Digestive System in Cockroach

Digestive System in Cockroach (Invertebrates)


Nutrition in cockroach is holozoic and it is an omnivore, feeding on different kinds of organic matter. It takes in pieces of food and has to grind them before digesting them. Thus its mouth parts are modified accordingly for chewing the food.

The digestive system includes the mouth parts, a pair of salivary glands and the alimentary canal.

Mouthparts of cockroach

To understand the position of the mouth parts, observe the external features of a cockroach in the diagram below.

The body of the cockroach is segmented into three portions head, thorax and the abdomen. The mouth parts are attached to the ventral side (underside) of the head portion and surrounds the mouth or the oral cavity which faces down.

The different mouthparts are -

Labrum or the upper lip
It is a broad, roughly rectangular shaped structure. It hangs from the front edge of the head on the lower side. It covers the mouth and the mandibles.

Mandibles
They are a pair of hard, strong, large, dark coloured triangular structures found one on either side with jagged inner edges and the two mandibles move in horizontal motion and crush food between them.

Maxillae
Maxillae are a pair of structures lying outside and behind the mandibles. Each of them consists of three parts - protopodite, exopodite and endopodite. Protopodite consists of cardo and stipes, exopodite is 5-segemented and sensory, also called maxillary palp and endopodite is made up of inner lacina and outer galea. The maxillae are used to manipulate the food before it enters the mouth.

Labium
It is said to be formed by the fusion of the second pair of maxillae. It forms the broad median lower lip consisting of several parts in addition to a pair of 3-segmented labial palps on either side.

The maxillary and labial palps have sense organs that help them to choose suitable food.

The mandibles and the maxillae grind the food by moving it laterally.

The labrum and labium help to hold the food between the mandibles and the maxillae.

Alimentary canal

Digestion takes place in specialised cavities joined together to form a continuous canal. It is called the alimentary canal.

The alimentary canal is divided into three main portions-

Foregut
Foregut consists of the mouth surrounded by the mouthparts. The mouth cavity is called the pharynx. It continues as the oesophagus that is short, narrow and thin-walled. The canal then enlarges into the crop, which is also thin-walled. The crop opens into a short, muscular organ, the gizzard or the proventriculus. Outside and lying below the crop are a pair of salivary glands.

Each salivary gland is branched, the secretions of all the branches being poured into a common duct. For either pair of salivary glands there is a thin walled salivary receptacle or reservoir which is like a bladder. It stores the salivary secretions. The receptacles of either side have a common receptacular duct which opens into the common salivary duct. This common salivary duct opens into the mouth cavity at the labium.

The entire foregut is lined with chitin. In the gizzard, the chitin forms proventricular teeth and the plate to facilitate grinding of the food.

Midgut
Midgut forms the true gut or the mesenteron and consists entirely of stomach or ventriculus. At the junction of the gizzard and stomach are six pairs of gastric caecae ('gastric' means pertaining to stomach). These are pouch-like structures arranged in a ring-like manner around the anterior end of the stomach. The anterior lobe of each pair of the caecae extends over the proventriculus and the posterior lobe extends over the ventriculus. The caecae secrete digestive juices and pour them into the stomach. The midgut is not lined by chitin or cuticle but by a peritrophic membrane. This membrane protects the stomach wall from abrasions and is fully permeable to enzymes and digested food.

Hindgut
Hindgut is a coiled structure consisting of anterior ileum, middle colon and posterior rectum. The rectum opens to the exterior through the anus. The hindgut is lined by cuticle. At the junction of the stomach and ileum are attached numerous long tubules called the Malpighian tubules.

Mechanism of digestion
Digestion starts in the mouth with the mandibles and the maxillae chewing the food. It is also acted upon by the salivary carbohydrases which partially digests the food. The food is then swallowed with the help of lubrication provided by the salivary juice.

The food then enters the oesophagus and then into the crop. Here, the masticated food is temporarily stored.

The food is then passed into the gizzard which acts as the grinding chamber. At the junction of the gizzard and the stomach is a valve called the stomodael valve. It allows the passage of only the thoroughly digested food into the stomach and also, prevents the regurgitation of food from the stomach.

The ground food, then enters the stomach. The digestive enzymes secreted by the gastric caecae act upon the food in the stomach. These enzymes include amylase, maltase, invertase, tryptase and lipase. The remaining carbohydrates, proteins and fats are digested here.

The digested food is absorbed through the stomach walls into the surrounding space which is called the haemocoel. The haemocoel consists of a large number of fat bodies which are fat cells having fat globules, protein granules and glycogen. They form storage structures. From here, it is transported to the different body parts.

In the hindgut, absorption of water takes place and the undigested food is formed into almost dry pellets. These are excreted through the anus as faeces.

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Hippopotamus - The River Horse

The Hippopotamus is the 3rd largest animal after elephants and rhinos. There are 2 species of hippo. The large or common hippo (Hippopotamus amphibius), is found in East Africa, south of the Sahara. The pygmy hippopotamus (Choeropsis liberiensis) comes from West Africa, and is rare. The common hippo can be 13 feet long and 5 feet tall, weighing up to 3 ½ tons (7000 pounds). The pygmy only weighs 440 to 600 pounds and is 4.9 to 5.7 feet long. Not as much is known about the pygmy hippo.

With no sweat glands, hippos keep cool in the water or in mud. But they do secrete a red fluid that helps them avoid sunburn. While most of its body is underwater, a hippo can hear, see, and breathe, since its eyes, ears, and nostrils are on the top of its head and nose. When completely underwater, its nose and ears close automatically.

Hippos live in herds of 10 to 30. The dominant male can mate will all the females in the herd. If challenged, a male hippopotamus will fight using its long canine tusks. These teeth can grow a foot long.

A hippopotamus is born underwater. The mother helps her baby to the surface to breathe. Hippos bear single young. Calves weigh 55 to 120 pounds and nurse underwater. Mother hippos protect them from lions, leopards, crocodiles and male hippos. Sometimes calves will rest on their mother’s back.

Hippos mature at an average age of 7 (males) to 9 (females) years and have a life expectancy of about 45 years. On top they are brownish gray and underneath pinkish. Hippos have good sight, sense of smell, and hearing.

The name hippopotamus comes from 2 Greek words that mean river horse. These animals are aggressive and not afraid of people.

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Superman aka Christopher Reeve

Christopher D'Olier Reeve (September 25, 1952 – October 10, 2004) was an American actor, film director, producer, screenwriter, author and activist. He achieved stardom for his acting achievements, including his notable motion picture portrayal of the fictional superhero Superman.

On May 27, 1995, Reeve became a quadriplegic after being thrown from a horse in an equestrian competition in Virginia. He required a wheelchair and breathing apparatus for the rest of his life. He lobbied on behalf of people with spinal cord injuries, and for human embryonic stem cell research afterward. He founded the Christopher Reeve Foundation and co-founded the Reeve-Irvine Research Center.

Reeve married Dana Morosini in April 1992. Christopher and Dana's son, William Elliot Reeve, was born on June 7, 1992. Reeve also had two children, Matthew Exton Reeve (born 1979) and Alexandra Exton Reeve (born 1983), from his previous relationship with his longtime girlfriend, Gae Exton.

Christopher Reeve was born in New York City on September 25, 1952, the son of Barbara Pitney, a journalist, and Franklin D'Olier Reeve, who was a teacher, novelist, poet and scholar. His paternal grandfather, Colonel Richard Henry Reeve, had been the CEO of Prudential Financial for over twenty-five years, and his great-grandfather, Franklin D'Olier, was a prominent businessman, veteran of World War I, and the first national commander of the American Legion. Reeve's father was also descended from a sister of statesman Elias Boudinot, as well as from Massachusetts governors Thomas Dudley and John Winthrop, Pennsylvania deputy governor Thomas Lloyd, and Henry Baldwin, a US Supreme Court Justice. Reeve's mother was the granddaughter of Mahlon Pitney, another U.S. Supreme Court Justice, and was also a descendant of William Bradford, a Mayflower passenger.

Reeve's father was a Princeton University graduate studying for a master's degree in Russian language at Columbia University prior to the birth of his son, Christopher.

In the late 1980s, Reeve became more active. He was taking horse riding, and trained five to six days a week for competition in combined training events. He built a sailboat, The Sea Angel, and sailed from the Chesapeake to Nova Scotia. He campaigned for Senator Patrick Leahy and made speeches throughout the state. He served as a board member for the Charles Lindbergh Fund, which promotes environmentally safe technologies. He lent support to causes such as Amnesty International, the Natural Resources Defense Council, and People for the American Way. He joined the Environmental Air Force, and used his Cheyenne II turboprop plane to take government officials and journalists over areas of environmental damage. In the fall of 1987, 77 actors in Santiago, Chile were threatened with execution by the dictator Augusto Pinochet. Reeve was asked by Ariel Dorfman to help save their lives. Reeve flew to Chile and helped lead a protest march. A cartoon then ran in a newspaper showing him carrying Pinochet by the collar with the caption, "Where will you take him, Superman?" For his heroics, he was awarded the Grand Cross of the Bernardo O'Higgins Order, the highest Chilean distinction for foreigners. He also received the Obie Prize and the Annual Walter Brielh Human Rights Foundation award.


Reeve took up horse riding in 1985 after learning to ride for the film Anna Karenina. He was initially allergic to horses, so he took antihistamines. He trained on Martha's Vineyard, and by 1989 he began eventing. As with every other sport and activity in which he participated (sailing, scuba diving, skiing, aviation, windsurfing, cycling, gliding, parasailing, mountain climbing, baseball, tennis), he took horse riding seriously and was intensely competitive with it. His allergies soon disappeared.

Reeve bought a 12-year-old American thoroughbred horse named Eastern Express, nicknamed "Buck," while filming Village of the Damned. He trained with Buck in 1994, and planned to do Training Level events in 1995 and move up to Preliminary in 1996. Though Reeve had originally signed up to compete at an event in Vermont, his coach invited him to go to the Commonwealth Dressage and Combined Training Association finals at the Commonwealth Park equestrian center in Culpeper, Virginia. Reeve finished at fourth place out of 27 in the dressage, before walking his cross-country course. He was concerned about jumps sixteen and seventeen, but paid little attention to the third jump, which was a routine three-foot-three fence shaped like the letter 'W'.

On May 27, 1995, Reeve's horse had a refusal. Reeve fell and sustained a cervical spinal injury that paralyzed him from the neck down. He had no recollection of the incident. Witnesses said that Buck started the jump over the third fence, and then suddenly stopped (refusal). Men are more likely to fall forward than women due to their higher center of gravity. Horses are easily spooked, and it is possible a rabbit, shadow or other rodent could have spooked the horse. Reeve held on and the bridle, the bit, and the reins were pulled off the horse and tied his hands together. He landed headfirst on the other side of the fence. His helmet prevented any brain damage, but the impact of his 215-pound (98 kg) body hitting the ground shattered his first and second vertebrae. Reeve had not been breathing for three minutes before paramedics arrived. He was taken to the local hospital, and then flown by helicopter to the University of Virginia Medical Center.

For the first few days after the accident, Reeve suffered from delirium, woke up sporadically and would mouth words to Dana such as "Get the gun" and "They're after us." After five days, he regained full consciousness, and Dr. John Jane explained that he had destroyed his first and second cervical vertebrae, which meant that his skull and spine were not connected. His lungs were filling with fluid and were suctioned by entry through the throat; this was said to be the most painful part of Reeve's recovery.

After considering his situation, believing that not only would he never walk again, but that he might never move a body part again, Reeve considered suicide. He mouthed to Dana, "Maybe we should let me go." She tearfully replied, "I am only going to say this once: I will support whatever you want to do, because this is your life, and your decision. But I want you to know that I'll be with you for the long haul, no matter what. You're still you. And I love you." Reeve never considered suicide as an option again.

Reeve went through inner anguish in the ICU, particularly when he was alone during the night. His approaching operation to reattach his skull to his spine (June 1995) "was frightening to contemplate. ... I already knew that I had only a fifty-fifty chance of surviving the surgery.

Dr. John Jane performed surgery to repair Reeve's neck vertebrae. He put wires underneath both laminae and used bone from Reeve's hip to fit between the C1 and C2 vertebrae. He inserted a titanium pin and fused the wires with the vertebrae, then drilled holes in Reeve's skull and fit the wires through to secure the skull to the spinal column.

Reeve suffered from asthma and allergies since childhood. At age 16, he began to suffer from alopecia areata, a condition that causes patches of hair to fall out from an otherwise healthy head of hair. Generally he was able to comb over it and often the problem disappeared for long periods of time. Later in life, the condition became more noticeable and he shaved his head.[84]

He had experienced several illnesses, including infectious mononucleosis, malaria, and superior mesenteric artery syndrome. He also suffered from mastocytosis, a blood cell disorder.

More than once he had a severe reaction to a drug.

Reeve suffered from asthma and allergies since childhood. At age 16, he began to suffer from alopecia areata, a condition that causes patches of hair to fall out from an otherwise healthy head of hair. Generally he was able to comb over it and often the problem disappeared for long periods of time. Later in life, the condition became more noticeable and he shaved his head.

He had experienced several illnesses, including infectious mononucleosis, malaria, and superior mesenteric artery syndrome. He also suffered from mastocytosis, a blood cell disorder.

More than once he had a severe reaction to a drug. In Kessler, he tried a drug named Sygen which was theorized to help reduce damage to the spinal cord. The drug caused him to go into anaphylactic shock and his heart stopped. He believed he had an out-of-body experience and remembered saying, "I'm sorry, but I have to go now" during the event. In his autobiography, he wrote, "and then I left my body. I was up on the ceiling...I looked down and saw my body stretched out on the bed, not moving, while everybody—there were 15 or 20 people, the doctors, the EMTs, the nurses—was working on me. The noise and commotion grew quieter as though someone were gradually turning down the volume." After receiving a large dose of epinephrine, he woke up and was able to stabilize later that night.

In 2002 and 2004, Reeve fought off a number of serious infections believed to have originated from the bone marrow. He recovered from three that could have been fatal.

In early October 2004, he was being treated for a pressure wound that was causing a sepsis, a complication that he had experienced many times before. On October 9, Reeve felt well and attended his son Will's hockey game. That night, he went into cardiac arrest after receiving an antibiotic for the infection. He fell into a coma and was taken to Northern Westchester Hospital in Mount Kisco, New York. Eighteen hours later, on October 10, 2004, Reeve died of cardiac arrest at the age of 52. His doctor, John McDonald, believed that it was an adverse reaction to the antibiotic that caused his death.

A memorial service for Reeve was held at the Unitarian Church in Westport, Connecticut, which his wife attended. Reeve was cremated and his ashes were scattered.

His wife, Dana Reeve, headed the Christopher Reeve Foundation after his death. She was diagnosed with lung cancer in 2005, and died on March 6, 2006.

They are survived by their son, William, and Reeve's son Matthew and daughter Alexandra, both from his relationship with Gae Exton. Christopher is also survived by his parents and Dana is survived by her father. Matthew and Alexandra now serve on the board of directors for the Christopher and Dana Reeve Foundation.

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Charles Robert Darwin

Darwin is the first of the evolutionary biologists, the originator of the concept of natural selection. His principal works, The Origin of Species by Means of Natural Selection (1859) and The Descent of Man (1871) marked a new epoch.

Charles Robert Darwin was born at Shrewsbury. His father was a doctor and his mother was the daughter of Josiah Wedgwood. Darwin first studied medicine at Edinburgh. Will as they might, it soon became clear to the family, and particularly to young Charles, that he was not cut out for a medical career; he was transferred to Cambridge (Christ's Church, 1828), there to train for the ministry. While at Cambridge, Darwin befriended a biology professor (John Stevens Henslow, 1796-1861) and his interest in zoology and geography grew. Eventually, Darwin came under the eye of a geology professor, Adam Sedgwick (1785-1873).

Darwin gained an experience which would prove to be a substantial foundation for his life's work; the almost immediate result was the publication of his findings in 1840, Zoology of the Beagle.

In 1859, Darwin's shattering work, The Origin of Species, came out ("a sell out in one day"); it is now recognized as a leading work in natural philosophy and in the history of mankind.

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Free Running

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River Rafting

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Escape

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Nathuram Godse

Nathuram Vinayak Godse (Birth: 19 May 1910 – Death: 15 November 1949), was the sole assassin of Mahatma Gandhi, the pre-eminent leader of Indian nationalism in British ruled India and apostle of non-violence shooting Gandhi in the chest three times at point blank range on 30 January 1948 in New Delhi. Godse, a Hindu nationalist activist from Pune, Maharashtra who resented what he considered was Gandhi's partiality to India's Muslims, plotted the assassination with Narayan Apte and six others. After a trial that lasted over a year, Godse was sentenced to death on 8 November, 1949. Although pleas for commutation were made by India's prime minister Jawaharlal Nehru and by Gandhi's two sons on the grounds that a death sentence would dishonour the legacy of a man opposed to all forms of violence, Godse was hanged a week later.

Nathuram Vinayak Godse was born in Baramati, Pune District in a Chitpavan Brahmin family. His father, Vinayak Vamanrao Godse, was a post office employee and his co mother was Lakshmi (near Godavari). At birth, he was named Ramachandra.

Nathuram was given his name because of an unfortunate incident. Before he was born, his parents had three sons and a daughter, with all three boys dying in their infancy. Fearing a curse that targeted male children, young Ramachandra was brought up as a girl for the first few years of his life, including having his nose pierced and being made to wear a nose-ring ("Nath" in Marathi). It was then that he earned the nickname "Nathuram" (literally "Ram with a nose-ring"). After his younger brother was born, they switched to treating him as a boy.

Godse attended the local school at Baramati through the fifth standard, after which he was sent to live with an aunt in Pune so that he could study at an English-language school. During his school days, he highly respected Gandhi.

Godse dropped out of high school and became an activist with Hindu nationalist organizations such as the Hindu Mahasabha, and the Rashtriya Swayamsevak Sangh, although the RSS has claimed he left during the mid-1930s.

They were particularly opposed to the separatist politics of the All India Muslim League. Godse started a Marathi newspaper for Hindu Mahasabha called Agrani, which some years later was renamed Hindu Rashtra.

The Hindu Mahasabha had initially backed Gandhi's campaigns of civil disobedience against the British government.

Godse later rejected Gandhi, after he saw Gandhi's repeated sabotage against the interests of Hindus by using the "fasting unto death" tactic on many issues. In Godse's view, Gandhi was giving into Muslim interests in ways that seemed unfair and anti-national. He blamed Gandhi for the Partition of India, which left hundreds of thousands of people dead in the wake of religious unrest.

Godse was against Gandhi's personal teachings of extreme or absolutist non violence. He thought that such non-violent ideology would lead to Hindus losing the will to fight against other religions, which he saw as a matter of self-defense, and thereby becoming permanently enslaved. This has been said to be one of the major reasons behind his decision to kill Gandhi.

Godse approached Gandhi on January 30, 1948 during the evening prayer. When he bowed, one of the girls flanking and supporting Gandhi, Abha Chattopadhyay, said to him, "Brother, Bapu is already late" and tried to put him off but he pushed her aside and shot Gandhi in the chest three times at point-blank range with a semi-automatic pistol. Gandhi died almost immediately. Godse was attacked and pinned to the ground by the crowd around him and was subsequently arrested when a small group of police officers arrived on the scene a few minutes later.

Following the assassination of Gandhi, he was put on trial at Peterhoff, Shimla which housed the Punjab High Court.

On November 8, 1949, Godse was sentenced to death. Among those calling for commutation of the death sentence for the defendants were Jawahar Lal Nehru, as well as Gandhi's two sons, who felt that executing their father's killers would dishonour his memory and legacy which included a staunch opposition to the death penalty. Godse was hanged at Ambala Jail on November 15, 1949, along with Narayan Apte, a co-conspirator. Savarkar was also charged with conspiracy in the assassination of Gandhi, but was acquitted and subsequently released.

Millions of Indians mourned Gandhi's assassination. The Hindu Mahasabha was vilified and the Rashtriya Swayamsevak Sangh was temporarily banned. However, investigators could find no evidence that the RSS bureaucracy had formally sponsored or even knew of Godse's plot. The RSS ban was lifted by Prime Minister Nehru and Sardar Vallabhbhai Patel in 1949.

The RSS, to this day, denies any connection with Godse, and disputes the claim that he was a member.

After the assassination, many criticized the Indian government for not doing more to protect Gandhi who, earlier in the week, had been the target of a bomb plot by the same conspirators. Of particular concern was the fact that a Bombay detective had wired the names and descriptions of the assassins along with the fact that they were known to be in Delhi stalking Gandhi. On the other hand, Gandhi had repeatedly refused to cooperate with his own security and had resigned himself to a violent death which he accepted as an inevitable part of his destiny.

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PENDRIVE

Very often, you must have seen people inserting a small flat rectangular object into a computer. This small thing, known as a pen drive can hold a great amount of information in all forms.

What is a Pen drive?
It is a type of Universal Serial Cable (USB) flash drive. It is a
kind of memory card that can be plugged into a computer’s USB
port. It is termed “Pen drive” with reference to its size. It is small
and compact thus making it fit into the palm of our hand. It is often
flat and rectangular like a highlighter pen. A pen drive is used to
store data and has a storage capacity of 64 MB to 32 GB. It is removable
and rewrittable. It is mostly used as a backup for CDROMs
or floppy disks.

Mechanism
Pen drive consists of a small printed circuit board. This circuit
board provides a strong base for the pen drive’s form and also
serves as a means to collect information. The circuit board consists
of a small microchip within it. This microchip enables the pen
drive to extract or feed in data. This process requires relatively low
electrical power compared to CD-R’s or Floppy. It is based on EEPROMS
technology that allows writing and erasure process in a
computer system.

Transferring the data
The data that is to be transferred is connected through a computer
programme. It is then read, transmitted or rewritten from a
pen drive to a computer or vice versa. Thus the required data gets
copied to any selected drive on the computer for further use.

The working
When a pen drive is connected to a USB port, it is activated. The
USB port gives the pen drive access to the information on a specific
computer drive. Most of the pen drives are designed in such
a way that they are compatible with any USB port on a computer.

Transferring the data
The data that is to be transferred is connected through a computer
programme. It is then read, transmitted or rewritten from a
pen drive to a computer or vice versa. Thus the required data gets
copied to any selected drive on the computer for further use.

Internals of a typical
USB flash drive
1 USB connector
2 USB mass storage controller
device
3 Test points
4 Flash memory chip
5 Crystal oscillator
6 LED
7 Write-protect switch (Optional)
8 Space for second flash
memory chip

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Bacteriology

Bacteriology: The science and study of bacteria and their relation to medicine andto other areas such as agriculture (e.g., farm animals) and industry. Bacteria are single-celled microorganisms which can live as independent organisms or, dependently, as parasites. Among the better known bacteria are strep, staph, and the agentsof tuberculosis and leprosy. Bacteriology is a part of microbiology which encompasses the study of bacteria, viruses, and all other sorts of microorganisms.

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Alexander Fleming

Alexander Fleming was born in 1881 at Lochfield, a farm outside Darvel, a small town in Ayrshire, Scotland. He was the third child, with seven other brothers and sisters. After completing his educationat Regent Street Polytechnic, London in 1897, he took an office job for a few years. In 1901, he quit his job and went to St. Mary Hospital to study medicine. He then worked in Almroth Wright's research team as a research assistant with a strong interest in bacteriology. During the war between Britain and Germany in 1914, Fleming joined the British Royal Army Medical Corps to develop a cure to reduce the number of soldiers dying from infected wounds. He argued that antiseptics were not effective in preventing wounds from becoming infected. His argument was, however, rejected and little was done to relieve the suffering of many wounded soldiers. When World War I was over, Fleming continued working at St. Mary's Hospital. One day in 1928, before tossing some old petri dishes of culture away, he made an accidental discovery of a blue mold growing on the culture of some harmful kind of bacteria. The mold seemed tobe able to kill off the bacteria. A series of experiments later proved his findings and led to the discovery of penicillin. It was a strain of penicillia which could kill off bacteria while not causing any damage to wounds. It worked against many kinds of bacteria and was mostly safe for the human body. Unfortunately, with insufficient support from the medical community, the research had to stop. Finally in the late 1930s, other scientists found a way to mass-produce penicillin. British and American drug companies began to manufacture the drug in large quantites. It was then used tocure many infections during World War II. In 1945, Flemingwas presented the Nobel Prize for Medicine. He humbly said, "Nature makes penicillin; I just found it." Fleming spent the rest of his career at St. Mary's Hospital until his death in 1955 of a sudden heart attack. Fleming was married twice and had one son.

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Exogamy

Exogamy is a social arrangement where marriage is allowed only outside of a social group. The social groups define the scope and extent of exogamy, and the rules and enforcement mechanisms that ensure its continuity.

In social studies, exogamy is viewed as a combination of two related aspects: biological and cultural.
Biological exogamy is marriage of non blood-related beings, regulated by forms of incest law. A form of exogamy is a dual exogamy, in which two groups engage in continual wife exchange.
Cultural exogamy is the marrying outside of a specific cultural group.

The opposite of exogamy is endogamy, a marriage within a social group.

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Forms of Marriage

Polygamy is a marriage which includes more than two partners.

Polygamy exists in three specific forms:

polygyny - wherein a man has multiple simultaneous wives

Polyandry - wherein a woman has more than one husband at the same time. Fraternal polyandry was traditionally practiced among nomadic Tibetans in Nepal, parts of China and part of northern India, in which two or more brothers are married to the same wife, with the wife having equal 'sexual access' to them. The Indian epic the Mahabharata includes the polyandrous marriage of Draupadi to the five Pandava brothers. Polyandry is believed to be more likely in societies with scarce environmental resources, as it is believed to limit human population growth and enhance child survival. It is a rare form of marriage that exists not only among poor families, but also the elite.

Group marriage - wherein the family unit consists of more than two partners, any of whom share parental responsibility for any children arising from the marriage.

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Mummy - Part 1

A mummy is a body, human or animal, whose skin and organs have been preserved by either intentional or incidental exposure to chemicals, extreme coldness (ice mummies), very low humidity, or lack of air when bodies are submerged in bogs, so that the recovered body will not decay further if kept in cool and dry conditions. Some authorities restrict the use of the term to bodies deliberately embalmed with chemicals, but the use of the word to cover accidentally desiccated bodies goes back at least to the 1730s.

Mummies of humans and other animals have been found all around the world, both as a result of natural preservation through unusual conditions, and as cultural artifacts. Over one million animal mummies have been found in Egypt, many of which are cats. The oldest known naturally mummified human corpse is a decapitated head dated as 6,000 years old, found in 1936 at the site named Inca Cueva No. 4 in South America.

In addition to the well-known mummies of Ancient Egypt, deliberate mummification was a feature of several ancient cultures in areas of South America and Asia which have very dry climates. There are more than 1000 mummies in Xinjiang, China. The oldest-known deliberate mummy is a child, one of the Chinchorro mummies found in the Camarones Valley, Chile, and dates from around 5050 BC.

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Language

Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication. The scientific study of language in any of its senses is called linguistics.

The approximately 3000–6000 languages that are spoken by humans today are the most salient examples, but natural languages can also be based on visual rather than auditory stimuli, for example in sign languages and written language. Codes and other kinds of artificially constructed communication systems such as those used for computer programming can also be called languages. A language in this sense is a system of signs for encoding and decoding information.

The formal study of language began in India with Pāṇini, the 5th century BC grammarian who formulated 3,959 rules of Sanskrit morphology. Pāṇini’s systematic classification of the sounds of Sanskrit into consonants and vowels, and word classes, such as nouns and verbs, was the first known instance of its kind.

Human languages are usually referred to as natural languages, and the science of studying them falls under the purview of linguistics. A common progression for natural languages is that they are considered to be first spoken and then written, and then an understanding and explanation of their grammar is attempted.

An artificial language is a language the phonology, grammar, and/or vocabulary of which have been consciously devised or modified by an individual or group, instead of having evolved naturally.

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