Hyraxes called dassies, are small, herbivorous mammals in the order Hyracoidea. Hyraxes are rotund animals with short tails, they measure between 30 and 70 cm long and weigh between 2 and 5 kg. They are superficially similar to pikas or rodents, but are more related to elephants and manatees. Five extant species are recognised, their distribution is limited to Africa, except for Procavia capensis, found in the Middle East. Hyraxes have re-developed a number of primitive mammalian characteristics. Unlike most other browsing and grazing animals, they do not use the incisors at the front of the jaw for slicing off leaves and grass; the two upper incisors are large and tusk-like, grow continuously through life, similar to rodents. The four lower incisors are grooved'comb teeth'. A diastema occurs between the cheek teeth; the dental formula for hyraxes is 188.8.131.52.0.4.3. Although not ruminants, hyraxes have complex, multichambered stomachs that allow symbiotic bacteria to break down tough plant materials, but their overall ability to digest fibre is lower than that of the ungulates.
Their mandibular motions are deceptively similar to chewing cud, but the hyrax is physically incapable of regurgitation as in the even-toed ungulates and the merycism of some of the macropods. This behaviour is referred to in a passage in the Bible; this chewing behaviour may be a form of agonistic behaviour. Hyraxes inhabit rocky terrain across the Middle East, their feet have rubbery pads with numerous sweat glands, which may help the animal maintain its grip when moving up steep, rocky surfaces. Hyraxes have stumpy toes with hoof-like nails, they have efficient kidneys, retaining water so that they can better survive in arid environments. Female hyraxes give birth to up to four young after a gestation period between seven and eight months, depending on the species; the young are weaned at one to five months of age, reach sexual maturity at 16 to 17 months. Hyraxes live in small family groups, with a single male that aggressively defends the territory from rivals. Where living space is abundant, the male may have sole access to multiple groups of females, each with their own range.
The remaining males live solitary lives on the periphery of areas controlled by larger males, mate only with younger females. Hyraxes have charged myoglobin, inferred to reflect an aquatic ancestry. Hyraxes share several unusual characteristics with elephants and the Sirenia, which have resulted in their all being placed in the taxon Paenungulata. Male hyraxes lack a scrotum and their testicles remain tucked up in their abdominal cavity next to the kidneys, the same as in elephants and dugongs. Female hyraxes have a pair of teats near their armpits, as well as four teats in their groin; the tusks of hyraxes develop from the incisor teeth. Hyraxes, like elephants, have flattened nails on the tips of their digits, rather than curved, elongated claws which are seen on mammals. References are made to hyraxes in the Old Testament. In Leviticus they are therefore not being kosher, it describes the hyrax as chewing its cud. The Hebrew phrase in question means "bringing up cud"; some of the modern translations refer to them as rock hyraxes....
Hyraxes are creatures of little power. The words "rabbit", "hare", "coney" appear as terms for the hyrax in some English translations of the Bible. Early English translators had no knowledge of the hyrax, therefore no name for them, though "badger" or "rock-badger" has been used more in new translations in "common language" translations such as the Common English Bible. All modern hyraxes are members of the family Procaviidae and are found only in Africa and the Middle East. In the past, hyraxes were more diverse, widespread; the order first appears in the fossil record at a site in the Middle East in the form of Dimaitherium, 37 million years ago. For many millions of years, hyraxes were the primary terrestrial herbivores in Africa, just as odd-toed ungulates were in North America. Through the middle to late Eocene, many different species existed, the largest of them weighing the same as a small horse and the smallest the size of a mouse. During the Miocene, competition from the newly developed bovids, which were efficient grazers and browsers, displaced the hyraxes into marginal niches.
Caecum is a genus of minute sea snails, marine gastropod micromolluscs or micromollusks in the family Caecidae or blind shells. This genus is distributed worldwide in temperate seas. Many species live in sponges, in sandy spots on reefs, or in grassy beds in shallow waters in bays and lagoons; some species are common and can be numerous where they do occur, such as the Beautiful Caecum, but they can be overlooked as they are so tiny. Many species are considered to be uncommon, but this assessment may be a result of lack of proper sampling; the shells in this genus, like the others in the family,are small with a length between 2 mm and 6 mm. >Their colour is white to yellowish white and some are translucent. They are unusual in. In the first stage of the shell it soon becomes cylindrical; the shell is sealed with a permanent calcareous plug at one end and with a circular,multispiral, horny operculum at the other end, the shell aperture. The sculpture consists of a close-set, large number of annular ridges.
These snails feed on one-celled organisms on sand pebbles. Species in the genus Caecum include: Subgenera brought into synonymy Caecum Weisbord, 1962: synonym of Caecum Fleming, 1813 Caecum Carpenter, 1859: synonym of Meioceras Carpenter, 1859Species brought into synonymy Caecum annulatum Emmons, 1858: synonym of Caecum floridanum Stimpson, 1851 Caecum berthae Lange de Morretes, 1954: synonym of Caecum plicatum Carpenter, 1858 Caecum biminicola Pilsbry, 1951: synonym of Caecum plicatum Carpenter, 1858 Caecum buccina de Folin, 1870: synonym of Caecum circumvolutum de Folin, 1867 Caecum bucheri Parenzan, 1979: synonym of Filogranula annulata Caecum butoti Jong & Coomans, 1988: synonym of Caecum marmoratum de Folin, 1869 Caecum capitanum de Folin, 1874: synonym of Caecum pulchellum Stimpson, 1851 Caecum carmenense de Folin, 1870: synonym of Caecum circumvolutum de Folin, 1867 Caecum cayoense Rehder, 1943: synonym of Caecum floridanum Stimpson, 1851 Caecum clenchi Olsson & McGinty, 1958: synonym of Caecum cycloferum de Folin, 1867 Caecum conjunctum de Folin, 1867: synonym of Caecum pulchellum Stimpson, 1851 Caecum contractum de Folin, 1870: synonym of Caecum bipartitum de Folin, 1870 Caecum corneum R. W. Dunker, 1875: synonym of Caecum ryssotitum de Folin, 1867 Caecum cornucopiae - horn-of-plenty caecum: synonym of Meioceras cornucopiae Carpenter, 1859 Caecum coronatum de Folin, 1867: synonym of Caecum imbricatum Carpenter, 1858 Caecum coronellum Dall, 1892: synonym of Caecum cycloferum de Folin, 1867 Caecum costatum A. E. Verrill, 1872: synonym of Caecum cooperi S. I.
Smith, 1860 Caecum crassicostum Gabb, 1881: synonym of Caecum floridanum Stimpson, 1851 Caecum curtatum de Folin, 1867: synonym of Caecum pulchellum Stimpson, 1851 Caecum decussatum de Folin, 1869: synonym of Caecum plicatum Carpenter, 1858 Caecum dux de Folin, 1871: synonym of Caecum floridanum Stimpson, 1851 Caecum eburneum de Folin, 1886: synonym of Caecum folini Kisch, 1959 Caecum elagans Deregaslavtseva, 1891: synonym of Caecum trachea Caecum elegans Perejoslavitseva, 1831: synonym of Caecum trachea Caecum fasciatum de Folin, 1876: synonym of Caecum trachea Caecum formulosum de Folin, 1869: synonym of Caecum imbricatum Carpenter, 1858 Caecum fulvum Kisch, 1959: synonym of Caecum neocaledonicum de Folin, 1867 Caecum heladum Olsson and Harbison, 1953 - fine-line caecum: synonym of Caecum multicostatum de Folin, 1867 Caecum heterapex T. Habe, 1963: synonym of Caecum clarum Lamy, 1910 Caecum hinoidei T. Habe, 1978: synonym of Caecum neocaledonicum de Folin, 1867 Caecum insigne de Folin, 1867: synonym of Caecum imbricatum Carpenter, 1858 Caecum instructum de Folin, 1870: synonym of Caecum bipartitum de Folin, 1870 Caecum legumen Hedley, 1904: synonym of Meioceras legumen Caecum leptoglyphos de Folin, 1881: synonym of Caecum textile de Folin, 1867 Caecum lermondi Dall, 1924: synonym of Meioceras nitidum Caecum lightfootae Pizzini, Oliverio, 1994: synonym of Caecum atlantidis Watson, 1897 Caecum lilianum Ch. Hedley, 1903: synonym of Caecum sepimentum de Folin, 1867 Caecum maculatum T. Habe, 1963: synonym of Caecum sepimentum de Folin, 1867 Caecum malleatum var. sublaevis de Folin, 1868: synonym of Caecum modestum de Folin, 1868 Caecum nitidum Stimpson, 1851 - little horn caecum: synonym of Meioceras nitidum Caecum obesum A. E. Verrill & Bush, 1900: synonym of Caecum plicatum Carpenter, 1858 Caecum orientale de Folin, 1868: synonym of Caecum clarkii Carpenter, 1859 Caecum phronimum de Folin, 1867: synonym of Caecum floridanum Stimpson, 1851 Caecum putnamense Mansfield, 1924: synonym of Caecum johnsoni Winkley, 1908 Caecum rotundum de Folin, 1868: synonym of Meioceras nitidum Caecum saavedrae Beltran, 1965: synonym of Caecum auriculatum de Folin, 1868 Caecum sardinianum de Folin, 1869: synonym of Caecum clarkii Carpenter, 1859 Caecum sculptum de Folin, 1881: synonym of Caecum imbricatum Carpenter, 1858 Caecum semitracheum S. Brusina, 1865: synonym of Caecum clarkii Carpenter, 1859 Caecum smithi Cooper, 1872: synonym of Caecum cooperi S. Smith, 1860 Caecum solitarium Oliver, 1915: synonym of Caecum maori Pizzini & Raines, 2006 Caecum syriacum de Folin, 1869: synonym of Caecum auriculatum de Folin, 1868 Caecum tenue A. E. Verrill & Bush, 1900: synonym of Caecum armoricum de Folin, 1869 Caecum termes Heilprin, 1889: synonym of Caecum plicatum Carpenter, 1858 Caecum tomaculum: synonym of Caecum ryssotitum de Folin, 1867 Caecum triornatum de Folin, 1870: synonym of
Cockroaches are insects of the order Blattodea, which includes termites. About 30 cockroach species out of 4,600 are associated with human habitats. About four species are well known as pests; the cockroaches are an ancient group, dating back at least as far as the Carboniferous period, some 320 million years ago. Those early ancestors however lacked the internal ovipositors of modern roaches. Cockroaches are somewhat generalized insects without special adaptations like the sucking mouthparts of aphids and other true bugs, they are common and hardy insects, can tolerate a wide range of environments from Arctic cold to tropical heat. Tropical cockroaches are much bigger than temperate species, contrary to popular belief, extinct cockroach relatives and'roachoids' such as the Carboniferous Archimylacris and the Permian Apthoroblattina were not as large as the biggest modern species; some species, such as the gregarious German cockroach, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition.
Cockroaches have appeared in human culture since classical antiquity. They are popularly depicted as dirty pests, though the great majority of species are inoffensive and live in a wide range of habitats around the world. Cockroaches are members of the order Blattodea, which includes the termites, a group of insects once thought to be separate from cockroaches. 4,600 species and over 460 genera are described worldwide. The name "cockroach" comes from the Spanish word for cockroach, transformed by 1620s English folk etymology into "cock" and "roach"; the scientific name derives from the Latin blatta, "an insect that shuns the light", which in classical Latin was applied not only to cockroaches, but to mantids. The name Blattaria was used interchangeably with the name Blattodea, but whilst the former name was used to refer to'true' cockroaches the latter includes the termites; the current catalogue of world cockroach species uses the name Blattodea for the group. Another name, Blattoptera, is sometimes used.
The earliest cockroach-like fossils are from the Carboniferous period 320 million years ago, as are fossil roachoid nymphs. Since the 19th century, scientists believed that cockroaches were an ancient group of insects that had a Devonian origin, according to one hypothesis. Fossil roachoids that lived during that time differ from modern cockroaches in having long external ovipositors and are the ancestors of mantises, as well as modern blattodeans; as the body, hind wings and mouthparts are not preserved in fossils the relationship of these roachoids and modern cockroaches remains disputed. The first fossils of modern cockroaches with internal ovipositors appeared in the early Cretaceous. A recent phylogenetic analysis suggests; the evolutionary relationships of the Blattodea shown in the cladogram are based on Eggleton, Beccaloni & Inward. The cockroach families Lamproblattidae and Tryonicidae are not shown but are placed within the superfamily Blattoidea; the cockroach families Corydiidae and Ectobiidae were known as the Polyphagidae and Blattellidae.
Termites were regarded as a separate order Isoptera to cockroaches. However, recent genetic evidence suggests that they evolved directly from'true' cockroaches, many authors now place them as an "epifamily" of Blattodea; this evidence supported a hypothesis suggested in 1934 that termites are related to the wood-eating cockroaches. This hypothesis was based on similarity of the symbiotic gut flagellates in termites regarded as living fossils and wood-eating cockroaches. Additional evidence emerged when F. A. McKittrick noted similar morphological characteristics between some termites and cockroach nymphs; the similarities among these cockroaches and termites have led some scientists to reclassify termites as a single family, the Termitidae, within the order Blattodea. Other scientists have taken a more conservative approach, proposing to retain the termites as the Termitoidea, an epifamily within the order; such measure preserves the classification of termites at family level and below. Most species of cockroach are about the size of a thumbnail.
The world's heaviest cockroach is the Australian giant burrowing cockroach Macropanesthia rhinoceros, which can reach 9 cm in length and weigh more than 30 g. Comparable in size is the Central American giant cockroach Blaberus giganteus, which grows to a similar length; the longest cockroach species is Megaloblatta longipennis, which can reach 97 mm in length and 45 mm across. A Central and South American species, Megaloblatta blaberoides, has the largest wingspan of up to 185 mm. Cockroaches are generalized insects, with few special adaptations, may be among the most primitive living neopteran insects, they have a small head and a broad, flattened body, most species are reddish-brown to dark brown. They have large compound eyes, two ocelli, long, flexible antennae; the mouthparts are on the underside of the head and include generalized chewing mandibles, salivary glands and various touch and taste receptors. The body is divided into a thorax of a ten-segmented abdomen; the external surface has a tough exoskeleton which contains calcium carbonate and protects the inner organs and provides attachment to muscles.
It is coated with wax to repel water. The wings are attached to the third thoracic segments; the tegmina, or fir
Anatomical terminology is a form of scientific terminology used by anatomists and health professionals such as doctors. Anatomical terminology uses many unique terms and prefixes deriving from Ancient Greek and Latin; these terms can be confusing to those unfamiliar with them, but can be more precise, reducing ambiguity and errors. Since these anatomical terms are not used in everyday conversation, their meanings are less to change, less to be misinterpreted. To illustrate how inexact day-to-day language can be: a scar "above the wrist" could be located on the forearm two or three inches away from the hand or at the base of the hand. By using precise anatomical terminology such ambiguity is eliminated. An international standard for anatomical terminology, Terminologia Anatomica has been created. Anatomical terminology has quite regular morphology, the same prefixes and suffixes are used to add meanings to different roots; the root of a term refers to an organ or tissue. For example, the Latin names of structures such as musculus biceps brachii can be split up and refer to, musculus for muscle, biceps for "two-headed", brachii as in the brachial region of the arm.
The first word describes what is being spoken about, the second describes it, the third points to location. When describing the position of anatomical structures, structures may be described according to the anatomical landmark they are near; these landmarks may include structures, such as the umbilicus or sternum, or anatomical lines, such as the midclavicular line from the centre of the clavicle. The cephalon or cephalic region refers to the head; this area is further differentiated into the cranium, frons, auris, nasus and mentum. The neck area is called cervical region. Examples of structures named according to this include the frontalis muscle, submental lymph nodes, buccal membrane and orbicularis oculi muscle. Sometimes, unique terminology is used to reduce confusion in different parts of the body. For example, different terms are used when it comes to the skull in compliance with its embryonic origin and its tilted position compared to in other animals. Here, Rostral refers to proximity to the front of the nose, is used when describing the skull.
Different terminology is used in the arms, in part to reduce ambiguity as to what the "front", "back", "inner" and "outer" surfaces are. For this reason, the terms below are used: Radial referring to the radius bone, seen laterally in the standard anatomical position. Ulnar referring to the ulna bone, medially positioned when in the standard anatomical position. Other terms are used to describe the movement and actions of the hands and feet, other structures such as the eye. International morphological terminology is used by the colleges of medicine and dentistry and other areas of the health sciences, it facilitates communication and exchanges between scientists from different countries of the world and it is used daily in the fields of research and medical care. The international morphological terminology refers to morphological sciences as a biological sciences' branch. In this field, the form and structure are examined as well as the changes or developments in the organism, it is functional.
It covers the gross anatomy and the microscopic of living beings. It involves the anatomy of the adult, it includes comparative anatomy between different species. The vocabulary is extensive and complex, requires a systematic presentation. Within the international field, a group of experts reviews and discusses the morphological terms of the structures of the human body, forming today's Terminology Committee from the International Federation of Associations of Anatomists, it deals with the anatomical and embryologic terminology. In the Latin American field, there are meetings called Iberian Latin American Symposium Terminology, where a group of experts of the Pan American Association of Anatomy that speak Spanish and Portuguese and studies the international morphological terminology; the current international standard for human anatomical terminology is based on the Terminologia Anatomica. It was developed by the Federative Committee on Anatomical Terminology and the International Federation of Associations of Anatomists and was released in 1998.
It supersedes Nomina Anatomica. Terminologia Anatomica contains terminology for about 7500 human gross anatomical structures. For microanatomy, known as histology, a similar standard exists in Terminologia Histologica, for embryology, the study of development, a standard exists in Terminologia Embryologica; these standards specify accepted names that can be used to refer to histological and embryological structures in journal articles and other areas. As of September 2016, two sections of the Terminologia Anatomica, including central nervous system and peripheral nervous system, were merged to form the Terminologia Neuroanatomica; the Terminologia Anatomica has been perceived with a considerable criticism regarding its content including coverage and spelling mistakes and errors. Anatomical terminology is chosen to highlight the relative location of body structures. For instance, an anatomist might describe one band of tissue as "inferior to" another or a physician might describe a tumor as "superficial to" a deeper body structure.
Anatomical terms used to describe location
Dead end (street)
A dead end known as a cul-de-sac, no through road or no exit road, is a street with only one inlet or outlet. The term "dead end" is understood in all varieties of English, but the official terminology and traffic signs include many different alternatives; some of these are used only regionally. In the United States and other countries, cul-de-sac is not an exact synonym for dead end and refers to dead ends with a circular end, allowing for easy turning at the end of the road. In Australia, they are referred to as a court when they have a bulbous end. Dead ends are created in urban planning to limit through-traffic in residential areas. While some dead ends provide no possible passage except in and out of their road entry, others allow cyclists, pedestrians or other non-automotive traffic to pass through connecting easements or paths, an example of filtered permeability; the International Federation of Pedestrians proposed to call such streets "living end streets" and to provide signage at the entry of the streets that make this permeability for pedestrians and cyclists clear.
Its application retains the dead end's primary function as a non-through road, but establishes complete pedestrian and bicycle network connectivity. The earliest examples of dead ends were unearthed in the El-Lahun workers' village in Egypt, built circa 1885 BC; the village is laid out with straight streets. The western part of the excavated village, where the workers lived, shows fifteen narrow and short dead-ends laid out perpendicularly on either side of a wider, straight street. Dead-end streets appeared during the classical period of Athens and Rome; the 15th century architect and planner Leon Battista Alberti implies in his writings that dead-end streets may have been used intentionally in antiquity for defense purposes. He writes: "The Ancients in All Towns were for having some intricate Ways and turn again Streets, without any Passage through them, that if an Enemy comes into them, he may be at a Loss, be in Confusion and Suspense; the same opinion is expressed by an earlier thinker, when he criticized the Hippodamian grid: "...but for security in war the opposite, as it used to be in ancient times.
For, difficult for foreign troops to enter and find their way about when attacking". In the UK, their prior existence is implied by an 1875 law which banned their use in new developments. Inferential evidence of their earlier use can be drawn from the text of a German architect, Rudolf Eberstadt, that explains their purpose and utility: We have, in our medieval towns, showing commendable methods of cutting up the land. I ought to mention here that to keep traffic out of residential streets is necessary not only in the general interest of the population, above all, for the sake of the children, whose health is dependent on the opportunity of moving about in close connection with their dwelling places, without the danger of being run over. In the earlier periods, traffic was excluded from residential streets by gates or by employing the cul-de-sac, it was in the United Kingdom that the cul-de-sac street type was first legislated into use, with The Hampstead Garden Suburb Act 1906. The proponents of the Act, Raymond Unwin and Barry Parker, thus gained permission to introduce culs-de-sac in their subsequent site plans, they promoted it as a suitable street type for Garden Suburbs.
Unwin's applications of the cul-de-sac and the related crescent always included pedestrian paths independent of the road network. This design feature reflects the predominance of pedestrian movement for local trips at the turn of the 20th century, presages the current planning priority for increased pedestrian accessibility; the 1906 Act defined the nature of the cul-de-sac as a non-through road and restricted its length to 500 feet. Garden cities in the UK that followed Hampstead, such as Welwyn Garden City, all included culs-de-sac. In the 1920s, the garden city movement gained ground in the United States and, with it, came its design elements, such as the cul-de-sac. Clarence Stein, a main proponent of the movement, incorporated it in the Radburn, New Jersey, to become a model for subsequent neighbourhood developments; the country's Federal Housing Authority recommended and promoted their use through their 1936 guidelines and the power of lending development funds. In Canada, a variation of Stein's Radburn 1929 plan that used crescents instead of culs-de-sac was built in 1947: Wildwood Park, designed by Hubert Bird.
In 1954, the Central Mortgage and Housing Corporation published its own guidelines in which the cul-de-sac was recommended for local streets and, as the FHA in the US, used its lending power to see its inclusion in development plans. The Varsity Village and Braeside, subdivisions in Calgary, Alberta used the Radburn model in the late 1960s. In the 1960s the cul-de-sac attained systematic international application in planned new cities such as Doxiadis’ Islamabad. In the UK, new towns such as Harlow by Sir Frederick Gibberd and Milton Keynes incorporated culs-de-sac and crescents in their layouts. Planning theorists have suggested the use alternatives to culs-de-sac. Most notably, Christopher Alexander et al. in his "A Pattern Language" 1977 book suggests the use of looped local roads which do not abruptly stop. Although dead end streets, would fit his definition of looped local roads Alexande
Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions; the molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. All metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps; the study of enzymes is called enzymology and a new field of pseudoenzyme analysis has grown up, recognising that during evolution, some enzymes have lost the ability to carry out biological catalysis, reflected in their amino acid sequences and unusual'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins; the latter are called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction rate by lowering its activation energy; some enzymes can make their conversion of substrate to product occur many millions of times faster.
An extreme example is orotidine 5'-phosphate decarboxylase, which allows a reaction that would otherwise take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. Enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules: inhibitors are molecules that decrease enzyme activity, activators are molecules that increase activity. Many therapeutic drugs and poisons are enzyme inhibitors. An enzyme's activity decreases markedly outside its optimal temperature and pH, many enzymes are denatured when exposed to excessive heat, losing their structure and catalytic properties; some enzymes are used commercially, in the synthesis of antibiotics. Some household products use enzymes to speed up chemical reactions: enzymes in biological washing powders break down protein, starch or fat stains on clothes, enzymes in meat tenderizer break down proteins into smaller molecules, making the meat easier to chew.
By the late 17th and early 18th centuries, the digestion of meat by stomach secretions and the conversion of starch to sugars by plant extracts and saliva were known but the mechanisms by which these occurred had not been identified. French chemist Anselme Payen was the first to discover an enzyme, diastase, in 1833. A few decades when studying the fermentation of sugar to alcohol by yeast, Louis Pasteur concluded that this fermentation was caused by a vital force contained within the yeast cells called "ferments", which were thought to function only within living organisms, he wrote that "alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells."In 1877, German physiologist Wilhelm Kühne first used the term enzyme, which comes from Greek ἔνζυμον, "leavened" or "in yeast", to describe this process. The word enzyme was used to refer to nonliving substances such as pepsin, the word ferment was used to refer to chemical activity produced by living organisms.
Eduard Buchner submitted his first paper on the study of yeast extracts in 1897. In a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts when there were no living yeast cells in the mixture, he named the enzyme that brought about the fermentation of sucrose "zymase". In 1907, he received the Nobel Prize in Chemistry for "his discovery of cell-free fermentation". Following Buchner's example, enzymes are named according to the reaction they carry out: the suffix -ase is combined with the name of the substrate or to the type of reaction; the biochemical identity of enzymes was still unknown in the early 1900s. Many scientists observed that enzymatic activity was associated with proteins, but others argued that proteins were carriers for the true enzymes and that proteins per se were incapable of catalysis. In 1926, James B. Sumner crystallized it; the conclusion that pure proteins can be enzymes was definitively demonstrated by John Howard Northrop and Wendell Meredith Stanley, who worked on the digestive enzymes pepsin and chymotrypsin.
These three scientists were awarded the 1946 Nobel Prize in Chemistry. The discovery that enzymes could be crystallized allowed their structures to be solved by x-ray crystallography; this was first done for lysozyme, an enzyme found in tears and egg whites that digests the coating of some bacteria. This high-resolution structure of lysozyme marked the beginning of the field of structural biology and the effort to understand how enzymes work at an atomic level of detail. An enzyme's name is derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase. Examples are alcohol dehydrogenase and DNA polymerase. Different enzymes that catalyze the same chemical reaction are called isozymes; the International Union of Biochemistry and Molecular Biology have developed a nomenclature for enzymes, the EC numbers. The first number broadly classifies the enzyme based on its mechanism; the top-level classification is: EC 1, Oxidoreductases: catalyze oxidation/reducti
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals have mouthparts adapted to rasping or grinding. Horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, other tough plant material. A large percentage of herbivores have mutualistic gut flora that help them digest plant matter, more difficult to digest than animal prey; this flora is made up of cellulose-digesting bacteria. Herbivore is the anglicized form of a modern Latin coinage, cited in Charles Lyell's 1830 Principles of Geology. Richard Owen employed the anglicized term in an 1854 work on fossil skeletons. Herbivora is derived from the Latin herba meaning a small plant or herb, vora, from vorare, to eat or devour. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants and photosynthesizing bacteria.
More organisms that feed on autotrophs in general are known as primary consumers. Herbivory is limited to animals that eat plants. Fungi and protists that feed on living plants are termed plant pathogens, while fungi and microbes that feed on dead plants are described as saprotrophs. Flowering plants that obtain nutrition from other living plants are termed parasitic plants. There is, however, no single exclusive and definitive ecological classification of consumption patterns. In zoology, an herbivore is an animal, adapted to eat plant matter. Our understanding of herbivory in geological time comes from three sources: fossilized plants, which may preserve evidence of defence, or herbivory-related damage. Although herbivory was long thought to be a Mesozoic phenomenon, fossils have shown that within less than 20 million years after the first land plants evolved, plants were being consumed by arthropods. Insects fed on the spores of early Devonian plants, the Rhynie chert provides evidence that organisms fed on plants using a "pierce and suck" technique.
During the next 75 million years, plants evolved a range of more complex organs, such as roots and seeds. There is no evidence of any organism being fed upon until the middle-late Mississippian, 330.9 million years ago. There was a gap of 50 to 100 million years between the time each organ evolved and the time organisms evolved to feed upon them. Further than their arthropod status, the identity of these early herbivores is uncertain. Hole feeding and skeletonisation are recorded in the early Permian, with surface fluid feeding evolving by the end of that period. Herbivory among four-limbed terrestrial vertebrates, the tetrapods developed in the Late Carboniferous. Early tetrapods were large amphibious piscivores. While amphibians continued to feed on fish and insects, some reptiles began exploring two new food types and plants; the entire dinosaur order ornithischia was composed with herbivores dinosaurs. Carnivory was a natural transition from insectivory for medium and large tetrapods, requiring minimal adaptation.
In contrast, a complex set of adaptations was necessary for feeding on fibrous plant materials. Arthropods evolved herbivory in four phases, changing their approach to it in response to changing plant communities. Tetrapod herbivores made their first appearance in the fossil record of their jaws near the Permio-Carboniferous boundary 300 million years ago; the earliest evidence of their herbivory has been attributed to dental occlusion, the process in which teeth from the upper jaw come in contact with teeth in the lower jaw is present. The evolution of dental occlusion led to a drastic increase in plant food processing and provides evidence about feeding strategies based on tooth wear patterns. Examination of phylogenetic frameworks of tooth and jaw morphologes has revealed that dental occlusion developed independently in several lineages tetrapod herbivores; this suggests that evolution and spread occurred within various lineages. Herbivores form an important link in the food chain because they consume plants in order to digest the carbohydrates photosynthetically produced by a plant.
Carnivores in turn consume herbivores for the same reason, while omnivores can obtain their nutrients from either plants or animals. Due to a herbivore's ability to survive on tough and fibrous plant matter, they are termed the primary consumers in the food cycle. Herbivory and omnivory can be regarded as special cases of Consumer-Resource Systems. Herbivores come in all sizes in the animal kingdom, they include aquatic and non-aquatic vertebrates. They can be large, like an elephant. Many herbivores found living in close proximity to humans, such as rodents, cows and camels. Two herbivore feeding strategies are browsing. For a terrestrial mammal to be called a grazer, at least 90% of the forage has to be grass, for a browser at least 90% tree leaves and/or twigs. An intermediate feeding strategy is called "mixed-feeding". In their daily need to take up energy from forage, herbivores of different body mass may be selective in choosing their food. "Selective" means that herbivores may choose their forage source depending on, e.g. season or food avail