North America referat

North America, 3rd largest of the seven continents, including Canada (the 2nd largest country in area in the world), the United States (4th largest), and Mexico (13th largest). The continent also includes Greenland, the largest island, as well as the small French overseas department of Saint-Pierre and Miquelon and the British dependency of Bermuda (both made up of small islands in the Atlantic Ocean). With more than 360 million inhabitants (1989 estimate), North America is the 4th most populous continent; the United States ranks 4th and Mexico 11th in population among the world's countries. Canada and the United States have technologically developed early modern economies, and Mexico, although less technologically developed than its neighbors, contains some of the world's greatest deposits of petroleum and natural gas.

Vegetation The natural vegetation of North America has been significantly modified by human activity, but its general nature is still apparent over much of the continent. The most notable forest is the taiga, or boreal forest, an enormous expanse of mostly coniferous trees (especially spruce, fir, hemlock, and larch) that covers most of southern and central Canada and extends into Alaska. In the eastern United States a mixed forest, dominated by deciduous trees in the north and by various species of yellow pine in the southeast, has mostly been cleared or cut over, but a considerable area has regrown since the 1940s. In the western portion of the continent, forests are primarily associated with mountain ranges, and coniferous trees are dominant. In California, the redwood and giant sequoia grow to enormous size. A great mixture of species characterizes the tropical forests of Mexico.

The vegetation cover in the drier parts of the continent is made up mainly of grassland and shrubland. The central plains and prairies of the United States and southern Canada were originally grass covered, but much of the natural flora has been replaced by commercial crops. The dry lands of the western United States and northern Mexico are sparsely covered with a variety of shrubs and many kinds of cactus. Beyond the tree line in the far north is a region of tundra, containing a mixture of low-growing sedges, grasses, mosses, and lichens.

Animal Life The native wildlife of North America was once numerous and diverse, but the spread of human settlement has resulted in contracting habitats and diminishing numbers. In general, the fauna of North America is similar to that of the northern areas of Europe and Asia. Notable large mammals include several kinds of bear, the largest being the grizzly; bighorn sheep; bison, now only in protected herds; caribou; moose, called elk in Europe; musk-ox; and wapiti. Large carnivores include the puma and, in southernmost regions, the jaguar; the wolf and its smaller relative, the coyote; and, in the far north, the polar bear. One species of marsupial, the common opossum, is indigenous to the continent. A few of the many reptiles are poisonous, including the coral snake, pit vipers such as the rattlesnake and copperhead, and the Gila monster and beaded lizard of the southwestern United States and Mexico, the only poisonous lizards in the world. A great variety of finfish and shellfish live in the marine waters off North America, and many kinds of fish are found in its freshwater rivers and lakes.

Mineral Resources North America has large deposits of many important minerals. Petroleum and natural gas are found in great quantity in northern Alaska, western Canada, the southern and western conterminous United States, and eastern Mexico; huge beds of coal are in eastern and western Canada and the United States; and great iron-ore deposits are in eastern Canada, the northern United States, and central Mexico. Canada also has major deposits of copper, nickel, uranium, zinc, asbestos, and potash; the United States contains great amounts of copper, molybdenum, nickel, phosphate rock, and uranium; and Mexico has large reserves of barite, copper, fluorite, lead, zinc, manganese, and sulfur. All three countries have significant deposits of gold and silver.

Agriculture Farming is relatively more important in Mexico than in the other North American countries and provides employment for about 25 percent of the labor force (compared with some 3 percent in the United States and 5 percent in Canada). Subsistence farming is still important throughout Mexico, especially in the south; commercial agriculture is well developed in many areas, however, particularly in the central plateau and in the north. The leading commodities are corn, wheat, and beans, which are raised mostly for domestic consumption, and cotton, cattle, coffee, and sugar, which are produced largely for export.

Agriculture in the United States and Canada is dominated by highly mechanized farms, which produce immense quantities of crops, livestock, and livestock products. The Great Plains of the central United States and the Canadian Prairie provinces (Alberta, Manitoba, Saskatchewan) are major world producers of grain (particularly wheat, but also barley, oats, rye, and grain sorghum), oilseeds, and livestock (dairy and beef cattle and sheep). Perhaps the world's finest large farming area is the Corn Belt, that part of the U.S. Middle West from western Ohio to eastern Nebraska, which is the world's largest producer of corn, as well as a major supplier of other grains, soybeans, cattle, and hogs. Farming in California yields a huge amount of high-value irrigated crops, notably fruits and vegetables. Florida and Texas also are great producers of fruits and vegetables, and potatoes are grown in vast quantities in Idaho, Washington State, Oregon, Maine, North Dakota, and southeastern Canada. Other outstanding agricultural products include cotton, broiler chickens, dairy products, and sugarcane.

Forestry and Fishing Forestry is an important sector of the Canadian economy, especially in British Columbia, Ontario, and Québec Province. Notable forest-products industries also flourish in the western United States (particularly in Washington, Oregon, and California) and in the southeastern United States.

Fishing is the leading economic activity in Greenland but is a relatively unimportant sector in Canada, the United States, and Mexico, even though the catch is large and some coastal areas are dependent on revenues from sales of finfish and shellfish. Besides the waters near Greenland, major fishing grounds are off the northern Pacific coast, off the northern Atlantic coast, and off the southern Atlantic and Gulf of Mexico coasts. In addition, large tuna fleets are based in southern California and western Mexico.

Mining The extraction of minerals is an increasingly important economic activity in the United States, Canada, and Mexico. The United States has been one of the world's leading petroleum producers for many years, Canada has been a major producer since the late 1940s, and Mexico became a world leader in oil production in the late 1970s. The United States ranks second among world natural-gas producers and is also a leader in mining coal, produced particularly in the vast Appalachian fields. Iron ore has long been a major product of both the United States and Canada, primarily from deposits around the western end of Lake Superior. More recently, much iron ore has been produced in the Québec Province-Labrador border area of eastern Canada. Among the other minerals that have been recovered in quantity in North America are copper, silver, lead, zinc, nickel, sulfur, asbestos, uranium, phosphate rock, and potash.

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