High Altitude

Beautiful view of the high altitude location of Tibet.

          High Altitude can negatively impact the survival of humans through Hypoxia, solar radiation, cold temperatures, low humidity, wind, reduced nutrition base and rough terrain. Hypoxia is when the human body has in sufficient levels of oxygen in the body tissue, or oxygen deficiency. This is the most dangerous to humans effecting their lungs, heart, and brain. Hypoxia leads to increased infant deaths due to the fetus not getting enough oxygen through the mother. Mothers have a higher chance of preeclampsia due to the elevation and higher chance of a miscarriage. If a baby survives to birth, they are more prone to be premature and/or have low birth weights putting them at a disadvantage to surviving.

Here is a child that has survived birth at a high altitude despite the odds. 

          Solar radiation can affect the skin color of a person through hemoglobin, protein carotene, and melanin, under the outer layer of skin which helps protect humans from UV radiation. With more solar radiation, depending on genetic bases for hemoglobin levels, can make a person more prone to skin cancer. For example, most Europeans have fair skin meaning their hemoglobin is far more relaxed from those that live closer to the equator. This makes them burn and peal painfully without developing a nice bronze tan. This also makes them more susceptible to skin cancer. Skin cancer usually develops later in life, meaning adults who develop skin cancer already have the ability to conceive meaning natural selection will not work in this scenario.  Also, offspring are affected with solar radiation with neural tube defects such as spinal bifida. With lack of vitamin D, which can come from UV, can also prevent bone development, cause rickets, bow legs, and other skeletal deformities. Natural selection can occur with vitamin D deficiency because skeletal defects in women can cause a misshapen pelvis which prevents her from reproducing. Solar radiation can kill any human exposed to UV, but also prevent humans from reproducing if there is a lack of exposure.

Here is a picture of the cold conditions in high altitude.
The person in this picture is covered in thick, warm clothes.
Also. within these clothes is a small child
Staying warm huddled together and staying busy while out in the cold.

          Living in a high altitude means colder temperatures meaning higher chances of hypothermia and frostbite. Winds will amplify these chances. Also, these locations mean difficult living conditions for other animals and plant life making substance difficult to find. With high altitude come low humidity making rapid dehydration a serious issue. All of these issues have the same major issue for humans, cold means humans burn more calories trying to stay warm, meaning they need more nutrition, with lack of game, humans will have to exert more energy trying to scout out food, exerting more energy, also creating a situation for dehydration.

Warmer temperatures in high altitudes, however,
the land looks barren and the only animals in sight belong to this farmer.

          Even though these stresses seem to make life in high altitudes impossible, humans have found a way to make it work. The first step is acclimating to high altitude, which all happens within one’s body and can be shown physically, except for increase breathing. Acclimating to high altitudes would make a person’s heart rate increase, metabolic rate will increase, and productions of red blood cells will also increase. Shortly after leaving the high altitude, the human body will return to normal. Those that choose to stay in these conditions find other ways to beat the cold by either increasing basal metabolic rate or fat insulation of vital organs. The ladder is only in places that show short temperature drops, not prolonged cold, as this would not be able to prevent frostbite from taking appendages. In consuming high calorie, fatty foods one can increase their basal metabolic rate which will create extra body heat.  Due to culture and technological advances survival is not as heavily based on intake or body acclimation. Buildings, homes with heating, fire, heavy clothes all keep people alive in high altitudes. Medicine and science have also created oxygen tanks, inhalers, and other assisted breathing contraptions. People tend to stay active while out in the cold and they might sleep in huddles at night to stay warmer. 

Another small child with his mother. They are wearing warm clothes and the clothes are distinctly made from their culture. Even the ox has a decorative blanket saddle. Nothing keeps these Tibetan people down, not the cold, lack of oxygen, or even age.

  

          Due to bottle neck, human variation isn’t very diverse. In studying extreme environmental differences and comparing the human body’s ability to adapt we not only see what humans are capable of, but we can see how our environment causes adaptation, mutation, and evolution forcing diversity in the human species. Studies of humans living in such conditions for long periods of time can give insight to secrets that only these people posses. For example, these studies have shown that people living in higher altitudes tend to live longer and have a lower risk of coronary artery disease. Exposing oneself to these harsh living conditions, can eventually show signs of a positive nature. Having a mild form of hypoxia from high altitude will improve the heart function. This might be particularly beneficial for someone with genetic heart problems. Perhaps an environmental change will increase life expectancy more than medicines. At least this is a good alternative for holistic type people.

Race is a newer term that was invented to describe groups
of people based on what was physically visible.
Race is only skin deep and will not show the adaptation
of these Tibetan people. To get a further understanding of
adaptation, one must take a look under the skin.

          Race is such a difficult thing to determine or distinguish between people. Basing characteristics, such as skin color, hair color, hair type, and other characteristics, is not a valid way to determine a person’s adaptations to environment. Natives to high altitudes have solar radiation causing a darker skin tone, much like those that live close to the equator, but they are not the same people. The only true physical indication of environmental locations would to use animals such as polar bears. Yes, they have white (or clear) fur like other arctic animals, however, it is their body surface compared to their size that make them ideal for the cold weather. Humans tend to have a similar tendency as this, with taller, skinnier people in more warmer climates, and shorter, compact people in colder climates. I feel that this comparison, like skin color, is too vague to distinguish a person’s environmental region. Looking at a human’s ability to overcome environmental stress gives a more clear distinguishing factors that race cannot do. Most environmental adaptations are below the surface of the skin, and race is only skin deep.

Picture taken from the reading this week. I felt like this was a great example of how two different people in high altitudes can be similar, but yet different.