Answer key

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Chapter: 08. North America

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Long Answers Answer Key

The Central Lowlands, also known as the Great Central Plains, represent the largest physical division of North America, extending over 6,000 km from Hudson Bay in the north to the Gulf of Mexico in the south. This vast plain, approximately 2,000 km wide, lies between the Western Cordilleras and the Eastern Highlands. The plains are higher in the west and exhibit a distinct slope: northwards in Canada, where the Mackenzie River drains into the Arctic Ocean, and southwards in the United States, dominated by the extensive Mississippi-Missouri river system flowing into the Gulf of Mexico. This river system is the largest in North America.

North America was named after Amerigo Vespucci, an Italian explorer who arrived in 1507 CE. However, Christopher Columbus is widely credited with its “discovery” in 1492 CE while searching for a new sea route to India. Despite earlier visits by Norsemen and Vikings around 986 CE, their expeditions remained largely forgotten. Thus, Columbus’s voyage became the universally accepted discovery, leading to the continent, along with South America, being termed the “New World” as they were explored by Europeans in the relatively recent 15th century.

The Eastern Highlands, or Appalachian Mountains, are old fold mountains running parallel to the continent’s eastern margin, from Newfoundland to Alabama-Georgia, spanning 2,575 km. Although once higher than the Rockies, they now appear lower due to millions of years of erosion by glaciers and rivers, with an an average height of 1,200-1,500 m. Their eastern slopes are steep, leading to rivers descending over the Piedmont Plateau in a series of waterfalls known as the Fall Line. These waterfalls are crucial for generating hydroelectric power, and the Appalachians are also a significant source of minerals and provide rivers for transportation.

Lumbering is a highly significant economic activity in Canada, primarily due to its vast coniferous (taiga) forests that stretch across the country and contain abundant softwood trees like spruce and pine. These softwoods are ideal for manufacturing paper, newsprint, and synthetic fibres, making Canada the largest exporter of paper and a major producer of newsprint globally. The industry involves not just felling trees but also sustainable practices like planting and preventing forest fires. Modernization with mechanical saws and cranes has made lumbering a permanent and less arduous activity, contributing substantially to Canada’s foreign exchange earnings.

The Canadian or Laurentian Shield is an ancient landform stretching from Hudson Bay south to the Great Lakes. It is composed of some of the oldest known hard rocks on Earth, making it incredibly rich in minerals like gold, iron, and copper. This semi-circular region was extensively worn down by ice sheets and glaciers over millennia, lowering its height to an average of 300-400 meters. The moving ice also scraped out deep depressions, which, after the Ice Age, filled with meltwater to form thousands of freshwater lakes, including the prominent Great Lakes and Great Bear Lake.

North America comprises many countries, with the United States of America and Canada occupying over three-fourths of its total area, both located north of the Tropic of Cancer. Mexico is another large country through which the Tropic of Cancer passes. South of this, the continent narrows, forming Central America, which includes countries like Guatemala and Panama. Additionally, the tropical islands in the Caribbean Sea are collectively known as the West Indies, encompassing nations such as Cuba and Jamaica. In the north, large snow-covered islands like Baffin Island and Greenland (belonging to Denmark) are also part of North America.

One distinct zone is the Tundra, found in Arctic areas, characterized by mosses, lichens, grasses, and dwarf bushes, with a permanently frozen subsoil. Its fauna includes polar bears, musk oxen, and Arctic foxes, adapted with thick fur or fat. Another is the Temperate Grasslands (Prairies) in the interior cool temperate latitudes, featuring rich, tall grasses (now largely wheat farms). Native animals include bison (nearing extinction) and prairie dogs, along with various birds. Thirdly, Coniferous or Taiga forests dominate vast northern belts, comprising cone-bearing trees like pine and spruce. Animals here, such as bears, wolves, and beavers, have thick fur and many hibernate due to heavy snowfall and extreme cold.

North America experiences a wide range of climates due to several influencing factors. Its vast latitudinal extent places parts of the continent in the torrid, temperate, and frigid zones. Distance from the sea results in maritime climates near coasts and extreme continental climates in the interior. Prevailing winds, such as the North-East Trade Winds and South Westerlies, bring varied rainfall patterns. The north-south orientation of the Western Cordilleras and Eastern Highlands allows cold winds from the Arctic to penetrate deep south in winter and warm winds from the torrid zone to push north in summer. Lastly, ocean currents, both warm (Gulf Stream, Alaskan Current) and cold (California, Labrador Current), significantly impact coastal temperatures and precipitation, even creating rich fishing grounds where they mix.

North America possesses a great variety of mineral wealth, primarily concentrated in the Canadian Shield, Appalachian Highlands, Western Cordilleras, and areas around the Great Lakes. It is a major global producer of essential minerals like iron ore, coal (high-grade bituminous and anthracite), copper, nickel, gold, and silver. In terms of power, the continent has vast water power resources, leading to the construction of large hydroelectric dams on rivers like the Columbia and at Niagara Falls. Given the exhaustion of coal and oil reserves, there has been significant development in new and renewable energy sources such as geothermal, wind, solar, and nuclear power to meet its high internal demand.

The Western Mountain System, or Western Cordilleras, is a series of young fold mountain ranges extending from Alaska to the Isthmus of Panama, covering about 6,500 km. Like the Himalayas, these mountains feature steep slopes and high peaks, with parallel ranges such as the Rockies and Sierra Nevada. Geologically, this region is highly active, characterized by numerous active and extinct volcanoes, hot springs, and frequent earthquakes. Its proximity to the Pacific Coast means it forms a significant part of the “Pacific Ring of Fire,” a zone of intense seismic and volcanic activity globally.

Lumbering is traditionally performed in the winter season, lasting about 100 days, as the frozen sap in trees makes cutting easier and frozen ground and rivers facilitate log transport. Logs can be easily dragged and piled on ice, then floated down rivers once the ice thaws in summer. Lumberjacks, living in camps away from their families, specialize in various tasks: “High Riggers” climb and cut branches and trunks; “Sawers or Buckers” cut trunks into smaller lengths; “Skidders” collect and stack logs; and “Haulers or Transporters” manage log movement down rivers, including clearing log-jams, often using spiked shoes and even dynamite for difficult jams.

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