Environmental stress can affect the survival of humans on a very negative scale. There are many different types of stressors but one of the worst is Solar Radiation. Humans have a granular substance in their pigment produced by their cells which is called Melanin; this helps to combat solar radiation but doesn’t stop it completely. It acts as built in sunburn because it absorbs UV light that could be very dangerous. Not everybody has the proper levels of melanin though and this can lead to serious consequences such as skin cancer.
One way that early humans adapted was to wear animal skins or other types of clothing wear blocked the UV rays. A second way was the protective mechanism of “tanning”. When the skin was exposed to sunlight the body started to and it temporarily increased melanin production. A third way was a bit of a longer adaption because it was the pigmentation of hominids from different places on the planet changed over time and stayed that color permanently. This meant that they were better protected against the UV rays from that area.
From this perspective human variation comes across very beneficial. This is good because it can help us discover other things such as new diseases or conditions that can arise as a result of the exposure to UV rays. This helped us learn about how the multitude of different pigmentations came to be that there currently are among the human race.
Different races or ethnicities have different pigmentation based on the areas that they originated from. Their pigmentation is based again on the melanin substance building the natural sun block against the UV rays that come from the sun. Environmental variations and influences are a better way to understand human variation than race because many people identify with different races rather than their ethnicity. Many individuals also have multiple ethnicities and may identify with one race more than the other.
In the first paragraph, did you mean "sun tan" instead of "sun burn"? :-) One is an adaptation, the other is harmful damage. Big difference!
ReplyDeleteI found your facultative, developmental, and cultural adaptations in your assignment, but not a short term biological (not cultural) adaptation to solar radiation? Can you think of one?
I agree with your assessment on the use of race to study human variation. It is the very fact that definitions of race are so confused and variable that makes it an impossible basis for study. There is not objective, biological way to define race.
BTW, I found it interesting to compare the hominid's face in the first image with Michael Jackson's face. Talk about a cultural adaptation!
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