Human Variations in High Altitude Populations
26 november 1996
Thesis:The purpose of this paper is to describe the high altitude stresses and the general adaptations made by the Tibetan population in the Himalayas and the Quechua in the Andes.
A Quechua People
B Tibetan People
III General Adaptations
3 Core temperature
4 Extremity temperature
B Non- Physical
"Some ten to twenty-five million people (that is less than 1% of the earth's population) currently make it[high altitude zones] their home(Moran,143)." The adjustment high altitude populations must make are firstly physical and secondly cultural. Although most people adapt culturally to their surroundings, in a high altitude environment these cultural changes alone aren't enough. Many physical adaptations that reflect "the genetic plasticity common to all of mankind(Molinar,219)" have to be made to survive and even more than that thrive in this type of environment.
In this paper I will describe the high altitude stresses. Along with adaptations made by the populations living in them. The two high altitude populations which I will examine in this paper are the Tibetan people of the Asian Himalayas and the Quechua of the South American Andes. The Quechua are an Indian people who inhabit the highlands of Peru and Bolivia. They speak Quechua, which is a branch of the Andean-Equitorial stock. They show many remnants of Inca heritage by their houses, music, and religion which has pagan rites under the Roman-Catholic surface. Their villages consist of kin groups . Their marriage partners are taken from within each village. Agriculture is the dominant subsistence pattern in the central Andean region but the Nunoa region where the Quechua reside can only support a few frost-resistant crops. Which include bitter potato, sweet potato, and a few grain crops of quinoa and canihua. The rest of the fruits and vegetables of the Quechua come from the eastern mountains on it's way to the markets. The most important subsistence pattern for the Quechua is stock raising. Which is limited to the few animals that do well in the high altitudes. Their stock include alpacas,llamas and sheep.
In the Himalayas only "5% of the geographical area(Baker,36)" can be used for agriculture. The main crops are barley, wheat and buckwheat. The crops are grown between 3,500 and 4,300 meters. These few crops are threatened by drought, hail, frost, snow and erosion. The Himalayas also have extensive pasture areas which are used by the nomadic and sedentary peoples. The higher regions have pastures where yak, sheep, and goats are the main animals used.
In the high altitude there are many environmental stresses that the people must endure. They include hypoxia, intense ultraviolet radiation, cold, aridity, and a limited nutritional base. The people adapt to these stresses in many ways.
Hypoxia, or low oxygen pressure, is the most prominent stress which populations living at high altitudes must deal with. "Hypoxia results whenever either physiological,pathological, or environmental conditions cannot deliver adequate supply of oxygen to the tissues. Since air is compressible, air at high altitudes is less concentrated and under less pressure. At 4500 meters the partial pressure of oxygen is decreased by as much as 40%, in comparison to pressure at sea level. This reduces the amount of oxygen finally available to the tissue(Moran,147-148)." The adaptations to hypoxia are all geared towards increasing the oxygen to the tissues.
One adaptation to hypoxia is an increase of red blood cells in circulation. A person living in high altitude conditions is likely to have "30% more red blood cells(Molinar,218)" than a person living at sea level. "This greater number...
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