World Regional Geography
What are common characteristics that Middle and South America have in common?
What is subduction and how does it relate to Middle and South America? P.102
This long mountain chain, known as the Sierra Madre in Mexico, by various local names i
America, and as the Andes in South America was formed by a process called subduction, in which the edge of on tectonic
plate descends under the edge of another. In this case, the eastward-moving oceanic plates—the Cocos Plate and the
Nazca Plate—are plunging beneath the three continental plates—the North American Plate, the Caribbean Plate, and the
South American Plate—at a lengthy subduction zone running thousands of miles along the Pacific (western) coast. The
overriding plate crumples to create mountain chains, often developing fissures that allow molten rock beneath the earth’s
crust to the surface and form volcanoes. These highlands constitute a major barrier to transportation and communication
throughout their length, but in northern and central South America, where the population is dense, they pose a special
Why is the Atacama Desert extremely dry? P.106
The Andes are a major influence on precipitation in South America.
Rains borne by the northeast
and southeast trade winds off the Atlantic are blocked, creating a rain shadow on the western side
of the Andes in northern Chile and eastern Peru.
Southern Chile is in the path of eastward-
trending winds that sweep north from Antarctica, bringing steady cold rains that support forests
similar to those of the Pacific Northwest of North America.
The Andes block this flow of wet,
cool air and divert it to the north, thus creating an extensive rain shadow on the eastern side of the
mountains along the southeastern coast of Argentina.
The pattern of precipitation is also influenced by the adjacent oceans and their currents.
the west coast of Peru and Chile, the cold surface waters of the Peru Current bring cold air that is
unable to carry much moisture.
The combined effects of the Peru Current and the central Andes
rain shadow have created what is possibly the world’s driest desert, the Atacama Desert of
Which group FIRST settled in the region of South and Middle America?
Between 13,000 and perhaps 40,000 years ago, groups of hunters and gatherers from Asia spread
throughout North America after the Bering land bridge, which once connected northeastern Asia
Many of these groups ventured south through only a few thousand years, these people
managed to adapt to a wide range of ecosystems:
the dry mountains and valleys of northern
Mexico, the tropical rain forests and upland zones of Central America, the vast Amazon Basin,
the Andes Mountains, and the cold, windy grasslands near the tip of South America.