Human Variation & Race
The mechanisms that maintain homeostasis evolves at lower altitudes, and for the populations that live in altitudes of 10,000 15,000 and even 17,000 feet above sea level their bodies faces stress that negatively impacts the body. These stresses include hypoxia (a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level), alternating daily extremes of climate that range from hot days to freezing nights, lower air pressure and aridity (characterized by a severe lack of available water, to the extent of hindering or preventing the growth and development of plant and animal life).
Four ways humans have adopted to this stress
Due to the decrease in amount of oxygen available in higher altitudes, the bodies first response is to increase heart rate to pump oxygen to cells.
The longer time a person spends in a higher altitude, their body will begin to produce more red blood cells. Red blood cells contain hemoglobin which is the protein that is responsible for spreading oxygen throughout the body.
Natural selection has caused natives born in higher altitudes to develop larger hearts and and greater lung capacity which gives them a more effect way to diffuse oxygen from blood to tissues and organs.
Mountaineering is a sport that involves ascending mountains, and these people that partake in this sport come from all different environments from all over the world and have to learn to adapt to high altitudes in order to safely make a trip up and back down a mountain. To accomplish their goal, these athletes must train their bodies to accommodate the low pressure, some may even use oxygen tanks to breath properly. Heavy and bulky clothing is another adaption to the freezing weather to protect the body from experiencing hypothermia.
The benefits of studying human variation from this perspective across environmental clines is to learn how and why humans are such a diverse species across the different environments across the globe. Information from explorations can be useful in helping humans better adjust to foreign environments. One example of how this information can be used in a productive way, is in assisting a persons bodily changes, if that person is from an arctic environment and wanted to move to a desert environment.
Most of the adaptations listed above are formed on the inside of the body and are not visible to the naked eye. You cannot use race to understand the variation of adaptations of higher altitudes, mainly because race is a social construct and does not distinguish what we are or where we come from. There are no such things as human subspecies, because humans have not had the opportunity to evolve into a subspecies. The study of environmental influences on adaptations is better to understand human variation than race because we begin to see the long term effects these adaptations have on populations over generations of people. Environmental adaptations like larger heart and lungs become permanent overtime through more generations become more equipped more the lack of oxygen. Larger lungs and hearts would adapt to anyone who spent enough time in low pressure, no matter their skin color, hair texture, blood type etc.
If more people knew more about human evolution they would understand that we are all originated from the same place and only different due to environmental adaptations from expanding into new territories. I feel like if this was a more wide known fact that racism would end and everyone would be treated as more equal, no matter skin color, place of birth, wealth status etc.
Excellent description of the stress of high altitude (though it will be the stress unique to high altitude that we will focus on here, namely hypoxia), and well done on your explanation of all four types of adaptations. Good images to go with your explanations.
ReplyDelete"One example of how this information can be used in a productive way, is in assisting a persons bodily changes... "
Does this really make sense? Three out of the four adaptations you identify are physiological/biological/genetic in nature. Do we have any control of how these changes occur? Can we make the occur faster or slower just from understanding them? No. Only the cultural adaptation is within our power to control. So, again, how can we use this information in a productive way? Can the information we gain from these types of studies have medical or scientific implications? Help people with lung diseases, such as cystic fibrosis? Can the biological/physiological information perhaps help the breathing difficulties of preemies?
"You cannot use race to understand the variation of adaptations of higher altitudes, mainly because race is a social construct and does not distinguish what we are or where we come from."
That comes closest to the key point I want you to take from this. 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.
Hi Kayla I like how you went into detail on all your answers to the questions. I would have to agree with you that we could not use race to understand the variation of adaptions because it applies to all races not just one or another. But, it is a fascinating topic to discuss. Wow I didn't know about the longer you are in high altitudes the more red blood cells you produce so that was great to read. Great post I enjoyed reading it and learning from it.
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