1. Environmental stress can be described as any force or event in human or natural environment that may cause a person to experience stress. There are many different stressors that we as humans in our environment experience one of them being heat. Temperatures can rise to over 100 degrees in the summer time and cause many people stress that is physiological in nature. As humans our bodies maintain a normal state of homeostasis which is the condition of balance or stability within our biological system and is maintained by the interaction of physiological mechanisms that compensate for changes both external which would be the heat and internal. Excessive environmental heat can take its toll on a humans body and a person can exhibit symptoms of headache, nausea, dizziness, and even heat stroke which can ultimately result in death. Excessive heat disturbs the homeostasis of the body by causing excessive sweating.
2. An example of short term adaptation would be sweating which is the bodies attempt at thermo-regulation. When a person's body temperature rises secondary to external heat the body responds by sweating liquid through the pores. Sweating helps with cooling the person down and the evaporation of sweat from the skin decreases surface temperature.-A facultative adaptation is vasodilatation. Vasodilatation is the widening of blood vessels from the relaxation of the smooth muscles within the blood vessels walls. When vasodilatation occurs in response to excessive heat the capillaries closet to the skins surface dilate and allow for sweating which allows for the body to get rid of hot fluid within the body and excrete it through to the skin in an attempt to regulate temperature.
-A developmental adaptation to heat or a hot environment would be body size, amount of hair on the body or the pigmentation of the skin. People who tend to live in hotter regions tend to be taller and thinner. The lighter the person less heat will be absorbed.
-Cultural adaptations to heat that humans use. There are different types of clothing which are lighter and cooler to wear, there are fans, air conditioning, cold liquids, pools and staying indoors to prevent the body from exposure to excessive heat. Different cultures have different kind of head wears, although they are more likely to be related to cultural expression, they are also protection against the heat, for example in India people wear turbans and during the summer it gets excessively hot the turbans therefore protect the person's heat from the heat.3.Understanding how a group of people adapt to live in even unfortunate environmental stresses (as every population does so in some way) is beneficial to understand why groups of people living in the same region share many traits. Looking at this information through an Anthropological point of view, we don't group these people as races but rather a group of people who have managed to survive and adapt even in these environmental stresses and we see what biological/physical/behavioral changes they have made to do so.
4. Although we wouldn't be able to change these environmental stresses, we gain insight on how humans have strive to survive and successfully done so, without regards to what their "race" is. If we sort people by their physical adaptations to environmental stresses, then we call them a race, a collective amount of people who have adapted similarly. Again, it is better to understand the scientific explanations of these changes in humans rather than categorize these physical/biological/cultural changes by classifying them all in one race. With constant evolutionary changes in populations, we cannot pinpoint one specific race that has surpassed an environmental stress and not had to adjust their being in any way.
Hi Marcos,
ReplyDeleteThis was a very interesting post. Considering that mine was on the opposite (cold environments) Really cool to read how homeostasis can adapt itself and put out its own defense mechanism to help your body adapt and survive. In cold environments, one of these defense mechanism is shivering, the involuntary muscle movement creates heat. The opposite of this which you mentioned is sweating which serves its purpose to cool off the body. While doing my research and reading, I was surprised to see that body mass/size was a factor of our bodies adapting towards our environments. I can understand and see how it took us so long to get these adaptations. For people living in cold environments, their bodies have adapted to being short and wide. But I asked myself the question, how will we be in thousands and thousands of years from now. Our technology has allowed us to survive in practically any environment. So how does that affect our evolution for the future?
I think our views are the same in regards to using Human variation as a result of environmental adaptation rather than race itself.
Again a really good post, I enjoyed reading it because I also encountered the same research while working on my post as well. Really great job and good pictures too.
Good background on heat stress but to clarify, excessive heat doesn't disrupt homeostasis by causing sweating. Excessive heat disrupts homeostasis by causing the core body temperature to rise out of the optimal range. Sweating is a response to prevent this from happening.
ReplyDeleteGood short term and facultative trait.
Body shape (not size) helps with heat stress, but how? There is debate about how body hair affects heat stress, since there are organisms both with and without body hair in hot climates. Darker skin is actually a response to solar radiation, not heat stress. If lighter skin absorbs less heat, why do populations on the equator have darker skin?
Good discussion on the cultural adaptation and the benefits of the adaptive approach.
"If we sort people by their physical adaptations to environmental stresses, then we call them a race, a collective amount of people who have adapted similarly."
But this isn't how we define race, historically. Using the academic definition of race, is it useful for understanding human variation? I believe you do understand that race is not useful for this purpose, but I am curious as to why there seems to be a need to find a positive use for the concept of race. Why is this necessary?
I learned a lot from your post. Quite honestly I did not know how to quite approach this week's post. However, there is something that you mentioned in your post that makes me wonder. You said that people who tend to live in hotter regions tend to be taller and thinner and that they will also be lighter in complexion so they will absorb less heat. This seems to conflict to what I have observed in regions near the Equator, known to have intense heat. Many cultures in that area tend to have a darker complexion. I believe this is due to the fact that the skin needs to be tougher to combat the Sun's rays. Otherwise it is a very insightful analysis. I have never considered that being thinner and taller help reduce heat.
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