1. High levels of solar radiation negatively impacts the survival of humans by disturbing homeostasis. If too much ultraviolet radiation hitting one’s skin can cause the breakdown of one of the B vitamins- folate, which may result in anemia. Women who don’t have enough folic acid are at a higher risk of having miscarriages or babies with neural tube defects. Folate is also essential for DNA replication in the process of dividing cells, so a lack of it may result in the reduction of production of sperm cells. Also, the more sunlight children are exposed to, the greater chance they will develop multiple sclerosis. It also obviously causes skin cancer. Having dark skin in northern latitudes can prevent people from producing enough vitamin D and can result in rickets disease in kids and osteoporosis in adults.
2. An example of a short term adaptation humans have to cope with high levels of solar radiation is perspiration. One loses heat through many sweat glands in evaporative cooling. Perspiration is considered to be the "most important factor in heat dissipation" according to the book.
An example of a developmental adaptation is the presence of the pigment called melanin. The number and size of melanin particles as well as the percentages of different kinds of melanin determine skin color. If someone has a higher percentage of pheomelanin their skin will probably be more red to yellow color, and those who have a higher percentage of eumelanin will
probably be more dark brown to black colored
.
An example of a developmental adaption is the presence of the pigment called melanin. The number and size pf melanin particles as well as the percentages of different kinds of melanin determine skin color.If someone has a higher percentage of pheomelanin their skin will probably be more red to yellow color, and those who have a higher percentage of eumelanin will probably be more dark brown to black colored.
Examples of cultural adaptations are sunglasses, hats, clothes and sunscreen. Before people spend a day in the sun, they will usually apply sunscreen to prevent or reduce risk of skin damage and tanning. People also wear sunglasses, hats and extra clothing (beach cover-up) to protect themselves from solar radiation.
3. It is beneficial to study human variations from this perspective across environmental clines because it helps to show why certain people have health problems, or are healthier than others or have the skin tone they do, or why it is beneficial to have the skin tone that they do. By looking at the clines of solar radiation (where melanin is protective) versus clines of solar vitamin D absorption (where melanin is not protective) it shows that in areas where UV protection is needed, skin color is darker, and where people need more vitamin D more than they need UV protection, their skin is lighter. By using UV radiation as a factor in studies like malnutrition among children indicating high frequencies of rickets disease, or vitamin D related to healthy pregnancies, it can be useful to figure out that certain people need more vitamin D, or need to be in the sun less or more to be healthier. In a study published in the Journal of Nutrition, researchers found that prenatal vitamins should contain higher doses of vitamin D, especially in the northern US. 16% of African Americans and 53% of European Americans had enough vitamin D in their bodies at the end of their pregnancies. Therefore, the information that was gathered from UV rays’ connection with vitamin D, and anthropological studies became the basis of further research for human nutrition and pregnancy.
4. Race is influenced by levels of solar radiation, especially in the developmental adaptation of the presence of melanin. Race is the result of the adaptations, especially those that are genetic and longer lasting. Race is the result of different environmental clines and the different makeup of melanin in individuals. It is one of the many adaptations to deal with high levels of solar radiation. The study of environmental influences on adaptations is a better way to understand human variation than by the use of race because race is the result of many different adaptations. These adaptations are what is a key to these major variations and changes in the appearance and makeup of humans. Environmental influences are what must be studied in order to learn about why there is variation among humans, especially skin color. It is interesting to learn why there is variation, because it shows that our bodies are influenced by many simple things that we wouldn’t even think of like the sun or altitude.
"Race is the result of the adaptations, especially those that are genetic and longer lasting."
ReplyDeleteThis was perfect! Yes, race is the result of our adaptations (and human attempts to categorize them), not a way to study them.
Does sweating help protect us from radiation or from heat stress?
Missing the facultative adaptation. You have the developmental trait section copied twice, so looks like it didn't transfer to Blogger well.
I did not know that too much solar radiation can cause a miscarriage and so many other diseases. I liked how you referred to race by the environmental stress and the color of their skin rather than by region of the world they are from.
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