High levels of solar radiation as long with low levels of solar radiation can be harmful to the human body. Overexposure of UVB rays can penetrate the skin and affect the DNA which may lead to skin cancer. On the other hand, inadequate amounts of UVB rays can lead to deficiency of Vitamin D which can contribute to high blood pressure, fatigue, and bone problems.
There are no short term adaptations our bodies have to help protect ourselves from high levels of solar radiation. If you sit out in the direct sunlight for too long, you more than likely get a sunburn. Although, some individuals may feel the heat of the sun on their skin and leave, this does not qualify as a short term adaptation because our bodies do not do it naturally.
A facultative adaptation humans have regarding high levels of solar radiation has to do with melatonin. Melatonin is a contributing factor to skin tone, when skin is exposed to high levels of solar radiation for a good amount of time then melatonin production increases which makes the skin tone darker. This happens when people go tanning. For many people, their skin tone changes depending on whether they have been exposed to high levels or low levels of radiation for a period of time (ie. summer and winter.)
This facultative adaption leads to developmental change. Individuals who live in warmer tropical climates tend to wear less clothes because of the heat. They in turn, have a darker skin tone since more of their skin is exposed to the sun. This is due to high levels of solar radiation which in turn increases melatonin production. Throughout generations, the cells will continue to adapt and increase melatonin so the individuals are less likely to be sunburned or develop skin cancer. The same developmental change is seen in individuals who live in colder climates. Obviously, they wear more layers of clothing due to the cold and are not exposed to high levels of solar radiation, so they have a fairer skin tone.
There are many examples of cultural adaptions to high levels of solar radiation. Individuals are able to protect themselves from the sun, ie. umbrellas, clothing, hats, and shelter. There is also sunscreen, however it doesn't one hundred percent protect us from the UVB rays. Sunscreen just allows us to stay in the sun for a longer amount of time without the worry of being sunburned.
The benefit of studying human variation across environmental clines is learning that not everyone reacts or adjusts the same way as everyone else. We get to see how people from different areas react to the same environmental changes. Information from explorations like these can help us understand better how individuals adapt to changes. Not every person will adjust the same because there are people with different environments than one another. This information can be used in a productive way by learning that some people are better adapted to high levels of solar radiation than others.
We use race to understand the variations of adaptions of high levels of solar radiation because there are certain races that are better adapted to the high levels of solar radiation. For example, the races living in tropical climates usually have darker skin tones since they have adapted to the high levels of solar radiation. However, the study of environmental influences on adaptions is a better way to understand human variation. We cannot expect to see a whole race react the same way to and environmental change. It is based on the individual and where they are on how one adapts.
The information you provided about solar radiation was stuff that I did not quite know. I knew why you became tan when sitting in the sun or burnt but the information you provided really help you understand the reasons why. Great job on this assignment.
ReplyDeletegood job explaining the project thoroughly, there is some very useful information. You explained the problems sun can cause to us. Good Job!
ReplyDeleteGreat job explaining the effects the sun has on the skin of humans. Your post was very knowledgeable and educational I learned things that I never knew before. Thank you for the great post.
ReplyDeleteVery good post. Good background description on the stress and your adaptations were well-described. You even picked up on the fact that we don't have a short term adaptation to solar radiation, which is why the stress is so dangerous. Well done.
ReplyDeleteGood discussion on the benefits of the adaptation approach. In your final section, you tend to give race more benefit of the doubt than I do. Why use race at all when you still end up just using the environment to explain the race? And how do you classify race? By appearance? If so, do all those with the same appearance live in the same environment? Race tends to lump people and ignores important variations that give us more information on how humans have developed. It is a cultural construct, not a useful biological tool.
Other than that point, good post.