In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. While these definitions may seem adequate, when looked at more they represent problematic species concepts. For example, the boundaries between related species become unclear with hybridisation, in a species complex of hundreds of similar microspecies, in a ring species. Among organisms that reproduce only asexually, the concept of a reproductive species breaks down, each clone is a microspecies. All species are given a two-part name, a "binomial"; the first part of a binomial is the genus.
The second part is called the specific epithet. For example, Boa constrictor is one of four species of the genus Boa. None of these is satisfactory definitions, but scientists and conservationists need a species definition which allows them to work, regardless of the theoretical difficulties. If species were fixed and distinct from one another, there would be no problem, but evolutionary processes cause species to change continually, to grade into one another. 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. Charles Darwin's 1859 book The Origin of Species explained how species could arise by natural selection; that understanding was extended in the 20th century through genetics and population ecology. Genetic variability arises from mutations and recombination, while organisms themselves are mobile, leading to geographical isolation and genetic drift with varying selection pressures.
Genes can sometimes be exchanged between species by horizontal gene transfer. Viruses are a special case, driven by a balance of mutation and selection, can be treated as quasispecies. Biologists and taxonomists have made many attempts to define species, beginning from morphology and moving towards genetics. Early taxonomists such as Linnaeus had no option but to describe what they saw: this was formalised as the typological or morphological species concept. Ernst Mayr emphasised reproductive isolation, but this, like other species concepts, is hard or impossible to test. Biologists have tried to refine Mayr's definition with the recognition and cohesion concepts, among others. Many of the concepts are quite similar or overlap, so they are not easy to count: the biologist R. L. Mayden recorded about 24 concepts, the philosopher of science John Wilkins counted 26. Wilkins further grouped the species concepts into seven basic kinds of concepts: agamospecies for asexual organisms biospecies for reproductively isolated sexual organisms ecospecies based on ecological niches evolutionary species based on lineage genetic species based on gene pool morphospecies based on form or phenotype and taxonomic species, a species as determined by a taxonomist.
A typological species is a group of organisms in which individuals conform to certain fixed properties, so that pre-literate people recognise the same taxon as do modern taxonomists. The clusters of variations or phenotypes within specimens would differentiate the species; this method was used as a "classical" method of determining species, such as with Linnaeus early in evolutionary theory. However, different phenotypes are not different species. Species named in this manner are called morphospecies. In the 1970s, Robert R. Sokal, Theodore J. Crovello and Peter Sneath proposed a variation on this, a phenetic species, defined as a set of organisms with a similar phenotype to each other, but a different phenotype from other sets of organisms, it differs from the morphological species concept in including a numerical measure of distance or similarity to cluster entities based on multivariate comparisons of a reasonably large number of phenotypic traits. A mate-recognition species is a group of sexually reproducing organisms that recognize one another as potential mates.
Expanding on this to allow for post-mating isolation, a cohesion species is the most inclusive population of individuals having the potential for phenotypic cohesion through intrinsic cohesion mechanisms. A further development of the recognition concept is provided by the biosemiotic concept of species. In microbiology, genes can move even between distantly related bacteria extending to the whole bacterial domain; as a rule of thumb, microbiologists have assumed that kinds of Bacteria or Archaea with 16S ribosomal RNA gene sequences more similar than 97% to each other need to be checked by DNA-DNA hybridisation to decide if they belong to the same species or not. This concept was narrowed in 2006 to a similarity of 98.7%. DNA-DNA hybri
The ear canal is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about 2.5 centimetres in length and 0.7 centimetres in diameter. The human ear canal is divided into two parts; the elastic cartilage part forms the outer third of the canal. The cartilage is the continuation of the cartilage framework of pinna; the cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen. The bony part forms the inner two thirds; the bony part is only a ring in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion. Size and shape of the canal vary among individuals; the canal is 2.5 centimetres long and 0.7 centimetres in diameter. It runs from behind and above downward and forward. On the cross-section, it is of oval shape; these are important factors to consider.
Due to its relative exposure to the outside world, the ear canal is susceptible to diseases and other disorders. Some disorders include: Atresia of the ear canal Cerumen impaction Bone exposure, caused by the wearing away of skin in the canal Auditory canal osteoma Cholesteatoma Contact dermatitis of the ear canal Fungal infection Ear mites in animals Ear myiasis, an rare infestation of maggots Foreign body in ear Granuloma, a scar caused by tympanostomy tubes Otitis externa, bacteria-caused inflammation of the ear canal Stenosis, a gradual closing of the canal Earwax known as cerumen, is a yellowish, waxy substance secreted in the ear canals, it plays an important role in the human ear canal, assisting in cleaning and lubrication, provides some protection from bacteria and insects. Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing, causing conductive hearing loss. If left untreated, cerumen impaction can increase the risk of developing an infection within the ear canal.
List of specialized glands within the human integumentary system Veterans Health Administration web site OSHA web site Continuing Medical Education Ear Photographs Otoscopy Tutorial w/ Images "Anatomy diagram: 34257.000-1". Roche Lexicon - illustrated navigator. Elsevier. Archived from the original on 2014-01-01
Vinegar is an aqueous solution of acetic acid and trace chemicals that may include flavorings. Vinegar contains 5–20% acetic acid by volume; the acetic acid is produced by the fermentation of ethanol or sugars by acetic acid bacteria. There are many types of vinegar, depending upon the source materials. Vinegar is now used in the culinary arts: as a flavorful, acidic cooking ingredient, or in pickling; as the most manufactured mild acid, it has had a wide variety of industrial and domestic uses. The word vinegar arrived in Middle English from Old French, which in turn derives from Latin: vinum + acer; the conversion of ethanol and oxygen to acetic acid takes place by the following reaction: CH3CH2OH + O2 → CH3COOH + H2O Vinegar contains numerous flavonoids, phenolic acids, aldehydes, which vary in content depending on the source material used to make the vinegar, such as orange peel or various fruit juice concentrates. Vinegar was used for conservation by the Babylonians as much as 5,000 years ago.
Traces of it have been found in Egyptian urns from around 3000 BC. Commercial vinegar is produced either by a slow fermentation process. In general, slow methods are used in traditional vinegars, where fermentation proceeds over the course of a few months to a year; the longer fermentation period allows for the accumulation of a nontoxic slime composed of acetic acid bacteria. Fast methods add mother of vinegar to the source liquid before adding air to oxygenate and promote the fastest fermentation. In fast production processes, vinegar may be produced in one to three days; the source materials for making vinegar are varied: different fruits, alcoholic beverages, other fermentable materials are used. Fruit vinegars are made from fruit wines without any additional flavoring. Common flavors of fruit vinegar include apple, raspberry and tomato; the flavors of the original fruits remain in the final product. Most fruit vinegars are produced in Europe, where there is a market for high-price vinegars made from specific fruits.
Several varieties are produced in Asia. Persimmon vinegar, called gam sikcho, is common in South Korea. Jujube vinegar, called zaocu or hongzaocu, wolfberry vinegar are produced in China. Apple cider vinegar is made from cider or apple must, has a brownish-gold color, it is sometimes sold unpasteurized with the mother of vinegar present. It can be sweetened for consumption. A byproduct of commercial kiwifruit growing is a large amount of waste in the form of misshapen or otherwise-rejected fruit and kiwifruit pomace. One of the uses for pomace is the production of kiwifruit vinegar, produced commercially in New Zealand since at least the early 1990s, in China in 2008. Pomegranate vinegar is used in Israel as a dressing for salad, but in meat stew and in dips. Vinegar made from raisins is used in cuisines of the Middle East, it is cloudy and medium brown in color, with a mild flavor. Vinegar made from dates is a traditional product of the Middle East, used in Saudi Arabia and the Gulf countries. Coconut vinegar, made from fermented coconut water or sap, is used extensively in Southeast Asian cuisine, as well as in some cuisines of India and Sri Lanka Goan cuisine.
A cloudy white liquid, it has a sharp, acidic taste with a yeasty note. In the Philippines, there are other types of vinegar made from palm sap. Like coconut vinegar, they are by-products of tubâ production; the two of the most produced are nipa palm vinegar and kaong palm vinegar. Along with coconut and cane vinegar, they are the four main traditional vinegar types in the Philippines and are an important part of Filipino cuisine. Nipa palm vinegar is made from the sap of the leaf stalks of nipa palm, it imparts a distinctly musky aroma. Kaong palm vinegar is made from the sap of flower stalks of the kaong palm, it is sweeter than all the other Philippine vinegar types and are used in salad dressing. Vinegar from the buri palm sap is produced, but not the same prevalence as coconut and kaong vinegars. Kaong palm vinegar is produced in Indonesia and Malaysia, though it's not as prevalent as in the Philippines because the palm wine industry is not as widespread in these Muslim-majority countries. Balsamic vinegar is an aromatic aged vinegar produced in the Modena and Reggio Emilia provinces of Italy.
The original product — traditional balsamic vinegar — is made from the concentrated juice, or must, of white Trebbiano grapes. It is dark brown, rich and complex, with the finest grades being aged in successive casks made variously of oak, chestnut, cherry and ash wood. A costly product available to only the Italian upper classes, traditional balsamic vinegar is marked "tradizionale" or "DOC" to denote its Protected Designation of Origin status, is aged for 12 to 25 years. A cheaper non-DOC commercial form described as "aceto balsamico di Modena" became known and available around the world in the late 20th century made with concentrated grape juice mixed with a strong vinegar coloured and sweetened with caramel and sugar. Balsamic vine
Psoroptes is a genus of mites, including the agents that cause psoroptic mange. Psoroptes mites are responsible for causing psoroptic mange in various animals, leading to economic losses among farmers of cattle and goats, it is known as sheep scab and cattle scab. The disease is infectious, is transmitted via fenceposts and other structures that livestock use when scratching themselves; the mites have mouthparts which do not pierce the skin, but are adapted to feeding on the surface, where the mites abrade the stratum corneum. See Mites of livestock for photographs of infestations by Psoroptes. Psoroptes has been traditionally considered to include five species living on different host species, but genetic analysis has reduced the genus to a single species, Psoroptes ovis. van Praag, Esther. "Ear mite: Psoroptes cuniculi"
The ferret is the domesticated form of the European polecat, a mammal belonging to the same genus as the weasel, Mustela, in the family Mustelidae. Their fur is brown, white, or mixed, they have an average length of 51 cm, including a 13 cm tail, weigh about 1.5–4 pounds, have a natural lifespan of 7 to 10 years. Ferrets are sexually dimorphic predators, with males being larger than females; the history of the ferret's domestication is uncertain, like that of most other domestic animals, but it is that they have been domesticated for at least 2,500 years. They are still used for hunting rabbits in some parts of the world, but they are kept only as pets. Being so related to polecats, ferrets hybridize with them, this has resulted in feral colonies of polecat–ferret hybrids that have caused damage to native fauna in New Zealand; as a result, New Zealand and some other parts of the world have imposed restrictions on the keeping of ferrets. Several other mustelids have the word ferret in their common names, including the black-footed ferret, an endangered species.
The name "ferret" is derived from the Latin furittus, meaning "little thief", a reference to the common ferret penchant for secreting away small items. The Greek word ictis occurs in a play written by Aristophanes, The Acharnians, in 425 BC. Whether this was a reference to ferrets, polecats, or the similar Egyptian mongoose is uncertain. A male ferret is called a hob. A spayed female is a sprite, a neutered male is a gib, a vasectomised male is known as a hoblet. Ferrets under one year old are known as kits. A group of ferrets is known as a "business", or as a "busyness". Other purported collective nouns, including "besyness", "fesynes", "fesnyng", "feamyng", appear in some dictionaries, but are certainly ghost words. Ferrets have a typical mustelid body-shape, being slender, their average length is about 50 cm including a 13 cm tail. Their pelage has various colorations including brown, white or mixed, they weigh between 0.7 and 2.0 kg and are sexually dimorphic as the males are larger than females.
The average gestation period is 42 days and females may have two or three litters each year. The litter size is between three and seven kits which are weaned after three to six weeks and become independent at three months, they become sexually mature at six months and the average life span is seven to 10 years. Ferrets are induced ovulators. Ferrets spend 14–18 hours a day asleep and are most active around the hours of dawn and dusk, meaning they are crepuscular. Unlike their polecat ancestors, which are solitary animals, most ferrets will live in social groups. A group of ferrets is referred to as a "business", they are territorial, like to burrow, prefer to sleep in an enclosed area. Like many other mustelids, ferrets have scent glands near their anus, the secretions from which are used in scent marking. Ferrets can recognize individuals from these anal gland secretions, as well as the sex of unfamiliar individuals. Ferrets may use urine marking for sex and individual recognition; as with skunks, ferrets can release their anal gland secretions when startled or scared, but the smell is much less potent and dissipates rapidly.
Most pet ferrets in the US are sold descented. In many other parts of the world, including the UK and other European countries, de-scenting is considered an unnecessary mutilation. If excited, they may perform a behavior called the "weasel war dance", characterized by frenzied sideways hops and bumping into nearby objects. Despite its common name, it is a joyful invitation to play, it is accompanied by a unique soft clucking noise referred to as "dooking". When scared, ferrets will hiss. Ferrets are obligate carnivores; the natural diet of their wild ancestors consisted of whole small prey, including meat, bones, skin and fur. Ferrets have short digestive systems and quick metabolism, so they need to eat frequently. Prepared dry foods consisting entirely of meat provide the most nutritional value and are the most convenient, though some ferret owners feed pre-killed or live prey to their ferrets to more mimic their natural diet. Ferret digestive tracts lack a cecum and the animal is unable to digest plant matter.
Before much was known about ferret physiology, many breeders and pet stores recommended food like fruit in the ferret diet, but it is now known that such foods are inappropriate, may in fact have negative ramifications on ferret health. Ferrets imprint on their food at around six months old; this can make introducing new foods to an older ferret a challenge, simply changing brands of kibble may meet with resistance from a ferret that has never eaten the food as a kit. It is therefore advisable to expose young ferrets to as many different types and flavors of appropriate food as possible. Ferrets have four types of teeth with a dental formula of 18.104.22.168.1.4.2: Twelve small incisor teeth located between the canines in the front of the mouth. These are used for grooming. Four canines used for killing prey. Twelve premolar teeth that the ferret uses to chew food—located at the sides of the mouth, directly behind the canines; the ferret uses these teeth to cut through flesh, using them in a scissors actio
Rabbits are small mammals in the family Leporidae of the order Lagomorpha. Oryctolagus cuniculus includes the European rabbit species and its descendants, the world's 305 breeds of domestic rabbit. Sylvilagus includes 13 wild rabbit species, among them the 7 types of cottontail; the European rabbit, introduced on every continent except Antarctica, is familiar throughout the world as a wild prey animal and as a domesticated form of livestock and pet. With its widespread effect on ecologies and cultures, the rabbit is, in many areas of the world, a part of daily life—as food, clothing, a companion, as a source of artistic inspiration. Male rabbits are called bucks. An older term for an adult rabbit is coney. Another term for a young rabbit is bunny, though this term is applied informally to rabbits especially domestic ones. More the term kit or kitten has been used to refer to a young rabbit. A group of rabbits is known as a nest. A group of baby rabbits produced from a single mating is referred to as a litter, a group of domestic rabbits living together is sometimes called a herd.
Rabbits and hares were classified in the order Rodentia until 1912, when they were moved into a new order, Lagomorpha. Below are some of the species of the rabbit. Order Lagomorpha Family Leporidae Hares are precocial, born mature and mobile with hair and good vision, while rabbits are altricial, born hairless and blind, requiring closer care. Hares live a solitary life in a simple nest above the ground, while most rabbits live in social groups underground in burrows or warrens. Hares are larger than rabbits, with ears that are more elongated, with hind legs that are larger and longer. Hares have not been domesticated, while descendants of the European rabbit are bred as livestock and kept as pets. Rabbits have long been domesticated. Beginning in the Middle Ages, the European rabbit has been kept as livestock, starting in ancient Rome. Selective breeding has generated a wide variety of rabbit breeds, many of which are kept as pets; some strains of rabbit have been bred as research subjects. As livestock, rabbits are bred for their fur.
The earliest breeds were important sources of meat, so became larger than wild rabbits, but domestic rabbits in modern times range in size from dwarf to giant. Rabbit fur, prized for its softness, can be found in a broad range of coat colors and patterns, as well as lengths; the Angora rabbit breed, for example, was developed for its long, silky fur, hand-spun into yarn. Other domestic rabbit breeds have been developed for the commercial fur trade, including the Rex, which has a short plush coat; because the rabbit's epiglottis is engaged over the soft palate except when swallowing, the rabbit is an obligate nasal breather. Rabbits have two sets of one behind the other; this way they can be distinguished from rodents, with which they are confused. Carl Linnaeus grouped rabbits and rodents under the class Glires. However, recent DNA analysis and the discovery of a common ancestor has supported the view that they do share a common lineage, thus rabbits and rodents are now referred to together as members of the superorder Glires.
Since speed and agility are a rabbit's main defenses against predators, rabbits have large hind leg bones and well developed musculature. Though plantigrade at rest, rabbits are on their toes while running, assuming a more digitigrade form. Rabbits use their strong claws for defense; each front foot has four toes plus a dewclaw. Each hind foot has four toes. Most wild rabbits have full, egg-shaped bodies; the soft coat of the wild rabbit is agouti in coloration. The tail of the rabbit is dark on white below. Cottontails have white on the top of their tails; as a result of the position of the eyes in its skull, the rabbit has a field of vision that encompasses nearly 360 degrees, with just a small blind spot at the bridge of the nose. The anatomy of rabbits' hind limbs are structurally similar to that of other land mammals and contribute to their specialized form of locomotion; the Bones of the hind limbs consist of long bones as well as short bones. These bones are created through endochondral ossification during development.
Like most land mammals, the round head of the femur articulates with the acetabulum of the ox coxae. The femur articulates with the tibia, but not the fibula, fused to the tibia; the tibia and fibula articulate with the tarsals of the pes called the foot. The hind limbs of the rabbit are longer than the front limbs; this allows them to produce their hopping form of locomotion. Longer hind limbs are more capable of producing faster speeds. Hares, which have longer legs than cottontail rabbits, are able to move faster. Rabbits stay just on their toes; the hind feet have four long toes that allow for this and are webbed to prevent them from spreading when hopping. Rabbits do not have paw
Boric acid called hydrogen borate, boracic acid, orthoboric acid and acidum boricum, is a weak, monobasic Lewis acid of boron, used as an antiseptic, flame retardant, neutron absorber, or precursor to other chemical compounds. It has the chemical formula H3BO3, exists in the form of colorless crystals or a white powder that dissolves in water; when occurring as a mineral, it is called sassolite. Boric acid, or sassolite, is found in its free state in some volcanic districts, for example, in the Italian region of Tuscany, the Lipari Islands and the US state of Nevada. In these volcanic settings it mixed with steam, from fissures in the ground, it is found as a constituent of many occurring minerals – borax, boracite and colemanite. Boric acid and its salts are found in seawater, it is found in plants, including all fruits. Boric acid was first prepared by Wilhelm Homberg from borax, by the action of mineral acids, was given the name sal sedativum Hombergi; however borates, including boric acid, have been used since the time of the ancient Greeks for cleaning, preserving food, other activities.
Boric acid may be prepared by reacting borax with a mineral acid, such as hydrochloric acid: Na2B4O7·10H2O + 2 HCl → 4 B3 + 2 NaCl + 5 H2OIt is formed as a by product of hydrolysis of boron trihalides and diborane: B2H6 + 6 H2O → 2 B3 + 6 H2BX3 + 3 H2O → B3 + 3 HX Boric acid is soluble in boiling water. When heated above 170 °C, it dehydrates, forming metaboric acid: H3BO3 → HBO2 + H2OMetaboric acid is a white, cubic crystalline solid and is only soluble in water. Metaboric acid melts at about 236 °C, when heated above about 300 °C further dehydrates, forming tetraboric acid called pyroboric acid: 4 HBO2 → H2B4O7 + H2OThe term boric acid may sometimes refer to any of these compounds. Further heating leads to boron trioxide. H2B4O7 → 2 B2O3 + H2OThere are conflicting interpretations for the origin of the acidity of aqueous boric acid solutions. Raman spectroscopy of alkaline solutions has shown the presence of B−4 ion, leading some to conclude that the acidity is due to the abstraction of OH− from water: B3 + H2O ↽ − ⇀ B−4 + H+ or more properly expressed in the aqueous solution: B3 + 2 H2O ↽ − ⇀ B−4 + H3O+This may be characterized as Lewis acidity of boron toward OH−, rather than as Brønsted acidity.
Polyborate anions are formed at pH 7–10 if the boron concentration is higher than about 0.025 mol/L. The best known of these is the'tetraborate' ion, found in the mineral borax: 4− + 2 H+ ⇌ 2− + 7H2OBoric acid makes an important contribution to the absorption of low frequency sound in seawater. With polyols such as glycerol and mannitol the acidity of the solution is increased. With mannitol for example the pK decreases to 5.15. This is due to the formation of a chelate, −, this feature is used in analytical chemistry. Boric acid dissolves in anhydrous sulfuric acid: B3 + 6H2SO4 → 3H3O+ + 2HSO4− + B4−Boric acid reacts with alcohols to form borate esters, B3 where R is alkyl or aryl. A dehydrating agent, such as concentrated sulfuric acid is added: B3 + 3 ROH → B3 +3 H2O The three oxygen atoms form a trigonal planar geometry around the boron; the B-O bond length is 136 pm and the O-H is 97 pm. The molecular point group is C3h. Crystalline boric acid consists of layers of B3 molecules held together by hydrogen bonds of length 272 pm.
The distance between two adjacent layers is 318 pm. Based on mammalian median lethal dose rating of 2,660 mg/kg body mass, boric acid is only poisonous if taken internally or inhaled in large quantities; the Fourteenth Edition of the Merck Index indicates that the LD50 of boric acid is 5.14 g/kg for oral dosages given to rats, that 5 to 20 g/kg has produced death in adult humans. For comparison's sake, the LD50 of salt is reported to be 3.75 g/kg in rats according to the Merck Index. According to the Agency for Toxic Substances and Disease Registry, "The minimal lethal dose of ingested boron was reported to be 2–3 g in infants, 5–6 g in children, 15–20 g in adults. However, a review of 784 human poisonings with boric acid reported no fatalities, with 88% of cases being asymptomatic."Long-term exposure to boric acid may be of more concern, causing kidney damage and kidney failure. Although it does not appear to be carcinogenic, studies in dogs have reported testicular atrophy after exposure to 32 mg/kg bw/day for 90 days.
This level is far lower than the LD50. According to the CLH report for boric acid published by the Bureau for Chemical Substances Lodz, boric acid in high doses shows significant developmental toxicity and teratogenicity in rabbit and mouse fetuses as well as cardiovascular defects, skeletal variations, mild kidney lesions; as a consequence in the 30th ATP to EU directive 67/548/EEC of August 2008, the European Commission decided to amend its classification as reprotoxic category 2, to apply the risk phrases R60 and R61. At a 2010 European Diagnostics Manufacturing Association Meeting, several new additions to the Substance of Very High Concern candidate list in relation to the Registration, Evaluation and Restriction of Chemicals Regulations 20