221-637: North Africa (sometimes Northern Africa ) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of the Western Sahara in the west, to Egypt and Sudan's Red Sea coast in the east. The most common definition for the region's boundaries includes Algeria , Egypt , Libya , Morocco , Tunisia , and Western Sahara ,
442-770: A confederation of seafaring peoples contributed to the New Kingdom 's collapse in 1069 BC, commencing the Third Intermediate Period . Egypt's collapse liberated the more Egyptianised Kingdom of Kush in Nubia, who manoeuvred into power in Upper Egypt and conquered Lower Egypt in 754 BC to form the Kushite Empire . The Kushites ruled for a century and oversaw a revival in pyramid building , until they were driven out of Egypt by
663-404: A derivative of Arabic . However, these areas are not generally considered part of North Africa, but rather Southern Europe, due to their proximity to mainland Europe and their European-based cultures and religion. The Maghreb or western North Africa on the whole is believed to have been inhabited by Berbers and their ancestors since at least 10,000 B.C., while the eastern part of North Africa or
884-530: A mammal adapted to desert life. It minimizes its water loss by producing concentrated urine and dry dung , and is able to lose 40% of its body weight through water loss without dying of dehydration. Carnivores can obtain much of their water needs from the body fluids of their prey. Many other hot desert animals are nocturnal , seeking out shade during the day or dwelling underground in burrows. At depths of more than 50 cm (20 in), these remain at between 30 and 32 °C (86 and 90 °F) regardless of
1105-455: A mosaic of smooth stones, often forming desert pavements , and little further erosion takes place. Other desert features include rock outcrops , exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate. There may be underground sources of water, in the form of springs and seepages from aquifers . Where these are found, oases can occur. Plants and animals living in
1326-557: A principality into a major power on the trade route between Rome and India through conquering its unfortunately unknown neighbours, gaining a monopoly on Indian Ocean trade in the region. Aksum's rise had them rule over much of the regions from Lake Tana to the valley of the Nile , and they further conquered parts of the ailing Kingdom of Kush , led campaigns against the Noba and Beja peoples, and expanded into South Arabia . This led
1547-456: A sand blasting mechanism which grinds away solid objects in its path as the kinetic energy of the wind is transferred to the ground. The sand eventually ends up deposited in level areas known as sand-fields or sand-seas, or piled up in dunes. Many people think of deserts as consisting of extensive areas of billowing sand dunes because that is the way they are often depicted on TV and in films, but deserts do not always look like this. Across
1768-428: A semi-arid climate and are less extreme than regular deserts. Like arid deserts, temperatures can vary greatly in semi deserts. They share some characteristics of a true desert and are usually located at the edge of deserts and continental dry areas. They usually receive precipitation from 250 to 500 mm (9.8 to 19.7 in) but this can vary due to evapotranspiration and soil nutrition. Semi-deserts can be found in
1989-616: A Berber tribe originally from Yafran (also known as Ifrane ) in northwestern Libya , as well as the city of Ifrane in Morocco . Under Roman rule, Carthage became the capital of the province then named Africa Proconsularis , following its defeat of the Carthaginians in the Third Punic War in 146 BC, which also included the coastal part of modern Libya . The Latin suffix -ica can sometimes be used to denote
2210-402: A continental scale rather than being confined to a particular corner of Africa. In September 2019, scientists reported the computerized determination, based on 260 CT scans , of a virtual skull shape of the last common human ancestor to modern humans / H. sapiens , representative of the earliest modern humans, and suggested that modern humans arose between 260,000 and 350,000 years ago through
2431-612: A date of up to 1.8 million BCE. Recent finds in Jebel Irhoud in Morocco have been found to contain some of the oldest Homo sapiens remains; This suggests that, rather than arising only in East Africa around 200,000 years ago, early Homo sapiens may already have been present across the length of Africa 100,000 years earlier. According to study author Jean-Jacques Hublin, "The idea is that early Homo sapiens dispersed around
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#17327648341462652-438: A desert conglomerate . In time, bacteria that live on the surface of the stones accumulate a film of minerals and clay particles, forming a shiny brown coating known as desert varnish . Other non-sandy deserts consist of exposed outcrops of bedrock , dry soils or aridisols , and a variety of landforms affected by flowing water , such as alluvial fans , sinks or playas , temporary or permanent lakes , and oases. A hamada
2873-505: A destructive effect on the exposed rocky surfaces. The repeated fluctuations put a strain on exposed rock and the flanks of mountains crack and shatter. Fragmented strata slide down into the valleys where they continue to break into pieces due to the relentless sun by day and chill by night. Successive strata are exposed to further weathering. The relief of the internal pressure that has built up in rocks that have been underground for aeons can cause them to shatter. Exfoliation also occurs when
3094-611: A distinctive Maghrebi ancestry formed from a mixture of Near Eastern and African ancestry, which is still found as a part of the genome of modern Northwest Africans. Later during the Neolithic , from around 7,500 years ago onwards, there was a migration into Northwest Africa of European Neolithic Farmers from the Iberian Peninsula (who had originated in Anatolia several thousand years prior), as well as pastoralists from
3315-710: A former Italian colony, gained independence. In 1956, Tunisia and Morocco won their independence from France. Ghana followed suit the next year (March 1957), becoming the first of the sub-Saharan colonies to be granted independence. Over the next decade, waves of decolonization took place across the continent, culminating in the 1960 Year of Africa and the establishment of the Organisation of African Unity in 1963. Portugal's overseas presence in sub-Saharan Africa (most notably in Angola , Cape Verde, Mozambique , Guinea-Bissau , and São Tomé and Príncipe) lasted from
3536-441: A handful of African countries succeeded in obtaining rapid economic growth prior to 1990. Exceptions include Libya and Equatorial Guinea, both of which possess large oil reserves. Desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation . About one-third of
3757-564: A land (e.g., in Celtica from Celtae , as used by Julius Caesar ). The later Muslim region of Ifriqiya , following its conquest of the Byzantine (Eastern Roman) Empire's Exarchatus Africae , also preserved a form of the name. According to the Romans, Africa lies to the west of Egypt, while "Asia" was used to refer to Anatolia and lands to the east. A definite line was drawn between
3978-660: A large amount of their genetic, ethnic, cultural and linguistic identity and influence with the Middle East / West Asia , a process that began with the Neolithic Revolution c. 10,000 BC and pre Dynastic Egypt. The countries of North Africa are also a major part of the Arab world . The Islamic and Arab influence in North Africa has remained dominant ever since, with the region being major part of
4199-415: A low basal metabolic rate and by remaining underground during the heat of the day, reducing loss of water through its skin and respiratory system when at rest. Herbivorous mammals obtain moisture from the plants they eat. Species such as the addax antelope , dik-dik , Grant's gazelle and oryx are so efficient at doing this that they apparently never need to drink. The camel is a superb example of
4420-595: A merging of populations in East and Southern Africa . The cave paintings found at Tassili n'Ajjer , north of Tamanrasset, Algeria, and at other locations depict vibrant and vivid scenes of everyday life in central North Africa during the Neolithic Subpluvial period (about 8000 to 4000 BCE). Some parts of North Africa began to participate in the Neolithic revolution in the 6th millennium BCE, just before
4641-698: A millennium. Towards the end of the ancient period, northern Ethiopia and Eritrea bore the Kingdom of D'mt beginning in 980 BC. In modern-day Somalia and Djibouti there was the Macrobian Kingdom , with archaeological discoveries indicating the possibility of other unknown sophisticated civilisations at this time. After D'mt's fall in the 5th century BC the Ethiopian Plateau came to be ruled by numerous smaller unknown kingdoms who experienced strong south Arabian influence , until
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#17327648341464862-625: A monopoly on gold heading north and salt heading south, despite not controlling the gold fields themselves, located in the forest regions . It is probable that Wagadu's dominance on trade allowed for the gradual consolidation of many polities into a confederated state , whose composites stood in varying relations to the core, from fully administered to nominal tribute-paying parity. Based on large tumuli scattered across West Africa dating to this period, it has been stipulated that relative to Wagadu, there were further simultaneous and preceding kingdoms that have unfortunately been lost to time. At
5083-586: A native Libyan tribe, an ancestor of modern Berbers ; see Terence for discussion. The name had usually been connected with the Phoenician word ʿafar meaning "dust", but a 1981 hypothesis has asserted that it stems from the Berber word ifri (plural ifran ) meaning "cave", in reference to cave dwellers. The same word may be found in the name of the Banu Ifran from Algeria and Tripolitania ,
5304-484: A number of ways, generally combining total precipitation, number of days on which this falls, temperature, and humidity, and sometimes additional factors. For example, Phoenix, Arizona , receives less than 250 mm (9.8 in) of precipitation per year, and is immediately recognized as being located in a desert because of its aridity-adapted plants. The North Slope of Alaska's Brooks Range also receives less than 250 mm (9.8 in) of precipitation per year and
5525-513: A second official language after Arabic. French also serves as an administrative language in Algeria, Morocco and Tunisia. The most spoken dialects are Maghrebi Arabic , a form of ancient Arabic dating back from the 8th century AD, and Egyptian Arabic . The largest and most numerous ethnic group in North Africa are the Arabs . In Algeria and Morocco, Berbers are the second largest ethnic group after
5746-423: A series of long, linear dunes known as seif dunes may form. These also occur parallel to a strong wind that blows in one general direction. Transverse dunes run at a right angle to the prevailing wind direction. Star dunes are formed by variable winds, and have several ridges and slip faces radiating from a central point. They tend to grow vertically; they can reach a height of 500 m (1,600 ft), making them
5967-461: A sparse trophic network . Plant growth is limited by rainfall , temperature extremes and desiccating winds. Deserts have strong temporal variability in the availability of resources due to the total amount of annual rainfall and the size of individual rainfall events. Resources are often ephemeral or episodic, and this triggers sporadic animal movements and 'pulse and reserve' or 'boom-bust' ecosystem dynamics. Erosion and sedimentation are high due to
6188-439: A steady wind begins to blow, fine particles lying on the exposed ground begin to vibrate. At greater wind speeds, some particles are lifted into the air stream. When they land, they strike other particles which may be jerked into the air in their turn, starting a chain reaction . Once ejected, these particles move in one of three possible ways, depending on their size, shape and density; suspension , saltation or creep. Suspension
6409-584: A storm that may be many kilometers away. Most deserts are in basins with no drainage to the sea but some are crossed by exotic rivers sourced in mountain ranges or other high rainfall areas beyond their borders. The River Nile , the Colorado River and the Yellow River do this, losing much of their water through evaporation as they pass through the desert and raising groundwater levels nearby. There may also be underground sources of water in deserts in
6630-485: A tolerable level. In many ways, birds are the ablest to do this of the higher animals. They can move to areas of greater food availability as the desert blooms after local rainfall and can fly to faraway waterholes. In hot deserts, gliding birds can remove themselves from the over-heated desert floor by using thermals to soar in the cooler air at great heights. In order to conserve energy, other desert birds run rather than fly. The cream-colored courser flits gracefully across
6851-468: A transition from " informal imperialism " – military influence and economic dominance – to direct rule. Imperial rule by Europeans continued until after the conclusion of World War II , when almost all remaining colonial territories gradually obtained formal independence. Independence movements in Africa gained momentum following World War II, which left the major European powers weakened. In 1951, Libya,
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7072-632: A type of cold desert . While they do not lack water, having a persistent cover of snow and ice, this is merely due to marginal evaporation rates and low precipitation. The McMurdo dry valleys of Antarctica, which lack water (whether rain, ice, or snow) much like a non-polar desert and even have such desert features as hypersaline lakes and intermittent streams that resemble (except for being frozen at their surfaces) hot or cold deserts for extreme aridity and lack of precipitation of any kind. Extreme winds and not seasonal heat desiccate these nearly-lifeless terrains. The concept of "biological desert" redefines
7293-400: A year; they have no annual seasonal cycle of precipitation and experience twelve-month periods with no rainfall at all. Arid deserts receive between 25 and 200 mm (1 and 8 in) in a year and semiarid deserts between 200 and 500 mm (8 and 20 in). However, such factors as the temperature, humidity, rate of evaporation and evapotranspiration, and the moisture storage capacity of
7514-705: Is "no or scanty evidence" of human presence in the Egyptian Nile Valley during these periods, which may be due to problems in site preservation. Several scholars have argued that the African origins of the Egyptian civilisation derived from pastoral communities which emerged in both the Egyptian and Sudanese regions of the Nile Valley in the fifth millennium BCE. When Egypt entered the Bronze Age,
7735-472: Is 150 km (93 mi) long and is the largest oasis in the Libyan Desert. A lake occupied this depression in ancient times and thick deposits of sandy-clay resulted. Wells are dug to extract water from the porous sandstone that lies underneath. Seepages may occur in the walls of canyons and pools may survive in deep shade near the dried up watercourse below. Lakes may form in basins where there
7956-538: Is a jumble of eroded sandstone outcrops , canyons , blocks, pinnacles , fissures , slabs and ravines . In some places the wind has carved holes or arches, and in others, it has created mushroom-like pillars narrower at the base than the top. On the Colorado Plateau , it is water that has been the prevailing eroding force. Here, rivers, such as the Colorado , have cut their way over the millennia through
8177-601: Is a significant minority of Coptic Christians . The Copts are the largest Christian denomination in the Middle East and North Africa . The Maghreb formerly had a significant Jewish population, almost all of whom emigrated to France or Israel when the North African nations gained independence. Prior to the modern establishment of Israel, there were about 500,000 Jews in Northern Africa, including both Sephardi Jews (refugees from Spain, France and Portugal from
8398-487: Is a type of desert landscape consisting of a high rocky plateau where the sand has been removed by aeolian processes . Other landforms include plains largely covered by gravels and angular boulders, from which the finer particles have been stripped by the wind. These are called "reg" in the western Sahara, "serir" in the eastern Sahara, "gibber plains" in Australia and "saï" in central Asia. The Tassili Plateau in Algeria
8619-633: Is continuous above 5,600 m (18,400 ft). Nevertheless, there is some plant life in the Atacama, in the form of specialist plants that obtain moisture from dew and the fogs that blow in from the Pacific. When rain falls in deserts, as it occasionally does, it is often with great violence. The desert surface is evidence of this with dry stream channels known as arroyos or wadis meandering across its surface. These can experience flash floods , becoming raging torrents with surprising rapidity after
8840-479: Is higher than that of forests or the sea. A desert is a region of land that is very dry because it receives low amounts of precipitation (usually in the form of rain, but it may be snow, mist or fog), often has little coverage by plants, and in which streams dry up unless they are supplied by water from outside the area. Deserts generally receive less than 250 mm (10 in) of precipitation each year. The potential evapotranspiration may be large but (in
9061-791: Is not always to be taken literally. Africa is considered by most paleoanthropologists to be the oldest inhabited territory on Earth, with the Human species originating from the continent. During the mid-20th century, anthropologists discovered many fossils and evidence of human occupation perhaps as early as seven million years ago ( Before present , BP). Fossil remains of several species of early apelike humans thought to have evolved into modern humans, such as Australopithecus afarensis radiometrically dated to approximately 3.9–3.0 million years BP, Paranthropus boisei (c. 2.3–1.4 million years BP) and Homo ergaster (c. 1.9 million–600,000 years BP) have been discovered. After
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9282-560: Is often classified as a cold desert. Other regions of the world have cold deserts, including areas of the Himalayas and other high-altitude areas in other parts of the world. Polar deserts cover much of the ice-free areas of the Arctic and Antarctic. A non-technical definition is that deserts are those parts of Earth's surface that have insufficient vegetation cover to support a human population. Potential evapotranspiration supplements
9503-434: Is often less than 40 mm or 1.5 in) to being very far from the nearest available sources of moisture and are often in the lee of mountain ranges. Montane deserts are normally cold, or may be scorchingly hot by day and very cold by night as is true of the northeastern slopes of Mount Kilimanjaro . Polar deserts such as McMurdo Dry Valleys remain ice-free because of the dry katabatic winds that flow downhill from
9724-421: Is only possible for particles less than 0.1 mm (0.0039 in) in diameter. In a dust storm, these fine particles are lifted up and wafted aloft to heights of up to 6 km (3.7 mi). They reduce visibility and can remain in the atmosphere for days on end, conveyed by the trade winds for distances of up to 6,000 km (3,700 mi). Denser clouds of dust can be formed in stronger winds, moving across
9945-592: Is particularly fertile and most of Egypt lives close to the river. Elsewhere, irrigation is essential to improve crop yields on the desert margins. The inhabitants of North Africa are roughly divided in a manner corresponding to the principal geographic regions of North Africa: the Maghreb , the Nile valley, and the Sahel . The countries making up North Africa all have Modern Standard Arabic as their official language. Additionally, Algeria and Morocco recognize Berber as
10166-486: Is sufficient precipitation or meltwater from glaciers above. They are usually shallow and saline, and wind blowing over their surface can cause stress, moving the water over nearby low-lying areas. When the lakes dry up, they leave a crust or hardpan behind. This area of deposited clay, silt or sand is known as a playa . The deserts of North America have more than one hundred playas, many of them relics of Lake Bonneville which covered parts of Utah, Nevada and Idaho during
10387-825: Is surrounded by the Mediterranean Sea to the north, the Arabian Plate and the Gulf of Aqaba to the northeast, the Indian Ocean to the southeast and the Atlantic Ocean to the west. The continent includes Madagascar and various archipelagos . It contains 54 fully recognised sovereign states , eight cities and islands that are part of non-African states , and two de facto independent states with limited or no recognition . This count does not include Malta and Sicily , which are geologically part of
10608-682: Is the Atacama Desert . It is virtually devoid of life because it is blocked from receiving precipitation by the Andes mountains to the east and the Chilean Coast Range to the west. The cold Humboldt Current and the anticyclone of the Pacific are essential to keep the dry climate of the Atacama. The average precipitation in the Chilean region of Antofagasta is just 1 mm (0.039 in) per year. Some weather stations in
10829-450: Is the key to plant growth. It can only take place during the day as energy from the sun is required, but during the day, many deserts become very hot. Opening stomata to allow in the carbon dioxide necessary for the process causes evapotranspiration , and conservation of water is a top priority for desert vegetation. Some plants have resolved this problem by adopting crassulacean acid metabolism , allowing them to open their stomata during
11050-431: Is the specializations of mammalian kidneys shown by desert-inhabiting species. Many examples of convergent evolution have been identified in desert organisms, including between cacti and Euphorbia , kangaroo rats and jerboas , Phrynosoma and Moloch lizards. Deserts present a very challenging environment for animals. Not only do they require food and water but they also need to keep their body temperature at
11271-528: Is very cold and carries little moisture so little precipitation occurs and what does fall, usually snow, is carried along in the often strong wind and may form blizzards, drifts and dunes similar to those caused by dust and sand in other desert regions. In Antarctica , for example, the annual precipitation is about 50 mm (2 in) on the central plateau and some ten times that amount on some major peninsulas. Based on precipitation alone, hyperarid deserts receive less than 25 mm (1 in) of rainfall
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#173276483414611492-671: The 11th dynasty , based in Thebes , conquered the others to form the Middle Kingdom of Egypt , with the 12th dynasty expanding into Lower Nubia at the expense of Kerma . In 1700 BC, the Middle Kingdom fractured in two, ushering in the Second Intermediate Period . The Hyksos , a militaristic people from Palestine , invaded and conquered Lower Egypt, while Kerma coordinated invasions deep into Egypt to reach its greatest extent. In 1550 BC,
11713-646: The 18th dynasty expelled the Hyksos , and established the New Kingdom of Egypt . Using the advanced military technology the Hyksos had brought, the New Kingdom conquered the Levant from the Canaanites , Mittani , Amorites , and Hittites , and extinguished Kerma , incorporating Nubia into the empire, and sending the Egyptian empire into its golden age. Internal struggles, drought, famine, and invasions by
11934-583: The Afroasiatic language family . The Tuareg Berber languages are notably more conservative than those of the coastal cities. Over the years, Berbers have been influenced by contact with other cultures: Egyptians , Greeks , Punic people , Romans , Vandals , Arabs , Europeans , and Africans . The cultures of the Maghreb and the Sahara therefore combines Arab, indigenous Berber and African elements. In
12155-641: The Atacama Desert . Deserts of this type are often long and narrow and bounded to the east by mountain ranges. They occur in Namibia , Chile , southern California and Baja California . Other coastal deserts influenced by cold currents are found in Western Australia , the Arabian Peninsula and Horn of Africa , and the western fringes of the Sahara. In 1961, Peveril Meigs divided desert regions on Earth into three categories according to
12376-685: The Benin Empire . Towards the end of the 3rd century AD, a wet period in the Sahel created areas for human habitation and exploitation that had not been habitable for the best part of a millennium, with the Kingdom of Wagadu , the local name of the Ghana Empire , rising out of the Tichitt culture , growing wealthy following the introduction of the camel to the western Sahel, revolutionising
12597-526: The Cold War , and neocolonialism . Despite this low concentration of wealth, recent economic expansion and a large and young population make Africa an important economic market in the broader global context. Africa has a large quantity of natural resources and food resources, including diamonds , sugar , salt , gold , iron , cobalt , uranium , copper , bauxite , silver , petroleum , natural gas , cocoa beans , and tropical fruit . The continent
12818-904: The Congo Basin , the Empire of Kitara in the African Great Lakes , the Luba Empire in the Upemba Depression , the Kilwa Sultanate in the Swahili coast by crowding out Azania , with Rhapta being its last stronghold by the 1st century AD, and forming various city states constituting the Swahili civilisation . These migrations also prefaced the Kingdom of Mapungubwe in the Zambezi basin . After reaching
13039-746: The Ekoi civilisation rose circa 2nd century AD, and are most notable for constructing the Ikom monoliths and developing the Nsibidi script . Pre-colonial Africa possessed as many as 10,000 different states and polities. These included small family groups of hunter-gatherers such as the San people of southern Africa; larger, more structured groups such as the family clan groupings of the Bantu peoples of central, southern, and eastern Africa; heavily structured clan groups in
13260-424: The Fatimids , Almoravids , Almohads , Ayyubids , Mamluks , Kongo , Mwene Muji , Luba , Lunda , Kitara , Aksum , Ethiopia , Adal , Ajuran , Kilwa , Sakalava , Imerina , Maravi , Mutapa , Rozvi , Mthwakazi , and Zulu . Slave trades created various diasporas , especially in the Americas . From the late 19th century to early 20th century, driven by the Second Industrial Revolution , most of Africa
13481-471: The Horn of Africa ; the large Sahelian kingdoms ; and autonomous city-states and kingdoms, such as those of the Akan ; Edo , Yoruba , and Igbo people in West Africa; and the Swahili coastal trading towns of Southeast Africa. By the 9th century AD, a string of dynastic states, including the earliest Hausa states, stretched across the sub-Saharan savannah from the western regions to central Sudan. The most powerful of these states were Ghana , Gao , and
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#173276483414613702-416: The Isthmus of Suez in Egypt. Other migrations of modern humans within the African continent have been dated to that time, with evidence of early human settlement found in Southern Africa, Southeast Africa, North Africa, and the Sahara . The size of the Sahara has historically been extremely variable, with its area rapidly fluctuating and at times disappearing depending on global climatic conditions. At
13923-401: The Kanem-Bornu Empire . Ghana declined in the eleventh century, but was succeeded by the Mali Empire , which consolidated much of western Sudan in the thirteenth century. Kanem accepted Islam in the eleventh century. In the forested regions of the West African coast, independent kingdoms grew with little influence from the Muslim north. The Kingdom of Nri , which was ruled by the Eze Nri ,
14144-472: The Kingdom of Dahomey , and the Oyo Empire ) adopted different ways of adapting to the shift. Asante and Dahomey concentrated on the development of "legitimate commerce" in the form of palm oil , cocoa , timber and gold, forming the bedrock of West Africa's modern export trade. The Oyo Empire, unable to adapt, collapsed into civil wars. The Scramble for Africa was the conquest and colonisation of most of Africa by seven Western European powers driven by
14365-430: The Levant , both of whom also significantly contributed to the ancestry of modern Northwest Africans. The proto-Berber tribes evolved from these prehistoric communities during the late Bronze - and early Iron ages. The majority of the people of the Maghreb and the Sahara regions speak varieties of Arabic and almost exclusively follow Islam. The Arabic and Berber languages are distantly related, both being members of
14586-439: The Mauro-Roman Kingdom and its numerous successor polities in the Maghreb, namely the kingdoms of Ouarsenis , Aurès , and Altava . The Vandals ruled Ifriqiya for a century until Byzantine reconquest in the early 6th century AD. The Byzantines and the Berber kingdoms fought minor inconsequential conflicts, such as in the case of Garmul , however largely coexisted. Further inland to the Byzantine Exarchate of Africa were
14807-414: The Middle Ages much of the area was loosely under the control of the Ottoman Empire . The Barbary pirates operated from the largely independent Barbary states located on the coast of North Africa. The Spanish Empire conquered several coastal cities between the 16th and 18th centuries. After the 19th century, the imperial and colonial presence of France , the United Kingdom , Spain and Italy left
15028-428: The Muslim world . North Africa is associated with the Middle East in the realm of geopolitics to form the Middle East-North Africa region. North Africa has three main geographic features: the Sahara desert in the south, the Atlas Mountains in the west, and the Nile River and delta in the east. The Atlas Mountains extend across much of northern Algeria , Morocco , and Tunisia . These mountains are part of
15249-484: The Nile Valley has mainly been home to the Egyptians and Nubians . Ancient Egyptians record extensive contact in their Western desert with people that appear to have been Berber or proto-Berber. As the Tassili n'Ajjer and other rock art findings in the Sahara have shown, the Sahara also hosted various populations before its rapid desertification in 3500 B.C and even today continues to host small populations of nomadic trans-Saharan peoples . Laboratory examination of
15470-512: The Noba caused their disintegration into Makuria , Alodia , and Nobatia in the 5th century AD. The Romans managed to hold on to Egypt for the rest of the ancient period. In the Horn of Africa , there was the Land of Punt , a kingdom on the Red Sea , likely located in modern-day Eritrea or northern Somaliland . The Ancient Egyptians initially traded via middle-men with Punt until in 2350 BC when they established direct relations. They would become close trading partners for over
15691-430: The Nok culture from 1500 BC in modern-day Nigeria , the Daima culture around Lake Chad from 550 BC, Djenné-Djenno from 250 BC in modern-day Mali , and the Serer civilisation in modern-day Senegal , which built the Senegambian stone circles from the 3rd century BC. There is also detailed record of Igodomigodo , a small kingdom founded presumably in 40 BC, which would later go on to form
15912-565: The Ovambo kingdoms , most of which were later conquered. The 1884 Berlin Conference regulated European colonisation and trade in Africa, and is seen as emblematic of the "scramble". In the last quarter of the 19th century, there were considerable political rivalries between the European empires , which provided the impetus for the colonisation. The later years of the 19th century saw
16133-528: The Punic Wars against the expansionary Roman Republic , however momentum in these wars was not linear, with Carthage initially experiencing considerable success in the Second Punic War following Hannibal 's infamous crossing of the alps into northern Italy . Their defeat and subsequent collapse of their empire would produce two further polities in the Maghreb; Numidia , which had assisted
16354-679: The Romans in 30 BC. The Crisis of the Third Century in the Roman Empire freed the Levantine city state of Palmyra , which conquered Egypt ; their brief rule ended when they were reconquered by the Romans . In the midst of this, Kush regained independence from Egypt, and they would persist as a major regional power until, having been weakened from internal rebellion amid worsening climatic conditions, invasions by Aksum and
16575-662: The Sanhaja in modern-day Algeria , a broad grouping of three groupings of tribal confederations , one of which is the Masmuda grouping in modern-day Morocco , along with the nomadic Zenata ; their composite tribes would later go onto shape much of North African history . In the western Sahel the rise of settled communities occurred largely as a result of the domestication of millet and of sorghum . Archaeology points to sizable urban populations in West Africa beginning in
16796-536: The Sao civilisation flourished for over a millennium beginning in the 6th century BC, in territory that later became part of present-day Cameroon and Chad . Sao artifacts show that they were skilled workers in bronze , copper , and iron , with finds including bronze sculptures, terracotta statues of human and animal figures, coins, funerary urns, household utensils, jewellery, highly decorated pottery, and spears. Nearby, around Lake Ejagham in south-west Cameroon ,
17017-707: The Sassanid Empire and the Himyarite Kingdom in Arabia. The Maghreb and Ifriqiya were mostly cut off from the cradle of civilisation in Egypt by the Libyan desert , exacerbated by Egyptian boats being tailored to the Nile and not coping well in the open Mediterranean Sea . This caused its societies to develop contiguous to those of Southern Europe , until Phoenician settlements came to dominate
17238-561: The Second Industrial Revolution during the era of " New Imperialism " (1833–1914): Belgium , France , Germany , United Kingdom , Italy , Portugal and Spain . In 1870, 10% of the continent was formally under European control. By 1914, this figure had risen to almost 90%; the only states retaining sovereignty were Liberia , Ethiopia , Egba , Aussa , Senusiyya , Mbunda , the Dervish State , and
17459-523: The Strait of Gibraltar , whereupon they overcame the fickle Roman defense. The loss of North Africa is considered a pinnacle point in the fall of the Western Roman Empire as Africa had previously been an important grain province that maintained Roman prosperity despite the barbarian incursions, and the wealth required to create new armies. The issue of regaining North Africa became paramount to
17680-747: The Uan Muhuggiag child mummy and Tin Hanakaten child, suggested that the Central Saharan peoples from the Epipaleolithic , Mesolithic , and Pastoral periods possessed dark skin complexions. The archaeological evidence from the Holocene period has shown that Nilo-Saharan speaking groups had populated the central and southern Sahara before the influx of Berber and Arabic speakers, around 1500 years ago, who now largely populate
17901-631: The Zambezi , the Bantu continued southward, with eastern groups continuing to modern-day Mozambique and reaching Maputo in the 2nd century AD. Further to the south, settlements of Bantu peoples who were iron-using agriculturists and herdsmen were well established south of the Limpopo River by the 4th century AD, displacing and absorbing the Khoisan . By the Chari River south of Lake Chad
18122-590: The eastern part of North Africa has been home to the Egyptians . In the seventh and eighth centuries, Arabs from the Arabian Peninsula swept across the region during the early Muslim conquests . The Arab migrations to the Maghreb began immediately after, which started a long process of Islamization and Arabization that has defined the cultural landscape of North Africa ever since. Many but not all Berbers and Egyptians gradually merged into Arab - Islamic culture . The countries and people of North Africa share
18343-538: The fold mountain system that also runs through much of Southern Europe . They recede to the south and east, becoming a steppe landscape before meeting the Sahara desert, which covers more than 75 percent of the region. The tallest peaks are in the High Atlas range in south-central Morocco, which has many snow-capped peaks. South of the Atlas Mountains is the dry and barren expanse of the Sahara desert,
18564-621: The horse latitudes at 30° to 35° North and South. These belts are associated with the subtropical anticyclone and the large-scale descent of dry air. The Sahara Desert is of this type. Mid-latitude deserts occur between 30° and 50° North and South. They are mostly in areas remote from the sea where most of the moisture has already precipitated from the prevailing winds. They include the Tengger and Sonoran Deserts . Monsoon deserts are similar. They occur in regions where large temperature differences occur between sea and land. Moist warm air rises over
18785-419: The presidential system of rule. However, few of them have been able to sustain democratic governments on a permanent basis—per the criteria laid out by Lührmann et al. (2018), only Botswana and Mauritius have been consistently democratic for the entirety of their post-colonial history. Most African countries have experienced several coups or periods of military dictatorship . Between 1990 and 2018, though,
19006-414: The rocks , which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter, and the resulting fragments and rubble strewn over the desert floor are further eroded by the wind. This picks up particles of sand and dust, which can remain airborne for extended periods – sometimes causing
19227-780: The trans-Saharan trade that linked their capital and Aoudaghost with Tahert and Sijilmasa in North Africa. Soninke traditions likely contain content from prehistory, mentioning four previous foundings of Wagadu , and holds that the final founding of Wagadu occurred after their first king did a deal with Bida , a serpent deity who was guarding a well, to sacrifice one maiden a year in exchange for assurance regarding plenty of rainfall and gold supply. Wagadu's core traversed modern-day southern Mauritania and western Mali , and Soninke tradition portrays early Ghana as warlike, with horse-mounted warriors key to increasing its territory and population, although details of their expansion are extremely scarce. Wagadu made its profits from maintaining
19448-410: The tropic of Cancer , in the northern temperate zone . In the other extreme of the continent, southern Namibia , southern Botswana , great parts of South Africa , the entire territories of Lesotho and Eswatini and the southern tips of Mozambique and Madagascar are located below the tropic of Capricorn , in the southern temperate zone . Africa is highly biodiverse ; it is the continent with
19669-417: The windward slope of the mountain range . When they descend on the leeward side, they warm and their capacity to hold moisture increases so an area with relatively little precipitation occurs. The Taklamakan Desert is an example, lying in the rain shadow of the Himalayas and receiving less than 38 mm (1.5 in) precipitation annually. Other areas are arid by virtue of being a very long way from
19890-487: The written word . During the colonial period , oral sources were deprecated by European historians, which gave them the impression Africa had no recorded history. African historiography became organized at the academic level in the mid-20th century, and saw a movement towards utilising oral sources in a multidisciplinary approach, culminating in the General History of Africa , edited by specialists from across
20111-697: The 16th and 19th centuries. In West Africa, the decline of the Atlantic slave trade in the 1820s caused dramatic economic shifts in local polities. The gradual decline of slave-trading, prompted by a lack of demand for slaves in the New World , increasing anti-slavery legislation in Europe and America, and the British Royal Navy's increasing presence off the West African coast, obliged African states to adopt new economies. Between 1808 and 1860,
20332-596: The 16th century to 1975, after the Estado Novo regime was overthrown in a military coup in Lisbon . Rhodesia unilaterally declared independence from the United Kingdom in 1965, under the white minority government of Ian Smith , but was not internationally recognized as an independent state (as Zimbabwe ) until 1980, when black nationalists gained power after a bitter guerrilla war . Although South Africa
20553-611: The 1st and 4th cataracts of the Nile . The 4th dynasty oversaw the height of the Old Kingdom , and constructed many great pyramids . Under the 6th dynasty power gradually decentralised to the nomarchs, culminating in the disintegration of the kingdom, exacerbated by drought and famine, thus commencing the First Intermediate Period in 2200 BC. This shattered state would last until 2055 BC when
20774-585: The 2nd century BC Mauretania fought alongside Numidia's Jugurtha in the Jugurthine War against the Romans after he had usurped the Numidian throne from a Roman ally. Together they inflicted heavy casualties that quaked the Roman Senate , with the war only ending inconclusively when Mauretania's Bocchus I sold out Jugurtha to the Romans. At the turn of the millennium, they both would face
20995-692: The 4th millennium BC the Congo Basin was inhabited by the Bambenga , Bayaka , Bakoya , and Babongo in the west, the Bambuti in the east , and the Batwa who were widely scattered and also present in the Great Lakes region ; together they are grouped as Pygmies . On the later-named Swahili coast there were Cushitic -speaking peoples, and the Khoisan (a neologism for the Khoekhoe and San ) in
21216-416: The 4th millennium BC, which had crucially developed iron metallurgy by 1200 BC, in both smelting and forging for tools and weapons. Extensive east-west belts of deserts , grasslands , and forests from north to south were crucial for the moulding of their respective societies and meant that prior to the accession of trans-Saharan trade routes , symbiotic trade relations developed in response to
21437-526: The African continent. Algeria is Africa's largest country by area, and Nigeria is its largest by population. African nations cooperate through the establishment of the African Union , which is headquartered in Addis Ababa . Africa straddles the equator and the prime meridian . It is the only continent to stretch from the northern temperate to the southern temperate zones. The majority of
21658-597: The Arab majority. Arabs constitute 70% to 80% of the population of Algeria, 92%97% of Libya, 67% to 70% of Morocco and 98% of Tunisia's population. The Berbers comprise 20% of Algeria, 10% of Libya, 35% of Morocco and 1% of Tunisia's population. The region is predominantly Muslim with a Jewish minority in Morocco and Tunisia , and significant Christian minority—the Copts —in Egypt , Algeria , Morocco, Libya, and Tunisia. In 2001,
21879-704: The Assyrians in 663 BC in reprisal for their expansion towards the Assyrian Empire . The Assyrians installed a puppet dynasty that later gained independence and once more unified Egypt , until they were conquered by the Achaemenid Empire in 525 BC. Egypt regained independence under the 28th dynasty in 404 BC but they were reconquered by the Achaemenids in 343 BC. The conquest of Achaemenid Egypt by Alexander
22100-492: The Atacama have never received rain. Evidence suggests that the Atacama may not have had any significant rainfall from 1570 to 1971. It is so arid that mountains that reach as high as 6,885 m (22,589 ft) are completely free of glaciers and, in the southern part from 25°S to 27°S, may have been glacier-free throughout the Quaternary , though permafrost extends down to an altitude of 4,400 m (14,400 ft) and
22321-573: The British West Africa Squadron seized approximately 1,600 slave ships and freed 150,000 Africans who were aboard. Action was also taken against African leaders who refused to agree to British treaties to outlaw the trade, for example against "the usurping King of Lagos ", deposed in 1851. Anti-slavery treaties were signed with over 50 African rulers. The largest powers of West Africa (the Asante Confederacy ,
22542-659: The Great in 332 BC marked the beginning of Hellenistic rule and the installation of the Macedonian Ptolemaic dynasty in Egypt. The Ptolemaics lost their holdings outside of Africa to the Seleucids in the Syrian Wars , expanded into Cyrenaica and subjugated Kush in the 3rd century BC. In the 1st century BC, Ptolemaic Egypt became entangled in a Roman civil war , leading to its conquest by
22763-514: The Iberian peninsula during the eleventh century. The Banu Hilal and Banu Ma'qil were a collection of Arab Bedouin tribes from the Arabian Peninsula who migrated westwards via Egypt between the eleventh and thirteenth centuries. Their migration resulted in the fusion of the Arabs and Berbers, where the locals were Arabized , and Arab culture absorbed elements of the local culture, under
22984-575: The Maghreb remained focused on small-scale subsistence in small, highly mobile groups. Some Phoenician and Greek colonies were established along the Mediterranean coast during the 7th century BCE. The most notable nations of antiquity in western North Africa are Carthage , Numidia and Mauretania . The Phoenicians colonized much of North Africa including Carthage and parts of present-day Morocco (including Chellah , Essaouira and Volubilis ). The Carthaginians were of Phoenician origin, with
23205-563: The Persian prophet Mani to consider Aksum as one of the four great powers of the 3rd century AD alongside Persia , Rome , and China . In the 4th century AD Aksum's king converted to Christianity and Aksum's population, who had followed syncretic mixes of local beliefs , slowly followed. The end of the 5th century saw Aksum allied with the Byzantine Empire , who viewed themselves as defenders of Christendom , balanced against
23426-579: The Renaissance era) as well as indigenous Mizrahi Jews . Today, less than 3,000 remain in the region, almost all in Morocco and Tunisia, and are mostly part of a French-speaking urban elite. (See Jewish exodus from Arab and Muslim countries .) Due to the recent African origin of modern humans , the history of Prehistoric North Africa is important to the understanding of pre-hominid and early modern human history in Africa. Some researchers have postulated that North Africa rather than East Africa served as
23647-554: The Roman myth of their origin being that Dido , a Phoenician princess, was granted land by a local ruler based on how much land she could cover with a piece of cowhide. She ingeniously devised a method to extend the cowhide to a high proportion, thus gaining a large territory. She was also rejected by the Trojan prince Aeneas according to Virgil , thus creating a historical enmity between Carthage and Rome , as Aeneas would eventually lay
23868-523: The Romans in the Second Punic War, Mauretania , a Mauri tribal kingdom and home of the legendary King Atlas , and various tribes such as Garamantes , Musulamii , and Bavares . The Third Punic War would result in Carthage's total defeat in 146 BC and the Romans established the province of Africa , with Numidia assuming control of many of Carthage's African ports. Towards the end of
24089-579: The Romans, resulting in the Carthaginian North African territories becoming the Roman province of Africa in 146 B.C. This led to tension and eventually conflict between Numidia and Rome. The Numidian wars are notable for launching the careers of both Gaius Marius , and Sulla , and stretching the constitutional burden of the Roman republic as Marius required a professional army, something previously contrary to Roman values, to overcome
24310-418: The Sahara in the modern era. After migrating to North Africa in the 1st millennium BC, Semitic Phoenician settlers from the Levant established over 300 coastal colonies throughout the region and built a powerful empire that controlled most of the region from the 8th century BC until the middle of the 2nd century BC. Several waves of Arab migrations to the Maghreb began in the 7th century, including
24531-773: The Sahara region was becoming increasingly dry and hostile. Around 3500 BC, due to a tilt in the Earth's orbit , the Sahara experienced a period of rapid desertification. The population trekked out of the Sahara region towards the Nile Valley below the Second Cataract where they made permanent or semi-permanent settlements. A major climatic recession occurred, lessening the heavy and persistent rains in Central and Eastern Africa . Since this time, dry conditions have prevailed in Eastern Africa and, increasingly during
24752-444: The Sahara, the distinction between sedentary oasis inhabitants and nomadic Bedouin Arabs and Tuaregs is particularly marked. Egyptians over the centuries have shifted their language from Egyptian (in its late form, varieties of Coptic ) to modern Egyptian Arabic while retaining a sense of national identity that has historically set them apart from other people in the region. Most Egyptians are Sunni Muslim , although there
24973-522: The Saharan climate started to become drier at an exceedingly fast pace. This climate change caused lakes and rivers to shrink significantly and caused increasing desertification . This, in turn, decreased the amount of land conducive to settlements and encouraged migrations of farming communities to the more tropical climate of West Africa. During the first millennium BC, a reduction in wild grain populations related to changing climate conditions facilitated
25194-541: The Spanish cities of Ceuta and Melilla , and the plazas de soberanía . It can also be considered to include Malta , as well as other Italian, Portuguese, and Spanish regions such as Lampedusa and Lampione , Madeira , and the Canary Islands , which are all closer or as close to the African continent than Europe. Northwest Africa has been inhabited by Berbers since the beginning of recorded history , while
25415-696: The Western Empire, but was frustrated by Vandal victories. The focus of Roman energy had to be on the emerging threat of the Huns . In 468 AD, the Romans made one last serious attempt to invade North Africa but were repelled. This perhaps marks the point of terminal decline for the Western Roman Empire . The last Roman emperor was deposed in 476 by the Heruli general Odoacer . Trade routes between Europe and North Africa remained intact until
25636-532: The absence of available water) the actual evapotranspiration may be close to zero. Semi-deserts are regions which receive between 250 and 500 mm (10 and 20 in) and when clad in grass, these are known as steppes . Most deserts on Earth such as the Sahara Desert , Grand Australian Desert and the Great Basin Desert , occur in low altitudes . One of the driest places on Earth
25857-401: The air but soon fall back to earth, ejecting other particles in the process. Their weight prevents them from being airborne for long and most only travel a distance of a few meters (yards). The sand streams along above the surface of the ground like a fluid, often rising to heights of about 30 cm (12 in). In a really severe steady blow, 2 m (6 ft 7 in) is about as high as
26078-722: The amount of precipitation they received. In this now widely accepted system, extremely arid lands have at least twelve consecutive months without precipitation, arid lands have less than 250 mm (9.8 in) of annual precipitation, and semiarid lands have a mean annual precipitation of between 250 and 500 mm (9.8 and 19.7 in). Both extremely arid and arid lands are considered to be deserts while semiarid lands are generally referred to as steppes when they are grasslands. Deserts are also classified, according to their geographical location and dominant weather pattern, as trade wind, mid-latitude, rain shadow, coastal, monsoon, or polar deserts . Trade wind deserts occur either side of
26299-411: The barren rock is to be found in the so-called Dry Valleys of Antarctica that almost never get snow, which can have ice-encrusted saline lakes that suggest evaporation far greater than the rare snowfall due to the strong katabatic winds that even evaporate ice. Deserts, both hot and cold, play a part in moderating Earth's temperature, because they reflect more of the incoming light and their albedo
26520-457: The capture of large quantities of solar energy . English desert and its Romance cognates (including Italian and Portuguese deserto , French désert and Spanish desierto ) all come from the ecclesiastical Latin dēsertum (originally "an abandoned place"), a participle of dēserere , "to abandon". The correlation between aridity and sparse population is complex and dynamic, varying by culture, era, and technologies; thus
26741-523: The cellular structure of which has been modified to allow them to store water. When rain falls, the water is rapidly absorbed by the shallow roots and retained to allow them to survive until the next downpour, which may be months or years away. The giant saguaro cacti of the Sonoran Desert form "forests", providing shade for other plants and nesting places for desert birds. Saguaro grows slowly but may live for up to two hundred years. The surface of
26962-615: The coldest part of the year. Animals adapted to live in deserts are called xerocoles . There is no evidence that body temperature of mammals and birds is adaptive to the different climates, either of great heat or cold. In fact, with a very few exceptions, their basal metabolic rate is determined by body size, irrespective of the climate in which they live. Many desert animals (and plants) show especially clear evolutionary adaptations for water conservation or heat tolerance and so are often studied in comparative physiology , ecophysiology , and evolutionary physiology . One well-studied example
27183-597: The collision between airborne particles and by the impacts of saltating sand grains landing on the ground. The mechanism is little understood but the particles usually have a negative charge when their diameter is under 250 μm and a positive one when they are over 500 μm. Deserts and semi-deserts are home to ecosystems with low or very low biomass and primary productivity in arid or semi-arid climates. They are mostly found in subtropical high-pressure belts and major continental rain shadows . Primary productivity depends on low densities of small photoautotrophs that sustain
27404-586: The color of the underlying surface. The desert lark takes frequent dust baths which ensures that it matches its environment. Water and carbon dioxide are metabolic end products of oxidation of fats, proteins, and carbohydrates. Oxidising a gram of carbohydrate produces 0.60 grams of water; a gram of protein produces 0.41 grams of water; and a gram of fat produces 1.07 grams of water, making it possible for xerocoles to live with little or no access to drinking water. The kangaroo rat for example makes use of this water of metabolism and conserves water both by having
27625-524: The coming of Islam. Some Berbers were members of the Early African Church (but evolved their own Donatist doctrine ), some were Berber Jews , and some adhered to traditional Berber religion . African pope Victor I served during the reign of Roman emperor Septimius Severus . Furthermore, during the rule of the Romans, Byzantines, Vandals, Ottomans and Carthaginians the Kabyle people were
27846-468: The concept of desert, without the characteristic of aridity, not lacking water, but instead lacking life. Such places can be so-called "ocean deserts", which are mostly at the centers of gyres , but also hypoxic or anoxic waters such as dead zones . Deserts usually have a large diurnal and seasonal temperature range, with high daytime temperatures falling sharply at night. The diurnal range may be as much as 20 to 30 °C (36 to 54 °F) and
28067-437: The continent and elements of human modernity appeared in different places, and so different parts of Africa contributed to the emergence of what we call modern humans today." Early humans may have comprised a large, interbreeding population dispersed across Africa whose spread was facilitated by a wetter climate that created a "green Sahara", around 330,000 to 300,000 years ago. The rise of modern humans may thus have taken place on
28288-550: The continent and its countries are in the Northern Hemisphere , with a substantial portion and a number of countries in the Southern Hemisphere . Most of the continent lies in the tropics, except for a large part of Western Sahara , Algeria , Libya and Egypt , the northern tip of Mauritania , and the entire territories of Morocco , Ceuta , Melilla , and Tunisia , which in turn are located above
28509-463: The continent as a whole has trended towards more democratic governance. Upon independence an overwhelming majority of Africans lived in extreme poverty . The continent suffered from the lack of infrastructural or industrial development under colonial rule, along with political instability. With limited financial resources or access to global markets, relatively stable countries such as Kenya still experienced only very slow economic development. Only
28730-424: The continent most vulnerable to climate change . The history of Africa is long, complex, and varied, and has often been under-appreciated by the global historical community . In African societies the oral word is revered, and they have generally recorded their history via oral tradition , which has led anthropologists to term them oral civilisations, contrasted with literate civilisations which pride
28951-409: The continent's south. The Bantu expansion constituted a major series of migrations of Bantu peoples from central Africa to eastern and southern Africa and was substantial in the settling of the continent. Commencing in the 2nd millennium BC, the Bantu began to migrate from Cameroon to central, eastern, and southern Africa, laying the foundations for future states such as the Kingdom of Kongo in
29172-422: The continent. Africa, particularly Eastern Africa , is widely accepted to be the place of origin of humans and the Hominidae clade , also known as the great apes . The earliest hominids and their ancestors have been dated to around 7 million years ago, and Homo sapiens (modern human) are believed to have originated in Africa 350,000 to 260,000 years ago. Africa is also considered by anthropologists to be
29393-452: The desert floor to scarify the seed coat. The seed of the mesquite tree, which grows in deserts in the Americas, is hard and fails to sprout even when planted carefully. When it has passed through the gut of a pronghorn it germinates readily, and the little pile of moist dung provides an excellent start to life well away from the parent tree. The stems and leaves of some plants lower the surface velocity of sand-carrying winds and protect
29614-500: The desert need special adaptations to survive in the harsh environment. Plants tend to be tough and wiry with small or no leaves, water-resistant cuticles , and often spines to deter herbivory . Some annual plants germinate , bloom and die in the course of a few weeks after rainfall, while other long-lived plants survive for years and have deep root systems able to tap underground moisture. Animals need to keep cool and find enough food and water to survive. Many are nocturnal , and stay in
29835-658: The desert: Tripolitania in the northwest and Cyrenaica in the northeast. Most of Egypt is also desert, with the exception of the Nile River and the irrigated land along its banks. The Nile Valley forms a narrow fertile thread that runs along the length of the country. Sheltered valleys in the Atlas Mountains, the Nile Valley and Delta , and the Mediterranean coast are the main sources of fertile farming land. A wide variety of valuable crops including cereals, rice and cotton, and woods such as cedar and cork , are grown. Typical Mediterranean crops, such as olives, figs, dates and citrus fruits, also thrive in these areas. The Nile Valley
30056-587: The driest season, and others curl their leaves up to reduce transpiration. Others, such as aloes , store water in succulent leaves or stems or in fleshy tubers. Desert plants maximize water uptake by having shallow roots that spread widely, or by developing long taproots that reach down to deep rock strata for ground water. The saltbush in Australia has succulent leaves and secretes salt crystals, enabling it to live in saline areas. In common with cacti, many have developed spines to ward off browsing animals. Some desert plants produce seed which lies dormant in
30277-428: The earliest instances of agriculture in human history. Its cultivation would gradually spread across Africa, before spreading to India around 2000 BC. People around modern-day Mauritania started making pottery and built stone settlements (e.g., Tichitt , Oualata ). Fishing, using bone-tipped harpoons , became a major activity in the numerous streams and lakes formed from the increased rains. In West Africa,
30498-457: The eleventh century, a reformist movement made up of members that called themselves the Almoravid dynasty expanded south into Sub-Saharan Africa . North Africa's populous and flourishing civilization collapsed after exhausting its resources in internal fighting and suffering devastation from the invasion of the Banu Sulaym and Banu Hilal . Ibn Khaldun noted that the lands ravaged by Banu Hilal invaders had become completely arid desert. After
30719-441: The end of the Ice ages , estimated to have been around 10,500 BC, the Sahara had again become a green fertile valley, and its African populations returned from the interior and coastal highlands in sub-Saharan Africa , with rock art paintings depicting a fertile Sahara and large populations discovered in Tassili n'Ajjer dating back perhaps 10 millennia. However, the warming and drying climate meant that by 5,000 BC,
30940-479: The entirety of the region under one form of European occupation. In World War II from 1940 to 1943 the area was the setting for the North African Campaign . During the 1950s and 1960s all of the North African states gained independence. There remains a dispute over Western Sahara between Morocco and the Algerian -backed Polisario Front . The wider protest movement known as the Arab Spring began with revolutions in Tunisia and Egypt which ultimately led to
31161-433: The evolution of Homo sapiens approximately 350,000 to 260,000 years BP in Africa, the continent was mainly populated by groups of hunter-gatherers . These first modern humans left Africa and populated the rest of the globe during the Out of Africa II migration dated to approximately 50,000 years BP, exiting the continent either across Bab-el-Mandeb over the Red Sea , the Strait of Gibraltar in Morocco, or
31382-435: The exit point for the modern humans who first trekked out of the continent in the Out of Africa migration. The earliest inhabitants of central North Africa have left behind significant remains: early remnants of hominid occupation in North Africa, for example, were found in Ain el Hanech, near Saïda ( c. 200,000 BCE ); in fact, more recent investigations have found signs of Oldowan technology there, and indicate
31603-535: The expansion of farming communities and the rapid adoption of rice cultivation around the Niger River. By the first millennium BC, ironworking had been introduced in Northern Africa. Around that time it also became established in parts of sub-Saharan Africa, either through independent invention there or diffusion from the north and vanished under unknown circumstances around 500 AD, having lasted approximately 2,000 years, and by 500 BC, metalworking began to become commonplace in West Africa. Ironworking
31824-455: The external temperature. Jerboas , desert rats , kangaroo rats and other small rodents emerge from their burrows at night and so do the foxes, coyotes, jackals and snakes that prey on them. Kangaroos keep cool by increasing their respiration rate, panting, sweating and moistening the skin of their forelegs with saliva . Mammals living in cold deserts have developed greater insulation through warmer body fur and insulating layers of fat beneath
32045-457: The form of springs , aquifers , underground rivers or lakes. Where these lie close to the surface, wells can be dug and oases may form where plant and animal life can flourish. The Nubian Sandstone Aquifer System under the Sahara Desert is the largest known accumulation of fossil water . The Great Man-Made River is a scheme launched by Libya's Muammar Gaddafi to tap this aquifer and supply water to coastal cities. Kharga Oasis in Egypt
32266-407: The formation of sand storms or dust storms . Wind-blown sand grains striking any solid object in their path can abrade the surface. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes . Other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of
32487-411: The foundations for Rome. Ancient Carthage was a commercial power and had a strong navy, but relied on mercenaries for land soldiers. The Carthaginians developed an empire in the Iberian Peninsula , Malta , Sardinia , Corsica and northwest Sicily , the latter being the cause of First Punic War with the Romans . Over a hundred years and more, all Carthaginian territory was eventually conquered by
32708-458: The fragmentation of harder granites , limestone and sandstone . There is a certain critical size (about 0.5 mm) below which further temperature-induced weathering of rocks does not occur and this provides a minimum size for sand grains. As the mountains are eroded, more and more sand is created. At high wind speeds, sand grains are picked up off the surface and blown along, a process known as saltation . The whirling airborne grains act as
32929-439: The ground from erosion. Even small fungi and microscopic plant organisms found on the soil surface (so-called cryptobiotic soil ) can be a vital link in preventing erosion and providing support for other living organisms. Cold deserts often have high concentrations of salt in the soil. Grasses and low shrubs are the dominant vegetation here and the ground may be covered with lichens . Most shrubs have spiny leaves and shed them in
33150-474: The ground have a marked effect on the degree of aridity and the plant and animal life that can be sustained. Rain falling in the cold season may be more effective at promoting plant growth, and defining the boundaries of deserts and the semiarid regions that surround them on the grounds of precipitation alone is problematic. A semi-arid desert or a steppe is a version of the arid desert with much more rainfall, vegetation and higher humidity. These regions feature
33371-432: The ground on its long legs, stopping periodically to snatch up insects. Like other desert birds, it is well-camouflaged by its coloring and can merge into the landscape when stationary. The sandgrouse is an expert at this and nests on the open desert floor dozens of kilometers (miles) away from the waterhole it needs to visit daily. Some small diurnal birds are found in very restricted localities where their plumage matches
33592-427: The ground rises quickly through a small pocket of cooler, low-pressure air above forming a whirling column of particles, a dust devil . Sandstorms occur with much less frequency than dust storms. They are often preceded by severe dust storms and occur when the wind velocity increases to a point where it can lift heavier particles. These grains of sand, up to about 0.5 mm (0.020 in) in diameter are jerked into
33813-455: The growth and expansion of Aksum in the 1st century BC. Along the Horn's coast there were many ancient Somali city-states that thrived off of the wider Red Sea trade and transported their cargo via beden , exporting myrrh , frankincense , spices , gum , incense , and ivory , with freedom from Roman interference causing Indians to give the cities a lucrative monopoly on cinnamon from ancient India . The Kingdom of Aksum grew from
34034-429: The high desert floor, creating canyons that are over a mile (6,000 feet or 1,800 meters) deep in places, exposing strata that are over two billion years old. Sand and dust storms are natural events that occur in arid regions where the land is not protected by a covering of vegetation. Dust storms usually start in desert margins rather than the deserts themselves where the finer materials have already been blown away. As
34255-422: The high elevations of the Tabernas Desert (and some parts of the Spanish Plateu ), The Sahel , The Eurasian Steppe , most of Central Asia , the Western US , most of Northern Mexico , portions of South America (especially in Argentina ) and the Australian Outback . They usually feature BSh (hot steppe) or BSk (temperate steppe) in the Köppen climate classification . Coastal deserts are mostly found on
34476-443: The historical process is largely a communal one, with eyewitness accounts, hearsay , reminiscences, and occasionally visions , dreams, and hallucinations, crafted into oral traditions . Time is sometimes mythical and social, and truth generally viewed as relativist . Oral tradition can be exoteric or esoteric . It speaks to people according to their understanding, unveiling itself in accordance with their aptitudes, and
34697-402: The import of water from an outside source. Many trade routes have been forged across deserts, especially across the Sahara , and traditionally were used by caravans of camels carrying salt, gold, ivory and other goods. Large numbers of slaves were also taken northwards across the Sahara. Some mineral extraction also takes place in deserts, and the uninterrupted sunlight gives potential for
34918-462: The kingdoms of Lower Egypt and Upper Egypt in northeast Africa . Around 3100 BC Upper Egypt conquered Lower Egypt to unify Egypt under the 1st dynasty , with the process of consolidation and assimilation completed by the time of the 3rd dynasty who formed the Old Kingdom of Egypt in 2686 BC. The Kingdom of Kerma emerged around this time to become the dominant force in Nubia , controlling territory as large as Egypt between
35139-523: The lack of heat to aid in the evaporation process. Deserts are sometimes classified as "hot" or "cold", "semiarid" or "coastal". The characteristics of hot deserts include high temperatures in summer; greater evaporation than precipitation, usually exacerbated by high temperatures, strong winds and lack of cloud cover; considerable variation in the occurrence of precipitation, its intensity and distribution; and low humidity. Winter temperatures vary considerably between different deserts and are often related to
35360-492: The land surface of the Earth is arid or semi-arid . This includes much of the polar regions , where little precipitation occurs, and which are sometimes called polar deserts or "cold deserts". Deserts can be classified by the amount of precipitation that falls, by the temperature that prevails, by the causes of desertification or by their geographical location. Deserts are formed by weathering processes as large variations in temperature between day and night put strains on
35581-431: The land with a billowing leading edge. The sunlight can be obliterated and it may become as dark as night at ground level. In a study of a dust storm in China in 2001, it was estimated that 6.5 million tons of dust were involved, covering an area of 134,000,000 km (52,000,000 sq mi). The mean particle size was 1.44 μm. A much smaller scale, short-lived phenomenon can occur in calm conditions when hot air near
35802-412: The land, deposits its water content and circulates back to sea. Further inland, areas receive very little precipitation. The Thar Desert near the India/Pakistan border is of this type. In some parts of the world, deserts are created by a rain shadow effect. Orographic lift occurs as air masses rise to pass over high ground. In the process they cool and lose much of their moisture by precipitation on
36023-453: The largest number of megafauna species, as it was least affected by the extinction of the Pleistocene megafauna . However, Africa also is heavily affected by a wide range of environmental issues , including desertification, deforestation, water scarcity , and pollution . These entrenched environmental concerns are expected to worsen as climate change impacts Africa . The UN Intergovernmental Panel on Climate Change has identified Africa as
36244-495: The largest sand desert in the world. In places the desert is cut by irregular watercourses called wadis —streams that flow only after rainfall but are usually dry. The Sahara's major landforms include ergs , large seas of sand that sometimes form into huge dunes ; the hammada , a level rocky plateau without soil or sand; and the reg , a desert pavement . The Sahara covers the southern part of Algeria, Morocco and Tunisia, and most of Libya. Only two regions of Libya are outside
36465-460: The last ice age when the climate was colder and wetter. These include the Great Salt Lake , Utah Lake , Sevier Lake and many dry lake beds. The smooth flat surfaces of playas have been used for attempted vehicle speed records at Black Rock Desert and Bonneville Speedway and the United States Air Force uses Rogers Dry Lake in the Mojave Desert as runways for aircraft and the Space Shuttle . Deserts have been defined and classified in
36686-440: The last 200 years, in Ethiopia . The domestication of cattle in Africa preceded agriculture and seems to have existed alongside hunter-gatherer cultures. It is speculated that by 6,000 BC, cattle were domesticated in North Africa. In the Sahara-Nile complex, people domesticated many animals, including the donkey and a small screw-horned goat that was common from Algeria to Nubia . Between 10,000 and 9,000 BC, pottery
36907-510: The life processes of plants. Potential evapotranspiration , then, is the amount of water that could evaporate in any given region. As an example, Tucson, Arizona receives about 300 mm (12 in) of rain per year, however about 2,500 mm (98 in) of water could evaporate over the course of a year. In other words, about eight times more water could evaporate from the region than actually falls as rain. Rates of evapotranspiration in cold regions such as Alaska are much lower because of
37128-412: The location of the desert on the continental landmass and the latitude. Daily variations in temperature can be as great as 22 °C (40 °F) or more, with heat loss by radiation at night being increased by the clear skies. Cold deserts, sometimes known as temperate deserts, occur at higher latitudes than hot deserts, and the aridity is caused by the dryness of the air. Some cold deserts are far from
37349-404: The measurement of precipitation in providing a scientific measurement-based definition of a desert. The water budget of an area can be calculated using the formula P − PE ± S , wherein P is precipitation, PE is potential evapotranspiration rates and S is the amount of surface storage of water. Evapotranspiration is the combination of water loss through atmospheric evaporation and through
37570-416: The migration of the Banu Hilal and the Banu Sulaym westward into the Maghreb in the eleventh century, which introduced Arab culture and language to the countryside. Historians mark their movement as a critical moment in the Arabization of North Africa. As Arab nomads spread, the territories of the local Berber tribes were moved and shrank. The Zenata were pushed to the west and the Kabyles were pushed to
37791-488: The most genetically diverse continent as a result of being the longest inhabited. In the 4th and 3rd millennia BC Ancient Egypt , Kerma , Punt , and the Tichitt Tradition emerged in North , East and West Africa , while from 4000 BC until 1000 AD the Bantu expansion was substantial in laying the foundations for societies and states in Central , East , and Southern Africa . Some African empires include Wagadu , Mali , Songhai , Sokoto , Ife , Benin , Asante ,
38012-399: The most lucrative trading locations in the Gulf of Tunis . Phoenician settlements subsequently grew into Ancient Carthage after gaining independence from Phoenicia in the 6th century BC, and they would build an extensive empire and a strict mercantile network, all secured by one of the largest and most powerful navies in the ancient Mediterranean . Carthage would meet its demise in
38233-430: The nearest available sources of moisture. Montane deserts are arid places with a very high altitude ; the most prominent example is found north of the Himalayas, in the Kunlun Mountains and the Tibetan Plateau . Many locations within this category have elevations exceeding 3,000 m (9,800 ft) and the thermal regime can be hemiboreal . These places owe their profound aridity (the average annual precipitation
38454-409: The night to allow CO 2 to enter, and close them during the day, or by using C4 carbon fixation . Many desert plants have reduced the size of their leaves or abandoned them altogether. Cacti are present in both North and South America with a post-Gondwana origin. The genus is desert specialist, and in most species, the leaves have been dispensed with and the chlorophyll displaced into the trunks,
38675-479: The north. The Berbers took refuge in the mountains whereas the plains were Arabized. This heavily shifted the demographics of the Maghreb. The trans-Saharan slave trade resulted in increased levels of sub-Saharan African ancestry in North Africa. The Haratin are commonly perceived as an endogamous group of former slaves or descendants of slaves. DNA studies of Iberomaurusian peoples at Taforalt , Morocco dating to around 15,000 years ago have found them to have
38896-412: The number of Christians in North Africa was estimated at 9 million, the majority of whom live in Egypt, with the remainder live in Maghreb countries. The inhabitants of the Spanish Canary Islands are of mixed Spanish and North African Berber ancestry, and the people of Malta are of primarily Southern Italian/Sicilian, as well as, to a lesser extent, North African and Middle Eastern ancestry and speak
39117-402: The ocean and others are separated by mountain ranges from the sea, and in both cases, there is insufficient moisture in the air to cause much precipitation. The largest of these deserts are found in Central Asia. Others occur on the eastern side of the Rocky Mountains , the eastern side of the southern Andes and in southern Australia. Polar deserts are a particular class of cold desert. The air
39338-439: The official religion, built mosques, and brought to Gao Muslim scholars, including al-Maghili (d.1504), the founder of an important tradition of Sudanic African Muslim scholarship. By the eleventh century, some Hausa states – such as Kano , Jigawa , Katsina , and Gobir – had developed into walled towns engaging in trade, servicing caravans , and the manufacture of goods. Until the fifteenth century, these small states were on
39559-479: The only or one of the few in North Africa who remained independent. The Kabyle people were incredibly resistible so much so that even during the Arab conquest of North Africa they still had control and possession over their mountains. The early Muslim conquests included North Africa by 640. By 700, most of North Africa had come under Muslim rule. Indigenous Berbers subsequently started to form their own polities in response in places such as Fez and Sijilmasa . In
39780-410: The opportunities afforded by north–south diversity in ecosystems. Various civilisations prospered in this period. From 4000 BC, the Tichitt culture in modern-day Mauritania and Mali was the oldest known complexly organised society in West Africa, with a four tiered hierarchical social structure. Other civilisations include the Kintampo culture from 2500 BC in modern-day Ghana ,
40001-426: The outer surfaces of rocks split off in flat flakes. This is believed to be caused by the stresses put on the rock by repeated thermal expansions and contractions which induces fracturing parallel to the original surface. Chemical weathering processes probably play a more important role in deserts than was previously thought. The necessary moisture may be present in the form of dew or mist. Ground water may be drawn to
40222-687: The overthrow of their governments, as well as civil war in Libya. Large protests also occurred in Algeria and Morocco to a lesser extent. Many hundreds died in the uprisings. Further information in the sections of Architecture of Africa : Further information in the sections of History of science and technology in Africa : Africa Africa is the world's second-largest and second-most populous continent after Asia . At about 30.3 million km (11.7 million square miles) including adjacent islands, it covers 20% of Earth 's land area and 6% of its total surface area. With nearly 1.4 billion people as of 2021, it accounts for about 18% of
40443-466: The pavement is formed. It may be that after the sand and dust is blown away by the wind the stones jiggle themselves into place; alternatively, stones previously below ground may in some way work themselves to the surface. Very little further erosion takes place after the formation of a pavement, and the ground becomes stable. Evaporation brings moisture to the surface by capillary action and calcium salts may be precipitated, binding particles together to form
40664-421: The periphery of the major Sudanic empires of the era, paying tribute to Songhai to the west and Kanem-Borno to the east. Slavery had long been practiced in Africa. Between the 15th and the 19th centuries, the Atlantic slave trade took an estimated 7–12 million slaves to the New World. In addition, more than 1 million Europeans were captured by Barbary pirates and sold as slaves in North Africa between
40885-474: The predecessor to the African Union. The nascent countries decided to keep their colonial borders, with traditional power structures used in governance to varying degrees. Afri was a Latin name used to refer to the inhabitants of what was then known as northern Africa , located west of the Nile river, and in its widest sense referring to all lands south of the Mediterranean , also known as Ancient Libya . This name seems to have originally referred to
41106-410: The rapid desertification of the Sahara around 3500 B.C. largely due to a tilt in the Earth's orbit. It was during this period that domesticated plants and animals were introduced in the region, spreading from the north and east to the southwest. There has been an inferred connection between areas of rapid drying and the introduction of livestock in which the natural (orbital) aridification was amplified by
41327-438: The rock surface experiences even greater temperature differentials. During the day the sky is usually clear and most of the sun 's radiation reaches the ground, but as soon as the sun sets, the desert cools quickly by radiating heat into space. In hot deserts, the temperature during daytime can exceed 45 °C (113 °F) in summer and plunge below freezing point at night during winter. Such large temperature variations have
41548-426: The same fate as Carthage and be conquered by the Romans who established Mauretania and Numidia as provinces of their empire, while Musulamii , led by Tacfarinas , and Garamantes were eventually defeated in war in the 1st century AD however weren't conquered. In the 5th century AD the Vandals conquered north Africa precipitating the fall of Rome . Swathes of indigenous peoples would regain self-governance in
41769-503: The sand stream can rise as the largest sand grains do not become airborne at all. They are transported by creep, being rolled along the desert floor or performing short jumps. During a sandstorm, the wind-blown sand particles become electrically charged . Such electric fields , which range in size up to 80 kV/m, can produce sparks and cause interference with telecommunications equipment. They are also unpleasant for humans and can cause headaches and nausea. The electric fields are caused by
41990-435: The shade or underground during the heat of the day. They tend to be efficient at conserving water, extracting most of their needs from their food and concentrating their urine . Some animals remain in a state of dormancy for long periods, ready to become active again during the rare rainfall. They then reproduce rapidly while conditions are favorable before returning to dormancy. People have struggled to live in deserts and
42211-441: The sheet consists of thin horizontal layers of coarse silt and very fine to medium grain sand, separated by layers of coarse sand and pea-gravel which are a single grain thick. These larger particles anchor the other particles in place and may also be packed together on the surface so as to form a miniature desert pavement. Small ripples form on the sand sheet when the wind exceeds 24 km/h (15 mph). They form perpendicular to
42432-412: The skin. The arctic weasel has a metabolic rate that is two or three times as high as would be expected for an animal of its size. Birds have avoided the problem of losing heat through their feet by not attempting to maintain them at the same temperature as the rest of their bodies, a form of adaptive insulation. The emperor penguin has dense plumage, a downy under layer, an air insulation layer next to
42653-466: The soil until sparked into growth by rainfall. With annuals , such plants grow with great rapidity and may flower and set seed within weeks, aiming to complete their development before the last vestige of water dries up. For perennial plants, reproduction is more likely to be successful if the seed germinates in a shaded position, but not so close to the parent plant as to be in competition with it. Some seed will not germinate until it has been blown about on
42874-464: The sparse vegetation cover and the activities of large mammals and people. Plants and animals in deserts are mostly adapted to extreme and prolonged water deficits , but their reproductive phenology often responds to short episodes of surplus. Competitive interactions are weak. Plants face severe challenges in arid environments. Problems they need to solve include how to obtain enough water, how to avoid being eaten and how to reproduce. Photosynthesis
43095-440: The spread of shrubs and open land due to grazing. Nevertheless, changes in northern Africa's ecology after 3500 BCE provided the backdrop for the formation of dynastic civilizations and the construction of monumental architecture such as the Pyramids of Giza . Archaeological evidence has attested that population settlements occurred in Nubia as early as the Late Pleistocene era and from the 5th millennium BC onwards, whereas there
43316-440: The surface by evaporation and the formation of salt crystals may dislodge rock particles as sand or disintegrate rocks by exfoliation. Shallow caves are sometimes formed at the base of cliffs by this means. As the desert mountains decay, large areas of shattered rock and rubble occur. The process continues and the end products are either dust or sand. Dust is formed from solidified clay or volcanic deposits whereas sand results from
43537-464: The surface of the ground. Dunes are sometimes solitary, but they are more often grouped together in dune fields. When these are extensive, they are known as sand seas or ergs . The shape of the dune depends on the characteristics of the prevailing wind. Barchan dunes are produced by strong winds blowing across a level surface and are crescent-shaped with the concave side away from the wind. When there are two directions from which winds regularly blow,
43758-405: The surrounding mountains. Former desert areas presently in non-arid environments, such as the Sandhills in Nebraska , are known as paleodeserts. In the Köppen climate classification system, deserts are classed as BWh (hot desert) or BWk (temperate desert). In the Thornthwaite climate classification system , deserts would be classified as arid megathermal climates. Polar deserts are
43979-487: The surrounding semi-arid lands for millennia. Nomads have moved their flocks and herds to wherever grazing is available, and oases have provided opportunities for a more settled way of life. The cultivation of semi-arid regions encourages erosion of soil and is one of the causes of increased desertification. Desert farming is possible with the aid of irrigation , and the Imperial Valley in California provides an example of how previously barren land can be made productive by
44200-405: The talented military leader Jugurtha . Kingdom of Mauretania remained independent until being annexed to the Roman Empire by Emperor Claudius in 42 AD. North Africa remained a part of the Roman Empire, producing notable citizens, including Augustine of Hippo , until incompetent leadership from Roman commanders in the early fifth century allowed the Germanic peoples , the Vandals , to cross
44421-399: The tallest type of dune. Rounded mounds of sand without a slip face are the rare dome dunes, found on the upwind edges of sand seas. In deserts where large amounts of limestone mountains surround a closed basin , such as at White Sands National Park in south-central New Mexico , occasional storm runoff transports dissolved limestone and gypsum into a low-lying pan within the basin where
44642-419: The territory disputed between Morocco and the partially recognized Sahrawi Arab Democratic Republic . The United Nations ' definition includes all these countries as well as the Sudan . The African Union defines the region similarly, only differing from the UN in excluding the Sudan. The Sahel , south of the Sahara Desert , can be considered as the southern boundary of North Africa. North Africa includes
44863-407: The trunk is folded like a concertina , allowing it to expand, and a large specimen can hold eight tons of water after a good downpour. Other xerophytic plants have developed similar strategies by a process known as convergent evolution . They limit water loss by reducing the size and number of stomata, by having waxy coatings and hairy or tiny leaves. Some are deciduous, shedding their leaves in
45084-425: The two continents by the geographer Ptolemy (85–165 CE), indicating Alexandria along the Prime Meridian and making the isthmus of Suez and the Red Sea the boundary between Asia and Africa. As Europeans came to understand the real extent of the continent, the idea of "Africa" expanded with their knowledge. Other etymological hypotheses have been postulated for the ancient name "Africa": In African societies,
45305-433: The unifying framework of Islam. Following the breakup of Mali, a local leader named Sonni Ali (1464–1492) founded the Songhai Empire in the region of middle Niger and the western Sudan and took control of the trans-Saharan trade. Sonni Ali seized Timbuktu in 1468 and Jenne in 1473, building his regime on trade revenues and the cooperation of Muslim merchants. His successor Askia Mohammad I (1493–1528) made Islam
45526-496: The use of the word desert can cause confusion. In English before the 20th century, desert was often used in the sense of "unpopulated area", without specific reference to aridity ; but today the word is most often used in its climate-science sense (an area of low precipitation). Phrases such as " desert island " and " Great American Desert ", or Shakespeare 's "deserts of Bohemia " ( The Winter's Tale ) in previous centuries did not necessarily imply sand or aridity; their focus
45747-416: The water evaporates, depositing the gypsum and forming crystals known as selenite . The crystals left behind by this process are eroded by the wind and deposited as vast white dune fields that resemble snow-covered landscapes. These types of dune are rare, and only form in closed arid basins that retain the highly soluble gypsum that would otherwise be washed into the sea. A large part of the surface area of
45968-476: The western edges of continental land masses in regions where cold currents approach the land or cold water upwellings rise from the ocean depths. The cool winds crossing this water pick up little moisture and the coastal regions have low temperatures and very low rainfall, the main precipitation being in the form of fog and dew. The range of temperatures on a daily and annual scale is relatively low, being 11 °C (20 °F) and 5 °C (9 °F) respectively in
46189-462: The wet phase ushered in an expanding rainforest and wooded savanna from Senegal to Cameroon . Between 9,000 and 5,000 BC, Niger–Congo speakers domesticated the oil palm and raffia palm . Black-eyed peas and voandzeia (African groundnuts), were domesticated, followed by okra and kola nuts . Since most of the plants grew in the forest, the Niger–Congo speakers invented polished stone axes for clearing forest. Around 4,000 BC,
46410-404: The wind blows, saltation and creep take place on the windward side of the dune and individual grains of sand move uphill. When they reach the crest, they cascade down the far side. The upwind slope typically has a gradient of 10° to 20° while the lee slope is around 32°, the angle at which loose dry sand will slip. As this wind-induced movement of sand grains takes place, the dune moves slowly across
46631-511: The wind direction and gradually move across the surface as the wind continues to blow. The distance between their crests corresponds to the average length of jumps made by particles during saltation. The ripples are ephemeral and a change in wind direction causes them to reorganise. Sand dunes are accumulations of windblown sand piled up in mounds or ridges. They form downwind of copious sources of dry, loose sand and occur when topographic and climatic conditions cause airborne particles to settle. As
46852-497: The world's human population . Africa's population is the youngest among all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Based on 2024 projections, Africa's population will reach 3.8 billion people by 2099. Africa is the least wealthy inhabited continent per capita and second-least wealthy by total wealth, ahead of Oceania . Scholars have attributed this to different factors including geography , climate , corruption , colonialism ,
47073-450: The world's deserts consists of flat, stone-covered plains dominated by wind erosion. In " eolian deflation ", the wind continually removes fine-grained material, which becomes wind-blown sand. This exposes coarser-grained material, mainly pebbles with some larger stones or cobbles , leaving a desert pavement , an area of land overlaid by closely packed smooth stones forming a tessellated mosaic. Different theories exist as to how exactly
47294-414: The world, around 20% of desert is sand, varying from only 2% in North America to 30% in Australia and over 45% in Central Asia. Where sand does occur, it is usually in large quantities in the form of sand sheets or extensive areas of dunes . A sand sheet is a near-level, firm expanse of partially consolidated particles in a layer that varies from a few centimeters to a few meters thick. The structure of
47515-418: Was rapidly conquered and colonised by European nations , save for Ethiopia and Liberia . European rule had significant impacts on Africa's societies , and colonies were maintained for the purpose of economic exploitation and extraction of natural resources. Most present states emerged from a process of decolonisation following World War II , and established the Organisation of African Unity in 1963,
47736-401: Was established around the ninth century, making it one of the oldest kingdoms in present-day Nigeri. The Nri kingdom is famous for its elaborate bronzes , found at the town of Igbo-Ukwu . The Kingdom of Ife , historically the first of these Yoruba city-states or kingdoms, established government under a priestly oba ('king' or 'ruler' in the Yoruba language ), called the Ooni of Ife . Ife
47957-450: Was fully established by roughly 500 BC in many areas of East and West Africa, although other regions did not begin ironworking until the early centuries AD. Copper objects from Egypt , North Africa, Nubia, and Ethiopia dating from around 500 BC have been excavated in West Africa, suggesting that Trans-Saharan trade networks had been established by this date. From 3500 BC, nomes (ruled by nomarchs ) coalesced to form
48178-474: Was independently invented in the region of Mali in the savannah of West Africa. In the steppes and savannahs of the Sahara and Sahel in Northern West Africa, people possibly ancestral to modern Nilo-Saharan and Mandé cultures started to collect wild millet , around 8,000 to 6,000 BC. Later, gourds , watermelons , castor beans , and cotton were also collected. Sorghum was first domesticated in Eastern Sudan around 4,000 BC, in one of
48399-444: Was noted as a major religious and cultural centre in West Africa and for its unique naturalistic tradition of bronze sculpture. The Ife model of government was adapted by the Oyo Empire , whose obas, called the Alaafins of Oyo , controlled many other Yoruba and non-Yoruba city-states and kingdoms including the Fon Kingdom of Dahomey . The Almoravids were a Berber dynasty from the Sahara that spread over northwestern Africa and
48620-514: Was one of the first African countries to gain independence, the state remained under the control of the country's white minority, initially through qualified voting rights and from 1956 by a system of racial segregation known as apartheid , until 1994. Today, Africa contains 54 sovereign countries. Since independence, African states have frequently been hampered by instability, corruption, violence, and authoritarianism. The vast majority of African states are republics that operate under some form of
48841-459: Was the sparse population. Deserts occupy about one third of Earth's land surface. Bottomlands may be salt -covered flats. Eolian processes are major factors in shaping desert landscapes. Polar deserts (also seen as "cold deserts") have similar features, except the main form of precipitation is snow rather than rain. Antarctica is the world's largest cold desert (composed of about 98% thick continental ice sheet and 2% barren rock). Some of
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