Human Variation & Race
For environmental stresses, I chose to discuss high altitude and how it negatively impacts the survival of humans. High altitude disturbs homeostasis with many different factors. As stated in our book, "Theses includes, hypoxia, more intense solar radiation, cold temperatures, aridity, wind, a reduce neutral base, and rough terrain."(page 449). However, what makes it difficult for the human body to maintain internal conditions is primarily because hypoxia, where there is a lack of oxygen that reaches the tissues. Hypoxia affects the heart, lungs, and brain and doesn't allow physiological to function correctly.Ultimately, hypoxia is caused by the pressure of the atmosphere due to the high altitude. In addition, reproduction is also affected with more infant deaths.
Humans have had the ability to cope with heat for many years. In order to do so, humans made a short term adaption by sweating. Sweating helps the body regulate its temperature. This is done through the sweat glands that are distributed throughout the skin and releasing heat through evaporative cooling.
When moving to higher altitudes, humans gave facultative traits to adapt to the atmosphere pressure. This includes an increased production of red blood cells which helps carry oxygen to the organs and tissues.
Body shape is developmental adaption that is an adjustment due to natural and cultural living conditions. This needed to help survive living conditions. A person living in the cold may put on more weight in an attempt to have more body heat to stay warm.
The clothing worn in different cultures help with adapting. A culture residing in warmer ares may have less clothing in an attempt to stay cool vs a culture in a cold area who is likely to wearing layers of clothing
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The benefit of studying human variation across environmental clines is to understand the different traits humans have in multiple living environments. It helps understand evolution and why certain traits were needed to survive. I think information is useful today to try and track where your ancestors are from and to trace diseases. This can also help find cures for diseases.
Based on the information provided from my response #2, race is not needed to understand the variation of the adaptions. Humans bodies are capable to respond to environmental changes on a regular basis which is due to the process of evolution and not race. Humans have been migrating to different locations around the world that are filled with different climates. In order to survive humans were capable of adapting to the environment based on short term changes, genetic traits, changes in DNA, and through culture. Race can not show adaption based on race. In other words, race does not determine ones ability to adapt rather environmental influences causes changes in evolution to survive living conditions.
Opening: Good discussion of the general impact of hypoxia on the human body. There is another aspect of hypoxia that is important to consider, and that is the impact of hypoxia in pregnant women. A fetus already gets reduced oxygen content via the placental system, so if you reduce that further in a low oxygen environment, you run a greater risk of poor development or even fetal death in a high altitude environment, unless your population has adapted over time to that stress.
ReplyDeleteShort term: You discuss heat stress here, but your chosen stress was high altitude. While your short term adaptation to heat is correct, you needed to explain how the body adapts immediately to high altitude stress. An example would be an immediate physiological response that increases respiration and heart rates, which increase the rate of oxygen delivery to the tissues.
Facultative: Good.
Developmental: This is an adaptation to cold stress, not high altitude. How about barrel-chest skeletal structure that allows for a larger lung capacity? And aren't there genes that have been identified in high altitude populations (e.g., EPAS1... https://www.sciencemag.org/news/2014/07/tibetans-inherited-high-altitude-gene-ancient-human) that allow for a more efficient use of available oxygen?
Cultural: This is an adaptation to cold stress. What is a cultural adaptation to high altitude environments? How about the use of oxygen tanks by mountain climbers or pressurized cabins in airplanes?
On the right track with the last sentence, but can you be more specific? Can this possibly offer solutions to diseases such as cystic fibrosis? Or provide solutions for pre-mature infants with immature lung development?
"...race is not needed to understand the variation of the adaptions."
I agree, but the question here is whether it is useful at all in explaining human variation. If you wanted to use it to explain human variation, could you?
To answer this question, you first need to explore what race actually is. Race is not based in biology but is a social construct, based in beliefs and preconceptions, and used only to categorize humans into groups based upon external physical features, much like organizing a box of crayons by color. Race does not *cause* adaptations like environmental stress do, and without that causal relationship, you can't use race to explain adaptations. Race has no explanatory value over human variation.
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DeleteHello Prof. L Rodriguez
DeleteThank you for the feedback. I misinterpreted some of part 2.
When it comes to short term adaption, in relation to the high altitude, it cause an increase to breathing. This allows the lungs to work harder in order to keep with the less oxygen.
When it comes to developmental adaption, those in higher altitudes have developed the ability to burn glucose that helps permit better oxygen use.
In addition, cultural adaptions have created ways for those who are not accustomed to living in high altitude. An example is pressurized airplane cabins and oxygen mask. This is so many of us can travel by airplanes and not have any side effects.
Thank you for the reply.
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