title: Elizabeth II

paragraphs: Elizabeth II (Elizabeth Alexandra Mary; born 21 April 1926) is the Queen of the United Kingdom, and the other Commonwealth realms.

paragraphs: She became Queen when her father, King George VI, died on 6 February 1952. Since 9 September 2015, Elizabeth II has ruled longer than any other king or queen in the history of the United Kingdom. She has also ruled longer than any other living king or queen in the world, since the death of Thailand's Bhumibol Adulyadej on 13 October 2016.

paragraphs: The countries of which she is Queen are known as Commonwealth realms. Their total population is over 129 million. Although Elizabeth II is the queen of each country separately, all are independent countries. Elizabeth II lives and spends most of her time in the United Kingdom. In all the other countries where she is queen, a person is chosen to represent her. This person may be known as the Governor General.

paragraphs: Elizabeth II has few political powers, and is not a ruler in the usual sense. She is Queen and interested in the running of her countries, but she does not tell the governments what to do. She has regular meetings with people from her governments, but it is they who run the countries. She performs ceremonies for the governments, gives out honours, and visits and supports many charities.

paragraphs: Since 1947, the Queen has been married to Prince Philip, Duke of Edinburgh. Prince Philip was born into the royal families of Greece and Denmark. Just before they were married, he officially became a citizen of the United Kingdom, and changed his name to Philip Mountbatten. He became the Duke of Edinburgh on the day he married, and became a "Prince of the United Kingdom" in 1957. The Queen and Prince Philip have four children, eight grandchildren and eight great-grandchildren.

paragraphs: Elizabeth was born in her grandparents' home at 17 Bruton street, Mayfair, London on 21 April 1926. Her father was Prince Albert, Duke of York, who later became George VI. His brother was the Prince of Wales. Her mother was Elizabeth, Duchess of York.

paragraphs: Princess Elizabeth was the granddaughter of King George V and Queen Mary. She was named after her mother. Her nickname was "Lilibet".

paragraphs: Princess Elizabeth had one sister, Princess Margaret. Margaret was born in 1930. The two young princesses were taught at home. They had a governess named Marion Crawford.

paragraphs: Princess Elizabeth was third in the line of succession to the British Throne. The first in line was her uncle, the Prince of Wales. The second in line was her father, the Duke of York. She was third in line.

paragraphs: Elizabeth's grandfather, King George V, died in 1936. Her uncle became King Edward VIII. He was king only for a short time. He abdicated.

paragraphs: His brother, Elizabeth's father the Duke of York, became King George VI. One day, Princess Elizabeth would be Queen.

paragraphs: Elizabeth was 13 years old when World War II started. London was bombed. Elizabeth and Margaret were moved to Windsor Castle. This was for their safety. People thought that they should be sent to Canada. Their mother did not approve this idea.

paragraphs: Princess Elizabeth joined the British army in 1945. She drove a truck. She was a mechanic. In 1947, she made her first official trip outside Britain. She went with her parents to South Africa. She made a speech on her 21st birthday. She said her whole life would be devoted to the service of British Commonwealth and Empire.

paragraphs: Princess Elizabeth married Prince Philip, Duke of Edinburgh on 20 November 1947. The wedding was held in Westminster Abbey. The couple lived mostly at Clarence House in London. The couple has four children; Charles, Prince of Wales was born 14 November 1948. Their second child is a daughter. She is Anne, Princess Royal. She was born 15 August 1950. The Royal couple had two more sons. Prince Andrew, Duke of York was born 19 February 1960. Prince Edward, Earl of Wessex was born 10 March 1964. The princes and princess sometimes use the name Mountbatten-Windsor. This is their official last name when they need one (royal families rarely use them).

paragraphs: In 1951, the King's health was poor. He could not go to many public events. Princess Elizabeth started to make official visits for him. The King died on 6 February 1952. Elizabeth was crowned queen on 2 June 1953. The ceremony was held in Westminster Abbey. She wore a dress that was decorated with the national flowers of the countries of the Commonwealth. Many people bought TV sets to watch the event.

paragraphs: In 1952, Her Majesty the Queen and Prince Philip moved into Buckingham Palace in central London. This is the main official home of the monarch.

paragraphs: Her early years as Queen were spent traveling to many places. In 1953, the Queen and Prince Philip began an around the world tour in the Royal Yacht, "Britannia". Their tour went for 6 months. She was the first reigning monarch to visit Australia, New Zealand and Fiji.

paragraphs: In October 1957, she made an official visit to the United States. She spoke to the United Nations General Assembly. She toured Canada. She became the first monarch to open the nation's Parliament. The Queen likes to go to Canada. She calls Canada her "home away from home".

paragraphs: In February 1961, she visited Turkey, India, Iran, Pakistan and Nepal for the first time. Since then, the Queen has made visits to most Commonwealth countries. She has also been to most European countries and many countries outside Europe.

paragraphs: In 1991, she became the first British monarch to speak to a joint session of the United States Congress. She goes to the Commonwealth Heads of Government Meetings. She is the most widely traveled head of state in history.

paragraphs: When Elizabeth became Queen on 6 February 1952, she was officially Queen of the United Kingdom, Canada, Australia, New Zealand, South Africa, Pakistan and Ceylon (now called Sri Lanka). These were the Commonwealth countries. She was also Queen of the Union of South Africa (which became a republic in 1961).

paragraphs: There were many more countries that she also ruled, because they belonged to the British Empire. One by one, many of the countries became independent, and as they gained independence she became Queen of many of them. Altogether, she was sovereign of 32 nations.

paragraphs: Some of the countries are now republics and have a president as "Head of State", while some of them keep the Queen as "Head of State". Queen Elizabeth II is the only monarch of more than one independent nation. The old British Empire became the Commonwealth of Nations.

paragraphs: It includes both monarchies and republics. It is now called "The Commonwealth". The Queen is the Head of the Commonwealth. She works hard to keep peace and good communication between all the nations that are members.

paragraphs: Ever since she became the Queen, Elizabeth has spent about three hours every day "doing the boxes". The "boxes" are two large red boxes that are brought to her from the Parliament every day. They are full of state papers sent to her from her various departments, embassies, and government offices. One of the most famous photos taken of Elizabeth as a teenager shows her with her father, the King, learning about "the boxes". Because she has been doing this since 1952, she knows a great deal about the government of the UK.

paragraphs: When the Queen is in London, she meets her Prime Minister once a week, to talk about events. She also has meetings with the First Minister of Scotland and other Ministers of the Parliament of the United Kingdom, and the Prime Ministers and Ministers of other countries, when she is in their country, or when they visit London.

paragraphs: In the late 1990s, there were "referendums" in which the people of Scotland and Wales were asked if they wanted parliaments that were separate from the parliament of the United Kingdom. This was called a "devolution policy". As a result, the new Scottish Parliament and the National Assembly of Wales, were set up. The Queen opened the first sessions of these two bodies.

paragraphs: Recently, some people in Australia wanted a republic, with an elected or appointed President as Head of State instead of the Queen. In 1999, the people of Australia were asked in a referendum whether they wanted a republic. The decision of the people was to remain a monarchy. The Queen visited Australia the following year and said that she would continue to serve Australians as she had done for 48 years.

paragraphs: Elizabeth II is friends with many world leaders. Her first Prime Minister of Australia, Sir Robert Menzies called her "My Dear" and recited a poem that said "I will love her till I die". She has friendships with Mary Robinson, President of Ireland (1990-1997) and George W. Bush, who was the first American President in more than 80 years to stay at Buckingham Palace. Nelson Mandela, in a BBC documentary, called her "my friend, Elizabeth".

paragraphs: In May 2007, the Queen and Prince Philip made a state visit to the United States, in honour of the 400th anniversary of the Jamestown settlement.

paragraphs: Elizabeth II, as the Monarch of the United Kingdom, is the "Supreme Governor" of the Church of England and sworn protector of the Church of Scotland. She is very interested in the Church of England, but the Archbishop of Canterbury runs the church. She rarely attends the yearly meeting of the General Assembly of the Church of Scotland.

paragraphs: The Queen is deeply religious. In her Christmas Day television broadcast in 2000, she said:

paragraphs: The Queen regularly goes to church wherever she is: at St. George's Chapel at Windsor Castle, St. Mary Magdalene Church at Sandringham House, Crathie Kirk at Balmoral Castle, and Canongate Kirk in Edinburgh, when she stays there in Holyroodhouse, her official home in Scotland.

paragraphs: The Queen often meets with leaders from other religions as well. In 1980, she became the first British Monarch to visit the Vatican, where she was welcomed by Pope John Paul II. She made another visit twenty years later on 17 October 2000. Queen Elizabeth II is Patron of "The Council of Christians and Jews" in the UK.

paragraphs: The Queen has shown a very strong sense of duty, ever since she was a girl. Her father, King George VI, was not meant to be king. Her uncle became king when her grandfather died. But he fell in love with an American woman who was divorced, and that wasn't allowed. So he had to give up being king very shortly after ascending. George VI didn't want to be king, because he was quite nervous and had a stammer. However, Elizabeth's grandfather said that he didn't think her uncle was very good as a king, and wanted George to reign, then Elizabeth. From the moment she realised that one day she would be Queen, she became very interested in her duties and did all she could to help her father. Her promise to serve her people all her life has always been very important to her. Some people think that now that she is old, perhaps she will retire ("abdicate") and let her son Prince Charles take over. People who know her well, including Prince Charles, have said that this will never happen.

paragraphs: The Queen has often shown courage, ever since she joined the military at 18. During a trip to Ghana in 1961, she was warned that it was dangerous to be near the President Kwame Nkrumah because people wanted to kill him. But she refused to stay away. The Prime Minister of the United Kingdom, Harold Macmillan, wrote that the Queen got very impatient with people if they tried to treat her like "a film star".

paragraphs: In 1964, when the Queen was invited to Quebec, there were fears for her safety because there was opposition to her visit. There were suggestions that the tour should be cancelled. But the Queen's secretary said that the Queen would not want to be stopped from going to Quebec because of any danger. During the Trooping the Colour in 1981, she was shot at, but she carried on. The Queen was praised for her courage and for her ability to keep her horse calm. It was later discovered that the shots were blanks. In 1982, a man called Michael Fagan broke into Buckingham Palace in the morning, and found the Queen's bedroom. He woke her up, and sat on her bed, until the guards came to take him away.

paragraphs: Throughout her long reign, Queen Elizabeth II has been supported in her duties by her husband, Prince Philip, Duke of Edinburgh. Prince Philip promised to help the Queen on the day of her Coronation. The Queen was also helped by her mother Queen Elizabeth, known as "The Queen Mother", who lived to be 101 years old, and stayed very active in her old-age. The Queen is the patron of many organisations and charities. She has many invitations and official duties. Many of the duties have been shared by other members of the Royal Family, who have also become patrons of many organisations.

paragraphs: The Queen was sad about the broken marriages and divorces of three of her children, Prince Charles, Princess Anne and Prince Andrew. Prince Charles's marriage to Lady Diana Spencer was thought to be a fairytale wedding because Diana was young and beautiful, and they seemed very happy. But soon the marriage became troubled, and after their divorce, she was killed in a car accident in 1997. On 9 April 2005, Prince Charles married Camilla Parker-Bowles, whom he had loved for many years. In the year 2002, within a few months of each other, the Queen's mother and sister, Princess Margaret, both died.

paragraphs: As the Queen is old, people worry about her health, but she is rarely sick. However, she is leaving more duties to the younger members of the Royal Family, particularly to Prince Charles, who will become King when she dies.

paragraphs: The Queen's wealth is private. It is difficult to estimate how much she is worth. She owns Sandringham House, Balmoral Castle, and other large properties. She does not own Buckingham Palace, Windsor Castle, or the royal collection of art. These are worth millions of pounds. In 2010, "Forbes" magazine estimated her personal fortune at about US$450 million (£300 million).

paragraphs: In 1977, the Queen celebrated her Silver Jubilee. This jubilee marked the 25 anniversary of her coming to the throne. There was a royal procession in the golden State Coach. A service of thanksgiving was held at St. Paul's Cathedral. Millions of people watched on television. There were parties across the UK. Five commemorative stamps were printed in honour of the event. The Jubilee line of the London Underground opened in 1979, named after the anniversary.

paragraphs: In 2002, Elizabeth II celebrated Golden Jubilee. This jubilee marked the 50th anniversary of her coming to the throne. She toured the Commonwealth countries. There was a pop concert in the gardens of Buckingham Palace. A service of thanksgiving was held at St. Paul's Cathedral.

paragraphs: The Queen and Prince Philip celebrated their sixtieth (diamond) wedding anniversary on 19 November 2007, with a special service at Westminster Abbey. The night before, Prince Charles gave a private dinner party at Clarence House for twenty members of the Royal Family.

paragraphs: On the following day, 20 November, the Queen and Prince Philip went on a visit to Malta, where they had stayed from 1949 to 1951 after getting married. A Royal Navy ship, which was nearby, got its sailors to line up on deck to form a big number '60' for the couple.

paragraphs: In 2012, the Queen's 60 years as monarch were marked by Diamond Jubilee celebrations, including a grand pageant of boats on the Thames and a service of thanksgiving at St Paul's Cathedral.

paragraphs: In 2017, the Sapphire Jubilee marked the Queen's 65 years as monarch. She was the first British monarch to have a Sapphire Jubilee. Instead of large celebrations, as usual, the Queen spent the day in "quiet reflection" because the day was also the anniversary of her father's death. Commemorative stamps and coins were made in honour of the Jubilee, and a portrait of the Queen wearing sapphire jewellery was reissued.

paragraphs: Also in 2017, the Queen and Prince Philip celebrated their seventieth (Platinum) wedding anniversary. They held a private celebration at Windsor Castle. Westminster Abbey, where they were married, held a three-hour bell ceremony.

paragraphs: When someone is talking about the Queen, she is called "The Queen" or "Her Majesty". When someone is talking to her, she is called "Your Majesty". After the first time, the person talking to the Queen can say "Ma'am". It is pronounced "Mam". These are the titles that she has had:

paragraphs: The Queen has several coats of arms. In the UK, they are known as the "Royal coat of arms of the United Kingdom". Every British monarch has used these arms since the reign of Queen Victoria. The coats of arms used in Scotland and Canada are different to the arms used in England and Wales.


title: Question

paragraphs: A question is what someone asks, usually when there is something that he or she does not know. In writing, a question mark ("?") comes at the end of a question. However, just because a question is asked does not mean there is an answer.

paragraphs: Sometimes a question has a simple answer like "Yes" or "No".

paragraphs: Sometimes a question has a more complicated answer like "Maybe", or "I don't know". There are so many types of questions and so many ways of answering questions.

paragraphs: People may give a short answer. People may give a long answer. It depends on the question.

paragraphs: Different kinds of why questions need different kinds of answers. A question like "Why did you do that?" clearly asks for an explanation. What that explanation might be depends on context. This kind of explanation is not right or wrong: it all depends on circumstance. The question and answer may also have to do with "who", "what", "when" and "where".

paragraphs: There are types or forms of explanations, including:

paragraphs: Many kinds of explanations are made up of more than one type.

paragraphs: An explanation can be valid or invalid or a combination of both. Some explanations may appear reasonable, but they turn out to be misleading or wrong.


title: Boss

paragraphs: A boss is a person who is in charge of workers in a company or organization. Bosses can have many different job titles. Simple examples include manager, supervisor and director.


title: Gun

paragraphs: The gun (also called a firearm) is a weapon used to shoot one or more metal projectiles called bullets. Guns made of wood or bamboo are thought to have been invented in China around 1000 AD. In the next few centuries they spread to other parts of Asia and to Europe where they were made of metal. Guns largely replaced catapults and bows and arrows when they became strong enough to reach out over longer distances to kill. They are of many different sizes. Some are small enough to hold in one hand. Others are large enough to sink a warship.

paragraphs: In military jargon, the word "firearm" is used for the type of weapons that soldiers carry. Most are either pistols or rifles. Guns that are small enough to be carried and used by one person have the same basic parts: a trigger, a barrel, and a handgrip or stock. The trigger is pulled by a finger to fire the weapon which releases a bullet. The barrel guides the bullet which then flies to the target. The handgrip is held by the shooter's hand. Guns can be very effective weapons. Their bullets fly faster than an arrow or spear. Their high kinetic energy makes them more deadly. They also shoot greater distances. Bullets are usually non-explosive pieces of metal.

paragraphs: A modern bullet is the front part of a "round" or cartridge. A cartridge consists of a "bullet", propellant and a primer. These are packaged in a metallic, paper, or plastic case which is sized exactly for the chamber of the firearm being used. When the rear of the case (containing the primer) is struck, an explosion in the back of the cartridge ignites the propellant. The controlled explosion forces the bullet out of the barrel. Cartridges have different ways of being loaded into different kinds of weapons. Cartridges can be loaded directly into a firearm into the chamber. Or, more commonly, into a clip, a magazine or other bullet container which is loaded into the firearm. Handguns known as revolvers have a cylinder with holes that the bullets are loaded into. Modern guns called pistols are handguns loaded with a magazine.

paragraphs: Guns have been used by armies since about the 14th century. Long barreled guns called muskets, that could be carried and used by one person, were in use by 1350. They became an important weapon in European armies about the 1600s.

paragraphs: Modern militaries use the word "gun" for larger artillery guns that need several people, and that fire big ammunition. For example, weapons on warships and tanks are called "guns". They may be in a "turret" (a rotating base). Big guns usually fire artillery shells, which explode upon impact.

paragraphs: In almost every country firearms are the main weapons used by armies. In modern armies, every soldier has at least one firearm as standard equipment. Soldiers are trained to use firearms, and to keep them clean and ready for use.

paragraphs: Shooting is a competitive sport involving tests of accuracy and speed. They use various types of guns such as pistols, revolvers, rifles, shotguns and airguns. Shooting sports are categorized by the type of firearm, targets, and distances at which the targets are shot. Target Shooting is an Olympic sport.

paragraphs: Since the first humans, hunting became a way of life. It was and still is in some places, the key to survival. Mankind is distinguished from other animals by the use of tools. At least 2 million years ago man learned to hunt animals for meat. They learned to create and use spears and axes. Bows and arrows were used at least 71,000 years ago. Modern hunting still uses more primitive tools. But many subsistence hunters have adapted to use modern firearms. In modern countries hunting is still allowed but is considered a sport. Hunting can be used to control the populations of many animal species. As with many aspects of gun ownership and use, modern hunting remains controversial. Handguns are not generally used for hunting.

paragraphs: Guns can be used to kill other people. For that reason many countries only allow soldiers, policemen, and certain social classes to have them. In some countries, a person must have a special permit (or license) if they want to own a gun. Depending on the gun, people need to be a certain age and may need to meet other criteria to get such a permit.

paragraphs: An example of this is that in the United States federal law allows buying rifles and/or shotguns at age 18—if purchased from a licensed firearms dealer. But a person must be age 21 or older to purchase a handgun—from a licensed firearms dealer. However, if purchased from an unlicensed person, with few exceptions, a handgun may not be sold to anyone under age 18. There is no age restriction on who may buy a rifle or shotgun from an unlicensed person. In the United States and other countries, people can buy guns for self-defense, hunting, and shooting sports like target shooting.

paragraphs: In some countries, such as Australia, people who live on farms are allowed to keep guns, but it is not easy for a person living in the city to get a gun without good reason. In the United Kingdom, access by the general public to firearms is tightly controlled by law. However, this is less restrictive in Northern Ireland. After the Dunblane school massacre in 1996 followed by the Hungerford massacre in 1987, Britain passed the Firearms (Amendment) Act 1988. It required registration for shotguns and banned semi-automatic and pump-action weapons. A further ban on all handguns in mainland Britain came a year and a half later.


title: Evolution

paragraphs: Evolution is a biological process. It describes how living things change over a long time. The explanation of how this process works and how living beings have come to be the way they are is called the theory of evolution.

paragraphs: Earth is very old. By studying the layers of rock that make up Earth's crust, scientists can find out about its past. This kind of research is called historical geology.

paragraphs: It is known that living things have changed over time, because their remains can be seen in the rocks. These remains are called 'fossils'. This proves that the animals and plants of today are different from those of long ago. The older the fossils, the bigger the differences from modern forms. This has happened because evolution has taken place. That evolution has taken place is a fact, because it is overwhelmingly supported by many lines of evidence. At the same time, evolutionary questions are still being actively researched by biologists.

paragraphs: Comparison of DNA sequences allows organisms to be grouped by how similar their sequences are. In 2010 an analysis compared sequences to phylogenetic trees, and supported the idea of common descent. There is now "strong quantitative support, by a formal test", for the unity of life.

paragraphs: The theory of evolution is the basis of modern biology. Theodosius Dobzhansky, a well-known evolutionary biologist, has said: "Nothing in biology makes sense except in the light of evolution".

paragraphs: The evidence for evolution is given in a number of books. Some of this evidence is discussed here.

paragraphs: The realization that some rocks contain fossils was a very important event in natural history. There are three parts to this story:

paragraphs: The evolution of the horse family (Equidae) is a good example of the way that evolution works. The oldest fossil of a horse is about 52 million years old. It was a small animal with five toes on the front feet and four on the hind feet. At that time, there were more forests in the world than today. This horse lived in woodland, eating leaves, nuts and fruit with its simple teeth. It was only about as big as a fox.

paragraphs: About 30 million years ago the world started to become cooler and drier. Forests shrank; grassland expanded, and horses changed. They ate grass, they grew larger, and they ran faster because they had to escape faster predators. Because grass wears teeth out, horses with longer-lasting teeth had an advantage.

paragraphs: For most of this long period of time, there were a number of horse types (genera). Now, however, only one genus exists: the modern horse, "Equus". It has teeth which grow all its life, hooves on single toes, great long legs for running, and the animal is big and strong enough to survive in the open plain. Horses lived in western Canada until 12,000 years ago, but all horses in North America became extinct about 11,000 years ago. The causes of this extinction are not yet clear. Climate change and over-hunting by humans are suggested.

paragraphs: So, scientists can see that changes have happened. They have happened slowly over a long time. How these changes have come about is explained by the theory of evolution.

paragraphs: This is a topic which fascinated both Charles Darwin and Alfred Russel Wallace. When new species occur, usually by the splitting of older species, this takes place in one place in the world. Once it is established, a new species may spread to some places and not others.

paragraphs: Australasia has been separated from other continents for many millions of years. In the main part of the continent, Australia, 83% of mammals, 89% of reptiles, 90% of fish and insects and 93% of amphibians are endemic. Its native mammals are mostly marsupials like kangaroos, bandicoots, and quolls. By contrast, marsupials are today totally absent from Africa and form a small portion of the mammalian fauna of South America, where opossums, shrew opossums, and the monito del monte occur (see the Great American Interchange).

paragraphs: The only living representatives of primitive egg-laying mammals (monotremes) are the echidnas and the platypus. They are only found in Australasia, which includes Tasmania, New Guinea, and Kangaroo Island. These monotremes are totally absent in the rest of the world. On the other hand, Australia is missing many groups of placental mammals that are common on other continents (carnivora, artiodactyls, shrews, squirrels, lagomorphs), although it does have indigenous bats and rodents, which arrived later.

paragraphs: The evolutionary story is that placental mammals evolved in Eurasia, and wiped out the marsupials and monotremes wherever they spread. They did not reach Australasia until more recently. That is the simple reason why Australia has most of the world's marsupials and all the world's monotremes.

paragraphs: In about , the Hawaiian Islands have the most diverse collection of "Drosophila" flies in the world, living from rainforests to mountain meadows. About 800 Hawaiian fruit fly species are known.

paragraphs: Genetic evidence shows that all the native fruit fly species in Hawaii have descended from "a single ancestral species" that came to the islands, about 20 million years ago. Later adaptive radiation was caused by a lack of competition and a wide variety of vacant niches. Although it would be possible for a single pregnant female to colonise an island, it is more likely to have been a group from the same species.

paragraphs: The combination of continental drift and evolution can explain what is found in the fossil record. "Glossopteris" is an extinct species of seed fern plants from the Permian period on the ancient supercontinent of Gondwana.

paragraphs: "Glossopteris" fossils are found in Permian strata in southeast South America, southeast Africa, all of Madagascar, northern India, all of Australia, all of New Zealand, and scattered on the southern and northern edges of Antarctica.

paragraphs: During the Permian, these continents were connected as Gondwana. This is known from magnetic striping in the rocks, other fossil distributions, and glacial scratches pointing away from the temperate climate of the South Pole during the Permian.

paragraphs: When biologists look at living things, they see that animals and plants belong to groups which have something in common. Charles Darwin explained that this followed naturally if "we admit the common parentage of allied forms, together with their modification through variation and natural selection".

paragraphs: For example, all insects are related. They share a basic body plan, whose development is controlled by master regulatory genes. They have six legs; they have hard parts on the outside of the body (an exoskeleton); they have eyes formed of many separate chambers, and so on. Biologists explain this with evolution. All insects are the descendants of a group of animals who lived a long time ago. They still keep the basic plan (six legs and so on) but the details change. They look different now because they changed in different ways: this is evolution.

paragraphs: It was Darwin who first suggested that all life on Earth had a single origin, and from that beginning "endless forms most beautiful and most wonderful have been, and are being, evolved". Evidence from molecular biology in recent years has supported the idea that all life is related by common descent.

paragraphs: Strong evidence for common descent comes from vestigial structures. The useless wings of flightless beetles are sealed under fused wing covers. This can be simply explained by their descent from ancestral beetles which had wings that worked.

paragraphs: Rudimentary body parts, those that are smaller and simpler in structure than corresponding parts in ancestral species, are called vestigial organs. Those organs are functional in the ancestral species but are now either nonfunctional or re-adapted to a new function. Examples are the pelvic girdles of whales, halteres (hind wings) of flies, wings of flightless birds, and the leaves of some xerophytes ("e.g." cactus) and parasitic plants ("e.g." dodder).

paragraphs: However, vestigial structures may have their original function replaced with another. For example, the halteres in flies help balance the insect while in flight, and the wings of ostriches are used in mating rituals, and in aggressive display. The ear ossicles in mammals are former bones of the lower jaw.

paragraphs: In 1893, Robert Wiedersheim published a book on human anatomy and its relevance to man's evolutionary history. This book contained a list of 86 human organs that he considered vestigial. This list included examples such as the appendix and the 3rd molar teeth (wisdom teeth).

paragraphs: The strong grip of a baby is another example. It is a vestigial reflex, a remnant of the past when pre-human babies clung to their mothers' hair as the mothers swung through the trees. This is borne out by the babies' feet, which curl up when it is sitting down (primate babies grip with the feet as well). All primates except modern man have thick body hair to which an infant can cling, unlike modern humans. The grasp reflex allows the mother to escape danger by climbing a tree using both hands and feet.

paragraphs: Vestigial organs often have some selection against them. The original organs took resources, sometimes huge resources. If they no longer have a function, reducing their size improves fitness. And there is direct evidence of selection. Some cave crustacea reproduce more successfully with smaller eyes than do those with larger eyes. This may be because the nervous tissue dealing with sight now becomes available to handle other sensory input.

paragraphs: From the eighteenth century it was known that embryos of different species were much more similar than the adults. In particular, some parts of embryos reflect their evolutionary past. For example, the embryos of land vertebrates develop gill slits like fish embryos. Of course, this is only a temporary stage, which gives rise to many structures in the neck of reptiles, birds and mammals. The proto-gill slits are part of a complicated system of development: that is why they persisted.

paragraphs: Another example are the embryonic teeth of baleen whales. They are later lost. The baleen filter is developed from different tissue, called keratin. Early fossil baleen whales did actually have teeth as well as the baleen.

paragraphs: A good example is the barnacle. It took many centuries before natural historians discovered that barnacles were crustacea. Their adults look so unlike other crustacea, but their larvae are very similar to those of other crustacea.

paragraphs: Charles Darwin lived in a world where animal husbandry and domesticated crops were vitally important. In both cases farmers selected for breeding individuals with special properties, and prevented the breeding of individuals with less desirable characteristics. The eighteenth and early nineteenth century saw a growth in scientific agriculture, and artificial breeding was part of this.

paragraphs: Darwin discussed artificial selection as a model for natural selection in the 1859 first edition of his work "On the Origin of Species", in Chapter IV: Natural selection:

paragraphs: Nikolai Vavilov showed that rye, originally a weed, came to be a crop plant by unintentional selection. Rye is a tougher plant than wheat: it survives in harsher conditions. Having become a crop like the wheat, rye was able to become a crop plant in harsh areas, such as hills and mountains.

paragraphs: There is no real difference in the genetic processes underlying artificial and natural selection, and the concept of artificial selection was used by Charles Darwin as an illustration of the wider process of natural selection. There are practical differences. Experimental studies of artificial selection show that "the rate of evolution in selection experiments is at least two orders of magnitude (that is 100 times) greater than any rate seen in nature or the fossil record".

paragraphs: Some have thought that artificial selection could not produce new species. It now seems that it can.

paragraphs: New species have been created by domesticated animal husbandry, but the details are not known or not clear. For example, domestic sheep were created by hybridisation, and no longer produce viable offspring with "Ovis orientalis", one species from which they are descended. Domestic cattle, on the other hand, can be considered the same species as several varieties of wild ox, gaur, yak, etc., as they readily produce fertile offspring with them.

paragraphs: The best-documented new species came from laboratory experiments in the late 1980s. William Rice and G.W. Salt bred fruit flies, "Drosophila melanogaster," using a maze with three different choices of habitat such as light/dark and wet/dry. Each generation was put into the maze, and the groups of flies that came out of two of the eight exits were set apart to breed with each other in their respective groups.

paragraphs: After thirty-five generations, the two groups and their offspring were isolated reproductively because of their strong habitat preferences: they mated only within the areas they preferred, and so did not mate with flies that preferred the other areas.

paragraphs: Diane Dodd was also able to show how reproductive isolation can develop from mating preferences in "Drosophila pseudoobscura" fruit flies after only eight generations using different food types, starch and maltose.

paragraphs: Dodd's experiment has been easy for others to repeat. It has also been done with other fruit flies and foods.

paragraphs: Some biologists say that evolution has happened when a trait that is caused by genetics becomes more or less common in a group of organisms. Others call it evolution when new species appear.

paragraphs: Changes can happen quickly in the smaller, simpler organisms. For example, many bacteria that cause disease can no longer be killed with some of the antibiotic medicines. These medicines have only been in use about eighty years, and at first worked extremely well. The bacteria have evolved so that they are no longer affected by antibiotics anymore. The drugs killed off all the bacteria except a few which had some resistance. These few resistant bacteria produced the next generation.

paragraphs: The Colorado beetle is famous for its ability to resist pesticides. Over the last 50 years it has become resistant to 52 chemical compounds used in insecticides, including cyanide. This is natural selection speeded up by the artificial conditions. However, not every population is resistant to every chemical. The populations only become resistant to chemicals used in their area.

paragraphs: Although there were a number of natural historians in the 18th century who had some idea of evolution, the first well-formed ideas came in the 19th century. Three biologists are most important.

paragraphs: Jean-Baptiste de Lamarck (1744–1829), a French biologist, claimed that animals changed according to natural laws. He said that animals could pass on traits they had acquired during their lifetime to their offspring, using inheritance. Today, his theory is known as Lamarckism. Its main purpose is to explain adaptations by natural means. He proposed a tendency for organisms to become more complex, moving up a ladder of progress, plus "use and disuse".

paragraphs: Lamarck's idea was that a giraffe's neck grew longer because it tried to reach higher up. This idea failed because it conflicts with heredity (Mendel's work). Mendel made his discoveries about half a century after Lamarck's work.

paragraphs: Charles Darwin (1809–1882) wrote his "On the Origin of Species" in 1859. In this book, he put forward much evidence that evolution had occurred. He also proposed natural selection as the way evolution had taken place. But Darwin did not understand about genetics and how traits were actually passed on. He could not accurately explain what made children look like their parents.

paragraphs: Nevertheless, Darwin's explanation of evolution was fundamentally correct. In contrast to Lamarck, Darwin's idea was that the giraffe's neck became longer because "those with longer necks survived better". These survivors passed their genes on, and in time the whole species got longer necks.

paragraphs: Alfred Russel Wallace OM FRS (1823–1913) was a British naturalist, explorer, biologist and social activist. He proposed a theory of natural selection at about the same time as Darwin. His idea was published in 1858 together with Charles Darwin's idea.

paragraphs: An Austrian monk called Gregor Mendel (1822–1884) bred plants. In the mid-19th century, he discovered how traits were passed on from one generation to the next.

paragraphs: He used peas for his experiments: some peas have white flowers and others have red ones. Some peas have green seeds and others have yellow seeds. Mendel used artificial pollination to breed the peas. His results are discussed further in Mendelian inheritance. Darwin thought that the inheritance from both parents blended together. Mendel proved that the genes from the two parents stay separate, and may be passed on unchanged to later generations.

paragraphs: Mendel published his results in a journal that was not well-known, and his discoveries were overlooked. Around 1900, his work was rediscovered. Genes are bits of information made of DNA which work like a set of instructions. A set of genes are in every living cell. Together, genes organise the way an egg develops into an adult. With mammals, and many other living things, a copy of each gene comes from the father and another copy from the mother. Some living organisms, including some plants, only have one parent, so get all their genes from them. These genes produce the genetic differences which evolution acts on.

paragraphs: Darwin's "On the Origin of Species" has two themes: the evidence for evolution, and his ideas on how evolution took place. This section deals with the second issue.

paragraphs: The first two chapters of the "Origin" deal with variation in domesticated plants and animals, and variation in nature.

paragraphs: All living things show variation. Every population which has been studied shows that animal and plants vary as much as humans do. This is a great fact of nature, and without it evolution would not occur. Darwin said that, just as man selects what he wants in his farm animals, so in nature the variations allow natural selection to work.

paragraphs: The features of an individual are influenced by two things, heredity and environment. First, development is controlled by genes inherited from the parents. Second, living brings its own influences. Some things are entirely inherited, others partly, and some not inherited at all.

paragraphs: The colour of eyes is entirely inherited; they are a genetic trait. Height or weight is only partly inherited, and the language is not at all inherited. Just to be clear: the fact that humans can speak is inherited, but what language is spoken depends on where a person lives and what they are taught. Another example: a person inherits a brain of somewhat variable capacity. What happens after birth depends on many things such as home environment, education and other experiences. When a person is adult, their brain is what their inheritance and life experience have made it.

paragraphs: "Evolution only concerns the traits which can be inherited", wholly or partly. The hereditary traits are passed on from one generation to the next through the genes. A person's genes contain all the traits which they inherit from their parents. The accidents of life are not passed on. Also, of course, each person lives a somewhat different life: that increases the differences.

paragraphs: Organisms in any population vary in reproductive success. From the point of view of evolution, 'reproductive success' means the total number of offspring which live to breed and leave offspring themselves.

paragraphs: Variation can only affect future generations if it is inherited. Because of the work of Gregor Mendel, we know that much variation is inherited. Mendel's 'factors' are now called genes. Research has shown that "almost every individual in a sexually reproducing species is genetically unique".

paragraphs: Genetic variation is increased by gene mutations. DNA does not always reproduce exactly. Rare changes occur, and these changes can be inherited. Many changes in DNA cause faults; some are neutral or even advantageous. This gives rise to genetic variation, which is the seed-corn of evolution. Sexual reproduction, by the crossing over of chromosomes during meiosis, spreads variation through the population. Other events, like natural selection and drift, reduce variation. So a population in the wild always has variation, but the details are always changing.

paragraphs: Evolution mainly works by natural selection. What does this mean? Animals and plants which are best suited to their environment will, on average, survive better. There is a struggle for existence. Those who survive will produce the next generation. Their genes will be passed on, and the genes of those who did not reproduce will not. This is the basic mechanism which changes a population and causes evolution.

paragraphs: Natural selection explains why living organisms change over time to have the anatomy, the functions and behaviour that they have. It works like this:

paragraphs: There are now many cases where natural selection has been proved to occur in wild populations. Almost every case investigated of camouflage, mimicry and polymorphism has shown strong effects of selection.

paragraphs: The force of selection can be much stronger than was thought by the early population geneticists. The resistance to pesticides has grown quickly. Resistance to "warfarin" in Norway rats ("Rattus norvegicus") grew rapidly because those that survived made up more and more of the population. Research showed that, in the absence of "warfarin", the resistant homozygote was at a 54% disadvantage to the normal wild type homozygote. This great disadvantage was quickly overcome by the selection for "warfarin" resistance.

paragraphs: Mammals normally cannot drink milk as adults, but humans are an exception. Milk is digested by the enzyme lactase, which switches off as mammals stop taking milk from their mothers. The human ability to drink milk during adult life is supported by a lactase mutation which prevents this switch-off. Human populations have a high proportion of this mutation wherever milk is important in the diet. The spread of this 'milk tolerance' is promoted by natural selection, because it helps people survive where milk is available. Genetic studies suggest that the oldest mutations causing lactase persistence only reached high levels in human populations in the last ten thousand years. Therefore, lactase persistence is often cited as an example of recent human evolution. As lactase persistence is genetic, but animal husbandry a cultural trait, this is gene–culture coevolution.

paragraphs: Adaptation is one of the basic phenomena of biology. Through the process of adaptation, an organism becomes better suited to its habitat.

paragraphs: Adaptation is one of the two main processes that explain the diverse species we see in biology. The other is speciation (species-splitting or cladogenesis). A favourite example used today to study the interplay of adaptation and speciation is the evolution of cichlid fish in African rivers and lakes.

paragraphs: When people speak about adaptation they often mean something which helps an animal or plant survive. One of the most widespread adaptations in animals is the evolution of the eye. Another example is the adaptation of horses' teeth to grinding grass. Camouflage is another adaptation; so is mimicry. The better adapted animals are the most likely to survive, and to reproduce successfully (natural selection).

paragraphs: An internal parasite (such as a fluke) is a good example: it has a very simple bodily structure, but still the organism is highly adapted to its particular environment. From this we see that adaptation is not just a matter of visible traits: in such parasites critical adaptations take place in the life cycle, which is often quite complex.

paragraphs: Not all features of an organism are adaptations. Adaptations tend to reflect the past life of a species. If a species has recently changed its life style, a once valuable adaptation may become useless, and eventually become a dwindling vestige.

paragraphs: Adaptations are never perfect. There are always tradeoffs between the various functions and structures in a body. It is the organism as a whole which lives and reproduces, therefore it is the complete set of adaptations which gets passed on to future generations.

paragraphs: In populations, there are forces which add variation to the population (such as mutation), and forces which remove it. Genetic drift is the name given to random changes which remove variation from a population. Genetic drift gets rid of variation at the rate of 1/(2N) where N = population size. It is therefore "a very weak evolutionary force in large populations".

paragraphs: Genetic drift explains how random chance can affect evolution in surprisingly big ways, but only when populations are quite small. Overall, its action is to make the individuals more similar to each other, and hence more vulnerable to disease or to chance events in their environment.

paragraphs: How species form is a major part of evolutionary biology. Darwin interpreted 'evolution' (a word he did not use at first) as being about speciation. That is why he called his famous book "On the Origin of Species".

paragraphs: Darwin thought most species arose directly from pre-existing species. This is called "anagenesis": new species by older species changing. Now we think most species arise by previous species splitting: "cladogenesis".

paragraphs: Two groups that start the same can also become very different if they live in different places. When a species gets split into two geographical regions, a process starts. Each adapts to its own situation. After a while, individuals from one group can no longer reproduce with the other group. Two good species have evolved from one.

paragraphs: A German explorer, Moritz Wagner, during his three years in Algeria in the 1830s, studied flightless beetles. Each species is confined to a stretch of the north coast between rivers which descend from the Atlas mountains to the Mediterranean. As soon as one crosses a river, a different but closely related species appears. He wrote later:

paragraphs: This was an early account of the importance of geographical separation. Another biologist who thought geographical separation was critical was Ernst Mayr.

paragraphs: One example of natural speciation is the three-spined stickleback, a sea fish that, after the last ice age, invaded freshwater, and set up colonies in isolated lakes and streams. Over about 10,000 generations, the sticklebacks show great differences, including variations in fins, changes in the number or size of their bony plates, variable jaw structure, and color differences.

paragraphs: The wombats of Australia fall into two main groups, common wombats and hairy-nosed wombats. The two types look very similar, apart from the hairiness of their noses. However, they are adapted to different environments. Common wombats live in forested areas and eat mostly green food with lots of moisture. They often feed in the daytime. Hairy-nosed wombats live on hot dry plains where they eat dry grass with very little water or nutrition in it. Their metabolic rate is slow and they sleep most of the day underground.

paragraphs: When two groups that started the same become different enough, then they become two different species. Part of the theory of evolution is that all living things started the same, but then split into different groups over billions of years.

paragraphs: This was an important movement in evolutionary biology, which started in the 1930s and finished in the 1950s. It has been updated regularly ever since.

paragraphs: The synthesis explains how the ideas of Charles Darwin fit with the discoveries of Gregor Mendel, who found out how we inherit our genes. The modern synthesis brought Darwin's idea up to date. It bridged the gap between different types of biologists: geneticists, naturalists, and palaeontologists.

paragraphs: When the theory of evolution was developed, it was not clear that natural selection and genetics worked together. But Ronald Fisher showed that natural selection would work to change species. Sewall Wright explained genetic drift in 1931.

paragraphs: Co-evolution is where the existence of one species is tightly bound up with the life of one or more other species.

paragraphs: New or 'improved' adaptations which occur in one species are often followed by the appearance and spread of related features in the other species. The life and death of living things is intimately connected, not just with the physical environment, but with the life of other species.

paragraphs: These relationships may continue for millions of years, as it has in the pollination of flowering plants by insects. The gut contents, wing structures, and mouthparts of fossilized beetles and flies suggest that they acted as early pollinators. The association between beetles and angiosperms during the Lower Cretaceous period led to parallel radiations of angiosperms and insects into the late Cretaceous. The evolution of nectaries in Upper Cretaceous flowers signals the beginning of the mutualism between hymenoptera and angiosperms.

paragraphs: Charles Darwin was the first to use this metaphor in biology. The "evolutionary tree" shows the relationships among various biological groups. It includes data from DNA, RNA and protein analysis. Tree of life work is a product of traditional comparative anatomy, and modern molecular evolution and molecular clock research.

paragraphs: The major figure in this work is Carl Woese, who defined the Archaea, the third domain (or kingdom) of life. Below is a simplified version of present-day understanding.

paragraphs: Macroevolution: the study of changes above the species level, and how they take place. The basic data for such a study are fossils (palaeontology) and the reconstruction of ancient environments. Some subjects whose study falls within the realm of macroevolution:

paragraphs: It is a term of convenience: for most biologists it does not suggest any change in the process of evolution. For some palaeontologists, what they see in the fossil record cannot be explained just by the gradualist evolutionary synthesis. They are in the minority.

paragraphs: Altruism – the willingness of some to sacrifice themselves for others – is widespread in social animals. As explained above, the next generation can only come from those who survive and reproduce. Some biologists have thought that this meant altruism could not evolve by the normal process of selection. Instead a process called "group selection" was proposed. Group selection refers to the idea that alleles can become fixed or spread in a population because of the benefits they bestow on groups, regardless of the alleles' effect on the fitness of individuals within that group.

paragraphs: For several decades, critiques cast serious doubt on group selection as a major mechanism of evolution.

paragraphs: In simple cases it can be seen at once that traditional selection suffices. For example, if one sibling sacrifices itself for three siblings, the genetic disposition for the act will be increased. This is because siblings share on average 50% of their genetic inheritance, and the sacrificial act has led to greater representation of the genes in the next generation.

paragraphs: Altruism is now generally seen as emerging from standard selection. The warning note from Ernst Mayr, and the work of William Hamilton are both important to this discussion.

paragraphs: Hamilton's equation describes whether or not a gene for altruistic behaviour will spread in a population. The gene will spread if rxb is greater than c:

paragraphs: At first, sexual reproduction might seem to be at a disadvantage compared with asexual reproduction. In order to be advantageous, sexual reproduction (cross-fertilisation) has to overcome a two-fold disadvantage (takes two to reproduce) plus the difficulty of finding a mate. Why, then, is sex so nearly universal among eukaryotes? This is one of the oldest questions in biology.

paragraphs: The answer has been given since Darwin's time: because the sexual populations adapt better to changing circumstances. A recent laboratory experiment suggests this is indeed the correct explanation.

paragraphs: In the main experiment, nematode worms were divided into two groups. One group was entirely outcrossing, the other was entirely selfing. The groups were subjected to a rugged terrain and repeatedly subjected to a mutagen. After 50 generations, the selfing population showed a substantial decline in fitness (= survival), whereas the outcrossing population showed no decline. This is one of a number of studies that show sexuality to have real advantages over non-sexual types of reproduction.

paragraphs: An important activity is artificial selection for domestication. This is when people choose which animals to breed from, based on their traits. Humans have used this for thousands of years to domesticate plants and animals.

paragraphs: More recently, it has become possible to use genetic engineering. New techniques such as 'gene targeting' are now available. The purpose of this is to insert new genes or knock out old genes from the genome of a plant or animal. A number of Nobel Prizes have already been awarded for this work.

paragraphs: However, the real purpose of studying evolution is to explain and help our understanding of biology. After all, it is the first good explanation of how living things came to be the way they are. That is a big achievement. The practical things come mostly from genetics, the science started by Gregor Mendel, and from molecular and cell biology.

paragraphs: In 2010 the journal "Nature" selected 15 topics as 'Evolution gems'. These were:

paragraphs: The idea that all life evolved had been proposed before Charles Darwin published "On the Origin of species". Even today, some people still discuss the concept of evolution and what it means to them, their philosophy, and their religion. Evolution does explain some things about our human nature. People also talk about the social implications of evolution, for example in sociobiology.

paragraphs: Some people have the religious belief that life on Earth was created by a god. In order to fit in the idea of evolution with that belief, people have used ideas like "guided evolution" or "theistic evolution". They say that evolution is real, but is being guided in some way.

paragraphs: There are many different concepts of "theistic evolution". Many creationists believe that the creation myth found in their religion goes against the idea of evolution. As Darwin realised, the most controversial part of the evolutionary thought is what it means for human origins.

paragraphs: In some countries, especially in the United States, there is tension between people who accept the idea of evolution and those who do not accept it. The debate is mostly about whether evolution should be taught in schools, and in what way this should be done.

paragraphs: Other fields, like cosmology and earth science also do not match with the original writings of many religious texts. These ideas were once also fiercely opposed. Death for heresy was threatened to those who wrote against the idea that Earth was the center of the universe.

paragraphs: Evolutionary biology is a more recent idea. Certain religious groups oppose the idea of evolution more than other religious groups do. For instance, the Roman Catholic Church now has the following position on evolution: Pope Pius XII said in his encyclical "Humani Generis" published in the 1950s:

paragraphs: Pope John Paul II updated this position in 1996. He said that Evolution was "more than a hypothesis":

paragraphs: The Anglican Communion also does not oppose the scientific account of evolution.

paragraphs: Many of those who accepted evolution were not much interested in biology. They were interested in using the theory to support their own ideas on society.

paragraphs: Some people have tried to use evolution to support racism. People wanting to justify racism claimed that certain groups, such as black people, were inferior. In nature, some animals do "survive" better than others, and it does lead to animals better adapted to their circumstances. With humans groups from different parts of the world, all evolution can say is that each group is probably well suited to its original situation. Evolution makes no judgements about better or worse. It does "not" say that any human group is superior to any other.

paragraphs: This amazing idea of eugenics was rather different. Two things had been noticed as far back as the 18th century. One was the great success of farmers in breeding cattle and crop plants. They did this by selecting which animals or plants would produce the next generation (artificial selection). The other observation was that lower class people had more children than upper-class people. If (and it's a big if) the higher classes were there on "merit", then their lack of children was the exact reverse of what should be happening. Faster breeding in the lower classes would lead to the society getting worse.

paragraphs: The idea to improve the human species by selective breeding is called eugenics. The name was proposed by Francis Galton, a bright scientist who meant to do good. He said that the human stock (gene pool) should be improved by selective breeding policies. This would mean that those who were considered "good stock" would receive a reward if they reproduced. However, other people suggested that those considered "bad stock" would need to undergo compulsory sterilization, prenatal testing and birth control. The German Nazi government (1933–1945) used eugenics as a cover for their extreme racial policies, with dreadful results.

paragraphs: The problem with Galton's idea is how to decide which features to select. There are so many different skills people could have, you could not agree who was "good stock" and who was "bad stock". There was rather more agreement on who should "not" be breeding. Several countries passed laws for the compulsory sterilisation of unwelcome groups. Most of these laws were passed between 1900 and 1940. After World War II, disgust at what the Nazis had done squashed any more attempts at eugenics.

paragraphs: Some equations can be solved using algorithms that simulate evolution. Evolutionary algorithms work like that.

paragraphs: Another example of using ideas about evolution to support social action is social darwinism. Social darwinism is a term given to the ideas of the 19th century social philosopher Herbert Spencer. Spencer believed the "survival of the fittest" could and should be applied to commerce and human societies as a whole.

paragraphs: Again, some people used these ideas to claim that racism, and ruthless economic policies were justified. Today, most biologists and philosophers say that the theory of evolution should not be applied to social policy.

paragraphs: Some people disagree with the idea of evolution. They disagree with it for a number of reasons. Most often these reasons are influenced by or based on their religious beliefs. People who do not agree with evolution usually believe in creationism or intelligent design.

paragraphs: Despite this, evolution is one of the most successful theories in science. People have discovered it to be useful for different kinds of research. None of the other suggestions explain things, such as fossil records, as well. So, for almost all scientists, evolution is not in doubt.

paragraphs: These books are mostly about the evidence for evolution.

paragraphs: These books cover most evolutionary topics.


title: Bedfordshire

paragraphs: Bedfordshire is a county of England. Its county town is Bedford. It borders Cambridgeshire, Northamptonshire, Buckinghamshire (with the Borough of Milton Keynes) and Hertfordshire. The highest elevation point is 243 m (797 ft) on Dunstable Downs in the Chilterns. The county motto is "Constant Be", which is taken from the hymn "To Be A Pilgrim" by John Bunyan.

paragraphs: There are forty Sites of Special Scientific Interest (SSSIs) in Bedfordshire, designated by Natural England. Thirty-five are listed for their biological interest, and five for their geological interest.

paragraphs: Three of the sites are also National nature reserves, twelve are in the Chilterns Area of Outstanding Natural Beauty, and eleven are managed wholly or partly by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire.


title: American football

paragraphs: American football, referred to as football in the United States and Canada and also known as gridiron, is a team sport. It is played by two teams with 11 players on each side. American football is played with a ball with pointed ends. Points are scored in many ways, usually by one team getting the ball into the end zone of the other team. The game started in the late 19th century as college football, an American version of rugby football.

paragraphs: The main leagues that play American football are the professional National Football League (NFL), and the National Collegiate Athletic Association (NCAA), which plays college football. In the National Football League, players can be paid millions of dollars. In the National Collegiate Athletic Association, players simply play for the pride of their school, scholarships, or for the chance to join a national team. Over a million boys (and a number of girls) play high school football. There is also a closely related sport called Canadian football (CFL).

paragraphs: An American football game is played with a ball called a football. The sport is played on a grass (or artificial turf) field. The field is exactly long and wide. The end zones, one at each end of the field, are long. The players wear protective equipment, including a helmet with face mask, shoulder pads, thigh pads, and often a mouth guard. A team has four chances, or "downs", to advance the ball while the opposing team tries to stop it. Certain players advance the ball by carrying or throwing it. Teams can score by advancing the ball to the other team's end zone or by kicking the ball through a goalpost placed at the back of the end zone. American football is carefully regulated by time and rules, which are enforced by officials, who also determine when a team scores.

paragraphs: A college or professional football game is 60 minutes long, and is divided into 15-minute quarters. In some high schools, the quarters are 12 minutes long, and games for younger children are often shorter still. After the first two quarters, the teams rest during halftime.

paragraphs: In NFL football, if the game is tied after the four quarters, the two teams compete in at least one more 15-minute period called overtime. During overtime, the first team to score points is usually the winner. However, under the current rules, first used for the 2011 postseason, if the team that has the ball first ends its possession by scoring a field goal, the other team has a chance to score. If that team does not score, or if it scores a touchdown, the game ends. If it scores a field goal, the game continues, and the next team to score wins. During the regular season, only one overtime period is played—if neither team scores, or if both teams score field goals when they first have the ball, the game ends in a tie. During the playoffs, the game will continue with as many overtime periods as needed to decide a winner. If the game is tied after each team has had the ball once in overtime, the first team to score wins.

paragraphs: In NCAA football overtime, which is based on the system used for high school football in most U.S. states, the teams take turns trying to score. The game ends when one team scores, and the other team fails to score as many points during its chance.

paragraphs: American football is played on a field long by wide. Most of the game is played on in the middle. It is divided by 20 lines drawing every . The field has two other sets of markings, running between the two end zones along the length of the field, known as "hashmarks". All plays must start between the hashmarks—if the last play ended outside the hashmarks, the ball is moved to the nearest hashmark. At the ends of the field there are scoring areas, called the end zones.

paragraphs: There are also two yellow poles on the end of each field called uprights. Sometimes, if the team can not score a touchdown they might want to kick it through the uprights for three points. The uprights are also used for scoring one point after a team scored a touchdown.

paragraphs: There are many types of players on a football team. For the offensive part of the team, a quarterback throws the football to wide receivers while offensive linemen block to protect him from defensive players. The offensive linemen also block when a running back runs to advance the football. Players on the Defensive line, a linebacker, and defensive backs (cornerbacks and American football safeties) attempt to tackle the offensive player who carries the football.

paragraphs: Some team members only play during certain times. These players belong to the Special Teams. The kicker can kick the ball to the other team or between the uprights, while the placeholder holds the ball steady. The kick returner runs the ball down the field in an attempt to score points after catching the ball.

paragraphs: A touchdown is achieved when a player has legal possession of the ball and the ball crosses an imaginary vertical plane above the opposing team's goal line. After a touchdown, the scoring team attempts a try for 1 or 2 points (see below). A successful touchdown is signaled by an official extending both arms vertically above the head.

paragraphs: A field goal is scored when the ball is place kicked between the goal posts behind the opponent's end zone. The most common type of kick used is the place kick. For a place kick, the ball must first be snapped to a placeholder, who holds the ball upright on the ground with his fingertip so that it may be kicked. Three points are scored if the ball crosses between the two upright posts and above the crossbar and remains over.

paragraphs: Immediately following a touchdown, the scoring team can attempt to kick the ball between the goal posts for 1 extra point. The team can also run or pass the ball into the end zone for 2 points. This is not done very often although it does happen.

paragraphs: A safety is scored if a player causes the ball to become dead in his own end zone. When this happens two points are awarded to the opposing (usually defending) team. This can happen if a player is either downed or goes out of bounds in the end zone while carrying the ball. It can also happen if he fumbles the ball, and it goes out of bounds in the end zone. A safety is also awarded to the defensive team if the offensive team commits a foul which is enforced in its own end zone.

paragraphs: Exhibition season (better known as Pre-Season) is in August. In the exhibition season, the teams get ready for the regular season by having training. Teams have practices to help the team get better and see who will make the team. All of the teams play 4 games before the regular season starts, and the games do not change what team gets to the post season. Because of it, teams do not use their best players much, and use the games as more practice.

paragraphs: The 32 NFL teams are divided into two conferences: the National Football Conference (NFC) and the American Football Conference (AFC). Each of them is divided in four divisions: North, South, West and East. Each division includes four teams.

paragraphs: The season lasts 17 weeks. Each team plays 16 games and has one week off. This week of rest is called a "bye week".

paragraphs: At the end of the regular season, the winners of each division, and the next two best teams in each conference and the best 6 AFC teams play in a tournament. NFC's champion and AFC's champion play the NFL's final game, the Super Bowl. The event is often treated as a National holiday as many stores close for the event. The day of the event is commonly known nationwide as Super Bowl Sunday.


title: The Ugly Duckling

paragraphs: "The Ugly Duckling" is a literary fairy tale by Hans Christian Andersen. Andersen lavished great care on this story, spending a year perfecting it. It was first published in 1844 with "The Angel", "The Sweethearts", and "The Nightingale" in "New Fairy Tales". The critics liked these stories. Andersen considered the story "a reflection of my own life." The moral of the tale: "it does not matter if you were born in a duck yard if you have lain in a swan's egg." The tale has been adapted to various media such as animated movies.

paragraphs: A mother duck hatches six pretty little ducklings. A seventh bird is hatched. He is homely. The other ducks abuse him. He runs away. He is given a home by an old woman. Her cat and hen do not like him. He runs away again. Winter comes and a kind farmer gives him a home. The little bird almost dies. Spring comes. The "ugly duckling" has grown into a beautiful swan. The other swans welcome him as their own. They bow to him. He is happy for the first time in his life.


title: General relativity

paragraphs: General relativity is a theory of space and time. The theory was published by Albert Einstein in 1915. The central idea of general relativity is that space and time are two aspects of spacetime. Spacetime is curved when there is matter, energy, and momentum resulting in what we perceive as gravity. The links between these forces are shown in the Einstein field equations.

paragraphs: A central idea in general relativity is the "principle of equivalence." An example is that two people, one in an elevator sitting on the surface of the earth, and the other in an elevator in outer space accelerating at 9.8 m/s, will each observe the same behavior of an object they drop from their hand. The object will accelerate to the floor at 9.8 m/s in either case, making it impossible for either to distinguish whether or not they are at rest in a gravitational field or accelerating upward at one . Other versions of this type of "thought experiment" were used to show that light would curve in an accelerating frame of reference. There are several forms of the equivalence principle. These include: Newton's equivalence principle, the weak equivalence principle, the gravitational weak equivalence principle, Einstein's equivalence principle and the strong equivalence principle.

paragraphs: The Sun can be seen as this kind of valley in spacetime, and one of the other objects in the valley is the Earth. The Earth does not roll directly towards the Sun (or ball) because it is moving too fast. The force pulling the Earth towards the sun is about the same as a second force. This second force is called the centrifugal force. The centrifugal force exists because the Earth moves sideways. This sideways motion makes the distance between the Earth and Sun increase. Since the Earth is being pulled towards the sun and moving away at the same time, it stays at about the same distance. This is also how the Moon orbits the earth. In this second case, Earth is the ball and the Moon is the object.

paragraphs: General relativity has predicted many things which were later seen. These include:


title: Rutland

paragraphs: Rutland is the smallest county of England. It is surrounded by the counties of Leicestershire, Lincolnshire and Northamptonshire.

paragraphs: The main towns of Rutland are Oakham and Uppingham.

paragraphs: In the mid-1970s, it was the inspiration for Eric Idle's TV show, Rutland Weekend Television.


title: Adlai Stevenson I

paragraphs: Adlai Ewing Stevenson (October 23, 1835 – June 14, 1914) was an American politician. He was Vice President of the United States under Grover Cleveland, and ran for United States President and several other political offices, but lost. He was also first assistant Postmaster General and a member of the United States House of Representatives from Illinois, as well. His grandson of the same name also was a notable politician and writer. Another grandson, McLean Stevenson was an actor. His other grandson was Illinois Senator Adlai Stevenson III.


title: Toledo, Ohio

paragraphs: Toledo is a city in Ohio, USA. It was named after Toledo, Spain. It is a large industrial city, and has many factories that make things like car parts and glass. In 1835 and 1836, Ohio and Michigan both claimed to own the city and surrounding territory. Michigan gave up its claim and got the Upper Peninsula in exchange. Toledo is about an hour from Detroit, Michigan. The main highways in and out of Toledo are Interstate 75, Interstate 90, and U.S. 24 (Detroit Boulevard, Telegraph Road). It is the 59th largest city in the United States.

paragraphs: Toledo's manufacturing industry concentrates on automobiles and glass.

paragraphs: Toledo has a humid continental climate ("Dfa" in the Köppen climate classification).


title: The Carpenters

paragraphs: The Carpenters were an American musical duo. The members were Richard Carpenter and his sister Karen. Starting in 1969, the duo had many popular songs including "We've Only Just begun", "Close to You", "Sing", "Rainy Days and Mondays" "Calling Occupants of Interplanetary Craft" and others. They continued until Karen's death in 1983 of bulimia in Downey, California. They sold over 100 million albums.


title: Jerry Reed

paragraphs: Jerry Reed (March 20, 1937 – September 1, 2008) was an American country music singer and actor. Best known for his songs "Amos Moses", "When You're Hot You're Hot" and "Eastbound and Down", he also acted in several movies including "Smokey and the Bandit" and "The Waterboy". He was born in Atlanta, Georgia. He died in Nashville, Tennessee due to complications from emphysema.


title: Bee Gees

paragraphs: The Bee Gees were a successful pop group. For most of its history, the band consisted of three brothers, all born on the Isle of Man to English parents: Barry Gibb (born 1 September 1946), and twins Maurice Gibb (22 December 1949 – 12 January 2003) and Robin Gibb (22 December 1949 – 20 May 2012). In the late 1960s, the band briefly expanded to include Australian born Vince Melouney and Colin Petersen. When the band reformed in 1970 after splitting in 1969, Australian born Geoff Bridgford briefly became a member. The Bee Gees existed for almost 40 years They are most famous for their album, "Saturday Night Fever", the soundtrack for the movie of the same name. They stopped performing after Maurice died. The two other brothers reunited as a duo in 2009. In 2012 Robin died. They had a younger brother, Andy Gibb (1958–1988), who was also a singer.

paragraphs: The Gibb brothers were born on the Isle of Man then in 1955, they moved to Manchester before moving to Australia. It was in Australia that the Bee Gees' band was formed. In January 1967, the Gibb brothers returned to England, where their band the Bee Gees started to become internationally famous. In 1967, Colin Petersen and Vince Melouney joined the band but by the end the decade both had left and the brothers themselves had briefly gone their separate ways, only to reform in 1970. Between 1970 and 1972, Geoff Bridgford was a member of the Bee Gees. In 1975, the brothers relocated to the United States.


title: Improverts

paragraphs: The Improverts are an improvised comedy group based in Edinburgh, Scotland. They are a part of the Edinburgh University Theatre Company. Their home is the Bedlam Theatre. It has been their home since they were created 18 years ago. The group is similar to "Who's Line is it Anyway?", Comedy Store Players, and Keith Johnstone in that they use short improvised games.

paragraphs: They have taken part in the Edinburgh Fringe Festival almost every year since they were formed. Also they have played every Friday night during the school year (as their main audience is Edinburgh University students).

paragraphs: Because they are always in Bedlam Theatre, the theatre technicians improvise the sounds, music and lights along with the scenes the performers are doing. The sounds can be loud and annoying at times. The technicians show off their very big iTunes library of songs and sound effects. British 80's children's programmes' themes are a favourite of theirs.

paragraphs: Past players have gone on to many different things. They have created an improv group in London, joined the Stand Players' "Who's Lunch is it anyway" free improv show at Edinburgh's The Stand comedy venue and become successful stand up comedians. Some have starred in British sitcoms, television dramas, movies and popular children's programmes


title: Taipei 101

paragraphs: Taipei 101 () is 101-floor building in Taipei, Republic of China (Taiwan). In 2004, it replaced the Willis Tower (which used to be called the Sears Tower) as the tallest completed building in the world. However, in 2010, it was surpassed by the Burj Khalifa in Dubai.

paragraphs: Taipei 101 does not hold the record for tallest building from ground to pinnacle. The Sears Tower has two television antennas on top of it, making its height from the ground to the top of the taller antenna 527 m (1,729 ft).

paragraphs: Taipei 101 is the recognized symbol of Taipei city, it brings a lot of tourists every day. The location of Taipei 101 is at the southern end of the Xinyi District, the newest area of Taipei city. Besides the tower, the base of the building houses includes a multi-level shopping mall, food court, various restaurants and stores, and an international grocery store. Every New Year's Eve, Taipei 101 is host to an impressive fireworks display that attracts people from all over Taiwan and other neighboring countries like Japan and Singapore to the area.

paragraphs: The Taipei 101 Observatory is open every day from 9AM to 10PM. The observatory is spread over 4 floors where visitors can enjoy the fantastic scenery and learn about the engineering marvel that is Taipei 101, the tallest green building in the world. Visitors can buy the tickets on the 5F Taipei 101 Mall, the general ticket costs NT$500 per each and the student ticket (with valid ID) costs NT$450 per each, all children (under 115 cm) are free. After purchasing the tickets, visitors may take the Guinness World Record breaking high-speed elevator to the observatory on the 89TH floor.

paragraphs: The 88th floor is the Beauty of Taiwan Multimedia Corridor, Super Big Wind Damper, Treasure Sky, the hallway connecting the two decks is designed to setting the natural beauty of Taiwan, providing 270-degree views of well-known scenic locations in Taiwan, leading to the engineering marvel known as a wind damper, a 5.5 meters diameter, 660 ton weight suspended within the building to offset the force of wind and help 101 stand upright. Also included is Treasury Sky, a collection of unique jewel crafts.

paragraphs: The 89th floor is the Indoor Observatory, visitors can learn about the design process and construction of Taipei 101 and other similar large-scale building projects around the world, including a free audio tour in eleven languages, as well as high-powered field glasses, snacks, and professional photography service.

paragraphs: The 91st floor is an outdoor Observatory. The outdoor observatory is accessible by stairs from the 89th floor. From the outside, it's possible to view the spire at the 508-meter-high apex, but tourists need to be careful of the strong winds. Inside the building, on the 91F, is a small theater showcasing films about the building and the annual New Year fireworks display. The 91st floor is only open on days with good weather conditions.

paragraphs: Taipei 101 has some of the most modern safety security of anything ever built, requiring a challenging combination of strength and flexibility, which allow it to withstand winds up to 216 km/h (134 mph), and earthquakes of a magnitude of 9.0. It has higher safer ratings than Taiwan’s nuclear power plants.

paragraphs: The “double stairstep”design reduce the potentially dangerous oscillations caused by high winds by about 30-40%, allowing the structure to stand, even under the force of relentless typhoons. And by now, they’ve become a recognizable design element of the structure.


title: Sergio Aragonés

paragraphs: Sergio Aragonés (1937-) is a popular cartoonist. He was born in Spain and grew up in Mexico. He is most famous for his cartoons for "MAD Magazine" and the comic book "Groo the Wanderer".


title: Lisa Bonet

paragraphs: Lisa Bonet (born Lisa Michelle Bonet; November 16, 1967), also known as Lilakoi Moon, is an American actress. She is best known for her roles as Denise Huxtable on television series, "The Cosby Show" and "A Different World". She was also married to singer Lenny Kravitz from 1987 to 1993. She is of African American and Ashkenazi Jewish (from Belarus, Moldova, Poland and Russia) descent.


title: Tobacco

paragraphs: Tobacco is a product prepared from the leaves of the tobacco plant by curing them. The plant is part of the genus "Nicotiana" and of the Solanaceae (nightshade) family.

paragraphs: Native Americans used tobacco before Europeans arrived in the Americas. The earliest know use of tobacco comes from nicotine residue from a pipe in the Southeastern United States. It is Radiocarbon dated at 1685-1530 BC. Europeans in the Americas learned to smoke and brought it back to Europe, where it became very popular. At that time tobacco was usually smoked in a pipe.

paragraphs: The Europeans who moved to America started to farm tobacco so that they could sell it in Europe. This became one of the main causes of the African slave trade. In 1610 a European man called John Rolfe arrived in the American state of Virginia and set up a tobacco farm which made him very rich. Rolfe was the first non-native farmer to use "nicotiana tabacum", which is the type of tobacco most commonly smoked today. He also married Pocahontas, a Native American woman who became famous when she went to live in London.

paragraphs: In the 17th and 18th centuries tobacco made farmers very rich and towns quickly grew in the states of Virginia, North Carolina and South Carolina. In 1883 one third of United States tax money came from tobacco.

paragraphs: In 1864 the first American tobacco factory opened to produce 20 million cigarettes annually. By 1964 the cigarette contained over 500 added chemicals. Today tobacco manufacturers are still not required by law to list the 500+ ingredients.

paragraphs: Tobacco users (especially smokers) risk many very serious and often deadly illnesses, such as cancer, strokes, heart disease, and lung disease. The United States' Centers for Disease Control and Prevention describes tobacco use as "the single most important preventable risk to human health in developed countries and an important cause of premature (early) death worldwide". There are over 4800 chemicals in tobacco, including arsenic. Sixty-four of them are known to cause cancer. Smoking can also make men lose erections, and make their penises a bit smaller.


title: Jerusalem

paragraphs: Jerusalem (; ; ) is one of the oldest cities in the world that people have lived in continuously. It is important to many major religions. Jews consider Jerusalem a holy city because it was their religious and political center during Biblical times and was the place where the Temple of God stood. Christians consider Jerusalem holy because many events in the life of Jesus took place there. Muslims believe that Muhammad rose to heaven from Jerusalem, and the Al-Aqsa Mosque is the first Qibla of Muslims after Mecca.

paragraphs: Jerusalem is the capital city of both Israel and Palestine, under their laws. Most other countries disagree. Most countries have their embassies with Israel in Tel Aviv.

paragraphs: Jerusalem is about 40 miles (64 kilometers) east of the Mediterranean Sea. It is a hilly city with many valleys around it.

paragraphs: Jerusalem is a very old city. It has great importance for three religions: Judaism, Christianity and Islam. The Bible says King David, the second king of Israel, took this city from pagans and settled his palace there. King Solomon, David's son and the next king, built the Temple of Solomon in Jerusalem. Later, as capital of Judah, Jerusalem was destroyed by Nebuchadnezzar II, the king of Babylon. The Palace of King David and the Temple of Solomon were burned, and the Jews were captured and taken to Babylon. Seventy years later, the Persian King Cyrus allowed them to return to Jerusalem and to rebuild the Temple.

paragraphs: Later the area was occupied by Romans. King Herod the Great, who ruled for the Roman Emperor, made the Temple larger to try and win Jewish favor. The Temple was famous for its greatness and beauty.

paragraphs: Jesus died in Jerusalem around 33 CE. In 70 CE, the Jews rebelled against the Romans, but the Romans destroyed the city and the Temple. Jewish people who lived in Jerusalem were caught and became slaves. The Romans renamed Jerusalem with a Latin name. Since then, the Temple has not been rebuilt, and only a part of its wall remains until today.

paragraphs: After the Roman Empire was split into two, the Byzantine Empire ruled Jerusalem. Later, Muslims took over the city from them. The Muslims believed Muhammad went to heaven from Jerusalem.

paragraphs: Later, the Pope in Rome sent the Crusaders from Western Europe to try and take Jerusalem back. They succeeded for a while, but eventually the city fell again to the Saracens. Until the 20th century, Jerusalem was a part of the Ottoman Empire. There were some Jews in Jerusalem all along, even though they were ruled by other people.

paragraphs: The "New City" of Jerusalem is the part outside the old stone walls. People started building the new city in the 1800s. Mishkenot Sha'annanim, Mea Shearim, and the Bukharan Quarter are some of the first neighborhoods in the new city.

paragraphs: After World War I, the Ottoman Empire had been defeated. In June 1922, the League of Nations approved the British Mandate of Palestine. This gave control of the area to the United Kingdom. The land west of the Jordan River was known as Palestine. It was under direct British control until 1948. The land east of the Jordan River was known as Transjordan, and was governed by the Hashemite family. Transjordan gained independence in 1946.

paragraphs: The mandate in Palestine ended at midnight on 14 May 1948. On the next day, the 1948 Arab–Israeli War began. Israel declared independence, the West Bank was annexed by Jordan, and Egypt took control of the Gaza Strip.

paragraphs: In 1949, at the end of the first Arab-Israeli War, Jerusalem was divided between Israel and Jordan. Israel controlled the western part of the city. Jordan controlled the eastern section, including the Old City, a walled section of Jerusalem dating from Biblical times. Israel took control of the entire city during the Six-Day War in 1967.

paragraphs: Jerusalem today is claimed by the state of Israeli as its capital. The United Nations does not agree to Israel saying that Jerusalem is the capital of Israel.

paragraphs: Jerusalem has been sacred to Judaism for roughly 3000 years, to Christianity for around 2000 years, and to Islam for approximately 1400 years. The 2000 Statistical Yearbook of Jerusalem lists 1204 synagogues, 158 churches, and 73 mosques within the city. Despite efforts to maintain peaceful religious coexistence, some sites, such as the Temple Mount, have been a continuous source of friction and controversy.

paragraphs: According to Jewish tradition, Jerusalem is where God told the patriarch Abraham to sacrifice his son, Isaac, to Him. The Jews built the Temple, the centre of Jewish worship in ancient times, at the site of Abraham's sacrifice on the Temple Mount in the Old City. Two buildings, one after the other, the First Temple and the Second Temple, stood at the site. The First Temple housed the Ark of the Covenant, a sacred box holding the tablets inscribed with the Ten Commandments.

paragraphs: The Western Wall is a part of the Second Temple and Judaism's most sacred shrine. It is a stone wall that strengthened the western side of the Temple Mount in ancient times. The wall is sometimes called the Wailing Wall because of the sad prayers Jewish people said there to mourn the destroyed Temple.

paragraphs: Other sites in the city that are sacred to the Jews include King David's tomb on Mount Zion, and the Jewish Cemetery and the Tombs of the Prophets on the Mount of Olives, a hill just east of the Old City. Many sites associated with Biblical figures are sacred to Christians, too.

paragraphs: Many monasteries, convents, shrines, and religious seminaries in Jerusalem mark events in the life of Jesus and in the formation of the Christian Church. According to the Bible, Jesus taught in Jerusalem and performed numerous miracles there. The Last Supper supposedly took place in a room known as the Cenacle (also called Coenaculum) on Mount Zion. The Church of the Holy Sepulcher in the Old City is said to be the place of Jesus's Crucifixion (called Calvary or Golgotha), as well as His burial and resurrection. Several Christian sects own the church, which was originally built by Constantine the Great, then rebuilt and dedicated by the Crusaders in 1149 CE. The building stands at the end of the Via Dolorosa (Way of Sorrows), believed to be the path over which Jesus carried His cross to Calvary. Jesus was last seen by His followers on the Mount of Olives before He went up to heaven. All of these sites attract many religious pilgrims each year.

paragraphs: Jerusalem is Islam's third holiest city, after Mecca and Medina in Saudi Arabia. According to Muslim tradition, Muhammad originally selected Jerusalem as the qibla: the direction Muslims should face during prayer. However, he later told his followers to face Mecca instead of Jerusalem when praying. Muhammad is said to have gone up to heaven from a stone now covered by a golden-domed shrine called the Dome of the Rock. The Dome of the Rock and the ancient Al-Aqsa Mosque are among the holiest sites in Islam. They are the main buildings on the Temple Mount, which Muslims call "Haram al-Sharif" (Noble Sanctuary).

paragraphs: Jerusalem's architecture is a mixture of old and new. The Old City contains architectural examples from each major period in the city's history. Many ancient historical sites and places of worship stand near modern shopping centers and industrial zones. Architecture from the late 1800s and early 1900s shows European influences. Usefulness rather than style characterizes new apartment buildings constructed by the government as housing for immigrants. Many buildings, old and new, have matching exteriors because all construction is required to be faced with a cream-colored limestone called Jerusalem stone, produced by nearby quarries.

paragraphs: Belz Beis HaMedrash HaGadol is the largest synagogue in Jerusalem.


title: Rocky Mountains

paragraphs: The Rocky Mountains (often 'The Rockies') are a range of mountains in the western United States and Canada. They stretch from the northernmost part of British Columbia, in western Canada, to New Mexico, in the southwestern United States. The Rocky Mountains are more than 3,000 miles long (4,800 kilometers).

paragraphs: The highest point in the Rocky Mountains is Mt. Elbert. Mt. Elbert is 14,433 ft tall.

paragraphs: The Rocky Mountains were formed from 80 million to 55 million years ago (mya) during the Laramide orogeny. North America began to move westwards as Pangaea broke up. A number of tectonic plates began to slide under the North American plate. The angle of subduction was shallow, resulting in a broad belt of mountains running down western North America. Since then, further tectonic activity and erosion by glaciers has sculpted the Rockies into dramatic peaks and valleys.

paragraphs: The rocks in the Rocky Mountains were formed before the mountains were raised by tectonic forces. The oldest rock is Precambrian metamorphic rock that forms the core of the North American continent. There is also Precambrian sedimentary argillite, dating back to 1.7 billion years ago. During the Paleozoic, western North America lay underneath a shallow sea, which deposited many kilometers of limestone and dolomite.

paragraphs: In the southern Rocky Mountains, near present-day Colorado, these ancestral rocks were disturbed by mountain building approximately 300 mya, during the Pennsylvanian. This mountain building produced the Ancestral Rocky Mountains. They consisted largely of Precambrian metamorphic rock forced upward through layers of the limestone laid down in the shallow sea. The mountains eroded throughout the late Paleozoic and early Mesozoic, leaving extensive deposits of sedimentary rock.


title: Brooklyn

paragraphs: Brooklyn is one of the five boroughs of New York City. It also covers the same area as Kings County. Brooklyn is the second largest borough in land area.

paragraphs: In the early 21st century, about 2.5 million live there. This is more than in any of the other four boroughs.

paragraphs: Brooklyn is the west end of Long Island. The East River separates it from Manhattan in the north. Brooklyn's only land boundary is with Queens in the east. Jamaica Bay separates Brooklyn from Rockaway in the south. The Narrows separates Brooklyn from Staten Island in the west.

paragraphs: Coney Island is the south end of Brooklyn. The Brooklyn Museum is near the middle of Brooklyn, near Prospect Park.

paragraphs: Brooklyn is named after a Dutch town called "Breukelen". Dutch people were the first people from Europe to live in the area. When they got there, there were already some Native American people living there called the Lenape. The Dutch started the town in 1634 as part of the colony of New Netherland.

paragraphs: During the 19th century Brooklyn expanded and filled Kings County. It remained a separate city before the people there voted to join New York City in 1898. Today, many parts of Brooklyn are home to people who are mostly from one culture or ethnicity. Other parts are mixed.

paragraphs: The Brooklyn Bridge is old and famous. It goes over the East River and connects Downtown Brooklyn to Lower Manhattan. The longest bridge in New York, the Verrazano-Narrows Bridge in Bay Ridge connects Brooklyn to Staten Island.