Africa

Africa, the second largest of the earth's seven continents, covering about 30,330,000 sq km (about 11,699,000 sq mi), including its adjacent islands. It comprises about 22 percent of the world's total land area. In 1990 about 12 percent of the world's population, an estimated 642 million people, lived in Africa, making it the world's second-most populous continent after Asia. g7t6tt

Vegetation African vegetation can be classified according to rainfall and climate zones. The tropical rain forest zone, where the average annual rain is more than 1270 mm (more than 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 890 to 1400 mm (35 to 55 in), covers vast areas with a layer of grass and fire-resistant shrubs, above which are found deciduous and leguminous fire-resistant trees. A savanna grassland zone, with annual rainfall of about 500 to 890 mm (about 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 about 300 to 510 mm (about 12 to 20 in), has a thinner grass covering and a scattering of succulent or 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 (less than 5 in), has sparse vegetation or none at all.

Animal Life 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 are found mainly in western Africa; boa constrictors are indigenous only to Madagascar. Freshwater fish abound, with more than 2000 species known. The continent has a variety of destructive insects, notably mosquitoes, driver ants, termites, locusts, and tsetse flies. The last named transmit sleeping sickness to humans and animals (in animals, the disease is called nagana).

Mineral Resources Africa is very 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.

Agriculture Despite the expansion of commerce and industry and the importance of these activities to the economy, most Africans remain farmers and herders. In northern and northwestern Africa, wheat, oats, corn, and barley are the important grain crops. Dates, olives, and citrus fruit are the main tree crops; a variety of vegetables are grown. Goats and sheep are the most significant livestock raised. In the Sahara region, nomadic herders raise camels, and a few farmers situated in oases grow dates and grains. South of the Sahara, shifting agriculture--a method in which small areas were burned, cleared, and planted and then allowed to revert to bush--has given way in most areas to settled farming. Grain is the main crop outside the rain forests; rice, yams, cassava, okra, plantains, and bananas are raised for food. Cattle cannot be raised in tsetse fly-infested areas, which cover more than one-third of the continent. Outside tsetse fly areas and dense forests, cattle are raised in large numbers, primarily for beef. Dairy farming is limited, located mainly around urban centers in eastern and southern Africa.