North America

North America

North America, third largest continent (1990 est. pop. 365,000,000), c.9,400,000 sq mi (24,346,000 sq km), the northern of the two continents of the Western Hemisphere. North America includes all of the mainland and related offshore islands lying N of the Isthmus of Panama (which connects it with South America). The term "Anglo-America" is frequently used in reference to Canada and the United States combined, while the term "Middle America" is used to describe the region including Mexico, the republics of Central America, and the Caribbean.

Geology and Geography

The continent is bounded on the north by the Arctic Ocean, on the west by the Pacific Ocean and the Bering Sea, and on the east by the Atlantic Ocean and the Gulf of Mexico. Its coastline is long and irregular. With the exception of the Gulf of Mexico, Hudson Bay is by far the largest body of water indenting the continent; others include the Gulf of St. Lawrence and the Gulf of California (Sea of Cortès). There are numerous islands off the continent's coasts; Greenland and the Arctic Archipelago, the Greater and Lesser Antilles, the Alexander Archipelago, and the Aleutian Islands are the principal groups. Mt. McKinley (Denali; 20,320 ft/6,194 m), Alaska, is the highest point on the continent; the lowest point (282 ft/86 m below sea level) is in Death Valley, Calif.

The Missouri-Mississippi river system (c.3,740 mi/6,020 km long) is the longest of North America. Together with the Ohio River and numerous other tributaries, it drains most of S central North America and forms the world's greatest inland waterway system. Other major rivers include the Colorado, Columbia, Delaware, Mackenzie, Nelson, Rio Grande, St. Lawrence, Susquehanna, and Yukon. Lake Superior (31,820 sq mi/82,414 sq km), the westernmost of the Great Lakes, is the continent's largest lake. The Saint Lawrence Seaway, which utilizes the St. Lawrence River and the Great Lakes, enables oceangoing vessels to penetrate into the heart of North America.

Physiographically, the Anglo-American section of the continent may be divided into five major regions: the Canadian Shield, a geologically stable area of ancient rock that occupies most of the northeastern quadrant, including Greenland; the Appalachian Mountains, a geologically old and eroded system that extends from the Gaspé Peninsula to Alabama; the Atlantic-Gulf Coastal Plain, a belt of lowlands widening to the south that extends from S New England to Mexico; the Interior Lowlands, which extend down the middle of the continent from the Mackenzie valley to the Gulf Coastal Plain and includes the Great Plains on the west and the agriculturally productive Interior Plains on the east; and the North American Cordillera, a complex belt of geologically young mountains and associated plateaus and basins, which extend from Alaska into Mexico and include two orogenic belts—the Pacific Margin on the west and the Rocky Mountains on the east—separated by a system of intermontane plateaus and basins. The Coastal Plain and the main belts of the North American Cordillera continue south into Mexico (where the Mexican Plateau, bordered by the Sierra Madre Oriental and the Sierra Madre Occidental, is considered a continuation of the intermontane system) to join the Transverse Volcanic Range, a zone of high and active volcanic peaks S of Mexico City.

During the Ice Age of the late Cenozoic era, a continental ice sheet, centered west of Hudson Bay (the floor of which is slowly rebounding after being depressed by the great weight of the ice), covered most of N North America; glaciers descended the slopes of the Rocky Mts. and those of the Pacific Margin. Extensive glacial lakes, such as Bonneville (see under Bonneville Salt Flats), Lahontan, Agassiz, and Algonquin, were formed by glacial meltwater; their remnants are still visible in the Great Basin and along the edge of the Canadian Shield in the form of the Great Salt Lake, the Great Lakes, and the large lakes of W central Canada.

Climate

North America, extending to within 10° of latitude of both the equator and the North Pole, embraces every climatic zone, from tropical rain forest and savanna on the lowlands of Central America to areas of permanent ice cap in central Greenland. Subarctic and tundra climates prevail in N Canada and N Alaska, and desert and semiarid conditions are found in interior regions cut off by high mountains from rain-bearing westerly winds. However, a high proportion of the continent has temperate climates very favorable to settlement and agriculture.

People

The first human inhabitants of North America are believed to be of Asian origin; they crossed over to Alaska from NE Asia roughly 20,000 years ago, and then moved southward through the Mackenzie River valley. European discovery and settlement of North America dates from the 10th cent., when Norsemen settled (986) in Greenland. Although evidence is fragmentary, they probably reached E Canada c.1000 at the latest. Of greater impact on the subsequent history of the continent were Christopher Columbus's exploration of the Bahamas in 1492 and later landings in the West Indies and Central America, and John Cabot's explorations of E Canada (1497), which established English claims to the continent. Spanish and French expeditions also explored much of North America.

Although the population of Canada and the United States is still largely of European origin, it is growing increasingly diverse with substantial immigration from Asia, Latin America, and Africa; it is also highly urbanized (about 74% live in urban areas); much of the population is centered in large conurbations and coalescing urban belts along the southern margin of Canada and in the northeastern quadrant of the United States around the Great Lakes and along the Atlantic coast. Mexico's population, about 60% mestizo (of European and Native American descent), is increasingly urbanized (about 72%). People of European descent are a minority in most Central American and Caribbean countries, and the population outside the major cities is largely rural. The largest urban agglomerations on the continent are Mexico City, New York City, Los Angeles, and Chicago.

Resources and Economy

North America's extensive agricultural lands (especially in Canada and the United States) are a result of the interrelationship of favorable climatic conditions, fertile soils, and technology. Irrigation has turned certain arid and semiarid regions into productive oases. North America produces most of the world's corn, meat, cotton, soybeans, tobacco, and wheat, along with a variety of other food and industrial raw material crops. Mineral resources are also abundant; the large variety includes coal, iron ore, bauxite, copper, natural gas, petroleum, mercury, nickel, potash, and silver. The manufacturing that provided a high standard of living for the people of Canada and the United States has significantly declined, and formerly abundant factory jobs are increasingly replaced by those in the service sector. Much of this manufacturing has moved to Mexico (especially in the border zone adjoining the United States), which offers a large and inexpensive labor force.

Bibliography

See T. H. Clark and C. W. Stearn, The Geological Evolution of North America (1968); W. P. Cumming et al., The Discovery of North America (1972); R. C. West et al., Middle America: Its Lands and Peoples (3d ed. 1989); T. L. McKnight, Regional Geography of the United States and Canada (1992); S. Birdsall, Regional Landscapes of the United States and Canada (4th rev. ed. 1992); T. Flannery, The Eternal Frontier: An Ecological History of North America and Its Peoples (2001); A. Taylor, American Colonies (2001).

Continent, Western Hemisphere. The third-largest continent on earth, it lies mostly between the Arctic Circle and the Tropic of Cancer. It is almost completely surrounded by bodies of water, including the Pacific Ocean, the Bering Strait, the Arctic Ocean, the Atlantic Ocean, and the Caribbean Sea and Gulf of Mexico. Area: 9,361,791 sq mi (24,247,039 sq km). Population (2001 est.): 454,225,000. Shaped like an inverted triangle, North America was apparently the first continent to achieve its current approximate size and shape. Its geologic structure is built around a stable platform of Precambrian rock called the Canadian Shield. To the southeast are the Appalachian Mountains and to the west are the younger and much taller Cordilleras. These mountains extend the length of the continent and occupy about one-third of the total land area. The Rocky Mountains constitute the eastern Cordillera. The highest point is Mount McKinley. The Mississippi River basin, including its major tributaries, the Missouri and Ohio, occupies more than one-eighth of the continent's total area. Generally temperate climatic conditions prevail. Arable land accounts for about one-eighth of the land area and forests for about one-third. English, the primary language of the U.S., predominates, followed by Spanish; French is spoken in parts of Canada. Most of the continent's population of European descent is found in the U.S. and Canada. Intermarriage between whites and Indians was common in Mexico, and mestizos constitute about three-fifths of the Mexican population. North America has a mixture of developed, partly developed, and developing economies, adequate reserves of most metallic resources, and the world's largest reserves of cadmium, copper, lead, molybdenum, silver, and zinc. It is the world's leading food producer, largely because of mechanized and scientific farming in the U.S. and Canada. Among the continent's democratically governed states are Canada, Mexico, Costa Rica, and the U.S. The nations of North America have sought hemispheric unity as members of the Organization of American States, which also includes South American countries. They also sought stronger economic ties, and in 1992 Canada, the U.S., and Mexico signed the North American Free Trade Agreement (NAFTA), which called for the elimination of most tariffs and other trade barriers between the three countries. The first inhabitants were American Indians, who migrated from Asia about 20,000 years ago. The greatest pre-Columbian civilizations were in Mesoamerica (see Mesoamerican civilization) and included the Olmec, Maya, Toltec, and Aztec, who were conquered by the Spanish. The continent long remained sparsely settled and undeveloped. Beginning in the 17th century it underwent a profound transformation with the coming of Europeans and the Africans they introduced as slaves. The style of life became Latin American south of the Rio Grande and Anglo-American to the north, with enclaves of French culture in Canada and Louisiana. Slavery, practiced in the 16th–19th centuries, added a significant minority culture of African origin, especially in the U.S. and the Caribbean (see West Indies). The huge industrial economy of the U.S., its abundant resources, and its military strength give the continent considerable global influence.

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(1867) Act of the British Parliament by which three British colonies—Nova Scotia, New Brunswick, and Canada—were united as “one Dominion under the name of Canada.” The act also divided the province of Canada into the provinces of Quebec and Ontario. It served as Canada's “constitution” until 1982, when it became the basis of the Canada Act.

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