Come see where Jungle Joan can take you!
I. Introduction
Africa, second largest of the Earth's seven continents, covering 30,244,000 sq km (11,677,000 sq mi), including its adjacent islands. It comprises 23 percent of the world's total land area. In 2000 some 13 percent of the world's population, an estimated 797 million people, lived in Africa, making it the world's second most populous continent, after Asia. Straddling the equator, Africa stretches 8,000 km (5,000 mi) from its northernmost point, Ra's al Abyad in Tunisia, to its southernmost tip, Cape Agulhas in South Africa. Advertisement The maximum width of the continent, measured from the tip of Cap Vert in Senegal, in the west, to Raas Xaafuun (Ras Hafun) in Somalia, in the east, is 7,560 km (4,700 mi). The highest point on the continent is the perpetually snowcapped Kilimanjaro (5,895 m/19,341 ft) in Tanzania, and the lowest is Lake 'Asal (153 m/502 ft below sea level) in Djibouti. Africa has a regular coastline characterized by few indentations. Its total length is only 30,500 km (19,000 mi); the length of the African coastline in proportion to its area is less than that of any other continent. The African continent is characterized by plateau land, with a few distinct mountain ranges and a narrow coastal plain. The continent is commonly divided along the lines of the Sahara, the world's largest desert, which cuts a huge swath through the northern half of the continent. The countries north of the Sahara make up the region of North Africa and include large and populous nations such as Egypt and Algeria. In general, these nations are more developed than are those countries to the south, due in part to the location here of the Nile, the world's longest river. Most of Africa's population lives in the region south of the Sahara, known as sub-Saharan Africa. In this area, eastern Africa includes countries such as Ethiopia, Somalia, and Uganda. Among the nations of Central and West Africa are Angola, Cameroon, Ghana, Nigeria, and Democratic Republic of the Congo (DRC, formerly Zaire). Southern Africa is dominated by the country of South Africa and also includes Botswana, Lesotho, and Namibia. Africa also encompasses many islands, the largest of which is Madagascar, located off the southeastern coast of the continent. As a whole, Africa encompasses about 50 nations, ranging from Nigeria, a country of an estimated 130 million people in 2002, to small island republics such as Comoros, with a population of 614,000. It is widely believed that human life began in Africa sometime between 5 million and 8 million years ago. The continent was home to one of the world's first great civilizations, the Egyptian empire that was unified more than 5,000 years ago. However, the last 500 years in Africa have been dominated by foreign colonization and political and ethnic struggles that have hampered industrial and social development. The continent remains mostly rural, despite urban growth in the second half of the 20th century. Africa's economy is the least developed of any continent after Antarctica. Agriculture is still the main economic activity. Devastating famine and outbreaks of disease are common, exacerbated by poor roads and the lack of medical personnel. Africa is rich in natural resources, and part of its economic base is the export of this wealth. Many African nations depend on foreign investment and aid, or on the trade of one or two resources that are subject to market fluctuations. Culturally, Africans are perhaps the most diverse of any continent's inhabitants, with thousands of ethnic groups and more than 1,000 different languages. With ethnicities that often cross national boundaries and continual political upheavals, African national identity is not as strong as racial ties or local kin group affiliations. Black Africans make up the majority of the continent's population, but there are also large populations of Arabs, Asians, Europeans, and Berbers. Communities range from rural cultures in which the foods, religions, dress, tribal roles, and daily life have remained unchanged for hundreds of years, to modern city environments, which feature skyscrapers, Western styles of dress and commerce, and a diverse mix of cultural influences. Music, art, and literature are culturally important and distinctive throughout Africa and have had considerable impact on other societies around the world. For example, African rhythms have influenced Western popular music styles such as jazz, blues, and rock (see Jazz: Origins).
Since the 1950s, most African nations have gained independence from their former colonial powers. Independence has brought many changes to these nations, including the introduction of multiparty democratic governments and greater efforts to educate their populations. With the world's highest population growth rate, Africa continues to face challenges in its industrial and social development.
II. The Natural EnvironmentPrint section
Except for the northern coast and the Atlas Mountains in the northwest, the terrain of Africa consists of a vast, rolling plateau, marked by a number of large, saucer-shaped basins.
A. Geological HistoryPrint section
A vast continental shield of Precambrian rocks, related in age and history to South America's Brazilian Highlands, extends south of the Atlas Mountains to the Cape of Good Hope. On the east, the shield encompasses two landmasses—the Arabian Peninsula and Madagascar—that were split off from Africa during the Tertiary period (see Plate Tectonics). Among these ancient rocks some of the earliest traces of life on Earth—fossil microorganisms 3.2 billion years old—have been found. Geologically, the Atlas Mountains of North Africa are part of Europe, having been raised by the same forces that created the Alpine mountain ranges of southern and central Europe. The tectonic forces that split Africa and South America apart during the breakup of the supercontinent Gondwanaland, more than 150 million years ago (see Jurassic Period), have continued into more recent times, creating East Africa's Great Rift Valley during the Tertiary Period and triggering eruptions there of the volcanic Mount Kenya and Kilimanjaro.
B. Natural RegionsPrint section
Africa may be divided into three major regions: the Northern Plateau, the Central and Southern Plateau, and the Eastern Highlands. In general, elevations increase across the continent from northwest to southeast, the average being 600 m (1,900 ft). Low-lying coastal strips, with the exception of the Mediterranean coast and the Guinea coast, are generally narrow and rise sharply to the plateau.
The outstanding feature of the Northern Plateau is the Sahara, which occupies more than one-quarter of Africa. At the fringes of the Northern Plateau are several mountainous regions. To the northwest lie the Atlas Mountains, a chain of rugged peaks linked by high plateaus, which extend from Morocco into Tunisia. Other prominent uplands are the Fouta Djallon (Futa Jallon), on the southwest, and the Adamawa Plateau and the Cameroon mountain range, on the south. The Lake Chad Basin is situated in the approximate center of the Northern Plateau.
The Central and Southern Plateau is considerably higher than the Northern Plateau and includes west central and southern Africa. It contains several major depressions, notably the Congo River Basin and the Kalahari Desert. Other features south of this plateau, which averages more than 900 m (3,000 ft) in elevation, are the Drakensberg Mountains, running some 1,100 km (700 mi) along the southeastern coast, and in the extreme south, the High Veld, an arid plateau covering much of South Africa.
The Eastern Highlands, the highest portion of the continent, lie near the eastern coast, extending from the Red Sea south to the Zambezi River. The region has an average elevation of more than 2,000 m (5,000 ft), although in the Ethiopian Plateau it rises in stages to 3,000 m (10,000 ft). Ras Dashen (4,620 m/15,157 ft) in northern Ethiopia is the highest peak of the plateau. South of the Ethiopian Plateau are a number of towering volcanic peaks, including Kilimanjaro, Mount Kenya, and Mount Elgon. A distinctive topographical feature of the Eastern Highlands is the Great Rift Valley, a vast geologic fault system that traverses the region in a northern to southern direction. West of the Great Rift Valley is the Ruwenzori Range, which attains a maximum elevation of 5,109 m (16,762 ft). The topography of the island of Madagascar features a rugged central highland extending in a generally north-south direction near the eastern coast.
Because most of the African continent has not been covered by the seas for millions of years, soils have developed locally, chiefly by weathering, and a few areas have benefited from soils transported by rivers or ocean currents. African soils, for the most part, have irregular drainage and no definite water tables. Most are relatively infertile due to mineral leaching from heavy rainfall and high temperatures. Desert soils (aridisols and entisols), which have little organic content, also cover large areas. The most fertile soils include the mollisols, also known as chernozems and black soils, of eastern Africa and the alfisols, or podzolic soils, of portions of western and southern Africa.
C. DrainagePrint section
Six major drainage networks exist in Africa. With the exception of the Chad Basin, all have outlets to the sea and all are cut by steep cataracts or rapids that impede navigation. The Nile River, with a length of 6,695 km (4,160 mi), drains northeastern Africa and is the longest river in the world. Formed from the Blue Nile, which originates at Lake T'ana in Ethiopia, and the White Nile, which originates at Lake Victoria in eastern Africa, the Nile flows west and north before emptying into the Mediterranean Sea. The Congo River, some 4,374 km (2,718 mi) long, drains much of central Africa. It originates in Zambia and flows north, west, and south to empty into the Atlantic Ocean. The third longest African river, the Niger River in western Africa, is 4,180 km (2,600 mi) long; its upper portions are navigable only during rainy seasons. The Niger rises in the highlands of the Fouta Djallon and flows north and east before turning south to empty into the Gulf of Guinea. The Zambezi River, 2,650 km (1,650 mi) long, originates in Zambia in southeastern Africa and flows south and east to empty into the Indian Ocean. The Zambezi is cut by various rapids, the most spectacular of which is Victoria Falls. Draining southern Africa is the Orange River, which, with its tributary, the Vaal River, has a length of 2,100 km (1,300 mi). It rises in the Drakensberg Mountains and flows west to the Atlantic. Lake Chad, a shallow freshwater lake with an average depth of only 1.2 m (4 ft), drains nearby rivers and constitutes one of the largest inland drainage areas on the continent.
The deep rift valleys of the Eastern Highlands hold a great series of lakes. This equatorial lake system includes Lakes Turkana, Albert, Tanganyika, and Nyasa (Malawi). Lake Victoria, the largest lake in Africa and the third largest in the world, is not part of this system, however; it occupies a shallow depression in the Eastern Highlands.
Achieving effective control of the water supply is a major problem in Africa. Vast areas suffer low rainfall; still larger areas receive only irregular rainfall and must store water as insurance against delayed or deficient rains. Other areas have an overabundance of water; great swamps exist, and large areas suffer from periodic flooding. In recent years, numerous dams and reservoirs have been constructed to channel water for irrigation and for hydroelectric power. The continent's numerous rivers and the abrupt descents of the waterways have led to estimates that Africa has approximately 40 percent of the total world hydroelectric potential.
D. ClimatePrint section
The climate of Africa, more than that of any other continent, is generally uniform. This results from the position of the continent in the Tropical Zone, the impact of cool ocean currents, and the absence of mountain chains serving as climatic barriers.
Seven main African climatic zones can be distinguished. The central portion of the continent and the eastern coast of Madagascar have a tropical rain forest climate. Here the average annual temperature is 27°C (80°F), and the average annual rainfall is 1,800 mm (70 in). The climate of the Guinea coast resembles the equatorial climate, except that rainfall is concentrated in one season; no months, however, are rainless.
To the north and south the rain forest climate is supplanted by a tropical savanna climate zone that encompasses about one-fifth of Africa. Here the climate is characterized by a wet season during the summer months and a dry season during the winter months. Total annual rainfall varies from 500 mm (20 in) to more than 1,500 mm (60 in). Away from the equator, to the north and south, the savanna climate zone grades into the drier steppe climate zone. Average annual rainfall varies between 250 and 500 mm (10 and 20 in) and is concentrated in one season.
Africa has a proportionately larger area in arid, or desert, climate zones than any continent except Australia. Each of these areas—the Sahara in the north, the Horn in the east, and the Kalahari and Namib deserts in the southwest—receives less than 250 mm (10 in) of rainfall annually. In the Sahara, daily and seasonal extremes of temperatures are great. The average July temperature is higher than 32°C (90°F); during the cold season the nighttime temperature often drops below freezing.
Mediterranean climate zones are found in the extreme northwest of Africa and in the extreme southwest. These regions are characterized by mild, wet winters and warm, dry summers. In the highlands of eastern Africa, particularly in Kenya and Uganda, rainfall is well distributed throughout the year, and temperatures are equable. The climate on the high plateau of southern Africa is temperate.
E. VegetationPrint section
African vegetation can be classified according to rainfall and climate zones. The tropical rain forest zone, where the average annual rain is more than 1,300 mm (50 in), has a dense surface covering of shrubs, ferns, and mosses, above which tower evergreens, oil palms, and numerous species of tropical hardwood trees. A mountain forest zone, with average annual rainfall only slightly less than in the tropical rain forests, is found in the high mountains of Cameroon, Angola, eastern Africa, and parts of Ethiopia. Here a ground covering of shrubs gives way to oil palms, hardwood trees, and primitive conifers. A savanna woodland zone, with annual rainfall of 900 to 1,400 mm (35 to 55 in), covers vast areas with a layer of grass and fire-resistant shrubs, above which are deciduous and leguminous fire-resistant trees. A savanna grassland zone, with annual rainfall of 500 to 900 mm (20 to 35 in), is covered by low grasses and shrubs and scattered, small deciduous trees. The thornbush zone, a steppe vegetation, with an annual rainfall of 300 to 500 mm (12 to 20 in), has a thinner grass covering and a scattering of succulent and semisucculent trees. The subdesert scrub zone, with an annual rainfall of 130 to 300 mm (5 to 12 in), has a covering of grasses and scattered low shrubs. The zone of desert vegetation, found in areas with an annual rainfall of less than 130 mm (5 in), has sparse vegetation or none at all.
F. Animal LifePrint section
Africa has two distinct zones of animal life: the North and Northwestern zone, including the Sahara; and the Ethiopian zone, including all of sub-Saharan Africa. The North and Northwestern zone is characterized by animals similar to those of Eurasia. Sheep, goats, horses, and camels are common. Barbary sheep, African red deer, and two types of ibex are native to the northern African coast. Desert foxes are found in the Sahara along with hares, gazelles, and the jerboa, a small leaping rodent. The Ethiopian zone is famous for its great variety of distinctive animals and birds. Woodland and grassland areas are inhabited by numerous species of antelope and deer, zebra, giraffe, buffalo, the African elephant, rhinoceros, and the baboon and various monkeys. Carnivores, or meat-eating animals, include the lion, leopard, cheetah, hyena, jackal, and mongoose. The gorilla, the largest ape in the world, inhabits the rain forests of equatorial Africa, as do monkeys, flying squirrels, bats, and lemurs.
Most bird life belongs to Eurasian groups. The guinea fowl is a leading game bird. Water birds, notably pelicans, goliath herons, flamingos, storks, and egrets, congregate in great numbers. The ibis is common in the Nile region, and the ostrich is found in eastern and southern Africa. Reptiles are mainly of Eurasian origin and include lizards, crocodiles, and tortoises. A variety of venomous snakes, including the mamba, are encountered throughout the Ethiopian zone. Among the constricting snakes, pythons live mainly in western Africa; boa constrictors are indigenous only to Madagascar. Freshwater fish abound, with more than 2,000 species known. The continent has a variety of destructive insects, notably mosquitoes, driver ants, termites, locusts, and tsetse flies. Tsetse flies transmit sleeping sickness to humans and animals (in animals, the disease is called nagana).
G. Mineral ResourcesPrint section
Africa is rich in mineral
resources, possessing most of the known mineral types of the world, many of
which are found in significant quantities, although the geographic distribution
is uneven. Fossil fuels are abundant, including major deposits of coal, petroleum,
and natural gas. Africa has some of the world's largest reserves of gold, diamonds,
copper, bauxite, manganese, nickel, platinum, cobalt, radium, germanium, lithium,
titanium, and phosphates. Other important mineral resources include iron ore,
chromium, tin, zinc, lead, thorium, zirconium, vanadium, antimony, and beryllium.
Also found in exploitable quantities are clays, mica, sulfur, salt, natron,
graphite, limestone, and gypsum.