A carbohydrate is a biomolecule consisting of carbon and oxygen atoms with a hydrogen–oxygen atom ratio of 2:1 and thus with the empirical formula Cmn. This formula holds true for monosaccharides; some exceptions exist. The carbohydrates are technically hydrates of carbon; the term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars and cellulose. The saccharides are divided into four chemical groups: monosaccharides, disaccharides and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars; the word saccharide comes from the Greek word σάκχαρον, meaning "sugar". While the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides often end in the suffix -ose, as in the monosaccharides fructose and glucose and the disaccharides sucrose and lactose. Carbohydrates perform numerous roles in living organisms. Polysaccharides serve as structural components; the 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA.
The related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the immune system, preventing pathogenesis, blood clotting, development, they are found in a wide variety of processed foods. Starch is a polysaccharide, it is abundant in cereals and processed food based on cereal flour, such as bread, pizza or pasta. Sugars appear in human diet as table sugar, lactose and fructose, both of which occur in honey, many fruits, some vegetables. Table sugar, milk, or honey are added to drinks and many prepared foods such as jam and cakes. Cellulose, a polysaccharide found in the cell walls of all plants, is one of the main components of insoluble dietary fiber. Although it is not digestible, insoluble dietary fiber helps to maintain a healthy digestive system by easing defecation. Other polysaccharides contained in dietary fiber include resistant starch and inulin, which feed some bacteria in the microbiota of the large intestine, are metabolized by these bacteria to yield short-chain fatty acids.
In scientific literature, the term "carbohydrate" has many synonyms, like "sugar", "saccharide", "ose", "glucide", "hydrate of carbon" or "polyhydroxy compounds with aldehyde or ketone". Some of these terms, specially "carbohydrate" and "sugar", are used with other meanings. In food science and in many informal contexts, the term "carbohydrate" means any food, rich in the complex carbohydrate starch or simple carbohydrates, such as sugar. In lists of nutritional information, such as the USDA National Nutrient Database, the term "carbohydrate" is used for everything other than water, fat and ethanol; this includes chemical compounds such as acetic or lactic acid, which are not considered carbohydrates. It includes dietary fiber, a carbohydrate but which does not contribute much in the way of food energy though it is included in the calculation of total food energy just as though it were a sugar. In the strict sense, "sugar" is applied for sweet, soluble carbohydrates, many of which are used in food.
The name "carbohydrate" was used in chemistry for any compound with the formula Cm n. Following this definition, some chemists considered formaldehyde to be the simplest carbohydrate, while others claimed that title for glycolaldehyde. Today, the term is understood in the biochemistry sense, which excludes compounds with only one or two carbons and includes many biological carbohydrates which deviate from this formula. For example, while the above representative formulas would seem to capture the known carbohydrates and abundant carbohydrates deviate from this. For example, carbohydrates display chemical groups such as: N-acetyl, carboxylic acid and deoxy modifications. Natural saccharides are built of simple carbohydrates called monosaccharides with general formula n where n is three or more. A typical monosaccharide has the structure H–x–y–H, that is, an aldehyde or ketone with many hydroxyl groups added one on each carbon atom, not part of the aldehyde or ketone functional group. Examples of monosaccharides are glucose and glyceraldehydes.
However, some biological substances called "monosaccharides" do not conform to this formula and there are many chemicals that do conform to this formula but are not considered to be monosaccharides. The open-chain form of a monosaccharide coexists with a closed ring form where the aldehyde/ketone carbonyl group carbon and hydroxyl group react forming a hemiacetal with a new C–O–C bridge. Monosaccharides can be linked togeth
The egg is the organic vessel containing the zygote in which an embryo develops until it can survive on its own. An egg results from fertilization of an egg cell. Most arthropods and mollusks lay eggs, although some, such as scorpions do not. Reptile eggs, bird eggs, monotreme eggs are laid out of water, are surrounded by a protective shell, either flexible or inflexible. Eggs laid on land or in nests are kept within a warm and favorable temperature range while the embryo grows; when the embryo is adequately developed it hatches, i.e. breaks out of the egg's shell. Some embryos have a temporary egg tooth they use to pip, or break the eggshell or covering; the largest recorded egg is from a whale shark, was 30 cm × 14 cm × 9 cm in size. Whale shark eggs hatch within the mother. At 1.5 kg and up to 17.8 cm × 14 cm, the ostrich egg is the largest egg of any living bird, though the extinct elephant bird and some dinosaurs laid larger eggs. The bee hummingbird produces the smallest known bird egg; some eggs laid by reptiles and most fish, amphibians and other invertebrates can be smaller.
Reproductive structures similar to the egg in other kingdoms are termed "spores," or in spermatophytes "seeds," or in gametophytes "egg cells". Several major groups of animals have distinguishable eggs; the most common reproductive strategy for fish is known as oviparity, in which the female lays undeveloped eggs that are externally fertilized by a male. Large numbers of eggs are laid at one time and the eggs are left to develop without parental care; when the larvae hatch from the egg, they carry the remains of the yolk in a yolk sac which continues to nourish the larvae for a few days as they learn how to swim. Once the yolk is consumed, there is a critical point after which they must learn how to hunt and feed or they will die. A few fish, notably the rays and most sharks use ovoviviparity in which the eggs are fertilized and develop internally; however the larvae still grow inside the egg consuming the egg's yolk and without any direct nourishment from the mother. The mother gives birth to mature young.
In certain instances, the physically most developed offspring will devour its smaller siblings for further nutrition while still within the mother's body. This is known as intrauterine cannibalism. In certain scenarios, some fish such as the hammerhead shark and reef shark are viviparous, with the egg being fertilized and developed internally, but with the mother providing direct nourishment; the eggs of fish and amphibians are jellylike. Cartilagenous fish eggs are fertilized internally and exhibit a wide variety of both internal and external embryonic development. Most fish species spawn eggs that are fertilized externally with the male inseminating the eggs after the female lays them; these eggs would dry out in the air. Air-breathing amphibians lay their eggs in water, or in protective foam as with the Coast foam-nest treefrog, Chiromantis xerampelina. Bird eggs are incubated for a time that varies according to the species. Average clutch sizes range from one to about 17; some birds lay eggs when not fertilized.
The default color of vertebrate eggs is the white of the calcium carbonate from which the shells are made, but some birds passerines, produce colored eggs. The pigment biliverdin and its zinc chelate give a green or blue ground color, protoporphyrin produces reds and browns as a ground color or as spotting. Non-passerines have white eggs, except in some ground-nesting groups such as the Charadriiformes and nightjars, where camouflage is necessary, some parasitic cuckoos which have to match the passerine host's egg. Most passerines, in contrast, lay colored eggs if there is no need of cryptic colors; however some have suggested that the protoporphyrin markings on passerine eggs act to reduce brittleness by acting as a solid state lubricant. If there is insufficient calcium available in the local soil, the egg shell may be thin in a circle around the broad end. Protoporphyrin speckling compensates for this, increases inversely to the amount of calcium in the soil. For the same reason eggs in a clutch are more spotted than early ones as the female's store of calcium is depleted.
The color of individual eggs is genetically influenced, appears to be inherited through the mother only, suggesting that the gene responsible for pigmentation is on the sex determining W chromosome. It used to be thought that color was applied to the shell before laying, but this research shows that coloration is an integral part of the development of the shell, with the same protein responsible for depositing calcium carbonate, or protoporphyrins when there is a lack of that mineral. In species such as the common guillemot, which nest in large groups, each female's eggs have different markings, making it easier for females to identify their own eggs on the crowded cliff ledges on which they breed. Bird eggshells are diverse. For example: cormorant eggs are rough and chalky tinamou eggs are shiny duck eggs are oily and waterproof cassowary eggs are pittedTiny pores in bird eggshells allow the embryo to breathe; the domestic
A carnivore, meaning "meat eater", is an organism that derives its energy and nutrient requirements from a diet consisting or of animal tissue, whether through predation or scavenging. Animals that depend on animal flesh for their nutrient requirements are called obligate carnivores while those that consume non-animal food are called facultative carnivores. Omnivores consume both animal and non-animal food, apart from the more general definition, there is no defined ratio of plant to animal material that would distinguish a facultative carnivore from an omnivore. A carnivore at the top of the food chain, not preyed upon by other animals, is termed an apex predator. "Carnivore" may refer to the mammalian order Carnivora, but this is somewhat misleading: many, but not all, Carnivora are meat eaters, fewer are true obligate carnivores. For example, while the Arctic polar bear eats meat most species of bears are omnivorous, the giant panda is herbivorous. There are many carnivorous species that are not members of Carnivora.
Outside the animal kingdom, there are several genera containing carnivorous plants and several phyla containing carnivorous fungi. Carnivores are sometimes characterized by their type of prey. For example, animals that eat insects and similar invertebrates are called insectivores, while those that eat fish are called piscivores; the first tetrapods, or land-dwelling vertebrates, were piscivorous amphibians known as labyrinthodonts. They gave rise to insectivorous vertebrates and to predators of other tetrapods. Carnivores may alternatively be classified according to the percentage of meat in their diet; the diet of a hypercarnivore consists of more than 70% meat, that of a mesocarnivore 30–70%, that of a hypocarnivore less than 30%, with the balance consisting of non-animal foods such as fruits, other plant material, or fungi. Obligate or "true" carnivores are those. While obligate carnivores might be able to ingest small amounts of plant matter, they lack the necessary physiology required to digest it.
In fact, some obligate carnivorous mammals will only ingest vegetation for the sole purpose of its use as an emetic, to self-induce vomiting of the vegetation along with the other food it had ingested that upset its stomach. Obligate carnivores include the axolotl, which consumes worms and larvae in its environment, but if necessary will consume algae, as well as all felids which require a diet of animal flesh and organs. Cats have high protein requirements and their metabolisms appear unable to synthesize essential nutrients such as retinol, arginine and arachidonic acid. Characteristics associated with carnivores include strength and keen senses for hunting, as well as teeth and claws for capturing and tearing prey. However, some carnivores do not hunt and are scavengers, lacking the physical characteristics to bring down prey. Carnivores have comparatively short digestive systems, as they are not required to break down the tough cellulose found in plants. Many hunting animals have evolved eyes facing forward.
This is universal among mammalian predators, while most reptile and amphibian predators have eyes facing sideways. Predation predates the rise of recognized carnivores by hundreds of millions of years; the earliest predators were microbial organisms, which grazed on others. Because the fossil record is poor, these first predators could date back anywhere between 1 and over 2.7 Gya. The rise of eukaryotic cells at around 2.7 Gya, the rise of multicellular organisms at about 2 Gya, the rise of mobile predators have all been attributed to early predatory behavior, many early remains show evidence of boreholes or other markings attributed to small predator species. Among more familiar species, the first vertebrate carnivores were fish, amphibians that moved on to land. Early tetrapods were large amphibious piscivores; some scientists assert that Dimetrodon "was the first terrestrial vertebrate to develop the curved, serrated teeth that enable a predator to eat prey much larger than itself." While amphibians continued to feed on fish and insects, reptiles began exploring two new food types: tetrapods and plants.
Carnivory was a natural transition from insectivory for medium and large tetrapods, requiring minimal adaptation. In the Mesozoic, some theropod dinosaurs such as Tyrannosaurus rex were obligate carnivores. Though the theropods were the larger carnivores, several carnivorous mammal groups were present. Most notable are the gobiconodontids, the triconodontid Jugulator, the deltatheroideans and Cimolestes. Many of these, such as Repenomamus and Cimolestes, were among the largest mammals in their faunal assemblages, capable of attacking dinosaurs. In the early-to-mid-Cenozoic, the dominant predator forms were mammals: hyaenodonts, entelodonts, ptolemaiidans and mesonychians, representing a great diversity of eutherian carnivores
Fish are gill-bearing aquatic craniate animals that lack limbs with digits. They form a sister group to the tunicates. Included in this definition are the living hagfish and cartilaginous and bony fish as well as various extinct related groups. Tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered 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, unless it is used in the cladistic sense, including tetrapods. 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.
Many fish of the Paleozoic developed external armor. The first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Most fish are ectothermic, allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature. Fish can communicate in their underwater environments through the use of acoustic communication. Acoustic communication in fish involves the transmission of acoustic signals from one individual of a species to another; the production of sounds as a means of communication among fish is most used in the context of feeding, aggression or courtship behaviour. The sounds emitted by fish can vary depending on the stimulus involved, they can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder.
Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams to the abyssal and hadal depths of the deepest oceans, although no species has yet been documented in the deepest 25% of the ocean. With 33,600 described species, fish exhibit greater species diversity than any other group of vertebrates. Fish are an important resource for humans worldwide as food. Commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean, they are caught by recreational fishers, kept as pets, raised by fishkeepers, exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, as the subjects of art and movies. Fish do not represent a monophyletic group, therefore the "evolution of fish" is not studied as a single event. Early fish from the fossil record are represented by a group of small, armored fish known as ostracoderms. Jawless fish lineages are 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, or a combination of factors. 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 larval form into adulthood, although the reverse is the case. Fish are a paraphyletic group: that is, any clade containing all fish contains the tetrapods, which are not fish. For this reason, groups such as the "Class Pisces" seen in older reference works are no longer used in formal classifications. Traditional classification divides fish into three extant classes, with extinct forms sometimes classified within the tree, sometimes as their own classes: Class Agnatha Subclass Cyclostomata Subclass Ostracodermi † Class Chondrichthyes Subclass Elasmobranchii Subclass Holocephali Class Placodermi † Class Acanthodii † Class Osteichthyes Subclass Actinopterygii Subclass Sarcopterygii The above scheme is the one most encountered in non-specialist and general works.
Many of the above groups are paraphyletic, in that they have given rise to successive groups: Agnathans are ancestral to Chondrichthyes, who again have given rise to Acanthodiians, the ancestors of Osteichthyes. With the arrival of phylogenetic nomenclature, the fishes has been split up into a more detailed scheme, with the following major groups: Class Myxini Class Pteraspidomorphi † Class Thelodonti † Class Anaspida † Class Petromyzontida or Hyperoartia Petromyzontidae Class Conodonta † Class Cephalaspidomorphi † Galeaspida † Pituriaspida † Osteostraci † Infraphylum Gnathostomata Class Placodermi † Class Chondrichthyes Class Acanthodii † Superclass Osteichthy
Meat is animal flesh, eaten as food. Humans have killed animals for meat since prehistoric times; the advent of civilization allowed the domestication of animals such as chickens, rabbits and cattle. This led to their use in meat production on an industrial scale with the aid of slaughterhouses. Meat is composed of water and fat, it is edible raw, but is eaten after it has been cooked and seasoned or processed in a variety of ways. Unprocessed meat will spoil or rot within hours or days as a result of infection with and decomposition by bacteria and fungi. Meat is important in economy and culture though its mass production and consumption has been determined to pose risks for human health and the environment. Many religions have rules about which meat may not be eaten. Vegetarians may abstain from eating meat because of concerns about the ethics of eating meat, environmental effects of meat production or nutritional effects of consumption; the word meat comes from the Old English word mete. The term is related to mad in Danish, mat in Swedish and Norwegian, matur in Icelandic and Faroese, which mean'food'.
The word mete exists in Old Frisian to denote important food, differentiating it from swiets and dierfied. Most meat refers to skeletal muscle and associated fat and other tissues, but it may describe other edible tissues such as offal. Meat is sometimes used in a more restrictive sense to mean the flesh of mammalian species raised and prepared for human consumption, to the exclusion of fish, other seafood, poultry, or other animals. In the context of food, meat can refer to "the edible part of something as distinguished from its covering", for example, coconut meat. Paleontological evidence suggests that meat constituted a substantial proportion of the diet of the earliest humans. Early hunter-gatherers depended on the organized hunting of large animals such as bison and deer; the domestication of animals, of which we have evidence dating back to the end of the last glacial period, allowed the systematic production of meat and the breeding of animals with a view to improving meat production.
Animals that are now principal sources of meat were domesticated in conjunction with the development of early civilizations: Sheep, originating from western Asia, were domesticated with the help of dogs prior to the establishment of settled agriculture as early as the 8th millennium BCE. Several breeds of sheep were established in ancient Mesopotamia and Egypt by 3500–3000 BCE. Today, more than 200 sheep-breeds exist. Cattle were domesticated in Mesopotamia after settled agriculture was established about 5000 BCE, several breeds were established by 2500 BCE. Modern domesticated cattle fall into the groups Bos taurus and Bos taurus indicus, both descended from the now-extinct aurochs; the breeding of beef cattle, cattle optimized for meat production as opposed to animals best suited for work or dairy purposes, began in the middle of the 18th century. Domestic pigs, which are descended from wild boars, are known to have existed about 2500 BCE in modern-day Hungary and in Troy. Pork sausages and hams were of great commercial importance in Greco-Roman times.
Pigs continue to be bred intensively as they are being optimized to produce meat best suited for specific meat products. Other animals have been raised or hunted for their flesh; the type of meat consumed varies much between different cultures, changes over time, depending on factors such as tradition and the availability of the animals. The amount and kind of meat consumed varies by income, both between countries and within a given country. Horses are eaten in France, Italy and Japan, among other countries. Horses and other large mammals such as reindeer were hunted during the late Paleolithic in western Europe. Dogs are consumed in South Korea and Vietnam. Dogs are occasionally eaten in the Arctic regions. Dog meat has been consumed in various parts of the world, such as Hawaii, Japan and Mexico. Cats are consumed in Southern China and sometimes in Northern Italy. Guinea pigs are raised for their flesh in the Andes. Whales and dolphins are hunted for their flesh, in Japan, Siberia, the Faroe Islands, Iceland, Saint Vincent and the Grenadines and by two small communities in Indonesia.
Modern agriculture employs a number of techniques, such as progeny testing, to speed artificial selection by breeding animals to acquire the qualities desired by meat producers. For instance, in the wake of well-publicised health concerns associated with saturated fats in the 1980s, the fat content of United Kingdom beef and lamb fell from 20–26 percent to 4–8 percent within a few decades, due to both selective breeding for leanness and changed methods of butchery. Methods of genetic engineering aimed at improving the meat production qualities of animals are now becoming available. Though it is a old industry, meat production continues to be shaped by the evolving demands of customers; the trend towards selling meat in pre-packaged cuts has increased the demand for larger breeds of cattle, which are better suited to producing such cuts. More animals not exploited for their meat are now being farmed the more agile and mobile species, whose muscles tend to be developed better than those of cattle, sheep or pigs.
Examples are the various antelope species, the zebra, water buffalo and camel, as well as non-
Cheese is a dairy product derived from milk, produced in a wide range of flavors and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk the milk of cows, goats, or sheep. During production, the milk is acidified, adding the enzyme rennet causes coagulation; the solids are pressed into final form. Some cheeses have molds throughout. Most cheeses melt at cooking temperature. Over a thousand types of cheese from various countries are produced, their styles and flavors depend on the origin of the milk, whether they have been pasteurized, the butterfat content, the bacteria and mold, the processing, aging. Herbs, spices, or wood smoke may be used as flavoring agents; the yellow to red color of many cheeses, such as Red Leicester, is produced by adding annatto. Other ingredients may be added to some cheeses, such as black pepper, chives or cranberries. For a few cheeses, the milk is curdled by adding acids such as lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid the addition of rennet completes the curdling.
Vegetarian alternatives to rennet are available. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, lower shipping costs. Cheese is valued for its portability, long life, high content of fat, protein and phosphorus. Cheese is more compact and has a longer shelf life than milk, although how long a cheese will keep depends on the type of cheese. Speaking, hard cheeses, such as Parmesan last longer than soft cheeses, such as Brie or goat's milk cheese; the long storage life of some cheeses when encased in a protective rind, allows selling when markets are favorable. There is some debate as to the best way to store cheese, but some experts say that wrapping it in cheese paper provides optimal results. Cheese paper is coated in a porous plastic on the inside, the outside has a layer of wax; this specific combination of plastic on the inside and wax on the outside protects the cheese by allowing condensation on the cheese to be wicked away while preventing moisture from within the cheese escaping.
A specialist seller of cheese is sometimes known as a cheesemonger. Becoming an expert in this field requires some formal education and years of tasting and hands-on experience, much like becoming an expert in wine or cuisine; the cheesemonger is responsible for all aspects of the cheese inventory: selecting the cheese menu, receiving and ripening. The word cheese comes from Latin caseus, from which the modern word casein is derived; the earliest source is from the proto-Indo-European root *kwat-, which means "to ferment, become sour". The word cheese comes from cīese or cēse. Similar words are shared by other West Germanic languages—West Frisian tsiis, Dutch kaas, German Käse, Old High German chāsi—all from the reconstructed West-Germanic form *kāsī, which in turn is an early borrowing from Latin; the Online Etymological Dictionary states that "cheese" comes from "Old English cyse, cese...from West Germanic *kasjus, from Latin caseus "cheese"." The Online Etymological Dictionary states. Compare fromage.
Old Norse ostr, Danish ost, Swedish ost are related to Latin ius "broth, juice.'"When the Romans began to make hard cheeses for their legionaries' supplies, a new word started to be used: formaticum, from caseus formatus, or "molded cheese". It is from this word that the French fromage, standard Italian formaggio, Catalan formatge, Breton fourmaj, Occitan fromatge are derived. Of the Romance languages, Portuguese, Romanian and Southern Italian dialects use words derived from caseus; the word cheese itself is employed in a sense that means "molded" or "formed". Head cheese uses the word in this sense; the term "cheese" is used as a noun and adjective in a number of figurative expressions. Cheese is an ancient food. There is no conclusive evidence indicating where cheesemaking originated, whether in Europe, Central Asia or the Middle East, but the practice had spread within Europe prior to Roman times and, according to Pliny the Elder, had become a sophisticated enterprise by the time the Roman Empire came into being.
Earliest proposed dates for the origin of cheesemaking range from around 8000 BCE, when sheep were first domesticated. Since animal skins and inflated internal organs have, since ancient times, provided storage vessels for a range of foodstuffs, it is probable that the process of cheese making was discovered accidentally by storing milk in a container made from the stomach of an animal, resulting in the milk being turned to curd and whey by the rennet from the stomach. There is a legend—wit
Biting is a common behavior which involves the opening and closing of the jaw found in many animals. This behavior is found in reptiles, mammals and amphibians. Arthropods can bite. Biting is a physical action in an attack but it is a normal activity or response in an animal as it eats, carries objects and prepares food for its young, removes ectoparasites from its body surface, removes plant seeds attached to its fur or hair, scratching itself, grooming other animals and for defense. Animal bites result in serious infections and death. Dog bites are commonplace, with human children the most bitten and the face being the most common target; the muscle fibers in the jaw are responsible for closing of the mouth. They allow the organism to open the jaw contract to bring the teeth together, resulting in a bite; this behavior has many implications and is exhibited by many different types of organisms dangerous species such as spiders and sharks. Biting is one of the main functions in an organism's life providing the ability to forage, build, play and much more.
The types of teeth organisms use to bite varies throughout the animal kingdom. Different types of teeth are seen in herbivores and omnivores as they are adapted over many years to better fit their diets. Carnivores possess canine and molar teeth, while herbivores are equipped with incisor teeth and wide-back molars. In general, tooth shape has traditionally been used to predict dieting habits. Carnivores have long sharp teeth for both gripping prey and cutting meat into chunks, they lack flat chewing teeth. An example of this is shown by the broad, serrated teeth of great white sharks which prey on large marine animals. On the other hand, herbivores have rows of flat teeth to bite and chew grass and other plants. Cows spend up to eleven hours a day grinding it with their molars. Omnivores consume both meat and plants, so they possess a mixture of flat teeth and sharp teeth. Biting can serve as a carrying mechanism for species such as beavers and ants, the raw power of their species-specific teeth allow them to carry large objects.
In beavers they have a large tooth adapted for gnawing wood. Their jaw muscles carry them back to their dam. In ant behavior, ants use their powerful jaws to lift material back to the colony, they can carry several thousand times their weight due to their bite and adapted to use this to forage for their colonies. Fire ants use their strong bite to get a grip on prey, inject a toxin via its abdomen carry back to its territory; some organisms have dangerous bites that produce venom to its victim. Snakes carry a neurotoxic venom from one of the three major groups of toxins: postsynaptically active neurotoxins, presynaptically active neurotoxins, myotoxic agents; the toxins in a spiders arsenal are polypeptides and they target specific ion channels. This excites both components of the peripheral nervous system, the somatic and autonomic systems, causing immense hyperactivity of the channels and neurotransmitter release within the peripheral nervous system. Spiders and snakes are known for having lethal bites and are considered fearful to humans.
Spider bites or, are a form of predation, but means of protection. When trapped or accidentally tampered with by humans, spiders retaliate with biting; the recluse spider and widow species have neurotoxins or necrotic agents that paralyze prey and/or harm humans. Snakes are equipped with frightening fangs and are known to use these to bite and envenom their prey. A snake bite can cause various symptoms ranging from the simplicity of bleeding to the tragedy of death. Snake bites are used as a method of hunting but can double as a means for protection as well. Biting is an age appropriate behavior and reaction for human children 30 months and younger. Conversely, children above this age are expected to have verbal skills to explain their needs and dislikes, as biting is not seen as age appropriate. Biting may be prevented by methods including redirection, change in the environment and responding to biting by talking about appropriate ways to express anger and frustration. School-age children, those older than 30 months, who habitually bite may require professional intervention.
Some discussion of human biting appears in The Kinsey Report on Sexual Behavior in the Human Female. Chewing