The term shrimp is used to refer to some decapod crustaceans, although the exact animals covered can vary. Used broadly, shrimp may cover any of the groups with elongated bodies and a swimming mode of locomotion – most Caridea and Dendrobranchiata. In some fields, the term is used more narrowly and may be restricted to Caridea, to smaller species of either group or to only the marine species. Under the broader definition, shrimp may be synonymous with prawn, covering stalk-eyed swimming crustaceans with long narrow muscular tails, long whiskers, slender legs. Any small crustacean which resembles a shrimp tends to be called one, they swim forward by paddling with swimmerets on the underside of their abdomens, although their escape response is repeated flicks with the tail driving them backwards quickly. Crabs and lobsters have strong walking legs, whereas shrimp have thin, fragile legs which they use for perching. Shrimp are abundant. There are thousands of species adapted to a wide range of habitats.
They can be found feeding near the seafloor on most coasts and estuaries, as well as in rivers and lakes. To escape predators, some species flip off the dive into the sediment, they live from one to seven years. Shrimp are solitary, though they can form large schools during the spawning season, they play important roles in the food chain and are an important food source for larger animals ranging from fish to whales. The muscular tails of many shrimp are edible to humans, they are caught and farmed for human consumption. Commercial shrimp species support an industry worth 50 billion dollars a year, in 2010 the total commercial production of shrimp was nearly 7 million tonnes. Shrimp farming became more prevalent during the 1980s in China, by 2007 the harvest from shrimp farms exceeded the capture of wild shrimp. There are significant issues with excessive bycatch when shrimp are captured in the wild, with pollution damage done to estuaries when they are used to support shrimp farming. Many shrimp species are small as the term shrimp suggests, about 2 cm long, but some shrimp exceed 25 cm.
Larger shrimp are more to be targeted commercially and are referred to as prawns in Britain. Shrimp are swimming crustaceans with long antennae. Unlike crabs and lobsters, shrimp have well developed slender walking legs, it was the distinction between walking and swimming that formed the primary taxonomic division into the former suborders Natantia and Reptantia. Members of the Natantia were adapted for swimming while the Reptantia were adapted for crawling or walking; some other groups have common names that include the word "shrimp". The following description refers to the external anatomy of the common European shrimp, Crangon crangon, as a typical example of a decapod shrimp; the body of the shrimp is divided into two main parts: the head and thorax which are fused together to form the cephalothorax, a long narrow abdomen. The shell which protects the cephalothorax is harder and thicker than the shell elsewhere on the shrimp and is called the carapace; the carapace surrounds the gills, through which water is pumped by the action of the mouthparts.
The rostrum, eyes and legs issue from the carapace. The rostrum, from the Latin rōstrum meaning beak, looks like a beak or pointed nose at the front of the shrimp's head, it can be used for attack or defense. It may stabilize the shrimp when it swims backward. Two bulbous eyes on stalks sit either side of the rostrum; these are compound eyes which have panoramic vision and are good at detecting movement. Two pairs of whiskers issue from the head. One of these pairs is long and can be twice the length of the shrimp, while the other pair is quite short; the antennae have sensors on them which allow the shrimp to feel where they touch, allow them to "smell" or "taste" things by sampling the chemicals in the water. The long antennae help the shrimp orient itself with regard to its immediate surroundings, while the short antennae help assess the suitability of prey. Eight pairs of appendages issue from the cephalothorax; the first three pairs, the maxillipeds, Latin for "jaw feet", are used as mouthparts.
In Crangon crangon, the first pair, the maxillula, pumps water into the gill cavity. After the maxilliped come five more pairs of appendages, the pereiopods; these form the ten decapod legs. In Crangon crangon, the first two pairs of pereiopods have claws or chela; the chela can bring them to the mouth. They can be used for fighting and grooming; the remaining six legs are long and slender, are used for walking or perching. The muscular abdomen has a thinner shell than the carapace; each segment has a separate overlapping shell. The first five segments each have a pair of appendages on the underside, which are shaped like paddles and are used for swimming forward; the appendages are called pleopods or swimmerets, can be used for purposes other than swimming. Some shrimp species use them for brooding eggs, others have gills on them for breathing, the males in some species use the first pair or two for insemination; the sixth segment terminates in the telson flanked by two pairs of appendages called the uropods.
The uropods allow the shrimp to swim backward, function like rudders, steering the shrimp when it
Crustaceans form a large, diverse arthropod taxon which includes such familiar animals as crabs, crayfish, krill and barnacles. The crustacean group is treated as a subphylum, because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, comprises all animals in the Pancrustacea clade other than hexapods; some crustaceans are more related to insects and other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from Stygotantulus stocki at 0.1 mm, to the Japanese spider crab with a leg span of up to 3.8 m and a mass of 20 kg. Like other arthropods, crustaceans have an exoskeleton, they are distinguished from other groups of arthropods, such as insects and chelicerates, by the possession of biramous limbs, by their larval forms, such as the nauplius stage of branchiopods and copepods. Most crustaceans are free-living aquatic animals, but some are terrestrial, some are parasitic and some are sessile; the group has an extensive fossil record, reaching back to the Cambrian, includes living fossils such as Triops cancriformis, which has existed unchanged since the Triassic period.
More than 10 million tons of crustaceans are produced by fishery or farming for human consumption, the majority of it being shrimp and prawns. Krill and copepods are not as fished, but may be the animals with the greatest biomass on the planet, form a vital part of the food chain; the scientific study of crustaceans is known as carcinology, a scientist who works in carcinology is a carcinologist. The body of a crustacean is composed of segments, which are grouped into three regions: the cephalon or head, the pereon or thorax, the pleon or abdomen; the head and thorax may be fused together to form a cephalothorax, which may be covered by a single large carapace. The crustacean body is protected by the hard exoskeleton, which must be moulted for the animal to grow; the shell around each somite can be divided into a dorsal tergum, ventral sternum and a lateral pleuron. Various parts of the exoskeleton may be fused together; each somite, or body segment can bear a pair of appendages: on the segments of the head, these include two pairs of antennae, the mandibles and maxillae.
The abdomen bears pleopods, ends in a telson, which bears the anus, is flanked by uropods to form a tail fan. The number and variety of appendages in different crustaceans may be responsible for the group's success. Crustacean appendages are biramous, meaning they are divided into two parts, it is unclear whether the biramous condition is a derived state which evolved in crustaceans, or whether the second branch of the limb has been lost in all other groups. Trilobites, for instance possessed biramous appendages; the main body cavity is an open circulatory system, where blood is pumped into the haemocoel by a heart located near the dorsum. Malacostraca have haemocyanin as the oxygen-carrying pigment, while copepods, ostracods and branchiopods have haemoglobins; the alimentary canal consists of a straight tube that has a gizzard-like "gastric mill" for grinding food and a pair of digestive glands that absorb food. Structures that function as kidneys are located near the antennae. A brain exists in the form of ganglia close to the antennae, a collection of major ganglia is found below the gut.
In many decapods, the first pair of pleopods are specialised in the male for sperm transfer. Many terrestrial crustaceans return to the sea to release the eggs. Others, such as woodlice, lay their eggs on land, albeit in damp conditions. In most decapods, the females retain the eggs; the majority of crustaceans are aquatic, living in either marine or freshwater environments, but a few groups have adapted to life on land, such as terrestrial crabs, terrestrial hermit crabs, woodlice. Marine crustaceans are as ubiquitous in the oceans; the majority of crustaceans are motile, moving about independently, although a few taxonomic units are parasitic and live attached to their hosts, adult barnacles live a sessile life – they are attached headfirst to the substrate and cannot move independently. Some branchiurans are able to withstand rapid changes of salinity and will switch hosts from marine to non-marine species. Krill are the bottom layer and the most important part of the food chain in Antarctic animal communities.
Some crustaceans are significant invasive species, such as the Chinese mitten crab, Eriocheir sinensis, the Asian shore crab, Hemigrapsus sanguineus. The majority of crustaceans have separate sexes, reproduce sexually. A small number are hermaphrodites, including barnacles and Cephalocarida; some may change sex during the course of their life. Parthenogenesis is widespread among crustaceans, where viable eggs are produced by a female without needing fertilisation by a male; this occurs in many branchiopods, some os
Carl Linnaeus known after his ennoblement as Carl von Linné, was a Swedish botanist and zoologist who formalised binomial nomenclature, the modern system of naming organisms. He is known as the "father of modern taxonomy". Many of his writings were in Latin, his name is rendered in Latin as Carolus Linnæus. Linnaeus was born in the countryside of Småland in southern Sweden, he received most of his higher education at Uppsala University and began giving lectures in botany there in 1730. He lived abroad between 1735 and 1738, where he studied and published the first edition of his Systema Naturae in the Netherlands, he returned to Sweden where he became professor of medicine and botany at Uppsala. In the 1740s, he was sent on several journeys through Sweden to find and classify plants and animals. In the 1750s and 1760s, he continued to collect and classify animals and minerals, while publishing several volumes, he was one of the most acclaimed scientists in Europe at the time of his death. Philosopher Jean-Jacques Rousseau sent him the message: "Tell him I know no greater man on earth."
Johann Wolfgang von Goethe wrote: "With the exception of Shakespeare and Spinoza, I know no one among the no longer living who has influenced me more strongly." Swedish author August Strindberg wrote: "Linnaeus was in reality a poet who happened to become a naturalist." Linnaeus has been called Princeps botanicorum and "The Pliny of the North". He is considered as one of the founders of modern ecology. In botany and zoology, the abbreviation L. is used to indicate Linnaeus as the authority for a species' name. In older publications, the abbreviation "Linn." is found. Linnaeus's remains comprise the type specimen for the species Homo sapiens following the International Code of Zoological Nomenclature, since the sole specimen that he is known to have examined was himself. Linnaeus was born in the village of Råshult in Småland, Sweden, on 23 May 1707, he was the first child of Christina Brodersonia. His siblings were Anna Maria Linnæa, Sofia Juliana Linnæa, Samuel Linnæus, Emerentia Linnæa, his father taught him Latin as a small child.
One of a long line of peasants and priests, Nils was an amateur botanist, a Lutheran minister, the curate of the small village of Stenbrohult in Småland. Christina was the daughter of the rector of Samuel Brodersonius. A year after Linnaeus's birth, his grandfather Samuel Brodersonius died, his father Nils became the rector of Stenbrohult; the family moved into the rectory from the curate's house. In his early years, Linnaeus seemed to have a liking for plants, flowers in particular. Whenever he was upset, he was given a flower, which calmed him. Nils spent much time in his garden and showed flowers to Linnaeus and told him their names. Soon Linnaeus was given his own patch of earth. Carl's father was the first in his ancestry to adopt a permanent surname. Before that, ancestors had used the patronymic naming system of Scandinavian countries: his father was named Ingemarsson after his father Ingemar Bengtsson; when Nils was admitted to the University of Lund, he had to take on a family name. He adopted the Latinate name Linnæus after a giant linden tree, lind in Swedish, that grew on the family homestead.
This name was spelled with the æ ligature. When Carl was born, he was named Carl Linnæus, with his father's family name; the son always spelled it with the æ ligature, both in handwritten documents and in publications. Carl's patronymic would have been Nilsson, as in Carl Nilsson Linnæus. Linnaeus's father began teaching him basic Latin and geography at an early age; when Linnaeus was seven, Nils decided to hire a tutor for him. The parents picked a son of a local yeoman. Linnaeus did not like him, writing in his autobiography that Telander "was better calculated to extinguish a child's talents than develop them". Two years after his tutoring had begun, he was sent to the Lower Grammar School at Växjö in 1717. Linnaeus studied going to the countryside to look for plants, he reached the last year of the Lower School when he was fifteen, taught by the headmaster, Daniel Lannerus, interested in botany. Lannerus gave him the run of his garden, he introduced him to Johan Rothman, the state doctor of Småland and a teacher at Katedralskolan in Växjö.
A botanist, Rothman broadened Linnaeus's interest in botany and helped him develop an interest in medicine. By the age of 17, Linnaeus had become well acquainted with the existing botanical literature, he remarks in his journal that he "read day and night, knowing like the back of my hand, Arvidh Månsson's Rydaholm Book of Herbs, Tillandz's Flora Åboensis, Palmberg's Serta Florea Suecana, Bromelii Chloros Gothica and Rudbeckii Hortus Upsaliensis...."Linnaeus entered the Växjö Katedralskola in 1724, where he studied Greek, Hebrew and mathematics, a curriculum designed for boys preparing for the priesthood. In the last year at the gymnasium, Linnaeus's father visited to ask the professors how his son's studies were progressing. Rothman believed otherwise; the doctor offered to have Linnaeus live with his family in Växjö and to teach him physiology and botany. Nils accepted this offer. Rothman showed Linnaeus that botany was a serious sub
Aquaculture known as aquafarming, is the farming of fish, molluscs, aquatic plants and other organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, can be contrasted with commercial fishing, the harvesting of wild fish. Mariculture refers to aquaculture practiced in underwater habitats. According to the Food and Agriculture Organization, aquaculture "is understood to mean the farming of aquatic organisms including fish, molluscs and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, protection from predators, etc. Farming implies individual or corporate ownership of the stock being cultivated." The reported output from global aquaculture operations in 2014 supplied over one half of the fish and shellfish, directly consumed by humans. Further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a piscivorous fish like salmon.
Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture and the cultivation of ornamental fish. Particular methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish farming and aquatic plant farming; the indigenous Gunditjmara people in Victoria, may have raised eels as early as 6000 BC. Evidence indicates they developed about 100 km2 of volcanic floodplains in the vicinity of Lake Condah into a complex of channels and dams, used woven traps to capture eels, preserve them to eat all year round. Aquaculture was operating in China circa 2000 BC; when the waters subsided after river floods, some fish carp, were trapped in lakes. Early aquaculturists fed their brood using nymphs and silkworm feces, ate them. A fortunate genetic mutation of carp led to the emergence of goldfish during the Tang dynasty. However, ancient Egyptians might have farmed fish from Lake Bardawil about 3,500 years ago, they traded them with Canaan.
Gim cultivation is the oldest aquaculture in Korea. Early cultivation methods used bamboo or oak sticks, which were replaced by newer methods that utilized nets in the 19th century. Floating rafts have been used for mass production since the 1920s. Japanese cultivated seaweed by providing bamboo poles and nets and oyster shells to serve as anchoring surfaces for spores. Romans bred fish in ponds and farmed oysters in coastal lagoons before 100 CE. In central Europe, early Christian monasteries adopted Roman aquacultural practices. Aquaculture spread in Europe during the Middle Ages since away from the seacoasts and the big rivers, fish had to be salted so they did not rot. Improvements in transportation during the 19th century made fresh fish available and inexpensive in inland areas, making aquaculture less popular; the 15th-century fishponds of the Trebon Basin in the Czech Republic are maintained as a UNESCO World Heritage Site. Hawaiians constructed oceanic fish ponds. A remarkable example is the "Menehune" fishpond dating from at least 1,000 years ago, at Alekoko.
Legend says. In the first half of the 18th century, German Stephan Ludwig Jacobi experimented with external fertilization of brown trouts and salmon, he wrote an article "Von der künstlichen Erzeugung der Forellen und Lachse". By the latter decades of the 18th century, oyster farming had begun in estuaries along the Atlantic Coast of North America; the word aquaculture appeared in an 1855 newspaper article in reference to the harvesting of ice. It appeared in descriptions of the terrestrial agricultural practise of subirrigation in the late 19th century before becoming associated with the cultivation of aquatic plant and animal species. In 1859, Stephen Ainsworth of West Bloomfield, New York, began experiments with brook trout. By 1864, Seth Green had established a commercial fish-hatching operation at Caledonia Springs, near Rochester, New York. By 1866, with the involvement of Dr. W. W. Fletcher of Concord, artificial fish hatcheries were under way in both Canada and the United States; when the Dildo Island fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world.
The word aquaculture was used in descriptions of the hatcheries experiments with cod and lobster in 1890. By the 1920s, the American Fish Culture Company of Carolina, Rhode Island, founded in the 1870s was one of the leading producers of trout. During the 1940s, they had perfected the method of manipulating the day and night cycle of fish so that they could be artificially spawned year around. Californians harvested wild kelp and attempted to manage supply around 1900 labeling it a wartime resource. Harvest stagnation in wild fisheries and overexploitation of popular marine species, combined with a growing demand for high-quality protein, encouraged aquaculturists to domesticate other marine species. At the outset of modern aquaculture, many were optimistic that a "Blue Revolution" could take place in aquaculture, just as the Green Revolution of the 20th century had revolutionized agriculture. Although land animals had long been domesticated, most seafood species were still caught from the wild.
Concerned about the impact of growing demand for seafood on the world's oceans, prominent ocean explorer Jacques Cousteau wrote in 1973: "With earth's burgeoning human populations to feed, we must turn to the sea with new understanding and new technology."About 430 of the species cultu
Lake Chad is a large, endorheic lake in Africa, which has varied in size over the centuries. According to the Global Resource Information Database of the United Nations Environment Programme, it shrank by as much as 95% from about 1963 to 1998, but "the 2007 image shows significant improvement over previous years." Lake Chad is economically important, providing water to more than 30 million people living in the four countries surrounding it on the edge of the Sahara. It is the largest lake in the Chad Basin. Lake Chad is a freshwater lake located in the Sahelian zone of west-central Africa, it is located in the interior basin which used to be occupied by a much larger ancient sea sometimes called Mega Chad. The lake is ranked as one of the largest lakes in Africa. However, its surface area varies by season and as well as from year to year. Lake Chad is in the far west of Chad, bordering on northeastern Nigeria; the Chari River, fed by its tributary the Logone, provides over 90% of the lake's water, with a small amount coming from the Yobe River in Nigeria/Niger.
Despite high levels of evaporation, the lake is fresh water. Over half of the lake's area is taken up by its many small islands and mud banks, a belt of swampland across the middle divides the northern and southern halves; the shorelines are composed of marshes. Because Lake Chad is shallow—only 10.5 metres at its deepest—its area is sensitive to small changes in average depth, it shows seasonal fluctuations in size. Lake Chad has no apparent outlet; the climate is dry most of the year, with moderate rainfall from July through September. Lake Chad gave its name to the country of Chad; the name Chad is a local word meaning "large expanse of water", in other words, a "lake". Lake Chad is the remnant of a former inland sea, paleolake Mega-Chad, which existed during the African humid period. At its largest, sometime before 5000 BC, Lake Mega-Chad was the largest of four Saharan paleolakes, is estimated to have covered an area of 1,000,000 km2, larger than the Caspian Sea is today, may have extended as far northeast as within 100 km of Faya-Largeau.
At its largest extent the river Mayo Kébbi represented the outlet of the paleolake Mega-Chad, connecting it to the Niger River and the Atlantic. The presence of African manatees in the inflows of Lake Chad is an evidence of that history. Romans reached the lake in the first century of their empire. Indeed, during the time of Augustus Lake Chad was still a huge lake and two Roman expeditions were performed in order to reach it: Septimius Flaccus and Julius Maternus reached the "lake of hippopotamus", they passed near the Tibesti mountains. Both expeditions passed through the territory of the Garamantes, were able to leave a small garrison on the "lake of hippopotamus and rhinoceros" after three months of travel in desert lands. Lake Chad was first surveyed from shore by Europeans in 1823, it was considered to be one of the largest lakes in the world then. In 1851, a party including the German explorer Heinrich Barth carried a boat overland from Tripoli across the Sahara Desert by camel and made the first European waterborne survey.
British expedition leader James Richardson died just days before reaching the lake. In Winston Churchill's book The River War: An Account of the Reconquest of the Sudan, published in 1899, he mentions the shrinking of Lake Chad, he writes: Altogether France has enough to occupy her in Central Africa for some time to come: and when the long task is finished, the conquered regions are not to be of great value. They include the desert of the Great Sahara and wide expanses of profitless scrub or marsh. Only one important river, the Shari, flows through them, never reaches the sea: and Lake Chad, into which the Shari flows, appears to be leaking through some subterranean exit, is changing from a lake into an immense swamp. Lake Chad has shrunk since the 1960s, when its shoreline had an elevation of about 286 metres above sea level and it had an area of more than 26,000 square kilometres, making its surface the fourth largest in Africa. An increased demand on the lake's water from the local population has accelerated its shrinkage over the past 40 years.
The size of Lake Chad varies seasonally with the flooding of the wetlands areas. In 1983, Lake Chad was reported to have covered 10,000 to 25,000 km2, had a maximum depth of 11 metres, a volume of 72 km3. By 2000, its extent had fallen to less than 1,500 km2. A 2001 study published in the Journal of Geophysical Research blamed the lake's retreat on overgrazing in the area surrounding the lake, causing desertification and a decline in vegetation; the United Nations Environment Programme and the Lake Chad Basin Commission concur that at least half of the lake's decrease is attributable to shifting climate patterns. UNEP blames human water use, such as inefficient damming and irrigation methods, for the rest of the shrinkage; as late as December 2014, Lake Chad was still sufficient in size and volume such that boats could capsize or sink. The European Space Agency has presented data showing an actual increase in lake extent of Lake Chad between the years of 1985 to 2011. Referring to the floodplain as a lake may be misleading, as less than half of Lake Chad is covered by water through an entire year.
The remaining sections are considered as wetla
Lake Victoria is one of the African Great Lakes. The lake was named after Queen Victoria by the explorer John Hanning Speke, the first Briton to document it. Speke accomplished this in 1858, while on an expedition with Richard Francis Burton to locate the source of the Nile River. With a surface area of 59,947 square kilometres, Lake Victoria is Africa's largest lake by area, the world's largest tropical lake, the world's second largest fresh water lake by surface area after Lake Superior in North America. In terms of volume, Lake Victoria is the world's ninth largest continental lake, containing about 2,424 cubic kilometres of water. Lake Victoria occupies a shallow depression in Africa; the lake has an average depth of 40 metres. Its catchment area covers 169,858 square kilometres; the lake has a shoreline of 7,142 kilometres when digitized at the 1:25,000 level, with islands constituting 3.7 percent of this length, is divided among three countries: Kenya and Tanzania. Geologically, Lake Victoria is young at about 400,000 years old.
It formed. During its geological history, Lake Victoria went through changes ranging from its present shallow depression, through to what may have been a series of much smaller lakes. Geological cores taken from its bottom show Lake Victoria has dried up at least three times since it formed; these drying cycles are related to past ice ages, which were times when precipitation declined globally. Lake Victoria last dried out about 17,300 years ago, it refilled 14,700 years ago as the African humid period began. Lake Victoria receives 80 percent of its water from direct rainfall. Average evaporation on the lake is between 2.0 and 2.2 metres per year double the precipitation of riparian areas. Lake Victoria receives its water additionally from rivers, thousands of small streams; the Kagera River is the largest river flowing into this lake, with its mouth on the lake's western shore. Lake Victoria is drained by the Nile River near Jinja, Uganda, on the lake's northern shore. In the Kenya sector, the main influent rivers are the Sio, Yala, Sondu Miriu and Migori.
The only outflow from Lake Victoria is the Nile River, which exits the lake near Uganda. In terms of contributed water, this makes Lake Victoria the principal source of the longest branch of the Nile. However, the most distal source of the Nile Basin, therefore the ultimate source of the Nile, is more considered to be one of the tributary rivers of the Kagera River, which originates in either Rwanda or Burundi; the uppermost section of the Nile is known as the Victoria Nile until it reaches Lake Albert. Although it is a part of the same river system known as the White Nile and is referred to as such speaking this name does not apply until after the river crosses the Uganda border into South Sudan to the north; the lake exhibits eutrophic conditions. In 1990–1991, oxygen concentrations in the mixed layer were higher than in 1960–1961, with nearly continuous oxygen supersaturation in surface waters. Oxygen concentrations in hypolimnetic waters were lower in 1990–1991 for a longer period than in 1960–1961, with values of less than 1 mg per litre occurring in water as shallow as 40 metres compared with a shallowest occurrence of greater than 50 metres in 1961.
The changes in oxygenation are considered consistent with measurements of higher algal biomass and productivity. These changes have arisen for multiple reasons: successive burning within its basin and ash from, deposited over the lake's wide area; the lake is considered a shallow lake considering its large geographic area with a maximum depth of 80 metres and an average depth of 40 metres. A 2016 project created the first true bathymetric map of the lake; the deepest part of the lake is offset to the east of the lake near Kenya and the lake is shallower in the west along the Ugandan shoreline and the south along the Tanzanian shoreline. Many mammal species live in the region of Lake Victoria, some of these are associated with the lake itself and the nearby wetlands. Among these are the hippopotamus, African clawless otter, spotted-necked otter, marsh mongoose, bohor reedbuck, defassa waterbuck, cane rats, giant otter shrew. Lake Victoria and its wetlands has a large population of Nile crocodiles, as well as African helmeted turtles, variable mud turtles, Williams' mud turtle.
The Williams' mud turtle is restricted to Lake Victoria and other lakes and swamps in the upper Nile basin. Lake Victoria was rich in fish, including many endemics, but a high percentage of these became extinct during the last 50 years; the main group in Lake Victoria is the haplochromine cichlids with more than 500 species all endemic and some still undescribed. This is far more species of fish except Lake Malawi. These
Egypt the Arab Republic of Egypt, is a country spanning the northeast corner of Africa and southwest corner of Asia by a land bridge formed by the Sinai Peninsula. Egypt is a Mediterranean country bordered by the Gaza Strip and Israel to the northeast, the Gulf of Aqaba and the Red Sea to the east, Sudan to the south, Libya to the west. Across the Gulf of Aqaba lies Jordan, across the Red Sea lies Saudi Arabia, across the Mediterranean lie Greece and Cyprus, although none share a land border with Egypt. Egypt has one of the longest histories of any country, tracing its heritage back to the 6th–4th millennia BCE. Considered a cradle of civilisation, Ancient Egypt saw some of the earliest developments of writing, urbanisation, organised religion and central government. Iconic monuments such as the Giza Necropolis and its Great Sphinx, as well the ruins of Memphis, Thebes and the Valley of the Kings, reflect this legacy and remain a significant focus of scientific and popular interest. Egypt's long and rich cultural heritage is an integral part of its national identity, which has endured, assimilated, various foreign influences, including Greek, Roman, Ottoman Turkish, Nubian.
Egypt was an early and important centre of Christianity, but was Islamised in the seventh century and remains a predominantly Muslim country, albeit with a significant Christian minority. From the 16th to the beginning of the 20th century, Egypt was ruled by foreign imperial powers: The Ottoman Empire and the British Empire. Modern Egypt dates back to 1922, when it gained nominal independence from the British Empire as a monarchy. However, British military occupation of Egypt continued, many Egyptians believed that the monarchy was an instrument of British colonialism. Following the 1952 revolution, Egypt expelled British soldiers and bureaucrats and ended British occupation, nationalized the British-held Suez Canal, exiled King Farouk and his family, declared itself a republic. In 1958 it merged with Syria to form the United Arab Republic, which dissolved in 1961. Throughout the second half of the 20th century, Egypt endured social and religious strife and political instability, fighting several armed conflicts with Israel in 1948, 1956, 1967 and 1973, occupying the Gaza Strip intermittently until 1967.
In 1978, Egypt signed the Camp David Accords withdrawing from the Gaza Strip and recognising Israel. The country continues to face challenges, from political unrest, including the recent 2011 revolution and its aftermath, to terrorism and economic underdevelopment. Egypt's current government is a presidential republic headed by President Abdel Fattah el-Sisi, described by a number of watchdogs as authoritarian. Islam is the official religion of Egypt and Arabic is its official language. With over 95 million inhabitants, Egypt is the most populous country in North Africa, the Middle East, the Arab world, the third-most populous in Africa, the fifteenth-most populous in the world; the great majority of its people live near the banks of the Nile River, an area of about 40,000 square kilometres, where the only arable land is found. The large regions of the Sahara desert, which constitute most of Egypt's territory, are sparsely inhabited. About half of Egypt's residents live in urban areas, with most spread across the densely populated centres of greater Cairo and other major cities in the Nile Delta.
The sovereign state of Egypt is a transcontinental country considered to be a regional power in North Africa, the Middle East and the Muslim world, a middle power worldwide. Egypt's economy is one of the largest and most diversified in the Middle East, is projected to become one of the largest in the world in the 21st century. In 2016, Egypt became Africa's second largest economy. Egypt is a founding member of the United Nations, Non-Aligned Movement, Arab League, African Union, Organisation of Islamic Cooperation. "Miṣr" is the Classical Quranic Arabic and modern official name of Egypt, while "Maṣr" is the local pronunciation in Egyptian Arabic. The name is of Semitic origin, directly cognate with other Semitic words for Egypt such as the Hebrew "מִצְרַיִם"; the oldest attestation of this name for Egypt is the Akkadian "mi-iṣ-ru" related to miṣru/miṣirru/miṣaru, meaning "border" or "frontier". There is evidence of rock carvings in desert oases. In the 10th millennium BCE, a culture of hunter-gatherers and fishers was replaced by a grain-grinding culture.
Climate changes or overgrazing around 8000 BCE began to desiccate the pastoral lands of Egypt, forming the Sahara. Early tribal peoples migrated to the Nile River where they developed a settled agricultural economy and more centralised society. By about 6000 BCE, a Neolithic culture rooted in the Nile Valley. During the Neolithic era, several predynastic cultures developed independently in Upper and Lower Egypt; the Badarian culture and the successor Naqada series are regarded as precursors to dynastic Egypt. The earliest known Lower Egyptian site, predates the Badarian by about seven hundred years. Contemporaneous Lower Egyptian communities coexisted with their southern counterparts for more than two thousand years, remaining culturally distinct, but maintaining frequent contact through trade; the earliest known evidence of Egyptian hieroglyphic inscriptions appeared during the predynastic period on Naqada III pottery vessels, dated to about 3200 BCE. A unified kingdom was founded c. 3150 BCE