1.
Chiton
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Chitons /ˈkaɪtənz/ are marine molluscs of varying size in the class Polyplacophora, formerly known as Amphineura. About 940 extant and 430 fossil species are recognized and they are also sometimes known as sea cradles or coat-of-mail shells, or more formally as loricates, polyplacophorans, and occasionally as polyplacophores. Chitons have a shell composed of eight separate plates or valves. These plates overlap slightly at the front and back edges, the shell plates are encircled by a skirt known as a girdle. Chitons live worldwide, from cold waters through to the tropics and they live on hard surfaces, such as on or under rocks, or in rock crevices. Some species live high in the intertidal zone and are exposed to the air. Most species inhabit intertidal or subtidal zones, and do not extend beyond the photic zone, chitons are exclusively and fully marine. All chitons bear a protective shell that is divided into eight articulating aragonite valves embedded in the tough muscular girdle that surrounds the chitons body. Compared with the single or two-piece shells of molluscs, this arrangement allows chitons to roll into a protective ball when dislodged. In some species the valves are reduced or covered by the girdle tissue, the valves are variously colored, patterned, smooth, or sculptured. The most anterior plate is crescent-shaped, and is known as the cephalic plate, the most posterior plate is known as the anal plate The inner layer of each of the six intermediate plates is produced anteriorly as an articulating flange, called the articulamentum. This inner layer may also be produced laterally in the form of notched insertion plates and these function as an attachment of the valve plates to the soft body. A similar series of insertion plates may be attached to the anterior border of the cephalic plate or the convex posterior border of the anal plate. The sculpture of the valves is one of the taxonomic characteristics, after a chiton dies, the individual valves which make up the eight-part shell come apart because the girdle is no longer holding them together, and then the plates sometimes wash up in beach drift. The individual shell plates from a chiton are known as butterfly shells due to their shape. The protein component of the scales and sclerites is minuscule in comparison with other biomineralized structures and this implies that polysaccharides make up the bulk of the matrix. The girdle spines often bear length-parallel striations, the wide form of girdle ornament suggests it serves a secondary role, chitons can survive perfectly well without them. Camouflage or defence are two likely functions, spicules are secreted by cells that do not express engrailed, but these cells are surrounded by engrailed-expressing cells
2.
Chitlin
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Chitterlings are a prepared food usually made from the small intestines of a pig, although the intestines of cattle and other animals are sometimes used. Chitterling is first documented in Middle English by the Oxford English Dictionary, in the form cheterling, various other spellings and dialect forms were used. The primary form and derivation are uncertain, the recipe explained the use of calfs, rather than the more usual pigs, intestines with the comment that sort of. Puddings must be made in summer, when hogs are seldom killed and this recipe was repeated by the English cookery writer Hannah Glasse in her 1784 cookery book Art of Cookery. As pigs are a source of meat in many parts of the world. It illustrates that chitterlings were the poorest choice of poor food, mutton they almost never tasted, but sometimes they had a calfs head, sometimes even, though less often, a joint of veal. Chitterlings are the subject of a song by 1970s Scrumpy and Western comedy folk band, The Wurzels, Chitterlings are rarely eaten in the UK in the present day. Kokoretsi, kukurec, or kokoreç, are prepared and stuffed. In several countries such as Turkey, Greece and Bulgaria, lamb intestines are widely used, in Turkish cuisine, the intestines are often chopped and cooked with oregano, peppers, and other spices. Gallinejas are a dish in Madrid. The dish consists of sheeps intestines, spleen, and pancreas. The dish is served hot, often with French fries, few establishments today serve gallinejas, as this is considered to be more of a speciality than a common dish. It is most commonly served during festivals, a similar dish from La Rioja is embuchados, and from the province of Aragon, madejas, all made with sheeps intestines and served as tapas. Tricandilles are a dish in Gironde. They are made of pigs small intestines, boiled in bouillon and this is considered an expensive delicacy. Andouillette is a type of sausage, found especially in Troyes, andouille is another kind of French chitterlings sausage found especially in Brittany and Normandy. People in the Caribbean and Latin America eat chitterlings, chinchulín or chunchule is the cows small intestine used as a foodstuff. Other name variations from country to country are caldo avá, choncholi, chunchullo, chinchurria or chunchurria, chinchurria, tripa mishqui, chunchullo Chitterlings are also eaten as a dish in many East Asian cuisines
3.
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
4.
N-Acetylglucosamine
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N-Acetylglucosamine is a monosaccharide and a derivative of glucose. It is an amide between glucosamine and acetic acid and it has a molecular formula of C8H15NO6, a molar mass of 221.21 g/mol, and it is significant in several biological systems. It is part of a biopolymer in the cell wall, built from alternating units of GlcNAc and N-acetylmuramic acid. This layered structure is called peptidoglycan, GlcNAc is the monomeric unit of the polymer chitin, which forms the outer coverings of insects and crustaceans. It is the component of the radulas of mollusks, the beaks of cephalopods. Polymerized with glucuronic acid, it forms hyaluronan, GlcNAc has been reported to be an inhibitor of elastase release from human polymorphonuclear leukocytes, however this is much weaker than the inhibition seen with N-acetylgalactosamine. It has been proposed as a treatment for diseases. Keratan sulfate Chitin N-Acetyllactosamine synthase N-Acetylgalactosamine Wheat germ agglutinin, a plant lectin that binds to this substrate Re Multiple Sclerosis
5.
Haworth projection
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A Haworth projection is a common way of writing a structural formula to represent the cyclic structure of monosaccharides with a simple three-dimensional perspective. Organic chemistry and especially biochemistry are the areas of chemistry that use the Haworth projection the most, the Haworth projection was named after the English chemist Sir Norman Haworth. A Haworth projection has the characteristics, Carbon is the implicit type of atom. In the example on the right, the atoms numbered from 1 to 6 are all carbon atoms, Carbon 1 is known as the anomeric carbon. Hydrogen atoms on carbon are implicit, in the example, atoms 1 to 6 have extra hydrogen atoms not depicted. A thicker line indicates atoms that are closer to the observer, in the example on the right, atoms 2 and 3 are the closest to the observer. Atoms 1 and 4 are farther from the observer, atom 5 and the other atoms are the farthest. The groups below the plane of the ring in Haworth projections correspond to those on the side of a Fischer projection. This rule does not apply to the groups on the two ring carbons bonded to the oxygen atom. Structural formula Skeletal formula Fischer projection Natta projection Newman projection
6.
Leafhopper
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Leafhopper is a common name applied to any species from the family Cicadellidae. These minute insects, colloquially known as hoppers, are plant feeders that suck plant sap from grass, shrubs, or trees. Their hind legs are modified for jumping, and are covered with hairs that facilitate the spreading of a secretion over their bodies that acts as a water repellent and they undergo a partial metamorphosis, and have various host associations, varying from very generalized to very specific. Some species have a distribution, or occur throughout the temperate. Some are pests or vectors of plant viruses and phytoplasmas, the family is distributed all over the world, and constitutes the second-largest hemipteran family, with at least 20,000 described species. Members of the tribe Proconiini of the subfamily Cicadellinae are commonly known as sharpshooters, the Cicadellidae combine the following features, The thickened part of the antennae is very short and ends with a bristle. Two ocelli are present on the top or front of the head, the tarsi are made of three segments. The femora are at front with, at most, weak spines, the hind tibiae have one or more distinct keels, with a row of movable spines on each, sometimes on enlarged bases. The base of the legs is close together where they originate under the thorax. The front wings not particularly thickened, an additional and unique character of leafhoppers is the production of brochosomes, which are thought to protect the animals, and particularly their egg clutches, from predation and pathogens. Like other Exopterygota, the leafhoppers undergo direct development from nymph to adult without a pupal stage, while many leafhoppers are drab little insects as is typical for the Membracoidea, the adults and nymphs of some species are quite colorful. Some – in particular Stegelytrinae – have largely translucent wings and resemble flies at a casual glance, leafhoppers have piercing-sucking mouthparts, enabling them to feed on plant sap. A leafhoppers diet commonly consists of sap from a wide and diverse range of plants, leafhoppers mainly are herbivores, but some are known to eat smaller insects, such as aphids, on occasion. A few species are known to be mud-puddling, but as it seems, leafhoppers can transmit plant pathogens, such as viruses, phytoplasmas and bacteria. In some cases, the plant pathogens distributed by leafhoppers are also pathogens of the insects themselves, some species such as the Australian Kahaono montana even build silk nests under the leaves of trees they live in, to protect them from predators. Hence, a recent trend treats the most advanced hemipterans as three or four lineages, namely Archaeorrhyncha, Coleorrhyncha and Heteroptera and Clypeorrhyncha, within the latter, the three traditional superfamilies – Cercopoidea, Cicadoidea and Membracoidea – appear to be monophyletic. The leafhoppers are the most basal living lineage of Membracoidea, which include the families Aetalionidae, Membracidae, Melizoderidae. The leafhoppers are divided into a number of subfamilies, which are listed here alphabetically
7.
Carbon
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Carbon is a chemical element with symbol C and atomic number 6. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds, three isotopes occur naturally, 12C and 13C being stable, while 14C is a radioactive isotope, decaying with a half-life of about 5,730 years. Carbon is one of the few elements known since antiquity, Carbon is the 15th most abundant element in the Earths crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is the second most abundant element in the body by mass after oxygen. The atoms of carbon can bond together in different ways, termed allotropes of carbon, the best known are graphite, diamond, and amorphous carbon. The physical properties of carbon vary widely with the allotropic form, for example, graphite is opaque and black while diamond is highly transparent. Graphite is soft enough to form a streak on paper, while diamond is the hardest naturally occurring material known, graphite is a good electrical conductor while diamond has a low electrical conductivity. Under normal conditions, diamond, carbon nanotubes, and graphene have the highest thermal conductivities of all known materials, all carbon allotropes are solids under normal conditions, with graphite being the most thermodynamically stable form. They are chemically resistant and require high temperature to react even with oxygen, the most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and transition metal carbonyl complexes. The largest sources of carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil. For this reason, carbon has often referred to as the king of the elements. The allotropes of carbon graphite, one of the softest known substances, and diamond. It bonds readily with other small atoms including other carbon atoms, Carbon is known to form almost ten million different compounds, a large majority of all chemical compounds. Carbon also has the highest sublimation point of all elements, although thermodynamically prone to oxidation, carbon resists oxidation more effectively than elements such as iron and copper that are weaker reducing agents at room temperature. Carbon is the element, with a ground-state electron configuration of 1s22s22p2. Its first four ionisation energies,1086.5,2352.6,4620.5 and 6222.7 kJ/mol, are higher than those of the heavier group 14 elements. Carbons covalent radii are normally taken as 77.2 pm,66.7 pm and 60.3 pm, although these may vary depending on coordination number, in general, covalent radius decreases with lower coordination number and higher bond order. Carbon compounds form the basis of all life on Earth
8.
Hydrogen
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Hydrogen is a chemical element with chemical symbol H and atomic number 1. With a standard weight of circa 1.008, hydrogen is the lightest element on the periodic table. Its monatomic form is the most abundant chemical substance in the Universe, non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed protium, has one proton, the universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays an important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a charge when it is known as a hydride. The hydrogen cation is written as though composed of a bare proton, Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing and ammonia production, mostly for the fertilizer market, Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen gas is flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion is −286 kJ/mol,2 H2 + O2 →2 H2O +572 kJ Hydrogen gas forms explosive mixtures with air in concentrations from 4–74%, the explosive reactions may be triggered by spark, heat, or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C, the detection of a burning hydrogen leak may require a flame detector, such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames, the destruction of the Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. The visible orange flames in that incident were the result of a mixture of hydrogen to oxygen combined with carbon compounds from the airship skin. H2 reacts with every oxidizing element, the ground state energy level of the electron in a hydrogen atom is −13.6 eV, which is equivalent to an ultraviolet photon of roughly 91 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, however, the atomic electron and proton are held together by electromagnetic force, while planets and celestial objects are held by gravity. The most complicated treatments allow for the effects of special relativity
9.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
10.
Nitrogen
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Nitrogen is a chemical element with symbol N and atomic number 7. It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772, although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. Nitrogen is the lightest member of group 15 of the periodic table, the name comes from the Greek πνίγειν to choke, directly referencing nitrogens asphyxiating properties. It is an element in the universe, estimated at about seventh in total abundance in the Milky Way. At standard temperature and pressure, two atoms of the element bind to form dinitrogen, a colourless and odorless diatomic gas with the formula N2, dinitrogen forms about 78% of Earths atmosphere, making it the most abundant uncombined element. Nitrogen occurs in all organisms, primarily in amino acids, in the nucleic acids, the human body contains about 3% nitrogen by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. The nitrogen cycle describes movement of the element from the air, into the biosphere and organic compounds, many industrially important compounds, such as ammonia, nitric acid, organic nitrates, and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen, the second strongest bond in any diatomic molecule. Synthetically produced ammonia and nitrates are key industrial fertilisers, and fertiliser nitrates are key pollutants in the eutrophication of water systems. Apart from its use in fertilisers and energy-stores, nitrogen is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric, Nitrogen is a constituent of every major pharmacological drug class, including antibiotics. Many notable nitrogen-containing drugs, such as the caffeine and morphine or the synthetic amphetamines. Nitrogen compounds have a long history, ammonium chloride having been known to Herodotus. They were well known by the Middle Ages, alchemists knew nitric acid as aqua fortis, as well as other nitrogen compounds such as ammonium salts and nitrate salts. The mixture of nitric and hydrochloric acids was known as aqua regia, celebrated for its ability to dissolve gold, the discovery of nitrogen is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as a different chemical substance, he clearly distinguished it from Joseph Blacks fixed air. The fact that there was a component of air that does not support combustion was clear to Rutherford, Nitrogen was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to it as burnt air or phlogisticated air. Nitrogen gas was inert enough that Antoine Lavoisier referred to it as air or azote, from the Greek word άζωτικός. In an atmosphere of nitrogen, animals died and flames were extinguished
11.
Polymer
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A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
12.
Cell wall
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A cell wall is a structural layer surrounding some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid and it provides the cell with both structural support and protection, and also acts as a filtering mechanism. Cell walls are present in most prokaryotes, in algae, plants and fungi, a major function is to act as pressure vessels, preventing over-expansion of the cell when water enters. The composition of cell walls varies between species and may depend on type and developmental stage. The primary cell wall of plants is composed of the polysaccharides cellulose, hemicellulose. Often, other such as lignin, suberin or cutin are anchored to or embedded in plant cell walls. Algae possess walls made of glycoproteins and polysaccharides such as carrageenan, in bacteria, the cell wall is composed of peptidoglycan. The cell walls of archaea have various compositions, and may be formed of glycoprotein S-layers, pseudopeptidoglycan, Fungi possess cell walls made of the glucosamine polymer chitin. Unusually, diatoms have a wall composed of biogenic silica. A plant cell wall was first observed and named by Robert Hooke in 1665, in 1804, Karl Rudolphi and J. H. F. Link proved that cells had independent cell walls, before, it had been thought that cells shared walls and that fluid passed between them this way. The mode of formation of the wall was controversial in the 19th century. Hugo von Mohl advocated the idea that the wall grows by apposition. Carl Nägeli believed that the growth of the wall in thickness, each theory was improved in the following decades, the apposition theory by Eduard Strasburger, and the intussusception theory by Julius Wiesner. In 1930, Ernst Münch coined the term apoplast in order to separate the living symplast from the dead plant region, Cell walls serve similar purposes in those organisms that possess them. They may give cells rigidity and strength, offering protection against mechanical stress, in multicellular organisms, they permit the organism to build and hold a definite shape. Cell walls also limit the entry of large molecules that may be toxic to the cell and they further permit the creation of stable osmotic environments by preventing osmotic lysis and helping to retain water. Their composition, properties, and form may change during the cell cycle, in most cells, the cell wall is flexible, meaning that it will bend rather than holding a fixed shape, but has considerable tensile strength
13.
Fungus
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A fungus is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from the other eukaryotic life kingdoms of plants, a characteristic that places fungi in a different kingdom from plants, bacteria and some protists, is chitin in their cell walls. Similar to animals, fungi are heterotrophs, they acquire their food by absorbing dissolved molecules, growth is their means of mobility, except for spores, which may travel through the air or water. Fungi are the principal decomposers in ecological systems and this fungal group is distinct from the structurally similar myxomycetes and oomycetes. The discipline of biology devoted to the study of fungi is known as mycology, in the past, mycology was regarded as a branch of botany, although it is now known fungi are genetically more closely related to animals than to plants. Abundant worldwide, most fungi are inconspicuous because of the size of their structures. Fungi include symbionts of plants, animals, or other fungi and they may become noticeable when fruiting, either as mushrooms or as molds. Fungi perform a role in the decomposition of organic matter and have fundamental roles in nutrient cycling. Since the 1940s, fungi have been used for the production of antibiotics, Fungi are also used as biological pesticides to control weeds, plant diseases and insect pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, the fruiting structures of a few species contain psychotropic compounds and are consumed recreationally or in traditional spiritual ceremonies. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans, losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. The fungus kingdom encompasses a diversity of taxa with varied ecologies, life cycle strategies. However, little is known of the biodiversity of Kingdom Fungi. Advances in molecular genetics have opened the way for DNA analysis to be incorporated into taxonomy, phylogenetic studies published in the last decade have helped reshape the classification within Kingdom Fungi, which is divided into one subkingdom, seven phyla, and ten subphyla. The English word fungus is directly adopted from the Latin fungus, used in the writings of Horace, a group of all the fungi present in a particular area or geographic region is known as mycobiota, e. g. the mycobiota of Ireland. Like plants, fungi grow in soil and, in the case of mushrooms, form conspicuous fruit bodies. The fungi are now considered a kingdom, distinct from both plants and animals, from which they appear to have diverged around one billion years ago. Fungi have membrane-bound cytoplasmic organelles such as mitochondria, sterol-containing membranes and they have a characteristic range of soluble carbohydrates and storage compounds, including sugar alcohols, disaccharides, and polysaccharides
14.
Exoskeleton
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An exoskeleton is the external skeleton that supports and protects an animals body, in contrast to the internal skeleton of, for example, a human. In usage, some of the kinds of exoskeletons are known as shells. Examples of animals with exoskeletons include insects such as grasshoppers and cockroaches, the shells of certain sponges and the various groups of shelled molluscs, including those of snails, clams, tusk shells, chitons and nautilus, are also exoskeletons. Some animals, such as the tortoise, have both an endoskeleton and an exoskeleton, exoskeletons have a role in defense from pests and predators, support, and in providing an attachment framework for musculature. Exoskeletons contain chitin, the addition of calcium carbonate makes them harder and stronger, ingrowths of the arthropod exoskeleton known as apodemes serve as attachment sites for muscles. These structures are composed of chitin, and are six times as strong. Similar to tendons, apodemes can stretch to store energy for jumping. Many different species produce exoskeletons, which are composed of a range of materials, bone, cartilage, or dentine is used in the Ostracoderm fish and turtles. Chitin forms the exoskeleton in arthropods including insects, arachnids such as spiders, crustaceans such as crabs and lobsters, calcium carbonates constitute the shells of molluscs, brachiopods, and some tube-building polychaete worms. Silica forms the exoskeleton in the microscopic diatoms and radiolaria, one species of mollusc, the scaly-foot gastropod, even makes use of the iron sulfides greigite and pyrite. Some organisms, such as some foraminifera, agglutinate exoskeletons by sticking grains of sand, contrary to a common misconception, echinoderms do not possess an exoskeleton, as their test is always contained within a layer of living tissue. Exoskeletons have evolved many times,18 lineages evolved calcified exoskeletons alone. Further, other lineages have produced tough outer coatings analogous to an exoskeleton and this coating is constructed from bone in the armadillo, and hair in the pangolin. The armor of reptiles like turtles and Ankylosaurs is constructed of bone, crocodiles have bony scutes, since exoskeletons are rigid, they present some limits to growth. Organisms with open shells can grow by adding new material to the aperture of their shell, as is the case in snails, bivalves, a true exoskeleton, like that found in arthropods, must be shed when it is outgrown. A new exoskeleton is produced beneath the old one, as the old one is shed, the new skeleton is soft and pliable. The animal will pump itself up to expand the new shell to maximal size, when the shell has set, the empty space inside the new skeleton can be filled up as the animal eats. Failure to shed the exoskeleton once outgrown can result in the animal being suffocated within its own shell and this is the mechanism behind some insect pesticides, such as Azadirachtin
15.
Arthropod
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An arthropod is an invertebrate animal having an exoskeleton, a segmented body, and jointed appendages. Arthropods form the phylum Arthropoda, which includes the insects, arachnids, myriapods, arthropods are characterized by their jointed limbs and cuticle made of chitin, often mineralised with calcium carbonate. The arthropod body plan consists of segments, each with a pair of appendages, the rigid cuticle inhibits growth, so arthropods replace it periodically by moulting. Their versatility has enabled them to become the most species-rich members of all guilds in most environments. They have over a million described species, making up more than 80% of all described living species, some of which. Arthropods range in size from the microscopic crustacean Stygotantulus up to the Japanese spider crab, arthropods primary internal cavity is a hemocoel, which accommodates their internal organs, and through which their haemolymph – analogue of blood – circulates, they have open circulatory systems. Like their exteriors, the organs of arthropods are generally built of repeated segments. Their nervous system is ladder-like, with paired ventral nerve cords running through all segments and their heads are formed by fusion of varying numbers of segments, and their brains are formed by fusion of the ganglia of these segments and encircle the esophagus. The respiratory and excretory systems of arthropods vary, depending as much on their environment as on the subphylum to which they belong, arthropods also have a wide range of chemical and mechanical sensors, mostly based on modifications of the many setae that project through their cuticles. Aquatic species use internal or external fertilization. Almost all arthropods lay eggs, but scorpions give birth to live young after the eggs have hatched inside the mother, arthropod hatchlings vary from miniature adults to grubs and caterpillars that lack jointed limbs and eventually undergo a total metamorphosis to produce the adult form. The level of care for hatchlings varies from nonexistent to the prolonged care provided by scorpions. The evolutionary ancestry of arthropods dates back to the Cambrian period, the group is generally regarded as monophyletic, and many analyses support the placement of arthropods with cycloneuralians in a superphylum Ecdysozoa. Overall however, the relationships of Metazoa are not yet well resolved. Likewise, the relationships between various groups are still actively debated. Arthropods contribute to the food supply both directly as food, and more importantly indirectly as pollinators of crops. Some species are known to spread disease to humans, livestock. The word arthropod comes from the Greek ἄρθρον árthron, joint, and πούς pous, i. e. foot or leg, arthropods are invertebrates with segmented bodies and jointed limbs
16.
Crustacean
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Crustaceans form a large, diverse arthropod taxon which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill, woodlice and barnacles. In other words, some crustaceans are more related to insects. The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm, to the Japanese spider crab with a leg span of up to 3.8 m, like other arthropods, crustaceans have an exoskeleton, which they moult to grow. Most crustaceans are free-living aquatic animals, but some are terrestrial, some are parasitic, the group has an extensive fossil record, reaching back to the Cambrian, and includes living fossils such as Triops cancriformis, which has existed apparently unchanged since the Triassic period. More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, krill and copepods are not as widely fished, but may be the animals with the greatest biomass on the planet, and form a vital part of the food chain. The scientific study of crustaceans is known as carcinology, and a scientist who works in carcinology is a carcinologist, the body of a crustacean is composed of segments, which are grouped into three regions, the cephalon or head, the thorax, and the pleon or abdomen. The head and thorax may be fused together to form a cephalothorax, the crustacean body is protected by the hard exoskeleton, which must be moulted for the animal to grow. The shell around each somite can be divided into a dorsal tergum, ventral sternum, various parts of the exoskeleton may be fused together. The abdomen bears pleopods, and ends in a telson, which bears the anus, the number and variety of appendages in different crustaceans may be partly responsible for the groups success. It is unclear whether the condition is a derived state which evolved in crustaceans. Trilobites, for instance, also possessed biramous appendages, the main body cavity is an open circulatory system, where blood is pumped into the haemocoel by a heart located near the dorsum. Malacostraca have haemocyanin as the pigment, while copepods, ostracods, barnacles. The alimentary canal consists of a tube that often has a gizzard-like gastric mill for grinding food and a pair of digestive glands that absorb food. Structures that function as kidneys are located near the antennae, a brain exists in the form of ganglia close to the antennae, and a collection of major ganglia is found below the gut. In many decapods, the first pair of pleopods are specialised in the male for sperm transfer, many terrestrial crustaceans mate seasonally and return to the sea to release the eggs. Others, such as woodlice, lay their eggs on land, in most decapods, the females retain the eggs until they hatch into free-swimming larvae. Marine crustaceans are as ubiquitous in the oceans as insects are on land, some branchiurans are able to withstand rapid changes of salinity and will also switch hosts from marine to non-marine species. Krill are the layer and the most important part of the food chain in Antarctic animal communities
17.
Crab
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Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail, usually entirely hidden under the thorax. They live in all the oceans, in fresh water. Many other animals with similar names – such as crabs, king crabs, porcelain crabs, horseshoe crabs. Crabs are generally covered with an exoskeleton, composed primarily of calcium carbonate. Crabs are found in all of the oceans, while many crabs live in fresh water and on land. Crabs vary in size from the pea crab, a few wide, to the Japanese spider crab. About 850 species of crab are freshwater, terrestrial or semi-terrestrial species and they were previously thought to be a monophyletic group, but are now believed to represent at least two distinct lineages, one in the Old World and one in the New World. The earliest unambiguous crab fossils date from the Jurassic, although Carboniferous Imocaris, known only from its carapace, the radiation of crabs in the Cretaceous and afterward may be linked either to the break-up of Gondwana or to the concurrent radiation of bony fish, crabs main predators. Crabs often show marked sexual dimorphism, males often have larger claws, a tendency which is particularly pronounced in the fiddler crabs of the genus Uca. In fiddler crabs, males have one claw which is greatly enlarged, another conspicuous difference is the form of the pleon, in most male crabs, this is narrow and triangular in form, while females have a broader, rounded abdomen. This is because female crabs brood fertilised eggs on their pleopods, crabs attract a mate through chemical, visual, acoustic, or vibratory means. Pheromones are used by most fully aquatic crabs, while terrestrial and semiterrestrial crabs often use visual signals, the vast number of brachyuran crabs have internal fertilisation and mate belly-to-belly. For many aquatic species, mating takes place just after the female has moulted and is still soft, females can store the sperm for a long time before using it to fertilise their eggs. When fertilisation has taken place, the eggs are released onto the abdomen, below the tail flap. In this location, they are protected during embryonic development, females carrying eggs are called berried since the eggs resemble round berries. When development is complete, the releases the newly hatched larvae into the water. The release is timed with the tides. The free-swimming tiny zoea larvae can float and take advantage of water currents and they have a spine, which probably reduces the rate of predation by larger animals
18.
Lobster
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Lobsters comprise a family of large marine crustaceans. They have long bodies with muscular tails, and live in crevices or burrows on the sea floor, three of their five pairs of legs have claws, including the first pair, which are usually much larger than the others. Highly prized as seafood, lobsters are economically important, and are one of the most profitable commodities in coastal areas they populate. Commercially important species include two species of Homarus from the northern Atlantic Ocean, and scampi – the Northern Hemisphere genus Nephrops, although several other groups of crustaceans have the word lobster in their names, the unqualified term lobster generally refers to the clawed lobsters of the family Nephropidae. Clawed lobsters are not closely related to spiny lobsters or slipper lobsters, the closest living relatives of clawed lobsters are the reef lobsters and the three families of freshwater crayfish. Lobsters are invertebrates with a protective exoskeleton. Like most arthropods, lobsters must moult to grow, which leaves them vulnerable, during the moulting process, several species change colour. Lobsters have 10 walking legs, the front three pairs bear claws, the first of which are larger than the others, although lobsters are largely bilaterally symmetrical like most other arthropods, some genera possess unequal, specialised claws. Lobster anatomy includes the cephalothorax which fuses the head and the thorax, the lobsters head bears antennae, antennules, mandibles, the first and second maxillae, and the first, second, and third maxillipeds. Because lobsters live in murky environments at the bottom of the ocean, the lobster eye has a reflective structure above a convex retina. In contrast, most complex eyes use refractive ray concentrators and a concave retina, the abdomen includes swimmerets and its tail is composed of uropods and the telson. Lobsters, like snails and spiders, have blue blood due to the presence of hemocyanin which contains copper, in contrast, vertebrates and many other animals have red blood from iron-rich hemoglobin. Lobsters possess a green hepatopancreas, called the tomalley by chefs, Lobsters of the family Nephropidae are similar in overall form to a number of other related groups. The distinctions from fossil families such as the Chilenophoberidae are based on the pattern of grooves on the carapace, Lobsters live up to an estimated 45 to 50 years in the wild, although determining age is difficult. Research suggests that lobsters may not slow down, weaken or lose fertility with age, and this longevity may be due to telomerase, an enzyme that repairs long repetitive sections of DNA sequences at the ends of chromosomes, referred to as telomeres. Telomerase is expressed by most vertebrates during embryonic stages, but is absent from adult stages of life. However, unlike most vertebrates, lobsters express telomerase as adults through most tissue, Lobster longevity is limited by their size. Lobsters, like many other crustaceans, grow throughout life and are able to add new muscle cells at each moult
19.
Shrimp
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The term shrimp is used to refer to some decapod crustaceans, although the exact animals covered can vary. Used broadly, it may cover any of the groups with elongated bodies, in some fields, however, the term is used more narrowly, and may be restricted to Caridea, to smaller species of either group, or to only the marine species. Under the broader definition, shrimp may be synonymous with prawn, covering stalk-eyed swimming crustaceans with long narrow muscular tails, long whiskers, any small crustacean which resembles a shrimp tends to be called one. They swim forward by paddling with swimmerets on the underside of their abdomens, crabs and lobsters have strong walking legs, whereas shrimp have thin fragile legs which they use primarily for perching. There are thousands of species adapted to a range of habitats. They can be found feeding near the seafloor on most coasts and estuaries, as well as in rivers, to escape predators, some species flip off the seafloor and dive into the sediment. They usually live from one to seven years, Shrimp are often solitary, though they can form large schools during the spawning season. They play important roles in the chain and are an important food source for larger animals ranging from fish to whales. The muscular tails of many shrimp are edible to humans, and they are widely caught, commercial shrimp species support an industry worth 50 billion dollars a year, and in 2010 the total commercial production of shrimp was nearly 7 million tonnes. Shrimp farming became prevalent during the 1980s, particularly in China. There are significant issues with excessive bycatch when shrimp are captured in the wild, many shrimp species are small as the term shrimp suggests, about 2 cm long, but some shrimp exceed 25 cm. Larger shrimp are likely to be targeted commercially, and are often referred to as prawns. Shrimp are swimming crustaceans with long narrow muscular abdomens and long antennae, unlike crabs and lobsters, shrimp have well developed pleopods and slender walking legs, they are more adapted for swimming than walking. Historically, it was the distinction between walking and swimming that formed the primary taxonomic division into the former suborders Natantia and Reptantia, members of the Natantia were adapted for swimming while the Reptantia were adapted for crawling or walking. Some other groups also have names that include the word shrimp. The following description refers mainly to the anatomy of the common European shrimp, Crangon crangon. The body of the shrimp is divided into two parts, the head and thorax which are fused together to form the cephalothorax. The shell which protects the cephlathorax is harder and thicker than the shell elsewhere on the shrimp, the carapace typically surrounds the gills, through which water is pumped by the action of the mouthparts
20.
Insect
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Insects are a class of hexapod invertebrates within the arthropod phylum that have a chitinous exoskeleton, a three-part body, three pairs of jointed legs, compound eyes and one pair of antennae. They are the most diverse group of animals on the planet, including more than a million described species, the number of extant species is estimated at between six and ten million, and potentially represent over 90% of the differing animal life forms on Earth. Insects may be found in all environments, although only a small number of species reside in the oceans. The life cycles of insects vary but most hatch from eggs, insect growth is constrained by the inelastic exoskeleton and development involves a series of molts. The immature stages can differ from the adults in structure, habit and habitat, Insects that undergo 3-stage metamorphosis lack a pupal stage and adults develop through a series of nymphal stages. The higher level relationship of the Hexapoda is unclear, fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonflies with wingspans of 55 to 70 cm. The most diverse insect groups appear to have coevolved with flowering plants, adult insects typically move about by walking, flying or sometimes swimming. As it allows for rapid yet stable movement, many insects adopt a tripedal gait in which they walk with their legs touching the ground in alternating triangles, Insects are the only invertebrates to have evolved flight. Many insects spend at least part of their lives under water, with adaptations that include gills. Some species, such as water striders, are capable of walking on the surface of water, Insects are mostly solitary, but some, such as certain bees, ants and termites, are social and live in large, well-organized colonies. Some insects, such as earwigs, show maternal care, guarding their eggs, Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances, other species communicate with sounds, crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyridae in the beetle order communicate with light, humans regard certain insects as pests, and attempt to control them using insecticides and a host of other techniques. Some insects damage crops by feeding on sap, leaves or fruits, a few parasitic species are pathogenic. Some insects perform complex ecological roles, blow-flies, for example, help consume carrion, Many other insects are considered ecologically beneficial as predators and a few provide direct economic benefit. Silkworms and bees have been used extensively by humans for the production of silk and honey, in some cultures, people eat the larvae or adults of certain insects. Insect first appears documented in English in 1601 in Hollands translation of Pliny, translations of Aristotles term also form the usual word for insect in Welsh, Serbo-Croatian, Russian, etc. The evolutionary relationship of insects to other animal groups remains unclear, in the Pancrustacea theory, insects, together with Entognatha, Remipedia, and Cephalocarida, make up a natural clade labeled Miracrustacea
21.
Radula
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The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared to a tongue. It is a toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the molluscs, and is found in class of mollusc except the bivalves. Within the gastropods, the radula is used in feeding by both herbivorous and carnivorous snails and slugs, the arrangement of teeth on the radula ribbon varies considerably from one group to another. In most of the ancient lineages of gastropods, the radula is used to graze, by scraping diatoms and other microscopic algae off rock surfaces. Predatory marine snails such as the Naticidae use the radula plus an acidic secretion to bore through the shell of other molluscs, other predatory marine snails, such as the Conidae, use a specialized radula tooth as a poisoned harpoon. Predatory pulmonate land slugs, such as the ghost slug, use elongated razor-sharp teeth on the radula to seize, predatory cephalopods, such as squid, use the radula for cutting prey. The introduction of the radula is usually attributed to Alexander von Middendorff in 1847. A typical radula comprises a number of bilaterally-symmetrical self-similar rows of teeth rooted in a radular membrane, the elastic, delicate radular membrane may be a single tongue, or may split into two. See Hyaline shield for more details, the odontophore is the tongue of flesh underlying the radular membrane, and controls the organs protrusion and return. It can be likened to a pulley wheel over which the string is pulled. The radular teeth can generally bend in a sideways direction, in the patellogastropods, though, the teeth lost this ability and became fixed. The radula comprises multiple, identical rows of teeth, often, each tooth can be divided into three sections, a base, a shaft, and a cusp. In radulae that just sweep, rather than rasp, the underlying substrate, the teeth often tesselate with their neighbours, and this interlocking serves to make it more difficult to remove them from the radular ribbon. Each row of radular teeth consists of One central or median tooth On each side, one or more lateral teeth And then beyond that, the morphology of the radula is related to diet. However, it is not fixed per species, some molluscs can adapt the form of their radular teeth according to food sources are abundant. Pointed teeth are best suited to grazing on algal tissue, whereas blunt teeth are preferable if feeding habits entail scraping epiphytes from surfaces. The radula is used in two ways, either as a rake, generally to comb up microscopic, filamentous algae from a surface, or as a rasp
22.
Mollusca
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The molluscs compose the large phylum Mollusca of invertebrate animals. Around 85,000 extant species of molluscs are recognized, molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats and they are highly diverse, not just in size and in anatomical structure, but also in behaviour and in habitat. The phylum is divided into 9 or 10 taxonomic classes. The gastropods are by far the most numerous molluscs in terms of classified species, the three most universal features defining modern molluscs are a mantle with a significant cavity used for breathing and excretion, the presence of a radula, and the structure of the nervous system. Other than these things, molluscs express great morphological diversity, so many textbooks base their descriptions on an ancestral mollusc. This has a single, limpet-like shell on top, which is made of proteins and chitin reinforced with calcium carbonate, the underside of the animal consists of a single muscular foot. Although molluscs are coelomates, the coelom tends to be small, the main body cavity is a hemocoel through which blood circulates, their circulatory systems are mainly open. The generalized mollusc has two paired nerve cords, or three in bivalves, the brain, in species that have one, encircles the esophagus. Most molluscs have eyes, and all have sensors to detect chemicals, vibrations, the simplest type of molluscan reproductive system relies on external fertilization, but more complex variations occur. All produce eggs, from which may emerge trochophore larvae, more complex veliger larvae, good evidence exists for the appearance of gastropods, cephalopods and bivalves in the Cambrian period 541 to 485.4 million years ago. Molluscs have, for centuries, also been the source of important luxury goods, notably pearls, mother of pearl, Tyrian purple dye and their shells have also been used as money in some preindustrial societies. Mollusc species can also represent hazards or pests for human activities, the bite of the blue-ringed octopus is often fatal, and that of Octopus apollyon causes inflammation that can last for over a month. Stings from a few species of large tropical cone shells can also kill, schistosomiasis is transmitted to humans via water snail hosts, and affects about 200 million people. Snails and slugs can also be serious pests, and accidental or deliberate introduction of some snail species into new environments has seriously damaged some ecosystems. The words mollusc and mollusk are both derived from the French mollusque, which originated from the Latin molluscus, from mollis, molluscus was itself an adaptation of Aristotles τα μαλακά, the soft things, which he applied to cuttlefish. The scientific study of molluscs is accordingly called malacology, as it is now known these groups have no relation to molluscs, and very little to one another, the name Molluscoida has been abandoned. The most universal features of the structure of molluscs are a mantle with a significant cavity used for breathing and excretion
23.
Cephalopod beak
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All extant cephalopods have a two-part beak, or rostrum, situated in the buccal mass and surrounded by the muscular head appendages. The dorsal mandible fits into the mandible and together they function in a scissor-like fashion. They can be used to estimate the length and total body weight of the original animal as well as the total ingested biomass of the species. Cephalopod beaks gradually become less stiff as one moves from the tip to the base, in hydrated beaks of the Humboldt squid this stiffness gradient spans two orders of magnitude. Fossilised remains of beaks are known from a number of cephalopod groups, aptychi – paired plate-like structures found in ammonites – may also have been jaw elements. The beak may also be referred to as the mandibles or jaws, the abbreviations LRL and URL are commonly used in teuthology to refer to lower rostral length and upper rostral length, respectively. This is the measure of beak size in Decapodiformes, hood length is preferred for Octopodiformes
24.
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
25.
Lissamphibia
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The Lissamphibia are a group of tetrapods that includes all modern amphibians. Lissamphibians consist of three living groups, the Salientia, the Caudata, and the Gymnophiona, a fourth group, the Allocaudata, was moderately successful, spanning 160 million years from the Middle Jurassic to the Early Pliocene, but became extinct 2.5 million years ago. Some writers have argued that the early Permian dissorophoid Gerobatrachus hottoni is a lissamphibian, if it is not, the earliest known lissamphibians are Triadobatrachus and Czatkobatrachus from the Early Triassic. Some, if not all, lissamphibians share the following characteristics, some of these apply to the soft body parts, hence do not appear in fossils. Nevertheless, Haeckel considered the caecilians to be related to what he called Lissamphibia. In the early to mid 20th century, an origin of amphibians was favoured. With the single origin of amphibians being accepted by most herpetologists and paleontologists, however, the origin and relationships of the various lissamphibian groups both with each other and among other early tetrapods remains controversial. Not all paleontologists today are convinced that Lissamphibia is indeed a natural group, one of the hypotheses regarding their ancestors is that they evolved by paedomorphosis and miniaturization from early tetrapods. Benton, M. J. Vertebrate Palaeontology, 3rd ed. Blackwell, carroll, R. L. Vertebrate Paleontology and Evolution, WH Freeman & Co. San Mauro, Diego, Miguel Vences, Marina Alcobendas, Rafael Zardoya, initial diversification of living amphibians predated the breakup of Pangaea. Biology 356 - Major Features of Vertebrate Evolution by Dr. Robert Reisz, University of Toronto
26.
Polysaccharide
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They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch and glycogen, and structural polysaccharides such as cellulose, polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their building blocks. They may be amorphous or even insoluble in water, natural saccharides are generally of simple carbohydrates called monosaccharides with general formula n where n is three or more. Examples of monosaccharides are glucose, fructose, and glyceraldehyde, polysaccharides, meanwhile, have a general formula of Cxy where x is usually a large number between 200 and 2500. When the repeating units in the backbone are six-carbon monosaccharides, as is often the case, the general formula simplifies to n. Polysaccharides are an important class of biological polymers and their function in living organisms is usually either structure- or storage-related. Starch is used as a polysaccharide in plants, being found in the form of both amylose and the branched amylopectin. In animals, the structurally similar glucose polymer is the more densely branched glycogen, glycogens properties allow it to be metabolized more quickly, which suits the active lives of moving animals. Cellulose and chitin are examples of structural polysaccharides, cellulose is used in the cell walls of plants and other organisms, and is said to be the most abundant organic molecule on Earth. It has many such as a significant role in the paper and textile industries, and is used as a feedstock for the production of rayon, cellulose acetate, celluloid. Chitin has a structure, but has nitrogen-containing side branches. It is found in arthropod exoskeletons and in the walls of some fungi. It also has multiple uses, including surgical threads, polysaccharides also include callose or laminarin, chrysolaminarin, xylan, arabinoxylan, mannan, fucoidan and galactomannan. Nutrition polysaccharides are common sources of energy, many organisms can easily break down starches into glucose, however, most organisms cannot metabolize cellulose or other polysaccharides like chitin and arabinoxylans. These carbohydrate types can be metabolized by bacteria and protists. Ruminants and termites, for example, use microorganisms to process cellulose, even though these complex carbohydrates are not very digestible, they provide important dietary elements for humans. Called dietary fiber, these carbohydrates enhance digestion among other benefits, the main action of dietary fiber is to change the nature of the contents of the gastrointestinal tract, and to change how other nutrients and chemicals are absorbed
27.
Cellulose
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Cellulose is an organic compound with the formula n, a polysaccharide consisting of a linear chain of several hundred to many thousands of β linked D-glucose units. Cellulose is an important structural component of the cell wall of green plants, many forms of algae. Some species of bacteria secrete it to form biofilms, Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, Cellulose is mainly used to produce paperboard and paper. Smaller quantities are converted into a variety of derivative products such as cellophane. Conversion of cellulose from energy crops into biofuels such as ethanol is under investigation as an alternative fuel source. Cellulose for industrial use is mainly obtained from wood pulp and cotton, some animals, particularly ruminants and termites, can digest cellulose with the help of symbiotic micro-organisms that live in their guts, such as Trichonympha. In humans, cellulose acts as a bulking agent for feces and is often referred to as a dietary fiber. Cellulose was discovered in 1838 by the French chemist Anselme Payen, Cellulose was used to produce the first successful thermoplastic polymer, celluloid, by Hyatt Manufacturing Company in 1870. Production of rayon from cellulose began in the 1890s and cellophane was invented in 1912, hermann Staudinger determined the polymer structure of cellulose in 1920. The compound was first chemically synthesized in 1992, by Kobayashi, Cellulose has no taste, is odorless, is hydrophilic with the contact angle of 20–30 degrees, is insoluble in water and most organic solvents, is chiral and is biodegradable. It was shown to melt at 467 °C in 2016 and it can be broken down chemically into its glucose units by treating it with concentrated mineral acids at high temperature. Cellulose is derived from D-glucose units, which condense through β-glycosidic bonds and this linkage motif contrasts with that for α-glycosidic bonds present in starch and glycogen. This confers tensile strength in cell walls, where cellulose microfibrils are meshed into a polysaccharide matrix, compared to starch, cellulose is also much more crystalline. Whereas starch undergoes a crystalline to amorphous transition when heated beyond 60–70 °C in water, cellulose requires a temperature of 320 °C, several different crystalline structures of cellulose are known, corresponding to the location of hydrogen bonds between and within strands. Natural cellulose is cellulose I, with structures Iα and Iβ, Cellulose produced by bacteria and algae is enriched in Iα while cellulose of higher plants consists mainly of Iβ. Cellulose in regenerated cellulose fibers is cellulose II, the conversion of cellulose I to cellulose II is irreversible, suggesting that cellulose I is metastable and cellulose II is stable. With various chemical treatments it is possible to produce the structures cellulose III, many properties of cellulose depend on its chain length or degree of polymerization, the number of glucose units that make up one polymer molecule
28.
French language
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French is a Romance language of the Indo-European family. It descended from the Vulgar Latin of the Roman Empire, as did all Romance languages, French has evolved from Gallo-Romance, the spoken Latin in Gaul, and more specifically in Northern Gaul. Its closest relatives are the other langues doïl—languages historically spoken in northern France and in southern Belgium, French was also influenced by native Celtic languages of Northern Roman Gaul like Gallia Belgica and by the Frankish language of the post-Roman Frankish invaders. Today, owing to Frances past overseas expansion, there are numerous French-based creole languages, a French-speaking person or nation may be referred to as Francophone in both English and French. French is a language in 29 countries, most of which are members of la francophonie. As of 2015, 40% of the population is in Europe, 35% in sub-Saharan Africa, 15% in North Africa and the Middle East, 8% in the Americas. French is the fourth-most widely spoken mother tongue in the European Union, 1/5 of Europeans who do not have French as a mother tongue speak French as a second language. As a result of French and Belgian colonialism from the 17th and 18th century onward, French was introduced to new territories in the Americas, Africa, most second-language speakers reside in Francophone Africa, in particular Gabon, Algeria, Mauritius, Senegal and Ivory Coast. In 2015, French was estimated to have 77 to 110 million native speakers, approximately 274 million people are able to speak the language. The Organisation internationale de la Francophonie estimates 700 million by 2050, in 2011, Bloomberg Businessweek ranked French the third most useful language for business, after English and Standard Mandarin Chinese. Under the Constitution of France, French has been the language of the Republic since 1992. France mandates the use of French in official government publications, public education except in specific cases, French is one of the four official languages of Switzerland and is spoken in the western part of Switzerland called Romandie, of which Geneva is the largest city. French is the language of about 23% of the Swiss population. French is also a language of Luxembourg, Monaco, and Aosta Valley, while French dialects remain spoken by minorities on the Channel Islands. A plurality of the worlds French-speaking population lives in Africa and this number does not include the people living in non-Francophone African countries who have learned French as a foreign language. Due to the rise of French in Africa, the total French-speaking population worldwide is expected to reach 700 million people in 2050, French is the fastest growing language on the continent. French is mostly a language in Africa, but it has become a first language in some urban areas, such as the region of Abidjan, Ivory Coast and in Libreville. There is not a single African French, but multiple forms that diverged through contact with various indigenous African languages, sub-Saharan Africa is the region where the French language is most likely to expand, because of the expansion of education and rapid population growth
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Greek language
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Greek is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean. It has the longest documented history of any living language, spanning 34 centuries of written records and its writing system has been the Greek alphabet for the major part of its history, other systems, such as Linear B and the Cypriot syllabary, were used previously. The alphabet arose from the Phoenician script and was in turn the basis of the Latin, Cyrillic, Armenian, Coptic, Gothic and many other writing systems. Together with the Latin texts and traditions of the Roman world, during antiquity, Greek was a widely spoken lingua franca in the Mediterranean world and many places beyond. It would eventually become the official parlance of the Byzantine Empire, the language is spoken by at least 13.2 million people today in Greece, Cyprus, Italy, Albania, Turkey, and the Greek diaspora. Greek roots are used to coin new words for other languages, Greek. Greek has been spoken in the Balkan peninsula since around the 3rd millennium BC, the earliest written evidence is a Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the worlds oldest recorded living language. Among the Indo-European languages, its date of earliest written attestation is matched only by the now extinct Anatolian languages, the Greek language is conventionally divided into the following periods, Proto-Greek, the unrecorded but assumed last ancestor of all known varieties of Greek. The unity of Proto-Greek would have ended as Hellenic migrants entered the Greek peninsula sometime in the Neolithic era or the Bronze Age, Mycenaean Greek, the language of the Mycenaean civilisation. It is recorded in the Linear B script on tablets dating from the 15th century BC onwards, Ancient Greek, in its various dialects, the language of the Archaic and Classical periods of the ancient Greek civilisation. It was widely known throughout the Roman Empire, after the Roman conquest of Greece, an unofficial bilingualism of Greek and Latin was established in the city of Rome and Koine Greek became a first or second language in the Roman Empire. The origin of Christianity can also be traced through Koine Greek, Medieval Greek, also known as Byzantine Greek, the continuation of Koine Greek in Byzantine Greece, up to the demise of the Byzantine Empire in the 15th century. Much of the written Greek that was used as the language of the Byzantine Empire was an eclectic middle-ground variety based on the tradition of written Koine. Modern Greek, Stemming from Medieval Greek, Modern Greek usages can be traced in the Byzantine period and it is the language used by the modern Greeks, and, apart from Standard Modern Greek, there are several dialects of it. In the modern era, the Greek language entered a state of diglossia, the historical unity and continuing identity between the various stages of the Greek language is often emphasised. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than a foreign language and it is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, Homeric Greek is probably closer to demotic than 12-century Middle English is to modern spoken English, Greek is spoken by about 13 million people, mainly in Greece, Albania and Cyprus, but also worldwide by the large Greek diaspora. Greek is the language of Greece, where it is spoken by almost the entire population
30.
Albert Hofmann
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Albert Hofmann was a Swiss scientist known best for being the first person to synthesize, ingest, and learn of the psychedelic effects of lysergic acid diethylamide. Hofmann was also the first person to isolate, synthesize, and he authored more than 100 scientific articles and numerous books, including LSD, Mein Sorgenkind. In 2007, he shared first place, alongside Tim Berners-Lee, in a list of the 100 greatest living geniuses, Hofmann was born in Baden, Switzerland, the first of four children to factory toolmaker Adolf Hofmann and his wife Elisabeth. Owing to his fathers low income, Alberts godfather paid for his education, when his father became ill, Hofmann obtained a position as a commercial apprentice in concurrence with his studies. At the age of twenty, Hofmann began his degree at the University of Zürich. This decision was not easy for me, I had already taken a Latin matricular exam, and therefore a career in the humanities stood out most prominently in the foreground. Moreover, a career was tempting. In the end, however, it was a problem of knowledge which induced me to study chemistry. He began studying the medicinal plant squill and the fungus ergot as part of a program to purify and his main contribution was to elucidate the chemical structure of the common nucleus of the Scilla glycosides. While researching lysergic acid derivatives, Hofmann first synthesized LSD on 16 November 1938 and it was set aside for five years, until 16 April 1943, when Hofmann decided to reexamine it. While re-synthesizing LSD, he touched his hand to his mouth, nose or possibly eye, accidentally ingesting a small amount. He described what he felt as being, affected by a remarkable restlessness, combined with a slight dizziness. At home I lay down and sank into a not unpleasant intoxicatedlike condition, in a dreamlike state, with eyes closed, I perceived an uninterrupted stream of fantastic pictures, extraordinary shapes with intense, kaleidoscopic play of colors. After some two hours this condition faded away, three days later, on 19 April 1943, Hofmann intentionally ingested 250 micrograms of LSD. This day is now known as Bicycle Day, because he began to feel the effects of the drug as he rode home on a bike and this was the first intentional acid trip. Hofmann, later, was to discover 4-Acetoxy-DET, also known as ethacetin, ethylacybin, or 4-AcO-DET and he first synthesized 4-AcO-DET in 1958 in the Sandoz lab. Hofmann became director of the natural products department at Sandoz and continued studying hallucinogenic substances found in Mexican mushrooms and this led to the synthesis of psilocybin, the active agent of many magic mushrooms. Hofmann also became interested in the seeds of the Mexican morning glory species Turbina corymbosa and he was surprised to find the active compound of ololiuhqui, ergine, to be closely related to LSD
31.
Biosynthesis
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Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds and this process often consists of metabolic pathways. Some of these pathways are located within a single cellular organelle, while others involve enzymes that are located within multiple cellular organelles. Examples of these pathways include the production of lipid membrane components. The prerequisite elements for biosynthesis include, precursor compounds, chemical energy and these elements create monomers, the building blocks for macromolecules. Biosynthesis occurs due to a series of chemical reactions, for these reactions to take place, the following elements are necessary, Precursor compounds, these compounds are the starting molecules or substrates in a reaction. These may also be viewed as the reactants in a chemical process. Chemical energy, chemical energy can be found in the form of high energy molecules and these molecules are required for energetically unfavorable reactions. Furthermore, the hydrolysis of these compounds drives a reaction forward, high energy molecules, such as ATP, have three phosphates. Often, the phosphate is split off during hydrolysis and transferred to another molecule. Catalytic enzymes, these molecules are special proteins that catalyze a reaction by increasing the rate of the reaction, coenzymes or cofactors, cofactors are molecules that assist in chemical reactions. These may be metal ions, vitamin derivatives such as NADH and acetyl CoA, in the case of NADH, the molecule transfers a hydrogen, whereas acetyl CoA transfers an acetyl group, and ATP transfers a phosphate. Two examples of type of reaction occur during the formation of nucleic acids. For some of these steps, chemical energy is required, Precursor molecule + ATP ↽ − − ⇀ product AMP + PP i Simple compounds that are converted into other compounds with the assistance of cofactors. For example, the synthesis of phospholipids requires acetyl CoA, while the synthesis of another component, shingolipids. The general equation for these examples is, Precursor molecule + Cofactor → e n z y m e macromolecule Simple compounds that join together to create a macromolecule, for example, fatty acids join together to form phopspholipids. In turn, phospholipids and cholesterol interact noncovalently in order to form the lipid bilayer and this reaction may be depicted as follows, Molecule 1 + Molecule 2 ⟶ macromolecule Many intricate macromolecules are synthesized in a pattern of simple, repeated structures. For example, the simplest structures of lipids are fatty acids, fatty acids are hydrocarbon derivatives, they contain a carboxyl group “head” and a hydrocarbon chain “tail. ”These fatty acids create larger components, which in turn incorporate noncovalent interactions to form the lipid bilayer
32.
Hydroxy group
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A hydroxy or hydroxyl group is the entity with the formula OH. It contains oxygen bonded to hydrogen, in organic chemistry, alcohol and carboxylic acids contain hydroxy groups. The anion, called hydroxide, consists of a hydroxy group, according to IUPAC rules, the term hydroxyl refers to the radical OH only, while the functional group −OH is called hydroxy group. Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be deprotonated readily and this behavior is rationalized by the disparate electronegativities of oxygen and hydrogen. Hydroxy-containing compounds engage in hydrogen bonding, which causes them to stick together, organic compounds, which are often poorly soluble in water, become water soluble when they contain two or more hydroxy groups, as illustrated by sugars and amino acid. The hydroxy group is pervasive in chemistry and biochemistry, many inorganic compounds contain hydroxy groups, including sulfuric acid, the chemical compound produced on the largest scale industrially. Hydroxy groups participate in the reactions that link simple biological molecules into long chains. The joining of a fatty acid to glycerol to form a triacylglycerol removes the −OH from the end of the fatty acid. The joining of two aldehyde sugars to form a disaccharide removes the −OH from the group at the aldehyde end of one sugar. The creation of a bond to link two amino acids to make a protein removes the −OH from the carboxy group of one amino acid. Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived, when biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they react with DNA, lipids, and proteins. In 2009, Indias Chandrayaan-1 satellite, NASAs Cassini spacecraft and the Deep Impact probe have each detected the presence of water by evidence of hydroxyl fragments on the Moon. As reported by Richard Kerr, A spectrometer detected an infrared absorption at a wavelength of 3.0 micrometers that only water or hydroxyl—a hydrogen, NASA also reported in 2009 that the LCROSS probe revealed an ultraviolet emission spectrum consistent with hydroxyl presence. The Venus Express orbiter sent back Venus science data from April 2006 until December 2014, results from Venus Express include the detection of hydroxyl in the atmosphere. Hydronium Ion Oxide Reece, Jane, Urry, Lisa, Cain, Michael, Wasserman, Steven, Minorsky, Peter, Jackson, berge, Susan, Golden, Brandy, Triglia, Logan
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Acetyl group
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In organic chemistry, acetyl is a moiety, the acyl with chemical formula CH3CO. It is sometimes represented by the symbol Ac, the acetyl group contains a methyl group single-bonded to a carbonyl. The carbonyl center of a radical has one nonbonded electron with which it forms a chemical bond to the remainder R of the molecule. In IUPAC nomenclature, acetyl is called ethanoyl, although this term is rarely heard, the introduction of an acetyl group into a molecule is called acetylation. Acetyl-CoA is also created during the stage of cellular respiration. Histones and other proteins are modified by acetylation. For example, on the DNA level, histone acetylation by acetyltransferases causes an expansion of chromatin architecture, however, removal of the acetyl group by histone deacetylases condenses DNA structure, thereby preventing transcription. In addition to HDACs, Methyl group additions are able to bind DNA resulting in DNA methylation, and this is another common way to block DNA acetylation and inhibit gene transcription. Acetylation can be achieved using a variety of methods, the most common one being via the use of acetic anhydride or acetyl chloride, acetylation helps a given drug reach the brain more quickly, making the drugs effects more intense and increasing the effectiveness of a given dose. The acetyl group in acetylsalicylic acid enhances its effectiveness relative to the natural anti-inflammatant salicylic acid, in similar manner, acetylation converts the natural painkiller morphine into the far more potent heroin. There is some evidence that acetyl-L-carnitine may be effective for some applications than L-carnitine. Acetylation of resveratrol holds promise as one of the first anti-radiation medicines for human populations, acetylaldehyde Acetoxy group Histone acetylation and deacetylation Polyoxymethylene plastic, a. k. a. acetal resin, a thermoplastic
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Amine
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In organic chemistry, amines are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group, important amines include amino acids, biogenic amines, trimethylamine, and aniline, see Category, Amines for a list of amines. Inorganic derivatives of ammonia are also called amines, such as chloramine, see Category, compounds with a nitrogen atom attached to a carbonyl group, thus having the structure R–CO–NR′R″, are called amides and have different chemical properties from amines. An aliphatic amine has no aromatic ring attached directly to the nitrogen atom, aromatic amines have the nitrogen atom connected to an aromatic ring as in the various anilines. The aromatic ring decreases the alkalinity of the amine, depending on its substituents, the presence of an amine group strongly increases the reactivity of the aromatic ring, due to an electron-donating effect. Amines are organized into four subcategories, Primary amines — Primary amines arise when one of three atoms in ammonia is replaced by an alkyl or aromatic. Important primary alkyl amines include, methylamine, most amino acids, Secondary amines — Secondary amines have two organic substituents bound to the nitrogen together with one hydrogen. Important representatives include dimethylamine, while an example of an aromatic amine would be diphenylamine, tertiary amines — In tertiary amines, nitrogen has three organic substituents. Examples include trimethylamine, which has a fishy smell. Cyclic amines — Cyclic amines are either secondary or tertiary amines, examples of cyclic amines include the 3-membered ring aziridine and the six-membered ring piperidine. N-methylpiperidine and N-phenylpiperidine are examples of tertiary amines. It is also possible to have four organic substituents on the nitrogen and these species are not amines but are quaternary ammonium cations and have a charged nitrogen center. Quaternary ammonium salts exist with many kinds of anions, Amines are named in several ways. Typically, the compound is given the prefix amino- or the suffix, the prefix N- shows substitution on the nitrogen atom. An organic compound with multiple amino groups is called a diamine, triamine, tetraamine, systematic names for some common amines, Hydrogen bonding significantly influences the properties of primary and secondary amines. Thus the melting point and boiling point of amines is higher than those of the corresponding phosphines, for example, methyl and ethyl amines are gases under standard conditions, whereas the corresponding methyl and ethyl alcohols are liquids. Amines possess a characteristic smell, liquid amines have a distinctive fishy smell. The nitrogen atom features a lone pair that can bind H+ to form an ammonium ion R3NH+
35.
Hydrogen bond
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Hydrogen bonds can occur between molecules or within different parts of a single molecule. Depending on geometry and environment, the hydrogen bond free energy content is between 1 and 5 kcal/mol and this makes it stronger than a van der Waals interaction, but weaker than covalent or ionic bonds. This type of bond can occur in molecules such as water and in organic molecules like DNA. Intermolecular hydrogen bonding is responsible for the boiling point of water compared to the other group 16 hydrides that have much weaker hydrogen bonds. Intramolecular hydrogen bonding is responsible for the secondary and tertiary structures of proteins. It also plays an important role in the structure of polymers, in 2011, an IUPAC Task Group recommended a modern evidence-based definition of hydrogen bonding, which was published in the IUPAC journal Pure and Applied Chemistry. An accompanying detailed technical report provides the rationale behind the new definition, a hydrogen atom attached to a relatively electronegative atom will play the role of the hydrogen bond donor. This electronegative atom is usually fluorine, oxygen, or nitrogen, a hydrogen attached to carbon can also participate in hydrogen bonding when the carbon atom is bound to electronegative atoms, as is the case in chloroform, CHCl3. An example of a hydrogen donor is the hydrogen from the hydroxyl group of ethanol. In a hydrogen bond, the electronegative atom not covalently attached to the hydrogen is named proton acceptor, because of the small size of hydrogen relative to other atoms and molecules, the resulting charge, though only partial, represents a large charge density. A hydrogen bond results when this positive charge density attracts a lone pair of electrons on another heteroatom. The hydrogen bond is described as an electrostatic dipole-dipole interaction. These covalent features are more substantial when acceptors bind hydrogens from more electronegative donors, the partially covalent nature of a hydrogen bond raises the following questions, To which molecule or atom does the hydrogen nucleus belong. And Which should be labeled donor and which acceptor, liquids that display hydrogen bonding are called associated liquids. Hydrogen bonds can vary in strength from weak to extremely strong. For example, the central interresidue N−H···N hydrogen bond between guanine and cytosine is much stronger in comparison to the N−H···N bond between the adenine-thymine pair, the length of hydrogen bonds depends on bond strength, temperature, and pressure. The bond strength itself is dependent on temperature, pressure, bond angle, the typical length of a hydrogen bond in water is 197 pm. The ideal bond angle depends on the nature of the hydrogen bond donor, moore and Winmill used the hydrogen bond to account for the fact that trimethylammonium hydroxide is a weaker base than tetramethylammonium hydroxide
36.
Cicada
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The cicadas are a superfamily, the Cicadoidea, of insects in the order Hemiptera. They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers and it is divided into the Tettigarctidae, with two species in Australia, and Cicadidae, with more than 1,300 species described from around the world, many undescribed species remain. Cicadas have prominent eyes set wide apart, short antennae, and they have an exceptionally loud song, produced not by stridulation, but by vibrating drumlike tymbals rapidly. The earliest known fossil Cicadomorpha appeared in the Upper Permian period and they typically live in trees, feeding on sap, and laying their eggs in a slit in the bark. Most cicadas are cryptic, singing at night to avoid predators, Cicadas have been featured in literature since the time of Homers Iliad, and as motifs in art from the Chinese Shang dynasty. They have been used in myths and folklore to represent carefree living, Cicadas are eaten in various countries, including China, where the nymphs are served deep-fried in Shandong cuisine. The name is directly from the Latin cicada, meaning tree cricket, Cicadas are arranged into two families, the Tettigarctidae and Cicadidae. The two extant species of Tettigarctidae include one in southern Australia and the other in Tasmania, the family Cicadidae is subdivided into the subfamilies Cicadinae, Tettigadinae, and Cicadettinae, they are found on all continents except Antarctica. Some previous works included a family-level taxon called the Tibiceninae. The largest species is the Malaysian emperor cicada Megapomponia imperatoria, its wingspan is up to about 20 cm and they are also notable for the great length of time some species take to mature. At least 1300 cicada species are distributed worldwide with the majority being in the tropics, most genera are restricted to a single biogeographical region and many species have a very limited range. This high degree of endemism has been used to study the biogeography of complex island groups such as in Indonesia, about 100 species occur in the Palaearctic. A few species are found in southern Europe, and a species is in England, the New Forest cicada, Melampsalta montana. Most of the North American species are in the genus Neotibicen, the best-known North American genus, however, is Magicicada. These periodical cicadas have a long life cycle of 13 or 17 years. Many of them go by names such as cherry nose, brown baker, red eye, greengrocer, yellow Monday, whisky drinker, double drummer. The Australian greengrocer, Cyclochila australasiae, is among the loudest insects in the world, forty-two species from five genera populate New Zealand, ranging from sea level to mountain tops, and all are endemic to New Zealand and the surrounding islands. Fossil Cicadomorpha first appeared in the Upper Permian, the superfamily Palaeontinoidea contains three families
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Composite material
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The individual components remain separate and distinct within the finished structure. The new material may be preferred for reasons, common examples include materials which are stronger, lighter. More recently, researchers have begun to actively include sensing, actuation, computation and communication into composites. The most advanced examples perform routinely on spacecraft and aircraft in demanding environments, the earliest man-made composite materials were straw and mud combined to form bricks for building construction. Ancient brick-making was documented by Egyptian tomb paintings, wattle and daub is one of the oldest man-made composite materials, at over 6000 years old. Concrete is also a material, and is used more than any other man-made material in the world. As of 2006, about 7.5 billion cubic metres of concrete are made each year—more than one metre for every person on Earth. 2181–2055 BC and was used for death masks Cob Mud Bricks, concrete was described by Vitruvius, writing around 25 BC in his Ten Books on Architecture, distinguished types of aggregate appropriate for the preparation of lime mortars. For structural mortars, he recommended pozzolana, which were volcanic sands from the beds of Pozzuoli brownish-yellow-gray in colour near Naples. Natural cement-stones, after burning, produced cements used in concretes from post-Roman times into the 20th century, the glass fiber is relatively strong and stiff, whereas the polymer is ductile. Thus the resulting fiberglass is relatively stiff, strong, flexible, concrete is the most common artificial composite material of all and typically consists of loose stones held with a matrix of cement. Concrete is a material, and will not compress or shatter even under quite a large compressive force. However, concrete cannot survive tensile loading, therefore, to give concrete the ability to resist being stretched, steel bars, which can resist high stretching forces, are often added to concrete to form reinforced concrete. Fibre-reinforced polymers or FRPs include carbon-fiber-reinforced polymer or CFRP, and glass-reinforced plastic or GRP, if classified by matrix then there are thermoplastic composites, short fiber thermoplastics, long fibre thermoplastics or long fibre-reinforced thermoplastics. There are numerous thermoset composites, including paper composite panels, many advanced thermoset polymer matrix systems usually incorporate aramid fibre and carbon fibre in an epoxy resin matrix. Shape memory polymer composites are high-performance composites, formulated using fibre or fabric reinforcement and they can also be reheated and reshaped repeatedly without losing their material properties. These composites are ideal for such as lightweight, rigid, deployable structures, rapid manufacturing. Although high strain composites exhibit many similarities to shape memory polymers, Composites can also use metal fibres reinforcing other metals, as in metal matrix composites or ceramic matrix composites, which includes bone, cermet and concrete
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Protein
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Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a period of time and are then degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism. Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
39.
Calcium carbonate
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Calcium carbonate is a chemical compound with the formula CaCO3. It is a substance found in rocks as the minerals calcite and aragonite and is the main component of pearls and the shells of marine organisms, snails. Calcium carbonate is the ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale. It is medicinally used as a supplement or as an antacid. Calcium carbonate shares the properties of other carbonates. CaCO3 + CO2 + H2O → Ca2 This reaction is important in the erosion of rock, forming caverns. An unusual form of calcium carbonate is the hexahydrate, ikaite, ikaite is stable only below 6 °C. The vast majority of calcium used in industry is extracted by mining or quarrying. Pure calcium carbonate, can be produced from a quarried source. Alternatively, calcium carbonate is prepared from calcium oxide, other forms can be prepared, the denser, orthorhombic λ-CaCO3 and μ-CaCO3, occurring as the mineral vaterite. The aragonite form can be prepared by precipitation at temperatures above 85 °C, calcite contains calcium atoms coordinated by 6 oxygen atoms, in aragonite they are coordinated by 9 oxygen atoms. The vaterite structure is not fully understood, magnesium carbonate MgCO3 has the calcite structure, whereas strontium and barium carbonate adopt the aragonite structure, reflecting their larger ionic radii. Calcite, aragonite and vaterite are pure calcium carbonate minerals, industrially important source rocks which are predominantly calcium carbonate include limestone, chalk, marble and travertine. Eggshells, snail shells and most seashells are predominantly calcium carbonate, oyster shells have enjoyed recent recognition as a source of dietary calcium, but are also a practical industrial source. While not practical as a source, dark green vegetables such as broccoli. Beyond Earth, strong evidence suggests the presence of Calcium carbonate on Mars, signs of Calcium Carbonate have been detected at more than one location. This provides some evidence for the past presence of liquid water, Carbonate is found frequently in geologic settings and constitute an enormous carbon reservoir. Calcium carbonate occurs as aragonite, calcite and dolomite, the carbonate minerals form the rock types, limestone, chalk, marble, travertine, tufa, and others
40.
Caterpillar
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Caterpillars /ˈkætərˌpɪlər/ are the larval stage of members of the order Lepidoptera. As with most common names, the application of the word is arbitrary, caterpillars of most species are herbivorous, but not all, some are insectivorous, even cannibalistic. Some feed on other products, for example clothes moths feed on wool. Caterpillars as a rule are voracious feeders and many of them are among the most serious of agricultural pests. In fact many moth species are best known in their caterpillar stages because of the damage cause to fruits and other agricultural produce, whereas the moths are obscure. Conversely, various species of caterpillar are valued as sources of silk, as human or animal food, the origins of the word caterpillar date from the early 16th century. They derive from Middle English catirpel, catirpeller, probably an alteration of Old North French catepelose, cate, cat + pelose, caterpillars have soft bodies that can grow rapidly between moults. Only the head capsule is hardened, the mandibles are tough and sharp for chewing leaves. Behind the mandibles of the caterpillar are the spinnerets, for manipulating silk, antennae are present on either side of the labrum, but small and relatively inconspicuous. Some larvae of the Hymenoptera order can appear like the caterpillars of the Lepidoptera, such larvae are mainly seen in the sawfly family. Caterpillars can be confused with the larvae of sawflies, lepidopteran larvae can be differentiated by, the numbers of pairs of pro-legs, sawfly larvae have 6 while caterpillars have up to 5 pairs. The number of stemmata, the larvae have only two, while a caterpillar has six. The presence of crochets on the prolegs, these are absent in the Symphyta, sawfly larvae have an invariably smooth head capsule with no cleavage lines, while lepidopterous caterpillars bear an inverted Y or V. Many animals feed on caterpillars as they are rich in protein, as a result, caterpillars have evolved various means of defense. The appearance of a caterpillar can often repel a predator, its markings and certain body parts can make it seem poisonous, or bigger in size and thus threatening, some types of caterpillars are indeed poisonous. Caterpillars have evolved defenses against physical conditions such as cold, hot or dry environmental conditions, some Arctic species like Gynaephora groenlandica have special basking and aggregation behaviours apart from physiological adaptations to remain in a dormant state. Many caterpillars are cryptically colored and resemble the plants on which they feed and they may even have parts that mimic plant parts such as thorns. Their size varies from as little as 1 mm to about 75 millimetres, some look like objects in the environment such as bird droppings
41.
Elytron
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An elytron is sometimes also referred to as a shard. The elytra primarily serve as protective wing-cases for the hindwings underneath, in some groups, the elytra are fused together, rendering the insect flightless. Some of the beetles are a good example of this. The term is used to describe the hard scales of some polychaete worms. These outgrowths of the wall are distinguished from chaeta, which grow from follicles
42.
Beetle
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Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings is hardened into wing-cases, elytra, the Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms, new species are discovered frequently. The largest of all families, the Curculionidae with some 70,000 member species and they are found in almost every habitat except the sea and the polar regions. They interact with their ecosystems in several ways, beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Beetles typically have a hard exoskeleton including the elytra, though some such as the rove beetles have very short elytra while blister beetles have softer elytra. Some, such as, stag beetles have a sexual dimorphism. Many beetles are aposematic, with colours and patterns warning of their toxicity. Many beetles, including those that live in places, have effective camouflage. Beetles are prominent in human culture, from the sacred scarabs of ancient Egypt to beetlewing art and use as pets or fighting insects for entertainment, many beetle groups are brightly and attractively coloured making them objects of collection and decorative displays. Over 300 species are used as food, mostly as larvae, species widely consumed include mealworms, however, the major impact of beetles on human life is as agricultural, forestry, and horticultural pests. Serious pests include the boll weevil of cotton, the Colorado potato beetle, the coconut hispine beetle, most beetles, however, do not cause economic damage and many, such as the lady beetles and dung beetles are beneficial by helping to control insect pests. The name of the order, Coleoptera, comes from the Greek koleopteros, given to the group by Aristotle for their elytra, hardened shield-like forewings, from koleos, sheath. The English name beetle comes from the Old English word bitela, little biter, related to bītan, another Old English name for beetle is ceafor, chafer, used in names such as cockchafer, from the Proto-Germanic *kabraz-. Beetles are by far the largest order of insects, the roughly 400,000 species make up about 40% of all species so far described. The four estimates made use of host-specificity relationships, ratios with other taxa, plant, beetle ratios, and extrapolations based on body size by year of description. The heaviest beetle, indeed the heaviest insect stage, is the larva of the beetle, Goliathus goliatus, which can attain a mass of at least 115 g. Adult male goliath beetles are the heaviest beetle in its stage, weighing 70–100 g. Adult elephant beetles, Megasoma elephas and Megasoma actaeon often reach 50 g and 10 cm, the longest beetle is the Hercules beetle Dynastes hercules, with a maximum overall length of at least 16.7 cm including the very long pronotal horn
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Gyroid
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A gyroid is an infinitely connected triply periodic minimal surface discovered by Alan Schoen in 1970. The gyroid is the unique non-trivial embedded member of the family of the Schwarz P and D surfaces with angle of association approximately 38. 01°. The gyroid is similar to the Lidinoid, the gyroid was discovered in 1970 by NASA scientist Alan Schoen. He calculated the angle of association and gave a convincing demonstration pictures of intricate plastic models, Schoen noted that the gyroid contains neither straight lines nor planar symmetries. Karcher gave a different, more contemporary treatment of the surface in 1989 using conjugate surface construction, the gyroid separates space into two oppositely congruent labyrinths of passages. The gyroid has space group Ia3d, one way to visualize the surface is to picture the “square catenoids” of the P surface, rotation about the edges of the square generate the P surface. In the associate family, these square catenoids “open up” to form gyrating ribbons, for one value of the associate family parameter the gyrating ribbons lie in precisely the locations required to have an embedded surface. In nature, self-assembled gyroid structures are found in certain surfactant or lipid mesophases, in the polymer phase diagram, the gyroid phase is between the lamellar and cylindrical phases. Such self-assembled polymer structures have applications in experimental supercapacitors, solar cells. Gyroid membrane structures are found inside cells. Gyroid structures have photonic band gaps that make them potential photonic crystals, Gyroid structures have been observed in biological structural coloration such as butterfly wing scales, inspiring work on biomimetic materials. The gyroid mitochondrial membranes in tree shrew cones might have an optical function, triply Periodic Minimal Surfaces at schoengeometry. com Gyroid at MathWorld Rotatable picture of a gyroids period The gyroid at loomingtons Virtual Minimal Surface Museum
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Photonics
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Photonics is the physical science of light generation, detection, and manipulation through emission, transmission, modulation, signal processing, switching, amplification, and detection/sensing. Though covering all lights technical applications over the spectrum, most photonic applications are in the range of visible. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s, Photonics as a field began with the invention of the laser in 1960. Other developments followed, the diode in the 1970s, optical fibers for transmitting information. These inventions formed the basis for the revolution of the late 20th century. Though coined earlier, the term came into common use in the 1980s as fiber-optic data transmission was adopted by telecommunications network operators. At that time, the term was used widely at Bell Laboratories and its use was confirmed when the IEEE Lasers and Electro-Optics Society established an archival journal named Photonics Technology Letters at the end of the 1980s. During the period leading up to the dot-com crash circa 2001, further growth of photonics is likely if current silicon photonics developments are successful. Photonics is closely related to optics, classical optics long preceded the discovery that light is quantized, when Albert Einstein famously explained the photoelectric effect in 1905. Optics tools include the lens, the reflecting mirror. Photonics is related to optics, optomechanics, electro-optics, optoelectronics. However, each area has different connotations by scientific and government communities. Quantum optics often connotes fundamental research, whereas photonics is used to connote applied research, the term optoelectronics connotes devices or circuits that comprise both electrical and optical functions, i. e. a thin-film semiconductor device. Photonics also relates to the science of quantum information and quantum optics. Included are all areas from everyday life to the most advanced science, just as applications of electronics have expanded dramatically since the first transistor was invented in 1948, the unique applications of photonics continue to emerge. The science of photonics includes investigation of the emission, transmission, amplification, detection, light sources used in photonics are usually far more sophisticated than light bulbs. Photonics commonly uses semiconductor light sources like light-emitting diodes, superluminescent diodes, other light sources include single photon sources, fluorescent lamps, cathode ray tubes, and plasma screens. Characteristic for research on semiconductor light sources is the frequent use of III-V semiconductors instead of the classical semiconductors like silicon and this is due to the special properties of III-V semiconductors that allow for the implementation of light emitting devices
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Iridescence
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Iridescence is the phenomenon of certain surfaces that appear to gradually change colour as the angle of view or the angle of illumination changes. Examples of iridescence include soap bubbles, butterfly wings and sea shells and it is often created by structural coloration. The word iridescence is derived in part from the Greek word ἶρις îris, meaning rainbow, Iris in turn derives from the goddess Iris of Greek mythology, who is the personification of the rainbow and acted as a messenger of the gods. Goniochromism is derived from the Greek words gonia, meaning angle, iridescence is an optical phenomenon of surfaces in which hue changes with the angle of observation and the angle of illumination. It is often caused by reflections from two or more semi-transparent surfaces in which phase shift and interference of the reflections modulates the incidental light. The thickness of the layers of the material determines the interference pattern, iridescence is also found in plants, animals and many other items. The range of colours of natural iridescent objects can be narrow, iridescence can also be created by diffraction. This is found in items like CDs, DVDs, or cloud iridescence, in the case of diffraction, the entire rainbow of colours will typically be observed as the viewing angle changes. In biology, this type of results from the formation of diffraction gratings on the surface. In biological uses, colours produced other than with pigments or dyes are called structural coloration and it was later found that iridescence in the peacock is due to a complex photonic crystal. The feathers of birds such as kingfishers, Birds-of-paradise, hummingbirds, parrots, starlings, grackles, ducks, the lateral line on the Neon tetra is also iridescent. A single iridescent species of gecko, Cnemaspis kolhapurensis, was identified in India in 2009, the tapetum lucidum, present in the eyes of many vertebrates, is also iridescent. Many groups of plants have developed iridescence as an adaptation to use light in dark environments such as the lower levels of tropical forests. Nanocellulose is sometimes iridescent, as are films of gasoline and some other hydrocarbons. Iridescent products in the cosmetic and clothing industries are often referred as being holographic
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Phenotype
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A phenotype is the composite of an organisms observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior. A phenotype results from the expression of a genetic code, its genotype, as well as the influence of environmental factors. When two or more clearly different phenotypes exist in the population of a species, the species is called polymorphic. A well-documented polymorphism is Labrador Retriever coloring, while the color depends on many genes, it is clearly seen in the environment as yellow, black. This genotype-phenotype distinction was proposed by Wilhelm Johannsen in 1911 to make clear the difference between an organisms heredity and what that heredity produces, the distinction is similar to that proposed by August Weismann, who distinguished between germ plasm and somatic cells. The term phenotype has sometimes incorrectly used as a shorthand for phenotypic difference from wild type. Despite its seemingly straightforward definition, the concept of the phenotype has hidden subtleties and it may seem that anything dependent on the genotype is a phenotype, including molecules such as RNA and proteins. It may seem that this goes beyond the intentions of the concept with its focus on the organism in itself. Either way, the term phenotype includes traits or characteristics that can be visible by some technical procedure. A notable extension to this idea is the presence of molecules or metabolites that are generated by organisms from chemical reactions of enzymes. Another extension adds behavior to the phenotype, since behaviors are also observable characteristics, behavioral phenotypes include cognitive, personality, and behavioral patterns. Some behavioral phenotypes may characterize psychiatric disorders or syndromes, phenotypic variation is a fundamental prerequisite for evolution by natural selection. It is the organism as a whole that contributes to the next generation. Without phenotypic variation, there would be no evolution by natural selection, the plant Hieracium umbellatum is found growing in two different habitats in Sweden. These habitats alternate along the coast of Sweden and the habitat that the seeds of Hieracium umbellatum land in, the concept of phenotype can be extended to variations below the level of the gene that affect an organisms fitness. For example, silent mutations that do not change the amino acid sequence of a gene may change the frequency of guanine-cytosine base pairs. The term extended phenotype refers to the idea that a phenotype is not restricted to biological processes, the concept generalized by Richard Dawkins explains that phenotype includes all the influence a gene has on the environment and other organisms. ”There are three types of extended phenotypes. The first describes an organism using architectural constructions to modify their environment for living, the most common example given by Dawkins is the beaver
. PMID 25772447.
