Week 8: Human Variation & Race Blog

1.    High Altitude- Living in a high altitude causes environmental stress to the people. As we know that adaptation is the process that an organism should undergo to adjust for beneficial adjustment in a particular environment. In high altitude geographical area only people who adapt or adjust how to live in high altitude locations could survive. “Ascent from sea level to high altitude has well-known effects upon respiration. The progressive fall in barometric pressure is accompanied by a fall in the partial pressure of oxygen, both in the ambient air and in the alveolar spaces of the lung; and it is this fall that poses the major respiratory challenge to humans at high altitude. Humans and some mammalian species like cattle adjust to the fall in oxygen pressure through the reversible and non-inheritable process of acclimatization, which, whether undertaken deliberately or not, commences from the time of exposure to high altitudes (Britannica Ency). Not all people can adjust abruptly living in high altitude areas. The human body is used to adapt the low land living wherein many of human being inhibits the geographic low land area rather than the high altitude. Human body uses oxygen and performs very well at sea level. The saturation of hemoglobin in human body will depend on the percentage of oxygen intake. As we know that the higher the latitude is also equivalent to lesser oxygen content. When the body is at the high altitude the oxygen intake plummets. Thus travelling in many higher altitude areas causes health stress such as Acute Mountain Sickness or it could be fatal that causes high pulmonary altitude edema where the lungs could no longer function normally as a result of breathing problem, weakness and cyanosis (which skin turn to blue). In a High Altitude (2500-3500 m or 8200-11500 feet) the human blood level will drop 90%. However in extreme altitude the human blood level will drop more than 90% at rest. It is extremely risky for the low landers to live in high altitude areas. It takes an extreme adaptation to survive and live in higher geographical areas.  How did some people survive living in high altitude area? The answer is adaptation.

The Andes Mountain

 

The Tibet's Mountain

 

2.    Facultative Adaptation-  Facultative traits are genetic traits. They do not require a change in an organism’s DNA but they do involve turning on and off genes to alter a phenotypic expression in response to an environmental stress. This adjustment in the phenotype will remain for as long as the stress exists, though the return to the original phenotype will require more time than the short-term adaptation. An example of this is the increase in oxygen carrying blood cells in response to a reduction in atmospheric oxygen, such as when a person moves into a high-altitude environment.

The Andean's Family

According to NatGeo, “Prehistoric and contemporary human populations living at altitudes of at least 8,000 feet (2,500 meters) above sea level may provide unique insights into human evolution, reports an interdisciplinary group of scientists. Indigenous highlanders living in the Andean Altiplano in South America, in the Tibetan Plateau in Asia, and at the highest elevations of the Ethiopian Highlands in east Africa have evolved three distinctly different biological adaptations for surviving in the oxygen-thin air found at high altitude. The Andean and Tibetan plateaus rise some 13,000 feet (4 kilometers) above sea level. As prehistoric hunter-gatherers moved into these environments, they encountered desolate landscapes, sparse vegetation, little water, and a cold, arid climate. In addition, early settlers to the high plateaus likely suffered acute hypoxia, a condition created by a diminished supply of oxygen to body tissues. At high altitudes the air is much thinner than at sea level. As a result, a person inhales fewer oxygen molecules with each breath. Symptoms of hypoxia, sometimes known as mountain sickness, include headaches, vomiting, sleeplessness, impaired thinking, and an inability to sustain long periods of physical activity. At elevations above 25,000 feet (7,600 meters), hypoxia can kill. The Andeans adapted to the thin air by developing an ability to carry more oxygen in each red blood cell. That is: They breathe at the same rate as people who live at sea level, but the Andeans have the ability to deliver oxygen throughout their bodies more effectively than people at sea level do. In addition, Tibetans may have a second biological adaptation, which expands their blood vessels, allowing them to deliver oxygen throughout their bodies more effectively than sea-level people do.”

The Tibetan's Family

The migration and the adaptation of living in high altitude help them to survive and the body shows genetic mutation. The lungs developed in a special way where they can take less oxygen and process it in their bodies without any symptoms and sickness experienced. So as the hemoglobin also works in a very special way by carrying more oxygen in each cell. The Andeans has different way of survival than of the Tibetans. Tibetans compensate for low oxygen content much differently. They increase their oxygen intake by taking more breaths per minute than people who live at sea level. According to NatGeo, “Andeans go the hematological route, Tibetans the respiratory route”. Different mode of adaptations but still it has to do with the body systems works differently than the rest of the low landers. With these kinds of body changes, it also resulted to genetic traits which called facultative adaptations. Thus people within this tribe and born in this tribe inherit the special genetic traits. As a result adaptation is important in any means of survival process.

3.    Adaptation is very important and has benefits of studying human variation. It is very helpful to us and the study of evolution. How these species survive can also be determined by the adaptation of the species. Let’s take an example the early humans. Hominid is very important discovery in the evolutionary process. Through the discovery of the fossil, we were able to know the evolution of the human. How they survive, their diet, the development of body, dental structure and brain, the usage of tools and how it transforms to modern human. It6 also benefits us because we were able to scientifically study how human evolve.

4.    Race is the categorization of humans into their physical appearance, culture, ancestry, ethnicity and language. Environmental influences on adaptations are a better way to understand human variation than by the use of race because it is much easier to categorized human variation by studying their environmental influences. Example: The Andeans and the Tibetans. For them to survive they live in high altitude areas where in they adapted and their body genetically mutated for adaptation process. Each of us are known for our special traits which begins with our adaptation in that certain geographical locations where diet, climate and other mode of subsistence affects the physical traits such eyes, hair and skin color. The successful acclimatization helped these people to survive better in high altitude areas. Their flexibility with the environmental changes helped them to cope the natural environment that helps them to sustain and survive. Environmental influences on adaptations helped us to understand human variation in many ways. Through environmental influences we could also identify their cultures and beliefs.

References:

Britannica Encyclopedia

NatGeo. www.natgeo.com

Photos: Google Images. www.googleimages.com

            Yahoo Images. www.yahooimages.com