High Altitude Populations
Awhile back I was watching a travel channel episode where a group of people traveled to a high elevation to explore. They used ‘porters’, who were all natives of the area, to carry their necessities because the natives were more adapt to the environment. I found some articles that explain how the native’s bodies have adapted to survive at the altitude where most would develop hypoxia.
The most successful populations have been the peoples living in the Andes Mountains of Peru and Bolivia as well as the Tibetans and Nepalese in the Himalayan Mountains because most of their ancestors have lived above 13,000 feet for 5,000-10,000 years. This suggests natural selection over thousands of years resulting in more genetically suited peoples to the stresses at high altitude. It turns out though, that they have adapted in different ways.
The Andean people (populations of Andes Mountains) have adapted to thin air by developing higher hemoglobin concentrations in their blood, allowing them to breath at the same rate as people who live at sea level and deliver oxygen through their bodies more effectively.
On the other hand, Tibetans compensate much differently. They increase their oxygen intake by taking more breaths per minute but also synthesize larger amounts of nitric oxide from the air, which causes the dilation of blood vessels, suggesting they offset low oxygen content with more blood volume.
Normally, a person experiencing high elevation at first develops insufficient physiological responses with increased breathing and heart rate causing a lot of stress on the body. Later, a more efficient response develops where more red blood cells and capillaries are produced to carry more oxygen along with an increase in lung size. When returning to lower elevation, this remains in effect for a few weeks, which is why Olympic athletes are trained in the mountains of Colorado.
Articles:
http://news.nationalgeographic.com/news/2004/02/0224_040225_evolution_2.html
http://anthro.palomar.edu/adapt/adapt_3.htm
http://www.nasonline.org/site/PageServer?pagename=INTERVIEWS_Cynthia_Beall
The most successful populations have been the peoples living in the Andes Mountains of Peru and Bolivia as well as the Tibetans and Nepalese in the Himalayan Mountains because most of their ancestors have lived above 13,000 feet for 5,000-10,000 years. This suggests natural selection over thousands of years resulting in more genetically suited peoples to the stresses at high altitude. It turns out though, that they have adapted in different ways.
The Andean people (populations of Andes Mountains) have adapted to thin air by developing higher hemoglobin concentrations in their blood, allowing them to breath at the same rate as people who live at sea level and deliver oxygen through their bodies more effectively.
On the other hand, Tibetans compensate much differently. They increase their oxygen intake by taking more breaths per minute but also synthesize larger amounts of nitric oxide from the air, which causes the dilation of blood vessels, suggesting they offset low oxygen content with more blood volume.
Normally, a person experiencing high elevation at first develops insufficient physiological responses with increased breathing and heart rate causing a lot of stress on the body. Later, a more efficient response develops where more red blood cells and capillaries are produced to carry more oxygen along with an increase in lung size. When returning to lower elevation, this remains in effect for a few weeks, which is why Olympic athletes are trained in the mountains of Colorado.
Articles:
http://news.nationalgeographic.com/news/2004/02/0224_040225_evolution_2.html
http://anthro.palomar.edu/adapt/adapt_3.htm
http://www.nasonline.org/site/PageServer?pagename=INTERVIEWS_Cynthia_Beall
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