Human Variation & Race

Oxygen is one of the essential elements for human survival. The environmental stress of high altitude impacts human survival, which disturbs homeostasis due to the lower air pressure in those regions. Pressure in high altitudes are much less when compared to pressure at sea level. When one is at sea level, oxygen enters much easier through lungs, making their way to vascular systems (blood streams). At high elevations, oxygen doesn’t enter our lungs as easily, which means one gets less of it in their blood stream. This high-elevation condition is called hypoxia, also known as oxygen deprivation. Hypoxia defuses physical activities, and some of the symptoms include; headache, fatigue, lack of appetite, vomiting, distorted vision, and difficulty with memorizing and thinking clearly. In some cases, symptoms could be more serious; developing pneumonia-like symptoms and accumulation of fluid around the brain. These pulmonary and cerebral complications are usually deadly if there is no return normal air pressures. Furthermore, the added stress on the lungs, heart and arteries increases the risk of heart failure (Palomar).

Humans in high altitudes could adapt to these higher regions in four ways; short-term adaptation, facultative adaptation, developmental adaptations, and cultural adaptation.

Hiking a mountain is a short-term adaptation. The goal is to climb on a mountain – reaching high elevation – and returning down to the original elevation. The human body responds quickly to this type of change in environment. Since the atmospheric pressure is less in elevated regions, it becomes difficult for some to breath, which causes physical inability to move at a normal pace. It is a temporary response of the body, until it returns to the original-lowered elevation.

If one were to visit the country of Bolivia, they would be faced with a considerable environmental stress of nearly 17,000 feet above sea level. The facultative adaptation would consist of the body responding to a prolonged stress of adjusting to the extreme climate. This process is called acclimatization; where red blood cells and capillaries are produced to carry more oxygen, and the lungs increase in size to facilitate the osmosis oxygen and carbon dioxide (Palomar). The increase of red blood cells are phenotypic expressions of the human genes that turn on and off as a response to such environmental stress. Acclimatization is a slow process, but never reaches the mental and physical fitness from its original lower altitudes. Acclimatization is fully successful, when one returns home – t o their original elevation.

Developmental adaptation are traits found in the DNA of people. Let’s continue to consider the people of Bolivia, who live in an estimated elevation of 17,000 feet above sea level. They are a population more successful in adjusting to long-term environmental stresses of high elevations. The reason they have adapted to such climate, is due to their long ancestral history in that region. The ancestors of Bolivians have lived in such altitudes for at least 2, 700 years (Palomar). The main solutions for Bolivians have been their body’s capability of producing extra hemoglobin in their blood and excess lung expansion. These two capabilities increase oxygen carried by the blood.

Being a native to Bolivia, I’ve been told that the consumption of coca leaves helps with symptoms of altitude sickness. This would be considered a cultural adaptation by Bolivian natives, as it has been a long tradition with some of the populace of the country. This adaptation may be genetically influenced if generations upon generations have consumed the leaf. The idea is to chew on coca leaves and retaining it in the mouth, swallowing its juices. Ingesting the juices is supposed to stimulate your body, making you feel less tired.

There is a benefit to studying human variations from this perspective across environmental clines, because it shows how humans are physiologically different based on the different environmental stresses that each live in. For example, when we look at skin color, we see that this is due to the continuous stress of solar radiation. Where darker skin tones show that more protection against radiation is needed and the lighter skin is in need of UV protection.

We tend to think of race as an isolated way to describe someone. This sort of description pins a person to a certain region where they may have come from. To some it becomes a tier system to identify another human. But It seems that a better way to understand our physical differences is by observing our variations and adaptations to the world; specifically, how we are influenced by our physical environments. The fact that certain people could adapt to clines such as high altitudes, shows how the body could adapt for short of long term of time. One would think that Bolivian people are a race of people that could live well in high altitude climate, but it really narrows down to how well their bodies adapt to their clines. Perhaps many foreign visitors to Bolivia would not adapt quickly or at all, but those that have lived there for generations, are able to sustain in such environment.