1. Select only ONE of the following environmental stresses: (a) heat, (b) high levels of solar radiation, (c) cold, or (d) high altitude. Discuss specifically how this environmental stress negatively impacts the survival of humans by disturbing homeostasis.
One negative environmental stressor that affects the survival of humans by disturbing homeostasis is high level of solar radiation. There are two types of solar radiation, one is UVA, and the other is UVB. UVA radiation can hit the dermis layer of skin causing damage when overexposed. UV radiation, when it touches the skin stimulates the production of vitamin D. Overexposure over a long period of time can cause genetic damage that may lead to skin cancer.
2. Identify 4 ways in which humans have adapted to this stress, choosing one specific adaptation from each of the different types of adaptations listed above
Short Term
When exposed to the suns UV ray for too long is causes a sunburn. Vitamin D is absorbed in the melanin, which causes skin tone, in fair skin tones, longer exposure can cause sunburns. People with darker skin tones produce more melanin allowing for more protection from the suns rays
Facultative
When we tan, the constant exposure to UV rays causes a steady production of melanin, in the summer months, peoples skin naturally darken as a response to longer periods of sun exposure
Developmental
In regions where there is a high density of UV radiation, you see higher concentrations of darker skinned people. So when you have a high number of darker skinned people natural selection comes into play and people are born with higher levels of melanin. In areas where there isn’t as much sun, skin tends to be lighter to absorb more vitamin D. Over exposure and under exposure are both equally dangerous to the species, over exposure can cause skin cancer, and prolonged limited exposure can weaken the bones.
Cultural
Shelter, clothing and sunscreen are all examples of cultural adoptions to UV radiation, over time human thought of a way to control their bodies exposure and from there became normal part of life
3. What are the benefits of studying human variation from this perspective across environmental clines? Can information from explorations like this be useful to help us in any way? Offer one example of how this information can be used in a productive way.
By studying humans adaption’s to the sun and their environment we can see that both populations have different diseases that are in direct contribution to exposure to the sun. Studying these diseases like rickets and sickle cell anemia by studying populations and regions they live in, we may be able to find cures in all populations.
4. How would you use race to understand the variation of the adaptations you listed in #2? Explain why the study of environmental influences on adaptations is a better way to understand human variation than by the use of race.
Race would only be used to classify geographic groups of people who have similar sets of adaptations to the same environment. In this way, we can see how our ancestors developed and changed over millions of years and understand our origins more fully.
Overall, great post. Good job bringing up the issue of understanding sickle cell anemia through this approach.
ReplyDeleteTwo points:
We really have no short term adaptation to radiation stress. A sunburn is not an adaptation... it is a failure to adapt rapidly enough to this stress.
What are the problems with using race in studies like these? You say how you would use it but you don't identify the problems with it that are corrected by using the clinal analysis.