Human Variation and Race Blog Post
1.) Solar radiation is an environmental stress that negatively impacts the survival of humans by disturbing homeostasis. Solar radiation comes into the Earth in form of radiation rays. These rays can disturb our skin. One example of such rays are UVA rays. These rays, when the skin is in contact with them for too long, can go through the epidermis layer of the skin and affect the skin cells in the skin negatively. These rays can cause defects in the skin cells that can lower the amount of protection they give against these rays. The more the skin cells are in contact with those rays, the cells will start dying off, which leads to less protection of the skin from the UVA rays. As more and more of these cells deform, the person will be more prone to getting skin cancer, which can disrupt homeostasis in the society. The person’s physiological conditions change by being prone to skin cancer, and this disadvantage can pass onto their future children.
2.) Short term: Humans are still adapting to solar radiation to this day. But some adaptations that are being used today is sweat, flushed skin, and the immediate need for something cold. When one or all of these happens to our body, it is signaling to the human that he or she needs to find some shade or go somewhere to cool down. This is a short term adaptation humans have developed to solar radiation.
Facultative: One example of a facultative adaptation to solar radiation is the tanning of skin. When the skin is exposed to too much UVA radiation, our skin becomes darker due to a high amount of melanin produced. This is slightly different from short term adaptation because tanning changes a human’s phenotype, darkening the skin. Tanning will take some time for the skin to become the shade it was before, which makes it facultative.
Developmental: Throughout time, people in different environments have genes that have changed depending on the environmental circumstances. For example, humans in places such as Africa have darker skin, but have almost the same risk for skin cancer for people that live in North America. Why is that? Well the genes of people in Africa have developed genes from birth to deal with the excessive heat. Their genes are the same as all humans, but are more stronger against the sun.
Cultural: Many clothing items have been made to provide protection against the UVA rays. Some of these products are hats and sunglasses. Throughout time, humans have developed such clothing item to help against the solar radiation, making it a cultural adaptation.
1.) Solar radiation is an environmental stress that negatively impacts the survival of humans by disturbing homeostasis. Solar radiation comes into the Earth in form of radiation rays. These rays can disturb our skin. One example of such rays are UVA rays. These rays, when the skin is in contact with them for too long, can go through the epidermis layer of the skin and affect the skin cells in the skin negatively. These rays can cause defects in the skin cells that can lower the amount of protection they give against these rays. The more the skin cells are in contact with those rays, the cells will start dying off, which leads to less protection of the skin from the UVA rays. As more and more of these cells deform, the person will be more prone to getting skin cancer, which can disrupt homeostasis in the society. The person’s physiological conditions change by being prone to skin cancer, and this disadvantage can pass onto their future children.
2.) Short term: Humans are still adapting to solar radiation to this day. But some adaptations that are being used today is sweat, flushed skin, and the immediate need for something cold. When one or all of these happens to our body, it is signaling to the human that he or she needs to find some shade or go somewhere to cool down. This is a short term adaptation humans have developed to solar radiation.
Facultative: One example of a facultative adaptation to solar radiation is the tanning of skin. When the skin is exposed to too much UVA radiation, our skin becomes darker due to a high amount of melanin produced. This is slightly different from short term adaptation because tanning changes a human’s phenotype, darkening the skin. Tanning will take some time for the skin to become the shade it was before, which makes it facultative.
Developmental: Throughout time, people in different environments have genes that have changed depending on the environmental circumstances. For example, humans in places such as Africa have darker skin, but have almost the same risk for skin cancer for people that live in North America. Why is that? Well the genes of people in Africa have developed genes from birth to deal with the excessive heat. Their genes are the same as all humans, but are more stronger against the sun.
Cultural: Many clothing items have been made to provide protection against the UVA rays. Some of these products are hats and sunglasses. Throughout time, humans have developed such clothing item to help against the solar radiation, making it a cultural adaptation.
3.) Studying human variation in terms of environmental clines would be beneficial for humans. This is because when studying human variations in different environments, we can observe how human’s DNA has changed overtime due to environmental changes and natural selection. Scientists can see how humans have evolved over time. For example, in regards to solar radiation, by studying human variation we can see how our skin’s genotype and phenotype have changed overtime to deal with solar radiation.
4.) The only way you can use race, in the terms of solar radiation which I have discussed above, is by looking at the skin colors of different races. You can observe how different races have developed different skin colors overtime due to different amount of exposure to the sun. Other than that, there is no other way race can really play a part in human variation in the topic of solar radiation and its effects.
Good description of the dangers of solar radiation. Do we gain any benefit from solar radiation that might complicate how we adapt to this stress?
ReplyDeleteShort term: Understand that solar radiation stress and heat stress are not the same thing. If you have been skiing before, you know that your face can get sunburn on a sunny day, even with temperatures dropping well below freezing. The adaptations you talk about here are to heat stress and don't help with the complications of solar radiation stress. Unfortunately, humans don't have a short term response to solar radiation stress, which is partly why this is such a dangerous stress.
Good discussion on your facultative trait.
I agree with your developmental trait, but this was a bit confusing:
"For example, humans in places such as Africa have darker skin, but have almost the same risk for skin cancer for people that live in North America."
This doesn't make sense as written. Equatorial populations, having evolved darker skin than populations from higher latitudes, have developed a lower incidence/risk level of skin cancer than lighter skinned populations. Was this mis-written?
Good cultural discussion.
I agree that knowledge is always useful, but can you identify a way this knowledge can be useful in a concrete way? Can knowledge on adaptations to solar radiation have medical implications, for cancer treatment or dietary applications (related to Vitamin D absorption)? Help us develop clothing that protects us from harmful rays but allows for Vitamin D absorption? Can we develop new windows for construction that provides a similar protection? How can we actually use this information in an applied fashion?
"You can observe how different races have developed different skin colors overtime due to different amount of exposure to the sun."
Are you actually using race here or are you just using the adaptive approach and layering race over-top of the results? Can you actually use race to explain human variation? Understand that it is entirely acceptable to answer this with a clear "no".
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.