Solar Radiation and Human Adaptation
2. There are four ways human individuals have learned to adapt from the high radiation the sun produces. Firstly, short-adaptation allows an organism to rapidly respond to changes within their environment in order to maintain homeostasis. This type of change does not involve genetics within the individual. The response is generally a quick one and once the stress is removed, the organism will return to its original state. In response to high levels of radiation, humans are known to receive what is called a sunburn. This is when the skin flushes red, turns itchy, or sometimes very painful depending on how badly an individual is exposed to the ultraviolet rays the sun produces. Depending on the severity of the burn, sun burns can generally last one to four days. As long as the stress is removed and treated, the burn heals within the long run.
Next, we have the term known as facultative adaption. Facultative adaption involves genetic traits. They do not require a change within the organism's DNA but they do involve turning on and off to alter a phenotypic expression in response to an environmental stress. The falcutative adaption in response to high radiation from the sun would be the skin becoming tanner. Above, sun burns are mentioned as a short-adaption. After sun burns heal, the skin typically becomes tanner in response to better aide and protect the human individual in the future against the sun's UV rays.
Third, there is also developmental adaptions in response to the sun's radiation. Developmental adaptions are actual changes in the DNA of a population of individuals in response to a long-term stress to produce a phenotypic change through evolutionary forces. An example of this would be the actual variation in skin color we can visibly see in human individuals. For example, if we were to take an individual who was of lighter pigment and move them to a continent or other landmass that experiences great heat and sun radiation, the generations that follow the lighter pigmentation individual will gradually grow darker in skin tone. Conversely, an individual who does not see much sun could turn lighter in pigmentation as the generations pass on. This trait is controlled by red cells in blood flowing close to the skin.
Finally, there are cultural adaptations. Humans are relatively unique in their use of culture to help them adapt to given environmental stresses. A significant example of this would be the invention of sunblock within society. Sun block is a cream or lotion individuals apply to their skin in order to protect them from the ultra violet rays of the sun. Many cultures apply this to their skin now in order to lessen the chances of receiving a sun burn. Additionally, some individuals may use umbrellas in order to aide in shielding their faces and skin from the sun when they're outside.
3. There are various benefits to studying human variation from this perspective across environmental clines. For one, it can benefit within our society by helping us discover we are all humans regardless of skin color, and the pigmentation we each possess aides in understanding how throughout millions of years we've grown more diverse. Furthermore, the ideology of human 'races' has developed from the variation in human skin pigmentation. From learning about where these pigmentation come from, we learn how the environment and evolution played a heavy role in producing all the variations within the human race. From skin pigmentation, we can also understand and piece together what the climate is like, depending on where the human individual came from. For instance, if we took someone from Ireland whose a lighter skin tone, we can infer that Ireland must not receive sun as much as other areas do.
4. As mentioned above, understanding human variation through adaption instead of race is able to be utilized to our advantage in a variety of positive ways. Humans are diverse in pigmentation that occurred due to the environments that surround us. We are all apart of the same species, and that is being human. We may look different and more diverse from one another, but that is because the environment has come to impact us and the appearance we may possess. Generally, the closer individuals are to the equator, the darker skin tone they may show and reflect. The physical environment does not affect personality or change the fact that we are human. Studying this subject specifically, overall can help us come to terms with how truly connected we are to one another.
Good opening description of solar radiation stress.
ReplyDeleteFor your short term adaptation, remember that adaptations help the body adjust to a stress. It is a physiological response that has a positive impact. A sunburn isn't a positive response, it is an indicator that the body hasn't responded quickly enough to solar radiation. It is a symptom that damage has already occured, not a response to deal with the stress.
There actually is no short term adaptation to solar radiation which is why it is such a dangerous stress.
Okay on your facultative adaptation, but "tanning" is the production of more melanin in the skin. It has nothing to do with the sunburn, with the production of melanin being independent from the damage of a sunburn.
"This trait is controlled by red cells in blood flowing close to the skin.
No, that's not how this works, but otherwise, the different skin colors are a result of long term exposure to different levels of solar radiation. Why do some people have less melanin? Wouldn't it be advantageous to keep darker skin, just in case?
Good cultural adaptation.
I don't disagree that knowledge is a good thing (and certainly a better understanding of race would benefit all society) but are there more concrete benefits to understanding how the body responds to solar radiation? Can this have medical implications, e.g., for cancer research? Can this help us build windows and clothing that helps block harmful radiation?
In the last section, you explain why the adaptive approach works but not why race doesn't. Why can't we use race to understand variation? What is it missing?
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.
Hello WildDreasmingFantasis,
ReplyDeleteYou had a great opening with the first two questions it showed a lot of insight into things like the causes for darker skin tones and why they are valuable. Good post I learned a lot.
Hi Kathleen, I thought you blog post was very descriptive and very well written! You opening paragraph made me want to read the rest of your blog post. It’s crazy to think of how normal/everyday things like sunburns have a much deeper purpose!
ReplyDeleteHi Kathleen,
ReplyDeleteGreat job on this blog. Well formatted, you provided a good amount of information for all your answers, and you had a very strong opening. I also like the pictures you chose for your adaptations.