1.
Science
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Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe. The formal sciences are often excluded as they do not depend on empirical observations, disciplines which use science, like engineering and medicine, may also be considered to be applied sciences. However, during the Islamic Golden Age foundations for the method were laid by Ibn al-Haytham in his Book of Optics. In the 17th and 18th centuries, scientists increasingly sought to formulate knowledge in terms of physical laws, over the course of the 19th century, the word science became increasingly associated with the scientific method itself as a disciplined way to study the natural world. It was during this time that scientific disciplines such as biology, chemistry, Science in a broad sense existed before the modern era and in many historical civilizations. Modern science is distinct in its approach and successful in its results, Science in its original sense was a word for a type of knowledge rather than a specialized word for the pursuit of such knowledge. In particular, it was the type of knowledge which people can communicate to each other, for example, knowledge about the working of natural things was gathered long before recorded history and led to the development of complex abstract thought. This is shown by the construction of calendars, techniques for making poisonous plants edible. For this reason, it is claimed these men were the first philosophers in the strict sense and they were mainly speculators or theorists, particularly interested in astronomy. In contrast, trying to use knowledge of nature to imitate nature was seen by scientists as a more appropriate interest for lower class artisans. A clear-cut distinction between formal and empirical science was made by the pre-Socratic philosopher Parmenides, although his work Peri Physeos is a poem, it may be viewed as an epistemological essay on method in natural science. Parmenides ἐὸν may refer to a system or calculus which can describe nature more precisely than natural languages. Physis may be identical to ἐὸν and he criticized the older type of study of physics as too purely speculative and lacking in self-criticism. He was particularly concerned that some of the early physicists treated nature as if it could be assumed that it had no intelligent order, explaining things merely in terms of motion and matter. The study of things had been the realm of mythology and tradition, however. Aristotle later created a less controversial systematic programme of Socratic philosophy which was teleological and he rejected many of the conclusions of earlier scientists. For example, in his physics, the sun goes around the earth, each thing has a formal cause and final cause and a role in the rational cosmic order. Motion and change is described as the actualization of potentials already in things, while the Socratics insisted that philosophy should be used to consider the practical question of the best way to live for a human being, they did not argue for any other types of applied science
2.
Technology
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Technology is the collection of techniques, skills, methods and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, and the like, the human species use of technology began with the conversion of natural resources into simple tools. The steady progress of technology has brought weapons of ever-increasing destructive power. It has helped develop more advanced economies and has allowed the rise of a leisure class, many technological processes produce unwanted by-products known as pollution and deplete natural resources to the detriment of Earths environment. Various implementations of technology influence the values of a society and raise new questions of the ethics of technology, examples include the rise of the notion of efficiency in terms of human productivity, and the challenges of bioethics. Philosophical debates have arisen over the use of technology, with disagreements over whether technology improves the condition or worsens it. The use of the technology has changed significantly over the last 200 years. Before the 20th century, the term was uncommon in English, the term was often connected to technical education, as in the Massachusetts Institute of Technology. The term technology rose to prominence in the 20th century in connection with the Second Industrial Revolution, the terms meanings changed in the early 20th century when American social scientists, beginning with Thorstein Veblen, translated ideas from the German concept of Technik into technology. In German and other European languages, a distinction exists between technik and technologie that is absent in English, which translates both terms as technology. By the 1930s, technology referred not only to the study of the industrial arts, dictionaries and scholars have offered a variety of definitions. Ursula Franklin, in her 1989 Real World of Technology lecture, gave another definition of the concept, it is practice, the way we do things around here. The term is used to imply a specific field of technology, or to refer to high technology or just consumer electronics. Bernard Stiegler, in Technics and Time,1, defines technology in two ways, as the pursuit of life by other than life, and as organized inorganic matter. Technology can be most broadly defined as the entities, both material and immaterial, created by the application of mental and physical effort in order to some value. In this usage, technology refers to tools and machines that may be used to solve real-world problems and it is a far-reaching term that may include simple tools, such as a crowbar or wooden spoon, or more complex machines, such as a space station or particle accelerator. Tools and machines need not be material, virtual technology, such as software and business methods. W. Brian Arthur defines technology in a broad way as a means to fulfill a human purpose
3.
Cheetah
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The cheetah /ˈtʃiːtə/ is a large felid of the subfamily Felinae that occurs mainly in eastern and southern Africa and a few parts of Iran. The only extant member of the genus Acinonyx, the cheetah was first described by Johann Christian Daniel von Schreber in 1775. The cheetah is characterised by a body, deep chest, spotted coat, a small rounded head, black tear-like streaks on the face, long thin legs. Its lightly built, slender form is in sharp contrast with the robust build of the big cats, the cheetah reaches nearly 70 to 90 cm at the shoulder, and weighs 21–72 kg. Though taller than the leopard, it is smaller than the lion. Basically yellowish tan or rufous to white, the coat is uniformly covered with nearly 2,000 solid black spots. Cheetahs are active mainly during the day, with hunting their major activity, adult males are sociable despite their territoriality, forming groups called coalitions. Females are not territorial, they may be solitary or live with their offspring in home ranges, carnivores, cheetah mainly prey upon antelopes and gazelles. They will stalk their prey to within 100–300 metres, charge towards it and kill it by tripping it during the chase, the cheetahs body is specialised for speed, it is the fastest land animal. Cheetahs are induced ovulators, breeding throughout the year, gestation is nearly three months long, resulting in a litter of typically three to five cubs. Weaning occurs at six months, siblings tend to stay together for some time, Cheetah cubs face higher mortality than most other mammals, especially in the Serengeti region. Cheetahs inhabit a variety of habitats – dry forests, scrub forests, thanks to its prowess at hunting, the cheetah was tamed and used to kill game at hunts in the past. The animal has been depicted in art, literature, advertising. Classified as vulnerable by the International Union for Conservation of Nature, several African countries have taken steps to improve the standards of cheetah conservation. The vernacular name cheetah is derived from the Hindi word चीता, the first recorded use of this word has been dated back to 1610. An alternative name for the cheetah is hunting leopard, the scientific name of the cheetah is Acinonyx jubatus. The generic name Acinonyx could have originated from the combination of two Greek words, akinetos means motionless, and onyx means claw, a rough translation of the word would be non-moving claws, a reference to the limited retractability of the claws of the cheetah relative to other cats. The specific name jubatus means maned in Latin, referring to the dorsal crest of this animal, the cheetah is the only extant species of the genus Acinonyx
4.
Joseph Priestley
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He is usually credited with the discovery of oxygen, having isolated it in its gaseous state, although Carl Wilhelm Scheele and Antoine Lavoisier also have a claim to the discovery. However, Priestleys determination to defend phlogiston theory and to reject what would become the chemical revolution eventually left him isolated within the scientific community, Priestleys science was integral to his theology, and he consistently tried to fuse Enlightenment rationalism with Christian theism. In his metaphysical texts, Priestley attempted to combine theism, materialism, and determinism and he believed that a proper understanding of the natural world would promote human progress and eventually bring about the Christian Millennium. Priestley, who believed in the free and open exchange of ideas, advocated toleration and equal rights for religious Dissenters. He spent his last ten years in Northumberland County, Pennsylvania and these educational writings were among Priestleys most popular works. Priestley was born to an established English Dissenting family in Birstall and he was the oldest of six children born to Mary Swift and Jonas Priestley, a finisher of cloth. To ease his mothers burdens, Priestley was sent to live with his grandfather around the age of one and he returned home, five years later, after his mother died. When his father remarried in 1741, Priestley went to live with his aunt and uncle, during his youth, Priestley attended local schools where he learned Greek, Latin, and Hebrew. Around 1749, Priestley became seriously ill and believed he was dying, raised as a devout Calvinist, he believed a conversion experience was necessary for salvation, but doubted he had had one. This emotional distress eventually led him to question his upbringing, causing him to reject election. As a result, the elders of his church, the Independent Upper Chapel of Heckmondwike. Priestleys illness left him with a permanent stutter and he gave up any thoughts of entering the ministry at that time, in preparation for joining a relative in trade in Lisbon, he studied French, Italian, and German in addition to Aramaic, and Arabic. Priestley eventually decided to return to his studies and, in 1752, matriculated at Daventry. Because he had read widely, Priestley was allowed to skip the first two years of coursework. He continued his study, this, together with the liberal atmosphere of the school, shifted his theology further leftward. Abhorring dogma and religious mysticism, Rational Dissenters emphasised the rational analysis of the natural world, Priestley later wrote that the book that influenced him the most, save the Bible, was David Hartleys Observations on Man. Hartleys psychological, philosophical, and theological treatise postulated a theory of mind. Hartley aimed to construct a Christian philosophy in both religious and moral facts could be scientifically proven, a goal that would occupy Priestley for his entire life
5.
Oxygen
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Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the group on the periodic table and is a highly reactive nonmetal. By mass, oxygen is the third-most abundant element in the universe, after hydrogen, at standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20. 8% of the Earths atmosphere, additionally, as oxides the element makes up almost half of the Earths crust. Most of the mass of living organisms is oxygen as a component of water, conversely, oxygen is continuously replenished by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. Oxygen is too reactive to remain a free element in air without being continuously replenished by the photosynthetic action of living organisms. Another form of oxygen, ozone, strongly absorbs ultraviolet UVB radiation, but ozone is a pollutant near the surface where it is a by-product of smog. At low earth orbit altitudes, sufficient atomic oxygen is present to cause corrosion of spacecraft, the name oxygen was coined in 1777 by Antoine Lavoisier, whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. One of the first known experiments on the relationship between combustion and air was conducted by the 2nd century BCE Greek writer on mechanics, Philo of Byzantium. In his work Pneumatica, Philo observed that inverting a vessel over a burning candle, Philo incorrectly surmised that parts of the air in the vessel were converted into the classical element fire and thus were able to escape through pores in the glass. Many centuries later Leonardo da Vinci built on Philos work by observing that a portion of air is consumed during combustion and respiration, Oxygen was discovered by the Polish alchemist Sendivogius, who considered it the philosophers stone. In the late 17th century, Robert Boyle proved that air is necessary for combustion, English chemist John Mayow refined this work by showing that fire requires only a part of air that he called spiritus nitroaereus. From this he surmised that nitroaereus is consumed in both respiration and combustion, Mayow observed that antimony increased in weight when heated, and inferred that the nitroaereus must have combined with it. Accounts of these and other experiments and ideas were published in 1668 in his work Tractatus duo in the tract De respiratione. Robert Hooke, Ole Borch, Mikhail Lomonosov, and Pierre Bayen all produced oxygen in experiments in the 17th and the 18th century but none of them recognized it as a chemical element. This may have been in part due to the prevalence of the philosophy of combustion and corrosion called the phlogiston theory, which was then the favored explanation of those processes. Established in 1667 by the German alchemist J. J. Becher, one part, called phlogiston, was given off when the substance containing it was burned, while the dephlogisticated part was thought to be its true form, or calx. The fact that a substance like wood gains overall weight in burning was hidden by the buoyancy of the combustion products
6.
Gas
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Gas is one of the four fundamental states of matter. A pure gas may be made up of atoms, elemental molecules made from one type of atom. A gas mixture would contain a variety of pure gases much like the air, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer, the interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image. One type of commonly known gas is steam, the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention, high-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas. For a comprehensive listing of these states of matter see list of states of matter. The only chemical elements which are stable multi atom homonuclear molecules at temperature and pressure, are hydrogen, nitrogen and oxygen. These gases, when grouped together with the noble gases. Alternatively they are known as molecular gases to distinguish them from molecules that are also chemical compounds. The word gas is a neologism first used by the early 17th-century Flemish chemist J. B. van Helmont, according to Paracelsuss terminology, chaos meant something like ultra-rarefied water. An alternative story is that Van Helmonts word is corrupted from gahst and these four characteristics were repeatedly observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, and consequently have weaker intermolecular bonds than liquids or solids. These intermolecular forces result from interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another, transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion, the drifting smoke particles in the image provides some insight into low pressure gas behavior
7.
London
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London /ˈlʌndən/ is the capital and most populous city of England and the United Kingdom. Standing on the River Thames in the south east of the island of Great Britain and it was founded by the Romans, who named it Londinium. Londons ancient core, the City of London, largely retains its 1. 12-square-mile medieval boundaries. London is a global city in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism. It is crowned as the worlds largest financial centre and has the fifth- or sixth-largest metropolitan area GDP in the world, London is a world cultural capital. It is the worlds most-visited city as measured by international arrivals and has the worlds largest city airport system measured by passenger traffic, London is the worlds leading investment destination, hosting more international retailers and ultra high-net-worth individuals than any other city. Londons universities form the largest concentration of education institutes in Europe. In 2012, London became the first city to have hosted the modern Summer Olympic Games three times, London has a diverse range of people and cultures, and more than 300 languages are spoken in the region. Its estimated mid-2015 municipal population was 8,673,713, the largest of any city in the European Union, Londons urban area is the second most populous in the EU, after Paris, with 9,787,426 inhabitants at the 2011 census. The citys metropolitan area is the most populous in the EU with 13,879,757 inhabitants, the city-region therefore has a similar land area and population to that of the New York metropolitan area. London was the worlds most populous city from around 1831 to 1925, Other famous landmarks include Buckingham Palace, the London Eye, Piccadilly Circus, St Pauls Cathedral, Tower Bridge, Trafalgar Square, and The Shard. The London Underground is the oldest underground railway network in the world, the etymology of London is uncertain. It is an ancient name, found in sources from the 2nd century and it is recorded c.121 as Londinium, which points to Romano-British origin, and hand-written Roman tablets recovered in the city originating from AD 65/70-80 include the word Londinio. The earliest attempted explanation, now disregarded, is attributed to Geoffrey of Monmouth in Historia Regum Britanniae and this had it that the name originated from a supposed King Lud, who had allegedly taken over the city and named it Kaerlud. From 1898, it was accepted that the name was of Celtic origin and meant place belonging to a man called *Londinos. The ultimate difficulty lies in reconciling the Latin form Londinium with the modern Welsh Llundain, which should demand a form *lōndinion, from earlier *loundiniom. The possibility cannot be ruled out that the Welsh name was borrowed back in from English at a later date, and thus cannot be used as a basis from which to reconstruct the original name. Until 1889, the name London officially applied only to the City of London, two recent discoveries indicate probable very early settlements near the Thames in the London area
8.
Second voyage of James Cook
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Alexander Dalrymple and others of the Royal Society still believed that this massive southern continent should exist. After a delay brought about by the botanist Joseph Banks unreasonable demands, on 17 January 1773, Resolution was the first ship to cross the Antarctic Circle which she crossed twice more on the voyage. The third crossing, on 3 February 1774, was to be the most southerly penetration, Cook undertook a series of vast sweeps across the Pacific, finally proving there was no Terra Australis by sailing over most of its predicted locations. Cook proved the Terra Australis Incognita to be a myth and predicted that an Antarctic land would be found beyond the ice barrier, on this voyage the Larcum Kendall K1 chronometer was successfully employed by William Wales to calculate longitude. This discovery led Dalrymple to publish An Historical Collection of the Several Voyages and Discoveries in the South Pacific Ocean, in 1770–1771 which aroused widespread interest in his claim of the existence of an unknown continent. Cook commanded HMS Resolution on this voyage, while Tobias Furneaux commanded its companion ship and she was 111 feet long and 35 feet abeam. She was originally registered as HMS Drake, but fearing this would upset the Spanish, twelve light 6-pounder guns and twelve swivel guns were carried. At his own expense Cook had brass door-hinges installed in the great cabin, HMS Adventure began her career as the 340 ton North Sea collier Marquis of Rockingham, launched at Whitby in 1771. She was purchased by the Navy that year for £2,103 and named Rayleigh and she was 97 feet long,28 feet abeam and her draft was 13 feet and carried ten guns. Both were built at the Fishburn yard at Whitby and purchased from Captain William Hammond of Hull, Cook was asked to test the Larcum Kendall K1 chronometer on this voyage. The Board of Longitude had asked Kendall to copy and develop John Harrisons fourth model of a clock useful for navigation at sea, the first model finished by Kendall in 1769 was an accurate copy of H4, cost £450, and is known today as K1. Although constructed like a watch, the chronometer had a diameter of 13 cm, three other clocks, constructed by John Arnold were carried but did not withstand the rigors of the journey. As anti-scorbutics they took nearly 20,000 pounds of Sour Krout and 30 imperial gallons of Mermalade of Carrots, both ships carried livestock, including bullocks, sheep, goats, hogs and poultry. The crews had fishing gear and a water system was carried for distilling sea-water or purifying foul fresh-water. Various pieces of hardware and trinkets to be used for barter or as gifts for the natives were taken aboard. Furneaux, commander of Adventure, was an explorer, having served on Samuel Walliss circumnavigation in Dolphin in 1766–1768. He headed a crew of 81 which included Joseph Shank as first lieutenant, there were also twelve marines headed by Lieutenant James Scott, Furneauxs personal servant, James Tobias Swilley, and, as masters mate John Rowe who was a relation of Furneaux. The ships astronomer was William Bayly and this refit cost £10,080 12s 9d
9.
Terra Australis
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Terra Australis is a hypothetical continent first posited in antiquity and which appeared on maps between the 15th and 18th centuries. The existence of Terra Australis was not based on any survey or direct observation and this theory of balancing land has been documented as early as the 5th century on maps by Macrobius, who uses the term Australis on his maps. Terra Australis was one of names applied to the largest landmass of what is now known as the continent of Australia. Other names for the hypothetical landmass have included Terra Australis Ignota, other names for the hypothetical continent have included Brasiliae Australis, Magallanica or Magellanica, La Australia del Espíritu Santo, and La grande isle de Java. Other names actually used for the continent were New Holland and Australia, Aristotle speculated, Now since there must be a region bearing the same relation to the southern pole as the place we live in bears to our pole. His ideas were expanded by Ptolemy, who believed that the Indian Ocean was enclosed on the south by land. Marcus Tullius Cicero used the term cingulus australis in referring to the Antipodes in Somnium Scipionis, the land in this zone was the Terra Australis. Christian thinkers did not discount the idea that there might be land beyond the southern seas, the first depiction of Terra Australis on a globe was probably on Johannes Schöners lost 1523 globe on which Oronce Fine is thought to have based his 1531 double cordiform map of the world. On this landmass he wrote recently discovered but not yet completely explored, the body of water beyond the tip of South America is called the “Mare Magellanicum, ” one of the first uses of navigator Ferdinand Magellans name in such a context. Schöner called the continent Brasiliae Australis in his 1533 tract, Opusculum geographicum, explorers of the Age of Discovery, from the late 15th century on, proved that Africa was almost entirely surrounded by sea, and that the Indian Ocean was accessible from both west and east. These discoveries reduced the area where the continent could be found, however, as new lands were discovered, they were often assumed to be parts of the hypothetical continent. Where Schöner departs most conspicuously from Waldseemüller is in his globes depiction of an Antarctic continent, the Zeytung described the Portuguese voyagers passing through a strait between the southernmost point of America, or Brazil, and a land to the south west, referred to as vndtere Presill. This supposed “strait” was in fact the Rio de la Plata, on this slender foundation he constructed his circum-Antarctic continent to which, for reasons that he does not explain, he gave an annular, or ring shape. Further, the distance is only moderate from this Region of Brazil to Malacca, on this scrap of information, united with the concept of the Antipodes inherited from Graeco-Roman antiquity, Schöner constructed his representation of the southern continent. His strait served as inspiration for Ferdinand Magellans expedition to reach the Moluccas by a westward route and it was taken up by his followers, the French cosmographer Oronce Fine in his world map of 1531, and the Flemish cartographers Gerardus Mercator in 1538 and Abraham Ortelius in 1570. Schöners concepts influenced the Dieppe school of mapmakers, notably in their representation of Jave la Grande, there was much interest in Terra Australis among Norman and Breton merchants at that time. In 1566 and 1570, Francisque and André dAlbaigne presented Gaspard de Coligny, Admiral of France, although the Admiral gave favourable consideration to these initiatives, they came to nought when Coligny was killed in 1572. Adjoining Guinea on the right are the numerous and vast Solomon Islands which lately became famous by the voyage of Alvarus Mendanius, juan Fernandez, sailing from Chile in 1576, claimed he had discovered the Southern Continent
10.
Florence
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Florence is the capital city of the Italian region of Tuscany and of the Metropolitan City of Florence. It is the most populous city in Tuscany, with 383,083 inhabitants, Florence was a centre of medieval European trade and finance and one of the wealthiest cities of the time. It is considered the birthplace of the Renaissance, and has called the Athens of the Middle Ages. A turbulent political history includes periods of rule by the powerful Medici family, from 1865 to 1871 the city was the capital of the recently established Kingdom of Italy. The Historic Centre of Florence attracts 13 million tourists each year and it was declared a World Heritage Site by UNESCO in 1982. The city is noted for its culture, Renaissance art and architecture, the city also contains numerous museums and art galleries, such as the Uffizi Gallery and the Palazzo Pitti, and still exerts an influence in the fields of art, culture and politics. Due to Florences artistic and architectural heritage, it has been ranked by Forbes as one of the most beautiful cities in the world, in 2008, the city had the 17th highest average income in Italy. Florence originated as a Roman city, and later, after a period as a flourishing trading and banking medieval commune. According to the Encyclopædia Britannica, it was politically, economically, and culturally one of the most important cities in Europe, the language spoken in the city during the 14th century was, and still is, accepted as the Italian language. Starting from the late Middle Ages, Florentine money—in the form of the gold florin—financed the development of all over Europe, from Britain to Bruges, to Lyon. Florentine bankers financed the English kings during the Hundred Years War and they similarly financed the papacy, including the construction of their provisional capital of Avignon and, after their return to Rome, the reconstruction and Renaissance embellishment of Rome. Florence was home to the Medici, one of European historys most important noble families, Lorenzo de Medici was considered a political and cultural mastermind of Italy in the late 15th century. Two members of the family were popes in the early 16th century, Leo X, catherine de Medici married king Henry II of France and, after his death in 1559, reigned as regent in France. Marie de Medici married Henry IV of France and gave birth to the future king Louis XIII, the Medici reigned as Grand Dukes of Tuscany, starting with Cosimo I de Medici in 1569 and ending with the death of Gian Gastone de Medici in 1737. The Etruscans initially formed in 200 BC the small settlement of Fiesole and it was built in the style of an army camp with the main streets, the cardo and the decumanus, intersecting at the present Piazza della Repubblica. Situated along the Via Cassia, the route between Rome and the north, and within the fertile valley of the Arno, the settlement quickly became an important commercial centre. Peace returned under Lombard rule in the 6th century, Florence was conquered by Charlemagne in 774 and became part of the Duchy of Tuscany, with Lucca as capital. The population began to again and commerce prospered
11.
Bird migration
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Bird migration is the regular seasonal movement, often north and south along a flyway, between breeding and wintering grounds. Migration carries high costs in predation and mortality, including from hunting by humans and it occurs mainly in the northern hemisphere, where birds are funnelled on to specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea. More recently, Johannes Leche began recording dates of arrivals of spring migrants in Finland in 1749, threats to migratory birds have grown with habitat destruction especially of stopover and wintering sites, as well as structures such as power lines and wind farms. The Arctic tern holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year, shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas. The timing of migration seems to be controlled primarily by changes in day length, migrating birds navigate using celestial cues from the sun and stars, the earths magnetic field, and probably also mental maps. Records of bird migration were made as much as 3,000 years ago by the Ancient Greek writers Hesiod, Homer, Herodotus and Aristotle. The Bible also notes migrations, as in the Book of Job, the author of Jeremiah wrote, Even the stork in the heavens knows its seasons, and the turtle dove, the swift and the crane keep the time of their arrival. Aristotle noted that cranes traveled from the steppes of Scythia to marshes at the headwaters of the Nile, pliny the Elder, in his Historia Naturalis, repeats Aristotles observations. Aristotle however suggested that swallows and other birds hibernated and this belief persisted as late as 1878, when Elliott Coues listed the titles of no less than 182 papers dealing with the hibernation of swallows. It was not until the end of the century that migration as an explanation for the winter disappearance of birds from northern climes was accepted. Bewick then describes an experiment which succeeded in keeping alive in Britain for several years. He concludes, These experiments have since been confirmed by. Migration is the seasonal movement, often north and south. Bird movements include those made in response to changes in food availability, habitat, sometimes, journeys are not termed true migration because they are irregular or in only one direction. Migration is marked by its annual seasonality, non-migratory birds are said to be resident or sedentary. Approximately 1800 of the worlds 10,000 bird species are long-distance migrants, many bird populations migrate long distances along a flyway. The most common pattern involves flying north in the spring to breed in the temperate or Arctic summer, of course, in the southern hemisphere the directions are reversed, but there is less land area in the far south to support long-distance migration. The primary motivation for migration appears to be food, for example, also, the longer days of the northern summer provide extended time for breeding birds to feed their young
