Wednesday, December 8, 2010

Human Variation & Race Blog

1.)  High altitude can lead to great stress on the human body and negatively effect one’s survival to stay alive.  The percentage of oxygen is roughly the same at sea level as it is compared to high altitudes, which is around 21%.  However, in higher altitudes the air pressure is lower and the air molecules are more dispersed all over the place, causing each breath of air to deliver less oxygen to the rest of the body.  In really harsh high altitude environments if one does not drink enough water it can lead to dehydration, edema, or even death!  Edema is caused by fluid building up in the body from dehydration.  This causes the legs, feet, or face to swell up and usually resolves after descending from high altitudes. 

2.)  Short-term adaptation- A short term adaptation to high altitude is an increase of breathing and heart rate.  Our hearts need to pump faster in order to get more oxygen to the rest of our body.  High altitude is a stressful change in environment towards those with weak hearts.  Higher altitudes cause moisture from your skin and lungs to evaporate at a fast rate.  That is why it is important to drink lots of water in order to keep hydrated from your body’s increased exertion.

Facultative adaptation- When one arrives at a high altitude their capillaries and red blood cell count goes up in order to produce more oxygen.  The lungs also increase and open up and the vascular network of muscles expand in order to transfer gases properly.  Many track stars and Olympians train in higher elevations in order to open their lungs.  One’s lungs require a bit more time to return to its’ original phenotype than the short-term adaptation.  This provides Olympians the ability to breathe effortless and make it easier on the heart and lungs when in low areas performing their event.  It gives them a higher competitive edge to those training at sea level.

Developmental adaptation- Some populations have developed actual changes in their DNA for high altitudes.  Over thousands of years natural selection takes place and only few populations respond differently to the stresses of high altitude.  Most of the time natural selection selects those who have had ancestors who had lived in high altitudes for thousands of years.  Many indigenous individuals who live in the mountains of Bolivia and Peru have been living there for at least 3,000 years with altitudes of 13,000 feet above sea level.  One who has been living in environments like these produce more hemoglobin in their blood causing them to be capable of breathing faster and transferring more oxygen to the rest of their body.

Cultural adaptation- Many individuals are very unique when it comes to their use of culture to help them to adapt to high altitudes.  When it comes to diet, one must always drink plenty of water.  This will help in order to be completely hydrated when hiking up to high elevation areas.  Those who use tools use oxygen tanks with masks in order to breathe easier and allowing one to climb drastically into higher areas.  Some individuals like monks, practice religious methods with controlling their breath for long periods of time while in prayer. 

3.)  There are some benefits to living in higher elevation environments.  Besides the altitude sickness, nausea, dry skin, and your heart working double the amount it would at sea level; studies have shown that those living in higher areas can lead to a longer life.  Not only do individuals live longer, but their rate for encountering heart diseases drop drastically.  Many scientists believe that living in higher altitude environments is very healthy for the heart and helps strengthen it to improve endurance and stamina.

4.)  You could use race based on how people developed over the years in order to adapt to the high altitude.  Peruvian Indians have a redness to their skin due to the increase of blood flow near their skin surface.  This helps them get more oxygen to the tissue in their bodies.  Certain races have been living in high areas for a long time and this helps to understand the variation of the adaptations; as opposed to those with ancestors who have been living in low altitude places.

1 comment:

  1. Excellent discussion. Thorough and on point and very informative.

    I'm concerned that you still feel race is a useful way of studying traits instead of clines. All of the adaptations you discuss could only be understood from the perspective of clinal analysis. Racially-based studies couldn't do it.