hagfish release, with singles for Stamp and Happiness both issued along with accompanying music videos that appeared on MTVs 120 Minutes. In 1996, Hagfish was voted best Alternative Rock/Pop act by the Dallas Observer, however, the momentum never translated into album sales and after numerous arguments with the bands label, the follow-up album was rejected by London Records, who subsequently dropped the group. Unidentified would be the song from these sessions to transpire when it was made available as a free download on the bands official website. The album would eventually be reworked, re-recorded and released independently, in 1997, Hagfish issued their second 7 vinyl EP, this time on Go-Kart Records. Following a long delay with their record label, Hagfish returned to The Blasting Room with Stevenson and Egerton. This recording attempt proved successful and the self-titled Hagfish saw release on March 24,1998, the album was issued through Honest Dons Records, a subsidiary label of Fat Wreck Chords. Two songs featured on Hagfish previously appeared as b-sides to the Happiness single, which included a version of 18 Days and a live version of Twisting. The band again toured in support of the release, Hagfish released the live album Caught Live on March 2,1999, produced by the Blair brothers and the first of three releases for Coldfront Records. The performance was captured in October 1998 at Trees in Dallas and included material from both Rocks Your Lame Ass and Hagfish, as well as the non-album tracks Grin Doggy and Moaner
2.
Hogfish
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The hogfish, is a species of wrasse native to the western Atlantic Ocean, with a range from Nova Scotia, Canada to northern South America, including the Gulf of Mexico. This species occurs around reefs, especially preferring areas with plentiful gorgonians and this species is currently the only known member of its genus. The hogfish is characterized by a large, laterally compressed body shape and it possesses a very elongated snout which it uses to search for crustaceans buried in the sediment. This very long snout and its rooting behavior give the hogfish its name. The caudal or tail fin is somewhat lunate and the fins are along the lateral sides of the body with the paired pelvic fins directly below. A prominent black spot behind the pectoral fins differentiates males from females, the dorsal fin usually is composed of three or four long dorsal spines followed by a series of shorter dorsal spines. It mainly feeds on small crustaseans, like many wrasses, the hogfish is a sequential hermaphrodite, which means it changes sex during different life stages. The hogfish is a protogynous, first female hermaphrodite, juvenile hogfish start out as female, the change usually occurs around three years of age and about 14 inches in length. Females and juveniles will usually start out as gray, brown, or reddish brown in color, with a paler underside. Males are distinguished by a deep, dark band spanning from the snout to the first dorsal spine, Hogfish reach a maximum of 91 cm in total length and about 11 kg and have been recorded to live up to 11 years. Spawning in South Florida occurs from November through June, Hogfish social groups are organized into harems where one male will mate and protect a group of females in his territory. Hogfish, is a targeted species for many spear and reef fisherman and is regarded highly by many for its taste. In 2007, the Florida landings of hogfish totaled 306,953 pounds, the fish stocks are regulated by the South Atlantic Fishery Management Council and Florida Fish and Wildlife Conservation Commission. Bag, size, and gear limits all have been placed on species to ensure a healthy stock. Florida Museum of Natural History, Hogfish
3.
Pacific hagfish
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The Pacific hagfish is a species of hagfish. It lives in the mesopelagic to abyssal Pacific ocean, near the ocean floor and it is a jawless fish and has a body plan that resembles early paleozoic fish. They are able to excrete prodigious amounts of slime in self-defense, the Pacific hagfish has a long, eel-like body, but is not closely related to eels. Maximum body lengths of 63 cm have been reported, typical length at maturity is around 42 cm and it is dark brown, gray or brownish red, often tinted with blue or purple. The belly is lighter and sometimes has white patches. It has no fins, but there is a dorsal fin-fold. The head, as in all agnathans, does not have jaws, hagfish have loosely fitting, slimy skins, and are notorious for their slime-production capability. When disturbed, they ooze proteins from slime glands in the skin respond to water by becoming a slimy outer coating, expanding into a huge mass of slime. This makes the fish very unsavory to predators, and can even be used to clog the gills of predatory fish, Pacific hagfish can create large amounts of slime in just minutes. The slime is notoriously difficult to remove from fishing gear and equipment, the Pacific hagfish occurs in the Eastern North Pacific from Canada to Mexico. It inhabits fine silt and clay bottoms on the continental shelves, the species appears to be abundant within its range. The Pacific hagfishs skin can absorb nutrients, which has demonstrated in the laboratory by showing the passage of amino acids through hagfish skin. The diet of other hagfish species includes shrimps, hermit crabs, cephalopods, brittlestars, bony fishes, sharks, birds and whale flesh, hagfish fertilise their eggs externally after the female has laid them. On average females lay about 28 eggs, about 5 mm in diameter, females will however try to stay in their burrows during this period to ensure the protection of their eggs. There is a well-developed hagfish fishery on the US West Coast that mostly supplies the Asian leather-market, hagfish-skin clothing, belts, or other accessories are advertised and sold as yuppie leather or eel-skin Media related to Eptatretus stoutii at Wikimedia Commons
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
5.
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.
Vertebrata
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Vertebrates /ˈvɜːrtᵻbrᵻts/ comprise all species of animals within the subphylum Vertebrata /-ɑː/. Vertebrates represent the majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the fish and the jawed vertebrates, which include the cartilaginous fish. A bony fish known as the lobe-finned fishes is included with tetrapods, which are further divided into amphibians, reptiles, mammals. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, vertebrates make up less than five percent of all described animal species, the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as Craniata when discussing morphology, molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a group of vertebrates in the common taxon of craniata. The word origin of vertebrate derives from the Latin word vertebratus, the Proto-Indo-European language origins are still unclear. Vertebrate is derived from the vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic body plan, a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it. In all vertebrates, the mouth is found at, or right below, the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon, jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills, the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch, the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their relatives have more than 50 pairs of gills. In amphibians and some primitive fishes, the larvae bear external gills. These are reduced in adulthood, their function taken over by the gills proper in fishes, some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish apparently being irrevocably lost very early in the evolution of tetrapods
8.
Cyclostomata
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Cyclostomata is a group of agnathans that comprises the living jawless fishes, the lampreys and hagfishes. Both groups have round mouths that lack jaws but have retractable horny teeth, the name Cyclostomata means round mouths. Their mouths cannot close due to the lack of a jaw and this taxon is often included in the paraphyletic superclass Agnatha, which also includes several groups of extinct armored fishes called ostracoderms. Most fossil agnathans, such as galeaspids, thelodonts, and osteostracans, are closely related to vertebrates with jaws than to cyclostomes. Cyclostomes seem to have split off before the evolution of dentine and bone, biologists disagree about whether cyclostomes are a clade. The vertebrate hypothesis holds that lampreys are more related to gnathostomes than they are to the hagfish. The cyclostome hypothesis, on the hand, holds that lampreys and hagfishes are more closely related. Most studies based on anatomy have supported the hypothesis, while most molecular phylogenies have supported the cyclostome hypothesis. There are exceptions in cases, however. Similarities in the cartilage and muscles of the apparatus also provide evidence of sister-group relationship between lampreys and hagfishes. And at least one molecular phylogeny has supported the vertebrate hypothesis, there is at present no consensus on the correct topology. Both hagfishes and lampreys have just one gonad, but for different reasons, in hagfishes it is because only a single gonad is developed during their ontogeny, while it is achieved through the fusion of gonads in lampreys. Unlike jawed vertebrates, which have three semicircular canals in inner ear, lampreys have only two and hagfishes just one. But the semicircular canal of hagfishes contains both stereocilia and a class of hair cells, apparently a derived trait, whereas lampreys. Because the inner ear of hagfishes has two forms of sensory ampullae, their single semicircular canal is assumed to be a result of two canals that have merged into just one. The hagfish blood is isotonic with seawater, while lampreys appears to use the same gill-based mechanisms of osmoregulation as marine teleosts, the lamprey intestine has a typhlosole that increases the inner surface like the spiral valve does in some jawed vertebrates. The spiral valve in the latter develops by twisting the whole gut, the mucous membranes of hagfishes have a primitive typhlosole in the form of permanent zigzag ridges. This trait could be a one, since it is also found in some sea squirts such as Ciona
9.
Constantine Samuel Rafinesque
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Constantine Samuel Rafinesque-Schmaltz, as he is known in Europe, was a nineteenth-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a man in the United States, ultimately settling in Ohio in 1815, where he made notable contributions to botany, zoology. He also contributed to the study of ancient Mesoamerican linguistics, in addition to work he had completed in Europe. Rafinesque was eccentric, and is portrayed as an erratic genius. He was an autodidact who excelled in fields of knowledge, as a zoologist, botanist, writer. He wrote prolifically on such topics as anthropology, biology, geology, and linguistics. Today, scholars agree that he was far ahead of his time in many areas, among his theories was that ancestors of Native Americans had migrated by the Bering Sea from Asia to North America. Rafinesque was born on October 22,1783 in Galata, a suburb of Constantinople and his father F. G. Rafinesque was a French merchant from Marseilles, his mother M. Schmaltz was of German descent and born in Constantinople. His father died in Philadelphia about 1793, Rafinesque spent his youth in Marseilles, and was mostly self-educated, he never attended university. By the age of twelve, he had begun collecting plants for a herbarium, by fourteen, he taught himself perfect Greek and Latin because he needed to follow footnotes in the books he was reading in his paternal grandmothers libraries. In 1802, at the age of nineteen, Rafinesque sailed to Philadelphia in the United States with his younger brother and they traveled through Pennsylvania and Delaware, where he made the acquaintance of most of the young nations few botanists. In 1805 Rafinesque returned to Europe with his collection of specimens, and settled in Palermo, Sicily. He became so successful in trade that he retired by age twenty-five, for a time Rafinesque also worked as secretary to the American consul. During his stay in Sicily, he studied plants and fishes and he was elected a Fellow of the American Academy of Arts and Sciences in 1808. After their son died in 1815, he left her and returned to the United States, when his ship Union foundered near the coast of Connecticut, he lost all his books and all his specimens. Settling in New York, Rafinesque became a member of the newly established Lyceum of Natural History. In 1817 his book Florula Ludoviciana or A Flora of the State of Louisiana was strongly criticized by fellow botanists, by 1818, he had collected and named more than 250 new species of plants and animals. Slowly he was rebuilding his collection of objects from nature, in 1819 Rafinesque became professor of botany at Transylvania University in Lexington, Kentucky, where he also gave private lessons in French, Italian and Spanish
10.
Genus
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A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of classification, genus comes above species. In binomial nomenclature, the name forms the first part of the binomial species name for each species within the genus. Felis catus and Felis silvestris are two species within the genus Felis, Felis is a genus within the family Felidae. The composition of a genus is determined by a taxonomist, the standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. Moreover, genera should be composed of units of the same kind as other genera. The term comes from the Latin genus, a noun form cognate with gignere, linnaeus popularized its use in his 1753 Species Plantarum, but the French botanist Joseph Pitton de Tournefort is considered the founder of the modern concept of genera. The scientific name of a genus may be called the name or generic epithet. It plays a role in binomial nomenclature, the system of naming organisms. The rules for the names of organisms are laid down in the Nomenclature Codes. The standard way of scientifically describing species and other lower-ranked taxa is by binomial nomenclature, the generic name forms its first half. For example, the gray wolfs binomial name is Canis lupus, with Canis being the name shared by the wolfs close relatives. The specific name is written in lower-case and may be followed by names in zoology or a variety of infraspecific names in botany. Especially with these names, when the generic name is known from context. Because animals are typically only grouped within subspecies, it is written as a trinomen with a third name. Dog breeds, meanwhile, are not scientifically distinguished, there are several divisions of plant species and therefore their infraspecific names generally include contractions explaining the relation. For example, the genus Hibiscus includes hundreds of other species apart from the Rose of Sharon or common garden hibiscus, Rose of Sharon doesnt have subspecies but has cultivars that carry desired traits, such as the bright white H. syriaca Diana. Hawaiian hibiscus, meanwhile, includes several separate species, since not all botanists agree on the divisions or names between species, it is common to specify the source of the name using author abbreviations
11.
Eptatretus
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Eptatretus is a large genus of hagfish. McMillan & Wisner,1984 Eptatretus cheni S. C, mcMillan,1990 Eptatretus goliath Mincarone & D. J. Stewart,2006 Eptatretus gomoni Mincarone & Fernholm,2010 Eptatretus grouseri C. B. McMillan,1999 Eptatretus hexatrema J. P. Müller,1836 Eptatretus indrambaryai Wongratana,1983 Eptatretus laurahubbsae C. B, mcMillan,1990 Eptatretus mccoskeri C. B. McMillan,1999 Eptatretus mendozai Hensley,1985 Eptatretus menezesi Mincarone,2000 Eptatretus minor Fernholm & C. L. Hubbs,1981 Eptatretus moki C. B. McMillan & Wisner,2004 Eptatretus multidens Fernholm & C. L. Hubbs,1981 Eptatretus nanii Wisner & C. B, mcMillan,1990 Eptatretus springeri Bigelow & Schroeder,1952 Eptatretus stoutii Lockington,1878 Eptatretus strahani C. B. McMillan & Wisner,1984 Eptatretus strickrotti Møller & W. J. Jones,2007 Eptatretus taiwanae S. C, shen & H. J. Tao,1975 Eptatretus walkeri C. B. McMillan & Wisner,2004 Eptatretus wayuu H. K. Mok, Saavedra-Diaz & Acero P,2001 Eptatretus yangi Teng,1958 Media related to Eptatretus at Wikimedia Commons
12.
Myxine
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Myxine is a genus of hagfish. Myxine affinis Günther,1870 Myxine australis Jenyns,1842 Myxine capensis Regan,1913 Myxine circifrons Garman,1899 Myxine debueni Wisner & C. B, mcMillan,1995 Myxine dorsum Wisner & C. B. McMillan,1995 Myxine fernholmi Wisner & C. B. McMillan,1995 Myxine formosana H. K. Mok & C. H. Kuo,2001 Myxine garmani D. S. Jordan & Snyder,1901 Myxine glutinosa Linnaeus,1758 Myxine hubbsi Wisner & C. B. McMillan,1995 Myxine hubbsoides Wisner & C. B, mcMillan,1995 Myxine ios Fernholm,1981 Myxine jespersenae Møller, Feld, I. H. Poulsen, Thomsen & Thormar,2005 Myxine knappi Wisner & C. B. McMillan, 1995) Myxine kuoi H. K. Mok,2002 Myxine limosa Girard,1859 Myxine mccoskeri Wisner & C. B, mcMillan,1995 Myxine mcmillanae Hensley,1991 Myxine paucidens Regan,1913 Myxine pequenoi Wisner & C. B. McMillan,1995 Myxine robinsorum Wisner & C. B, mcMillan,1995 Myxine sotoi Mincarone,2001
13.
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
14.
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
15.
Skull
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The skull is a bony structure that forms the head of the skeleton in most vertebrates. It supports the structures of the face and provides a cavity for the brain. The skull is composed of two parts, the cranium and the mandible, in the human these two parts are the neurocranium and the viscerocranium or facial skeleton that includes the mandible as its largest bone. The skull forms the anterior most portion of the skeleton and is a product of cephalisation—housing the brain, and several sensory structures such as the eyes, ears, nose, in the human these sensory structures are part of the facial skeleton. In some animals such as horned ungulates, the skull also has a function by providing the mount for the horns. The English word skull is probably derived from Old Norse skulle, while the Latin word cranium comes from the Greek root κρανίον, the skull is made up of a number of fused flat bones, and contains many foramina and processes, and several cavities or sinuses. For details and the constituent bones, see neurocranium and viscerocranium, the human skull is the bony structure that forms the head in the human skeleton. It supports the structures of the face and forms a cavity for the brain, like the skulls of other vertebrates, it protects the brain from injury. The skull consists of two parts, of different embryological origin—the neurocranium and the facial skeleton, the neurocranium forms the protective cranial cavity that surrounds and houses the brain and brainstem. The facial skeleton is formed by the supporting the face. Except for the mandible, all of the bones of the skull are joined together by sutures—synarthrodial joints formed by bony ossification, sometimes there can be extra bone pieces within the suture known as wormian bones or sutural bones. The human skull is considered to consist of twenty-two bones—eight cranial bones. In the neurocranium these are the bone, two temporal bones, two parietal bones, the sphenoid, ethmoid and frontal bones. The bones of the skeleton are the vomer, two nasal conchae, two nasal bones, two maxilla, the mandible, two palatine bones, two zygomatic bones, and two lacrimal bones. Some of these bones—the occipital, parietal, frontal, in the neurocranium, and the nasal, lacrimal, the skull also contains sinus cavities and numerous foramina. The sinuses are lined with respiratory epithelium and their known functions are the lessening of the weight of the skull, the aiding of resonance to the voice and the warming and moistening of the air drawn through the nasal cavity. The foramina are openings in the skull, the largest of these is the foramen magnum that allows the passage of the spinal cord as well as nerves and blood vessels. The many processes of the include the mastoid process and the zygomatic process
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Vertebral column
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The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column houses the spinal canal, a cavity that encloses, there are about 50,000 species of animals that have a vertebral column. The human vertebral column is one of the most-studied examples, the articulating vertebrae are named according to their region of the spine. There are seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae, the number of vertebrae in a region can vary but overall the number remains the same. The number of those in the region however is only rarely changed. There are ligaments extending the length of the column at the front and the back, the vertebrae in the human vertebral column are divided into different regions, which correspond to the curves of the spinal column. The articulating vertebrae are named according to their region of the spine, vertebrae in these regions are essentially alike, with minor variation. These regions are called the spine, thoracic spine, lumbar spine, sacrum. There are seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae, the number of vertebrae in a region can vary but overall the number remains the same. The number of those in the region however is only rarely changed. The vertebrae of the cervical, thoracic and lumbar spines are independent bones, the vertebrae of the sacrum and coccyx are usually fused and unable to move independently. Two special vertebrae are the atlas and axis, on which the head rests, a typical vertebra consists of two parts, the vertebral body and the vertebral arch. The vertebral arch is posterior, meaning it faces the back of a person, together, these enclose the vertebral foramen, which contains the spinal cord. Because the spinal cord ends in the spine, and the sacrum and coccyx are fused. Two transverse processes and one process are posterior to the vertebral body. The spinous process comes out the back, one transverse process comes out the left, the spinous processes of the cervical and lumbar regions can be felt through the skin. Above and below each vertebra are joints called facet joints and these restrict the range of movement possible, and are joined by a thin portion of the neural arch called the pars interarticularis. In between each pair of vertebrae are two small holes called intervertebral foramina, the spinal nerves leave the spinal cord through these holes
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Lampreys
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Lampreys are any jawless fish of the order Petromyzontiformes, placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like sucking mouth, the common name lamprey is probably derived from Latin lampetra, which may mean stone licker, though the etymology is uncertain. Currently there are about 38 known extant species of lampreys, parasitic species are the best known, and feed by boring into the flesh of other fish to suck their blood, but only 18 species of lampreys are parasitic. Adults of the species do not feed, they live off reserves acquired as ammocoetes. The lampreys are an ancient lineage of vertebrates, though their exact relationship to hagfishes. Adults superficially resemble eels in that they have scaleless, elongated bodies, lacking paired fins, adult lampreys have large eyes, one nostril on the top of the head, and seven gill pores on each side of the head. The pharynx is subdivided, the part forming a respiratory tube that is isolated from the mouth by a valve called the velum. Near the gills are the eyes, which are developed and buried under skin in the larvae. The eyes complete their development during metamorphosis, and in adults are covered by a thin, instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord. Hagfish, which resemble lampreys, have traditionally considered the sister taxon of the true vertebrates. Studies have shown that lampreys are amongst the most energy-efficient swimmers and their swimming movements generate low-pressure zones around their body, which pull rather than push their bodies through the water. Parasitic lampreys feed on prey as adults by attaching their mouthparts to the animals body, then using their teeth to cut through surface tissues until they reach blood. A study of stomach content of some lampreys have also shown remains of intestines, fins, although attacks on humans do occur, they will generally not attack humans unless starved. Non-parasitic lampreys, which are freshwater species, do not feed as adults, they live off reserves acquired as ammocoetes. Lamprey leukocytes express surface variable lymphocyte receptors generated from somatic recombination of leucine-rich repeat gene segments in a recombination activating gene-independent manner, northern lampreys have the highest number of chromosomes among vertebrates. Pouched lamprey larvae also have a high tolerance for free iron in their bodies. Adult lampreys spawn in rivers and then die, the young larvae, ammocoetes, spend several years in the rivers, where they live burrowed in fine sediment, filter feeding on detritus and microorganisms. Then, ammocoetes undergo a metamorphosis lasting several months, some species do not feed after metamorphosis, while others migrate to the sea or lakes, where they feed on different species of fish and even on marine mammals
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Lancelets
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They are the modern representatives of the subphylum Cephalochordata, formerly thought to be the sister group of the craniates. In Asia, they are harvested commercially as food for humans and they are an important object of study in zoology as they provide indications about the evolutionary origins of the vertebrates. Lancelets serve as an intriguing comparison point for tracing how vertebrates have evolved and adapted, although lancelets split from vertebrates more than 520 million years ago, their genomes hold clues about evolution, particularly how vertebrates have employed old genes for new functions. They are regarded as similar to the archetypal vertebrate form, the first representative organism of the group to be described was Branchiostoma lanceolatum. It was described by Peter Simon Pallas in 1774 as molluscan slugs in the genus Limax and it was not until 1834 that Gabriel Costa brought the phylogenetic position of the group closer to the agnathan vertebrates, including it in the new genus Branchiostoma. In 1836, Yarrel renamed the genus as Amphioxus, now considered a synonym of the genus Branchiostoma. Today, the term amphioxus is still used as a name for the Amphioxiformes, along with lancelet. A non-technical review of all aspects of biology is, Stokes, M. D. and Holland. The genome of the Florida lancelet has been sequenced, lancelets are typically 5 centimetres long, or 7 centimetres at the longest. They have a translucent, somewhat fish-like body, but without any paired fins or other limbs, a relatively poorly developed tail fin is present, so they are not especially good swimmers. While they do possess some cartilage-like material stiffening the gill slits, mouth, in common with vertebrates, lancelets have a hollow nerve cord running along the back, pharyngeal slits and a tail that runs past the anus. Also like vertebrates, the muscles are arranged in blocks called myomeres, unlike vertebrates, the dorsal nerve cord is not protected by bone but by a simpler notochord made up of a cylinder of cells that are closely packed to form a toughened rod. The lancelet notochord, unlike the vertebrate spine, extends into the head and this gives the subphylum its name. The nerve cord is only larger in the head region than in the rest of the body. However, developmental gene expression and Transmission electron microscopy indicate the presence of a diencephalic forebrain, a possible midbrain, lancelets have two known kinds of light-sensing structures, Joseph cells, and Hesse organs, as well as a frontal eye and lamellar body. The frontal eye is thought to be light-sensitive, although this has not been confirmed by electrophysiological measurement. The lamellar body, a homologue of the pineal body, was once thought to be light-sensitive. All of these organs and structures are located in the tube, with the frontal eye at the front, followed by the lamellar body, the Joseph cells
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Agnatha
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Agnatha is a superclass of jawless fish in the phylum Chordata, subphylum Vertebrata, consisting of both present and extinct species. The group excludes all vertebrates with jaws, known as gnathostomes, the agnathans as a whole are paraphyletic, because most extinct agnathans belong to the stem group of gnathostomes. Recent molecular data, both from rRNA and from mtDNA as well as embryological data strongly supports the hypothesis that living agnathans, the oldest fossil agnathans appeared in the Cambrian, and two groups still survive today, the lampreys and the hagfish, comprising about 120 species in total. In addition to the absence of jaws, modern agnathans are characterised by absence of paired fins, lampreys have a light sensitive pineal eye. All living and most extinct Agnatha do not have a stomach or any appendages. Fertilization and development are both external, there is no parental care in the Agnatha class. The Agnatha are ectothermic or cold blooded, with a skeleton. Agnathans are ectothermic, meaning they do not regulate their own body temperature, Agnathan metabolism is slow in cold water, and therefore they do not have to eat very much. They have no stomach, but rather a long gut. Lampreys feed on fish and mammals. They rely on a row of teeth to shred their host. Anticoagulant fluids preventing blood clotting are injected into the host, causing the host to more blood. Hagfish are scavengers, eating mostly dead animals and they also use a sharp set of teeth to break down the animal. The fact that Agnathan teeth are unable to move up and down limits their possible food types, in modern agnathans, the body is covered in skin, with neither dermal or epidermal scales. The skin of hagfish has copious slime glands, the slime constituting their defense mechanism, the slime can sometimes clog up enemy fishes gills, causing them to die. In direct contrast, many extinct agnathans sported extensive exoskeletons composed of either massive, almost all agnathans, including all extant agnathans, have no paired appendages, although most do have a dorsal or a caudal fin. Some fossil agnathans, such as osteostracans and pituriaspids, did have paired fins, mode of fertilization in hagfishes is not known. Development in both groups probably is external, there is no known parental care
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Vertebrates
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Vertebrates /ˈvɜːrtᵻbrᵻts/ comprise all species of animals within the subphylum Vertebrata /-ɑː/. Vertebrates represent the majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the fish and the jawed vertebrates, which include the cartilaginous fish. A bony fish known as the lobe-finned fishes is included with tetrapods, which are further divided into amphibians, reptiles, mammals. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, vertebrates make up less than five percent of all described animal species, the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as Craniata when discussing morphology, molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a group of vertebrates in the common taxon of craniata. The word origin of vertebrate derives from the Latin word vertebratus, the Proto-Indo-European language origins are still unclear. Vertebrate is derived from the vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic body plan, a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it. In all vertebrates, the mouth is found at, or right below, the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon, jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills, the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch, the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their relatives have more than 50 pairs of gills. In amphibians and some primitive fishes, the larvae bear external gills. These are reduced in adulthood, their function taken over by the gills proper in fishes, some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish apparently being irrevocably lost very early in the evolution of tetrapods
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Gnathostomes
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Gnathostomata /ˌneɪθoʊstoʊˈmɑːtə/ are the jawed vertebrates. The term derives from Greek, γνάθος jaw + στόμα mouth, gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates. Another is an immune system that uses VJ recombination to create antigen recognition sites. It is now assumed that Gnathostomata evolved from ancestors that possessed a pair of both pectoral and pelvic fins. The Osteostraci are generally considered the taxon of Gnathostomata. The mouth could then grow bigger and wider, making it possible to capture larger prey and this close and open mechanism would, with time, become stronger and tougher, being transformed into real jaws. Newer research suggests that a branch of Placoderms was most likely the ancestor of present-day gnathostomes and it also indicates that spiny sharks and Chondrichthyes represent a single sister group to the bony fishes. Late Ordovician-aged microfossils of what have been identified as scales of either acanthodians or shark-like fishes, undeniably unambiguous gnathostome fossils, mostly of primitive acanthodians, begin appearing by the early Silurian, and become abundant by the start of the Devonian. Some classification systems have used the term Amphirhina and it is a sister group of the jawless craniates Agnatha. Tree of Life discussion of Gnathostomata The Gill Arches, Meckels Cartilage
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Craniata
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A craniate is a member of the Craniata, a proposed clade of chordate animals with a skull of hard bone or cartilage. Included in the clade are the vertebrates, and non-vertebrate chordates with skulls, living representatives are the Myxini, Hyperoartia, and the much more numerous Gnathostomata. The craniate head consists of a brain, sense organs, including eyes, in addition to distinct crania, craniates possess many derived characteristics, which have allowed for more complexity to follow. In general, craniates are much more active than tunicates and lancelets and, as a result, have greater metabolic demands, aquatic craniates have gill slits, which are connected to muscles and nerves that pump water through the slits, engaging in both feeding and gas exchange. Muscles line the canal, moving food through the canal. Craniates have cardiovascular systems that include a heart with two or more chambers, red cells, and oxygen transporting hemoglobin, as well as kidneys. Linnaeus used the terms Craniata and Vertebrata interchangeably to include lampreys, jawed fishes, hagfishes were classified as Vermes, possibly representing a transitional form between worms and fishes. Dumeril grouped hagfishes and lampreys in the taxon Cyclostomi, characterized by horny teeth borne on an apparatus, a large notochord as adults. Cyclostomes were regarded as either degenerate cartilaginous fishes or primitive vertebrates, cope coined the name Agnatha for a group that included the cyclostomes and a number of fossil groups in which jaws could not be observed. Vertebrates were subsequently divided into two major sister-groups, the Agnatha and the Gnathostomata, stensiö suggested that the two groups of living agnathans arose independently from different groups of fossil agnathans. e. On this basis Janvier proposed to use the names Vertebrata and Craniata as two distinct and nested taxa, the argument is that, if Cyclostomata is indeed monophyletic, Vertebrata would return to its old content and the name Craniata, being superfluous, would become a junior synonym. Lines show probable evolutionary relationships, including extinct taxa, which are denoted with a dagger, the positions of the Lancelet, Tunicate, and Craniata clades are as reported in the scientific journal Nature. Note that this cladogram, in showing the extant cyclostomes as paraphyletic, is contradicted by all recent molecular data. Extinct genera Haikouella and Haikouichthys Campbell, Neil A. Reece, cleveland P. Hickman, J. Roberts, L. S. Keen, S. L. Larson, A. & Eisenhour, D. J. Animal Diversity, Fourth Edition. CS1 maint, Uses authors parameter Cracraft, Joel, Donoghue, new York, Oxford University Press US. Delarbre, Christiane, Gallut, C, Barriel, V, Janvier, P, Gachelin, G, complete Mitochondrial DNA of the Hagfish, Eptatretus burgeri, The Comparative Analysis of Mitochondrial DNA Sequences Strongly Supports the Cyclostome Monophyly. Parker, T. J. Haswell, W. A
23.
Paddle
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A paddle is a tool used for pushing against liquids, either as a form of propulsion in a boat or as an implement for mixing. Paddles commonly used in canoes consist of a wooden, fibreglass, carbon fibre or metal rod with a handle on one end, paddles for use in kayaks are longer, with a blade on each end, they are handled from the middle of the shaft. Kayak paddles having blades in the plane are called un-feathered. Paddles with blades in different planes are called feathered, feathered paddles are measured by the degree of feather, such as 30,45, or even 90 degrees. Many modern paddles are made of two pieces which can be snapped together in either feathered or unfeathered settings, the shaft is normally straight but in some cases a crank is added with the aim of making the paddle more comfortable and reducing the strain on the wrist. In addition, weight savings are more desirable at the ends of the rather than in the middle. Cheaper kayak paddles have a shaft while more expensive ones use a lighter fibreglass or carbon fibre shaft. Some paddles have a smaller diameter shaft for people with smaller hands, Paddle length varies with a longer paddle being better suited for stronger people, taller people, and people using the paddle in a wider kayak. Some paddle makers have an online paddle size calculator, blades vary in size and shape. A blade with a surface area may be desirable for a strong person with good shoulder joints. Some paddle makers offer blades in three sizes, for this reason white or yellow blades may offer a safety advantage over black or blue blades. Of course, kayakers should wear a headlamp or have other lighting on their kayak under conditions of limited lighting. However, if an operator must look straight into a sun low in the sky to see a kayaker. Highly reflective water resistant tape may be affixed to the paddle blades, the paddle is held with two hands, some distance apart from each other. For normal use, it is drawn through the water front to back to drive the boat forwards. The two blades of a paddle are dipped alternately on either side of the kayak. Gloves may be worn to prevent blistering for long periods of paddling, on mechanical paddle steamers, the motorized paddling is not done with a mass of paddles or oars but by rotating one or a few paddle wheels. Racing paddles also have special designs and they are generally less flat and are curved to catch more water which will enable racing paddlers to maximize the efficiency of their stroke
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Tail
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The tail is the section at the rear end of an animals body, in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, tailed objects are sometimes referred to as caudate and the part of the body associated with or proximal to the tail are given the adjective caudal. Animal tails are used in a variety of ways and they provide a source of locomotion for fish and some other forms of marine life. Many land animals use their tails to brush away flies and other biting insects, tails are also used for social signaling. Some species tails are armored, and some, such as those of scorpions, some species of lizard can detach their tails from their bodies. This can help them to escape predators, which are either distracted by the wriggling, tails cast in this manner generally grow back over time, though the replacement is typically darker in colour than the original. Most birds tails end in long feathers called rectrices and these feathers are used as a rudder, helping the bird steer and maneuver in flight, they also help the bird to balance while it is perched. In some species—such as birds of paradise, lyrebirds, and most notably peafowl—modified tail feathers play an important role in courtship displays, the extra-stiff tail feathers of other species, including woodpeckers and woodcreepers, allow them to brace themselves firmly against tree trunks. The tails of grazing animals, such as horses, are used both to sweep away insects and positioned or moved in ways that indicate the physical or emotional state. Human embryos have a tail measures about one-sixth of the size of the embryo itself. As the embryo develops into a fetus, the tail is absorbed by the growing body, humans have a tail bone attached to the pelvis, formed of fused vertebrae, usually four, at the bottom of the vertebral column. Rump Empennage, the tail of an aircraft
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Cartilage
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It is not as hard and rigid as bone, but it is stiffer and less flexible than muscle. Because of its rigidity, cartilage often serves the purpose of holding tubes open in the body, cartilage is classified in three types, elastic cartilage, hyaline cartilage and fibrocartilage, which differ in relative amounts of collagen and proteoglycan. Cartilage does not contain blood vessels or nerves, nutrition is supplied to the chondrocytes by diffusion. The compression of the cartilage or flexion of the elastic cartilage generates fluid flow. Compared to other tissues, cartilage has a very slow turnover of its extracellular matrix. In embryogenesis, the system is derived from the mesoderm germ layer. Following the initial chondrification that occurs during embryogenesis, cartilage growth consists mostly of the maturing of immature cartilage to a mature state. The division of cells within cartilage occurs very slowly, and thus growth in cartilage is not based on an increase in size or mass of the cartilage itself. The articular cartilage function is dependent on the composition of the extracellular matrix. The ECM consists mainly of proteoglycan and collagens, the main proteoglycan in cartilage is aggrecan, which, as its name suggests, forms large aggregates with hyaluronan. These aggregates are negatively charged and hold water in the tissue, the collagen, mostly collagen type II, constrains the proteoglycans. The ECM responds to tensile and compressive forces that are experienced by the cartilage, cartilage growth thus refers to the matrix deposition, but can also refer to both the growth and remodeling of the extracellular matrix. Due to the stress on the patellofemoral joint during resisted knee flexion. The mechanical properties of articular cartilage in load bearing joints such as knee and hip have been studied extensively at macro, micro and these mechanical properties include the response of cartilage in frictional, compressive, shear and tensile loading. Cartilage is resilient and displays viscoelastic properties, lubricin, a glycoprotein abundant in cartilage and synovial fluid, plays a major role in bio-lubrication and wear protection of cartilage. Cartilage has limited capabilities, Because chondrocytes are bound in lacunae. Therefore, cartilage damage is difficult to heal, also, because hyaline cartilage does not have a blood supply, the deposition of new matrix is slow. Damaged hyaline cartilage is replaced by fibrocartilage scar tissue
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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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Keratin
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Keratin is one of a family of fibrous structural proteins. Keratin is the protein that protects cells from damage or stress. It is the key structural material making up the layer of human skin. Keratin monomers assemble into bundles to form filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians. The only other biological matter known to approximate the toughness of keratinized tissue is chitin, keratin derives from Greek κερατίνη from Greek keras meaning horn originating from the Proto-Indo-European *ḱer- of the same meaning. It is composed of horn like, i. e. kerato, to which the chemical suffix -in is appended, the Greek keras is used in many animal names, e. g. Rhinoceros, meaning nose with a horn. Keratin filaments are abundant in keratinocytes in the layer of the epidermis. In addition, keratin filaments are present in cells in general. For example, mouse thymic epithelial cells are known to react with antibodies for keratin 5, keratin 8 and these antibodies are used as fluorescent markers to distinguish subsets of TECs in genetic studies of the thymus. The α-keratins in the hair, stratum corneum, horns, nails, claws and hooves of mammals, the harder β-keratins found in nails and in the scales and claws of reptiles, their shells, and in the feathers, beaks, claws of birds and quills of porcupines. The baleen plates of filter-feeding whales are made of keratin, keratins are polymers of type I and type II intermediate filaments, which have only been found in the genomes of chordates. Nematodes and many other animals seem to only have type VI intermediate filaments, lamins. The human genome encodes 54 functional keratin genes which are located in two clusters on chromosomes 12 and 17 and this suggests that they have originated from a series of gene duplications on these chromosomes. The first sequences of keratins were determined by Hanukoglu and Fuchs and these sequences revealed that there are two distinct but homologous keratin families which were named as Type I keratin and Type II keratins. This model has been confirmed by the determination of the structure of a helical domain of keratins. Fibrous keratin molecules supercoil to form a stable, left-handed superhelical motif to multimerise. The major force that keeps the structure is hydrophobic interactions between apolar residues along the keratins helical segments. Limited interior space is the reason why the triple helix of the protein collagen, found in skin, cartilage and bone
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Color
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Color or colour is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. This perception of color derives from the stimulation of cells in the human eye by electromagnetic radiation in the spectrum of light. Color categories and physical specifications of color are associated with objects through the wavelength of the light that is reflected from them and this reflection is governed by the objects physical properties such as light absorption, emission spectra, etc. By defining a color space, colors can be identified numerically by coordinates, there may also be more than three color dimensions in other color spaces, such as in the CMYK color model, wherein one of the dimensions relates to a colours colorfulness). The photo-receptivity of the eyes of species also varies considerably from our own. Honeybees and bumblebees for instance have trichromatic color vision sensitive to ultraviolet but is insensitive to red, papilio butterflies possess six types of photoreceptors and may have pentachromatic vision. The most complex color vision system in the kingdom has been found in stomatopods with up to 12 spectral receptor types thought to work as multiple dichromatic units. The science of color is sometimes called chromatics, colorimetry, or simply color science and it includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range. Electromagnetic radiation is characterized by its wavelength and its intensity, when the wavelength is within the visible spectrum, it is known as visible light. Most light sources emit light at different wavelengths, a sources spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, in each such class the members are called metamers of the color in question. The table at right shows approximate frequencies and wavelengths for various pure spectral colors, the wavelengths listed are as measured in air or vacuum. A common list identifies six main bands, red, orange, yellow, green, blue, Newtons conception included a seventh color, indigo, between blue and violet. It is possible that what Newton referred to as blue is nearer to what today is known as cyan, the color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Some objects not only light, but also transmit light or emit light themselves. This effect is known as color constancy, opaque objects that do not reflect specularly have their color determined by which wavelengths of light they scatter strongly. If objects scatter all wavelengths with roughly equal strength, they appear white, if they absorb all wavelengths, they appear black. Opaque objects that reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences
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Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
30.
Pink
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Pink is a pale red color which takes its name from the flower of the same name. According to surveys in Europe and the United States, pink is the color most often associated with charm, politeness, sensitivity, tenderness, sweetness, childhood, femininity, when combined with white, it is associated with innocence. When combined with violet or black, it is associated with eroticism, Pink was first used as a color name in the late 17th century. The color pink is named after the flowers called pinks, flowering plants in the genus Dianthus, the name derives from the frilled edge of the flowers—the verb to pink dates from the 14th century and means to decorate with a perforated or punched pattern. The color pink has been described in literature since ancient times, in the Odyssey, written in approximately 800 BCE, Homer wrote Then, when the child of morning, rosy-fingered dawn appeared. Roman poets also described the color, roseus is the Latin word meaning rosy or pink. Lucretius used the word to describe the dawn in his epic poem On the Nature of Things, Pink was not a common color in the fashion of the Middle Ages, nobles usually preferred brighter reds, such as crimson. However, it did appear in fashion, and in religious art. In the 13th and 14th century, in works by Cimabue and Duccio, the Christ child was sometimes portrayed dressed in pink, in the high Renaissance painting the Madonna of the Pinks by Raphael, the Christ child is presenting a pink flower to the Virgin Mary. The pink was a symbol of marriage, showing a spiritual marriage between the mother and child, during the Renaissance, pink was mainly used for the flesh color of faces and hands. John’s white, as it is called in Florence, and this white is made from thoroughly white, and when these two pigments have been thoroughly mulled together, make little loaves of them like half walnuts and leave them to dry. When you need some, take much of it seems appropriate. And this pigment does you great credit if you use it for painting faces, hands, the golden age of the color pink was the Rococo Period in the 18th century, when pastel colors became very fashionable in all the courts of Europe. Pink was particularly championed by Madame de Pompadour, the mistress of King Louis XV of France. Who wore combinations of blue and pink, and had a particular tint of pink made for her by the Sevres porcelain factory, created by adding nuances of blue, black. In this painting, it symbolized childhood, innocence and tenderness, sarah Moulton was just eleven years old when the picture was painted, and died the following year. In 19th century England, pink ribbons or decorations were worn by young boys, boys were simply considered small men. In fact the clothing for children in the 19th century was almost always white, since, before the invention of chemical dyes, queen Victoria was painted in 1850 with her seventh child and third son, Prince Arthur, who wore white and pink
31.
Blue
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Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres, which is between 4500 and 4950 ångströms. Blues with a frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency. Pure blue, in the middle, has a wavelength of 470 nanometers, in painting and traditional colour theory, blue is one of the three primary colours of pigments, along with red and yellow, which can be mixed to form a wide gamut of colours. Red and blue mixed together form violet, blue and yellow together form green, Blue is also a primary colour in the RGB colour model, used to create all the colours on the screen of a television or computer monitor. The clear sky and the sea appear blue because of an optical effect known as Rayleigh scattering. When sunlight passes through the atmosphere, the wavelengths are scattered more widely by the oxygen and nitrogen molecules. An optical effect called Tyndall scattering, similar to Rayleigh scattering, explains blue eyes, distant objects appear more blue because of another optical effect called atmospheric perspective. Blue has been used for art and decoration since ancient times and it is the most important color in Judaism. In the Middle Ages, cobalt blue was used to colour the stained glass windows of cathedrals, beginning in the 9th century, Chinese artists used cobalt to make fine blue and white porcelain. Blue dyes for clothing were made from woad in Europe and indigo in Asia, in 1828 a synthetic ultramarine pigment was developed, and synthetic blue dyes and pigments gradually replaced mineral pigments and vegetable dyes. Pierre-Auguste Renoir, Vincent van Gogh and other late 19th century painters used ultramarine and cobalt blue not just to depict nature, in the late 18th century and 19th century, blue became a popular colour for military uniforms and police uniforms. In the 20th century, because blue was associated with harmony, it was chosen as the colour of the flags of the United Nations. Surveys in the US and Europe show that blue is the colour most commonly associated with harmony, faithfulness, confidence, distance, infinity, the imagination, cold, and sometimes with sadness. In US and European public opinion polls it is the most popular colour, Blue is the colour of light between violet and green on the visible spectrum. Blues also vary in shade or tint, darker shades of blue contain black or grey, darker shades of blue include ultramarine, cobalt blue, navy blue, and Prussian blue, while lighter tints include sky blue, azure, and Egyptian blue. Today most blue pigments and dyes are made by a chemical process, the modern English word blue comes from Middle English bleu or blewe, from the Old French bleu, a word of Germanic origin, related to the Old High German word blao. In heraldry, the azure is used for blue
32.
Grey
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Grey or gray is an intermediate color between black and white. It is a neutral or achromatic color, meaning literally that it is a color without color and this means that there are equal components of red, green, and blue. The variations in intensity of these colors uniformly produce different shades of grey and it is the color of a cloud-covered sky, of ash and of lead. The first recorded use of grey as a name in the English language was in AD700. Grey is the dominant spelling in European and Commonwealth English, although remained in common usage in the UK until the second half of the 20th century. Gray has been the preferred American spelling since approximately 1825, although grey is an accepted variant, in Europe and the United States, surveys show that grey is the color most commonly associated with neutrality, conformity, boredom, uncertainty, old age, indifference, and modesty. Only one percent of respondents chose it as their favorite color, Grey comes from the Middle English grai or grei, from the Anglo-Saxon graeg, and is related to the Dutch grauw and grijs and German grau. The first recorded use of grey as a name in the English language was in AD700. In antiquity and the Middle Ages, grey was the color of undyed wool, and thus was the color most commonly worn by peasants and the poor. It was also the color worn by monks of the Franciscan order, Cistercian Order, Franciscan monks in England and Scotland were commonly known as the Grey friars, and that name is now attached to many places in Great Britain. During the Renaissance and the Baroque, grey began to play an important role in fashion, Black became the most popular color of the nobility, particularly in Italy, France, and Spain, and grey and white were harmonious with it. Grey was also used for the drawing of oil paintings. The painting would first be composed in grey and white, and then the colors, made with thin transparent glazes, the grisaille beneath would provide the shading, visible through the layers of color. Sometimes the grisaille was simply left uncovered, giving the appearance of carved stone, Grey was a particularly good background color for gold and for skin tones. It became the most common background for the portraits of Rembrandt Van Rijn and for many of the paintings of El Greco, the palette of Rembrandt was composed almost entirely of somber colors. Over this he put a layer of glaze made of mixture of blue smalt, red ochre. Using these ingredients and many others, he made greys which had, according to art historian Philip Ball, the warm, dark and rich greys and browns served to emphasize the golden light on the faces in the paintings. Grey became a fashionable color in the 18th century, both for womens dresses and for mens waistcoats and coats
33.
Black
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Black is the darkest color resulting from the absence or complete absorption of light. Like white and grey, it is a color, literally a color without hue. It is one of the four colors in the CMYK color model, along with cyan, yellow. Black is often used to represent darkness, it is the symbolic opposite of white, Black was one of the first colors used by artists in neolithic cave paintings. In the 14th century, it began to be worn by royalty and it became the color worn by English romantic poets, businessmen and statesmen in the 19th century, and a high fashion color in the 20th century. In the Roman Empire, it became the color of mourning, according to surveys in Europe and North America, it is the color most commonly associated with mourning, the end, secrets, magic, force, violence, evil, and elegance. More distant cognates include Latin flagrare, and Ancient Greek phlegein, the Ancient Greeks sometimes used the same word to name different colors, if they had the same intensity. Kuanos could mean both dark blue and black, the Ancient Romans had two words for black, ater was a flat, dull black, while niger was a brilliant, saturated black. Ater has vanished from the vocabulary, but niger was the source of the country name Nigeria the English word Negro, old High German also had two words for black, swartz for dull black and blach for a luminous black. These are parallelled in Middle English by the terms swart for dull black, swart still survives as the word swarthy, while blaek became the modern English black. In heraldry, the used for the black color is sable, named for the black fur of the sable. Black was one of the first colors used in art, the Lascaux Cave in France contains drawings of bulls and other animals drawn by paleolithic artists between 18,000 and 17,000 years ago. They began by using charcoal, and then made more vivid black pigments by burning bones or grinding a powder of manganese oxide, for the ancient Egyptians, black had positive associations, being the color of fertility and the rich black soil flooded by the Nile. It was the color of Anubis, the god of the underworld, who took the form of a black jackal, and offered protection against evil to the dead. For the ancient Greeks, black was also the color of the underworld, separated from the world of the living by the river Acheron and those who had committed the worst sins were sent to Tartarus, the deepest and darkest level. In the center was the palace of Hades, the king of the underworld, Black was one of the most important colors used by ancient Greek artists. In the 6th century BC, they began making pottery and later red figure pottery. In black-figure pottery, the artist would paint figures with a clay slip on a red clay pot
34.
White
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White is an achromatic color, a color without hue. An incoming light to the eye that stimulates all its three types of color sensitive cone cells in nearly equal amounts results in white. White is one of the most common colors in nature, the color of sunlight, snow, milk, chalk, limestone, in many cultures white represents or signifies purity, innocence, and light, and is the symbolic opposite of black, or darkness. According to surveys in Europe and the United States, white is the color most often associated with perfection, the good, honesty, cleanliness, the beginning, the new, neutrality, and exactitude. In ancient Egypt and ancient Rome, priestesses wore white as a symbol of purity, in the Middle Ages and Renaissance a white unicorn symbolized chastity, and a white lamb sacrifice and purity, the widows of kings dressed in white rather than black as the color of mourning. It was also used in 20th century modern architecture as a symbol of modernity, simplicity. White is an important color for almost all world religions, the Pope, the head of the Roman Catholic Church, has worn white since 1566, as a symbol of purity and sacrifice. In Islam, and in the Shinto religion of Japan, it is worn by pilgrims, in Western cultures and in Japan, white is the most common color for wedding dresses, symbolizing purity and virginity. In many Asian cultures, white is also the color of mourning, the white color on television screens and computer monitors is created with the RGB color model by mixing red, green and blue light at equal intensities. The word white continues Old English hwīt, ultimately from a Common Germanic *χwītaz also reflected in OHG wîz, ON hvítr, the root is ultimately from Proto-Indo-European language *kwid-, surviving also in Sanskrit śveta to be white or bright and Slavonic světŭ light. The Icelandic word for white, hvítur, is derived from the Old Norse form of the word hvítr. Common Germanic also had the word *blankaz, borrowed into Late Latin as *blancus, the antonym of white is black. Some non-European languages have a variety of terms for white. The Inuit language has seven different words for seven different nuances of white, Japanese has six different words, depending upon brilliance or dullness, or if the color is inert or dynamic. White was one of the first colors used in art, the Lascaux Cave in France contains drawings of bulls and other animals drawn by paleolithic artists between 18,000 and 17,000 years ago. Paleolithic artists used calcite or chalk, they sometimes as a background, sometimes as a highlight, along with charcoal and red, in ancient Egypt, white was connected with the goddess Isis. The priests and priestesses of Isis dressed only in white linen, in Greece and other ancient civilizations, white was often associated with mothers milk. In Greek mythology, the chief god Zeus was nourished at the breast of the nymph Amalthea, in the Talmud, milk was one of four sacred substances, along with wine, honey, and the rose
35.
Eye
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Eyes are organs of the visual system. They provide organisms vision, the ability to process visual detail, eyes detect light and convert it into electro-chemical impulses in neurons. Eyes with resolving power have come in ten different forms. Image-resolving eyes are present in molluscs, chordates and arthropods, the simplest eyes, such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms. Complex eyes can distinguish shapes and colours, the visual fields of many organisms, especially predators, involve large areas of binocular vision to improve depth perception. In other organisms, eyes are located so as to maximise the field of view, such as in rabbits and horses, the first proto-eyes evolved among animals 600 million years ago about the time of the Cambrian explosion. The last common ancestor of animals possessed the biochemical toolkit necessary for vision, in most vertebrates and some molluscs, the eye works by allowing light to enter and project onto a light-sensitive panel of cells, known as the retina, at the rear of the eye. The cone cells and the rod cells in the retina detect, the visual signals are then transmitted to the brain via the optic nerve. The eyes of most cephalopods, fish, amphibians and snakes have fixed lens shapes, and focusing vision is achieved by telescoping the lens—similar to how a camera focuses. Compound eyes are found among the arthropods and are composed of many simple facets which, depending on the details of anatomy, may give either a single pixelated image or multiple images, each sensor has its own lens and photosensitive cell. Some eyes have up to 28,000 such sensors, which are arranged hexagonally, compound eyes are very sensitive to motion. Some arthropods, including many Strepsiptera, have eyes of only a few facets, each with a retina capable of creating an image. With each eye viewing a different thing, an image from all the eyes is produced in the brain, providing very different. Possessing detailed hyperspectral colour vision, the Mantis shrimp has been reported to have the worlds most complex colour vision system, trilobites, which are now extinct, had unique compound eyes. They used clear calcite crystals to form the lenses of their eyes, in this, they differ from most other arthropods, which have soft eyes. The number of lenses in such an eye varied, however, some trilobites had only one, in contrast to compound eyes, simple eyes are those that have a single lens. For example, jumping spiders have a pair of simple eyes with a narrow field of view. Some insect larvae, like caterpillars, have a different type of simple eye which gives a rough image, some of the simplest eyes, called ocelli, can be found in animals like some of the snails, which cannot actually see in the normal sense
36.
Fin
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A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation. Fins first evolved on fish as a means of locomotion, Fish fins are used to generate thrust and control the subsequent motion. Fish, and other animals such as cetaceans, actively propel and steer themselves with pectoral. As they swim, they use other fins, such as dorsal and anal fins to achieve stability, foil shaped fins generate thrust when moved, the lift of the fin sets water or air in motion and pushes the fin in the opposite direction. Aquatic animals get significant thrust by moving back and forth in water. Often the tail fin is used, but some aquatic animals generate thrust from pectoral fins, fins can also generate thrust if they are rotated in air or water. Turbines and propellers use a number of rotating fins, also called foils, wings, propellers use the fins to translate torquing force to lateral thrust, thus propelling an aircraft or ship. Turbines work in reverse, using the lift of the blades to generate torque, cavitation can be a problem with high power applications, resulting in damage to propellers or turbines, as well as noise and loss of power. Cavitation occurs when negative pressure causes bubbles to form in a liquid and it can cause significant damage and wear. Cavitation damage can occur to the tail fins of powerful swimming marine animals, such as dolphins. Cavitation is more likely to occur near the surface of the ocean, even if they have the power to swim faster, dolphins may have to restrict their speed because collapsing cavitation bubbles on their tail are too painful. Cavitation also slows tuna, but for a different reason, unlike dolphins, these fish do not feel the bubbles, because they have bony fins without nerve endings. Nevertheless, they cannot swim faster because the cavitation bubbles create a film around their fins that limits their speed. Lesions have been found on tuna that are consistent with cavitation damage, scombrid fishes are particularly high-performance swimmers. Along the margin at the rear of their bodies is a line of small rayless, non-retractable fins, there has been much speculation about the function of these finlets. Fish use multiple fins, so it is possible that a given fin can have an interaction with another fin. In particular, the fins immediately upstream of the fin may be proximate fins that can directly affect the flow dynamics at the caudal fin
37.
Barbel (anatomy)
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A barbel on a fish is a slender, whiskerlike sensory organ near the mouth. Fish that have include the catfish, the carp, the goatfish, hagfish, sturgeon. Barbels house the taste buds of such fish and are used to search for food in murky water, Barbels are often erroneously referred to as barbs, which are found in bird feathers for flight. Barbels may be located in a variety of locations on the head of a fish, maxillary barbels refers to barbels on either side of the mouth. Barbels may also be nasal, extending from the nostrils, also, barbels are often mandibular or mental, being located on the chin. Adriaens, D. and Verraes, W. Ontogeny of the maxillary barbel muscles in Clarias gariepinus, eakin, R. R. Eastman, J. T. and Vacchi, M. Sexual dimorphism and mental barbel structure in the South Georgia plunderfish Artedidraco mirus. Pourkazemi, M. Tavakoli, M. Joushideh, H. Khoshghalb, hosseini, M. R. and Abdulhay, H. Tagging and tracking juvenile sturgeons in shallow waters of the Caspian Sea using CWT and barbel incision. Journal of Applied Ichthyology 22, 160-165, fox, H. Barbels and barbel-like tentacular structures in sub-mammalian vertebrates, A review. Fine structure of taste buds in the barbel of the catfish, joyce, E. C. and Chapman, G. B. Fine structure of the nasal barbel of the catfish, Ictalurus punctatus. Leclair, E. and Topczewski, J. Methods for the study of the maxillary barbel. LeClair, E. and Topczewski, J. Development and regeneration of the maxillary barbel. Ogawa, K. Marui, T. and Caprio, J. Bimodal fibers innervate the maxillary barbel in the channel catfish
38.
Nostril
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A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to air on inhalation. Fish do not breathe through their noses, but they do have two holes used for smelling, which may, indeed, be called nostrils. The Procellariiformes are distinguished from other birds by having tubular extensions of their nostrils, in humans, the nasal cycle is the normal ultradian cycle of each nostrils blood vessels becoming engorged in swelling, then shrinking. The nostrils are separated by the septum, the septum can sometimes be deviated, causing one nostril to appear larger than the other. With extreme damage to the septum and columella, the two nostrils are no longer separated and form a larger external opening. Like other tetrapods, humans have two external nostrils and two additional nostrils at the back of the cavity, inside the head. Each choana contains approximately 1000 strands of nasal hair and they also connect the nose to the throat, aiding in respiration. It has two nostrils between its front teeth, similar to human embryos at an early stage, if these fail to join up, the result is a cleft palate. Dilator naris muscle nares at Dorlands Medical Dictionary
39.
Jaw
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The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. In arthropods, the jaws are chitinous and oppose laterally, and these jaws are often composed of numerous mouthparts. Their function is fundamentally for food acquisition, conveyance to the mouth, many mouthparts and associate structures are modified legs. In most vertebrates, the jaws are bony or cartilaginous and oppose vertically, comprising an upper jaw, the vertebrate jaw is derived from the most anterior two pharyngeal arches supporting the gills, and usually bears numerous teeth. The vertebrate jaw probably originally evolved in the Silurian period and appeared in the Placoderm fish which further diversified in the Devonian, the two most anterior pharyngeal arches are thought to have become the jaw itself and the hyoid arch, respectively. The hyoid system suspends the jaw from the braincase of the skull and it is thought that the original selective advantage offered by the jaw was not related to feeding, but to increased respiration efficiency. The jaws were used in the pump that pumps water across the gills of fish or air into the lungs in the case of amphibians. Over evolutionary time the familiar use of jaws, in feeding, was selected for. Many teleost fish have substantially modified jaws for feeding and jaw protrusion. The jaw in tetrapods is substantially simplified compared to fish, most of the upper jaw bones have been fused to the braincase, while the lower jaw bones have been fused together into a unit called the mandible. The jaw articulates via a joint between the quadrate and articular. The jaws of tetrapods exhibit varying degrees of mobility between jaw bones, some species have jaw bones completely fused, while others may have joints allowing for mobility of the dentary, quadrate, or maxilla. The snake skull shows the greatest degree of cranial kinesis, which allows the snake to swallow large prey items. In the evolution of the jaw, two of the bones of the jaw structure were reduced in size and incorporated into the ear. As a result, mammals show little or no cranial kinesis, temporomandibular joint dysfunction is a common disorder of these joints, characterized by pain, clicking and limitation of mandibular movement. Sea urchins possess unique jaws which display five-part symmetry, termed the Aristotles lantern, each unit of the jaw holds a single, perpetually growing tooth composed of crystalline calcium carbonate. Gnathostomata – jawed vertebrates Muscles of mastication Otofacial syndrome Predentary Premaxilla Prognathism Rostral bone Tooth Jaw at the US National Library of Medicine Medical Subject Headings
40.
Gnathostomata
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Gnathostomata /ˌneɪθoʊstoʊˈmɑːtə/ are the jawed vertebrates. The term derives from Greek, γνάθος jaw + στόμα mouth, gnathostome diversity comprises roughly 60,000 species, which accounts for 99% of all living vertebrates. Another is an immune system that uses VJ recombination to create antigen recognition sites. It is now assumed that Gnathostomata evolved from ancestors that possessed a pair of both pectoral and pelvic fins. The Osteostraci are generally considered the taxon of Gnathostomata. The mouth could then grow bigger and wider, making it possible to capture larger prey and this close and open mechanism would, with time, become stronger and tougher, being transformed into real jaws. Newer research suggests that a branch of Placoderms was most likely the ancestor of present-day gnathostomes and it also indicates that spiny sharks and Chondrichthyes represent a single sister group to the bony fishes. Late Ordovician-aged microfossils of what have been identified as scales of either acanthodians or shark-like fishes, undeniably unambiguous gnathostome fossils, mostly of primitive acanthodians, begin appearing by the early Silurian, and become abundant by the start of the Devonian. Some classification systems have used the term Amphirhina and it is a sister group of the jawless craniates Agnatha. Tree of Life discussion of Gnathostomata The Gill Arches, Meckels Cartilage
41.
Vertebrate
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Vertebrates /ˈvɜːrtᵻbrᵻts/ comprise all species of animals within the subphylum Vertebrata /-ɑː/. Vertebrates represent the majority of the phylum Chordata, with currently about 66,000 species described. Vertebrates include the fish and the jawed vertebrates, which include the cartilaginous fish. A bony fish known as the lobe-finned fishes is included with tetrapods, which are further divided into amphibians, reptiles, mammals. Extant vertebrates range in size from the frog species Paedophryne amauensis, at as little as 7.7 mm, to the blue whale, vertebrates make up less than five percent of all described animal species, the rest are invertebrates, which lack vertebral columns. The vertebrates traditionally include the hagfish, which do not have proper vertebrae due to their loss in evolution, though their closest living relatives, hagfish do, however, possess a cranium. For this reason, the vertebrate subphylum is sometimes referred to as Craniata when discussing morphology, molecular analysis since 1992 has suggested that hagfish are most closely related to lampreys, and so also are vertebrates in a monophyletic sense. Others consider them a group of vertebrates in the common taxon of craniata. The word origin of vertebrate derives from the Latin word vertebratus, the Proto-Indo-European language origins are still unclear. Vertebrate is derived from the vertebra, which refers to any of the bones or segments of the spinal column. All vertebrates are built along the basic body plan, a stiff rod running through the length of the animal, with a hollow tube of nervous tissue above it. In all vertebrates, the mouth is found at, or right below, the remaining part of the body continuing after the anus forms a tail with vertebrae and spinal cord, but no gut. However, a few vertebrates have secondarily lost this anatomy, retaining the notochord into adulthood, such as the sturgeon, jawed vertebrates are typified by paired appendages, but this trait is not required in order for an animal to be a vertebrate. All basal vertebrates breathe with gills, the gills are carried right behind the head, bordering the posterior margins of a series of openings from the pharynx to the exterior. Each gill is supported by a cartilagenous or bony gill arch, the bony fish have three pairs of arches, cartilaginous fish have five to seven pairs, while the primitive jawless fish have seven. The vertebrate ancestor no doubt had more arches than this, as some of their relatives have more than 50 pairs of gills. In amphibians and some primitive fishes, the larvae bear external gills. These are reduced in adulthood, their function taken over by the gills proper in fishes, some amphibians retain the external larval gills in adulthood, the complex internal gill system as seen in fish apparently being irrevocably lost very early in the evolution of tetrapods
42.
Horizontal plane
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Alternatively, a spirit level, which exploits the buoyancy of a bubble, can be used to determine if the plane is horizontal. In radio science, horizontal plane is used to plot an antennas relative field strength in relation to the ground on a polar graph. Normally the maximum of 1.000 or 0 dB is at the top, other field strengths are expressed as a decimal less than 1.000, a percentage less than 100%, or decibels less than 0 dB. If the graph is of an actual or proposed installation, rotation is applied so that the top is 0o true north, see also the perpendicular vertical plane. In general, something that is horizontal can be drawn from left to right, although the word horizontal is commonly used in daily life and language, it is subject to many misconceptions. The concept of horizontality only makes sense in the context of a clearly measurable gravity field, i. e. in the neighborhood of a planet, star, when the gravity field becomes very weak, the notion of being horizontal loses its meaning. A plane is only at the chosen point. Horizontal planes at two points are not parallel, they intersect. Thus both horizontality and verticality are strictly speaking local concepts, and it is necessary to state to which location the direction or the plane refers to. In reality, the gravity field of a planet such as Earth is deformed due to the inhomogeneous spatial distribution of materials with different densities. Actual horizontal planes are not even parallel even if their reference points are along the same vertical line. At any given location, the gravitational force is not quite constant over time. For instance, on Earth the horizontal plane at a given point changes with the position of the Moon. On a rotating planet such as Earth, the gravitational pull of the planet is different from the apparent net force that can be measured in the laboratory or in the field. This difference is the force associated with the planets rotation. This is a force, it only arises when calculations or experiments are conducted in non-inertial frames of reference. Hence, the world appears to be flat locally, and horizontal planes in nearby locations appear to be parallel, such statements are nevertheless approximations, whether they are acceptable in any particular context or application depends on the applicable requirements, in particular in terms of accuracy. In this case, the direction is typically from the left side of the paper to the right side
43.
California
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California is the most populous state in the United States and the third most extensive by area. Located on the western coast of the U. S, California is bordered by the other U. S. states of Oregon, Nevada, and Arizona and shares an international border with the Mexican state of Baja California. Los Angeles is Californias most populous city, and the second largest after New York City. The Los Angeles Area and the San Francisco Bay Area are the nations second- and fifth-most populous urban regions, California also has the nations most populous county, Los Angeles County, and its largest county by area, San Bernardino County. The Central Valley, an agricultural area, dominates the states center. What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries, the Spanish Empire then claimed it as part of Alta California in their New Spain colony. The area became a part of Mexico in 1821 following its war for independence. The western portion of Alta California then was organized as the State of California, the California Gold Rush starting in 1848 led to dramatic social and demographic changes, with large-scale emigration from the east and abroad with an accompanying economic boom. If it were a country, California would be the 6th largest economy in the world, fifty-eight percent of the states economy is centered on finance, government, real estate services, technology, and professional, scientific and technical business services. Although it accounts for only 1.5 percent of the states economy, the story of Calafia is recorded in a 1510 work The Adventures of Esplandián, written as a sequel to Amadis de Gaula by Spanish adventure writer Garci Rodríguez de Montalvo. The kingdom of Queen Calafia, according to Montalvo, was said to be a land inhabited by griffins and other strange beasts. This conventional wisdom that California was an island, with maps drawn to reflect this belief, shortened forms of the states name include CA, Cal. Calif. and US-CA. Settled by successive waves of arrivals during the last 10,000 years, various estimates of the native population range from 100,000 to 300,000. The Indigenous peoples of California included more than 70 distinct groups of Native Americans, ranging from large, settled populations living on the coast to groups in the interior. California groups also were diverse in their organization with bands, tribes, villages. Trade, intermarriage and military alliances fostered many social and economic relationships among the diverse groups, the first European effort to explore the coast as far north as the Russian River was a Spanish sailing expedition, led by Portuguese captain Juan Rodríguez Cabrillo, in 1542. Some 37 years later English explorer Francis Drake also explored and claimed a portion of the California coast in 1579. Spanish traders made unintended visits with the Manila galleons on their trips from the Philippines beginning in 1565
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Cordell Bank National Marine Sanctuary
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Cordell Bank National Marine Sanctuary is a marine sanctuary located off the coast of California. It protects an area of 1,286 sq mi of marine wildlife, the administrative center of the sanctuary is on an offshore granite outcrop 4.5 sq mi by 9.5 sq mi, located on the continental shelf off of California. The outcrop is, at its closest,6 mi from the sanctuary itself, the seamount was discovered in 1853 by the U. S. Coast Survey, and named for Edward Cordell, who surveyed the area more thoroughly in 1869. It was extensively explored and described during 1978-86 by Robert Schmieder and it has been protected as a sanctuary since 1989. The protected area encompasses 526 square miles of ocean, the unique blend of ocean conditions and undersea topography creates a rich and diverse underwater ecosystem. A subsurface island rises from soft sediments covering the continental shelf, the upper pinnacles reach to within 115 ft of the surface, and the average depth is 400 ft. The sanctuary serves as a ground for migratory marine mammals, birds. The prevailing California Current flows southward along to coast, causing an upwelling of nutrient-rich water that provided the foundation for the marine ecosystem. Sanctuary regulations prohibit extraction of hydrocarbons, the removal of organisms, discharge of wastes. Recreational scuba diving is not recommended in the due to depth. Cordell Bank was originally created 93 million years ago, as a member of the Sierra Nevada, eventually this grinding carried Cordell Bank to its present location opposite Reyes Point. Cordell Bank is still moving, by an average of 3 cm per year, between 20,000 and 15,000 years ago the sea level in the area was 360 ft below the current level, leaving most of Cordell Bank exposed and making it a true island. Today the bank out of soft sediment, deposited on the bank more recently by coastal erosion. Within just 7 miles of Cordell Bank, the shelf drops to over 1 mi deep. The seamount is largely composed of granite, coastal California has a rich history of marine utilization by Native Americans and early settlers. Many European mariners sailed right over Cordell Bank without even knowing it was there, in the later half of the 1800s there was a strong incentive to survey the coast of California so as to promote maritime safety. Cordell Bank was discovered in 1853 by George Davidson of the US Coast Survey during an expedition on Californias north coast. In 1869 Edward Cordell was sent to additional information on a shoal west of Point Reyes
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. PMID 21041649. doi:10.1073/pnas.1014583107. 
