A short term adaptation that happens to the body when it starts getting hot is that sweat starts to be releases from the pores in order to lower the temperature in the body and return to homeostasis.
A faculatative adaptation that happens because of the sun rays is that people who are exposed to much higher UV rays tend to have darker skin to help the amount of sun rays the body captures. The chart above illustrates the different skin colors according to the location.
A developmental adaptation happens throughout generations due to alot of sun that with time the body develops a certain metabolism that reaches a certain temperature that is homeostasis.
Cultural adaptation when it comes to high solar rays is influenced by the location. People who live in hot tropical temperature wear less clothes and spend more time outside than people who live in the cold temperature.The benefit from studying humans variation across environmental cine is that allows us to explore the possibilities of genes that are evolving. It also helps us learn more about distinguished traits that certain cultures have passed on through generations.
Race has much in the understanding of variations because every culture is different that have certain traditions that have allowed them to survive. Due to the different cultures this will allow us to compare the techniques of different cultures that will allow us to understand the geographic and requirements of surviving every different origin of race.
Great post, wonderful pics! I did my blog on heat and after reading your blog they both kind of relates to each other. I actually feel like race plays a part in understanding variations but not the major role. I didn't know anemia was effected by high levels of solar in environmental stress. Good job!
ReplyDeleteIn general, good explanation of the dangers of solar radiation, but make sure you tell the whole story. You mention anemia, but solar radiation itself does not cause anemia. High exposures to solar radiation can break down the vitamin folate (related to B9, folic acid), which can cause multiple problems, including anemia and also reproductive problems, such as spontaneous abortions. This is why taking folic acid supplements are usually so important for pregnant women.
ReplyDeleteUnfortunately, a short term adaptation does not exist for solar radiation, which is why it is such a dangerous stress. Sweating is a response to heat stress, not solar radiation.
There are two ways you can develop darker skin. You can acquire it by tanning, which is the temporary development of more melanin in the skin. This is a facultative trait. You can also have the genetic coding for producing a higher base level of melanin, as found in populations living in environments with higher levels of solar radiation year round, such as equatorial populations. This is a developmental trait. It isn't clear from your discussion of the facultative trait that you understand this distinction and it is complicated by your image which actually displace the levels of base level melanin level in global populations, i.e, it is displaying developmental trait, not the facultative trait. In fact, you use the phrase "tend to have", indicating a possession of a developmental trait, not facultative.
You go in the next section to describe melanin levels as a developmental trait, so you have that correct, but you haven't explained how the faculative expression of melanin levels if different from the developmental expression.
For your cultural adaptation, are you identifying an adaptation to solar radiation or heat? In areas with high levels of solar radiation, wouldn't you want to shield the body from the sun (if you didn't have dark skin already)? The amount of clothing you wear is really an adaptation to heat (or the lack thereof) not solar radiation. Cultural adaptations for solar radiation would include protective clothing (think of the full body covering of Saharan populations) or even relatively new tools such as sun screen.
I agree with the scientific benefit of using the adaptive approach, but is there a more concrete, applied benefit? Can we use the information to develop other tools/clothing that might help us adapt to solar radiation? Could there be medical applications for this type of information?
Where does the concept of race come from? Is it genetic/biological? Or is it a social construct, originating as a way to classify and organize humans into categories based upon superficial, external phenotypes? The answer is the latter.
Because race is an artificial creation of humans, not something arising from our genes, it is subject to cultural bias. Different cultures have different systems of race. Which system would we use? And in order for race to explain human variation, it would have to have a causal relationship with variation. The environment has that causal relationship with human variation, which is why it *can* explain variation. Does race have that causal relationship? Does race cause variation? Or does race only lump humans into different groups, with no explanation of why those groups exist? Again, the correct answer is the latter, and without this causal relationship, race cannot be used to explain human variation.
Good images.