Solar Radiation

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.
   - High levels of solar radiation is probably the most disturbing environmental stressor that could impact the survival of humans because of the relatively recent rise in the world's pollution which has affected how the Earth's atmosphere protects us from solar radiation. Solar radiation can directly cause mutations in our DNA, resulting in cancers and degeneration of healthy tissues. The more pollution we create the more we disturb the Earth's homeostasis, and ultimately our own.
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, facultative, developmental and cultural). Include images of the adaptations.
   - There are no short term adaptations to solar radiation.
   - An example of facultative adaptation to solar radiation is tanning. This adaptation will occur if the skin is exposed to sunlight more than it usually is, such as during the hotter seasons. As long as there is prolonged exposure to sunlight, an individual will gradually adapt a darker skin tone by increasing the production of melanin, thereby protecting the individual over the course of the hotter season. But this is temporary as the skin will return to it's normal skin tone when the environmental stress is removed during the colder season.
   - Developmental adaptations are long-term adaptations that have evolved in larger groups or populations as a result of long-term climate and altitude conditions. For example, humans from Africa have evolved to produce much more melanin in their skin than humans from Northern Europe, because of the differences in the exposure of solar radiation. Darker skin protects us from the sun's harmful rays, but in colder, less sunny areas like Europe it was probably more necessary to have lighter skin, resulting in Europeans having to produce considerably less melanin than their African counterparts.
   - Cultural adaptations to solar radiation include using sunscreen, wearing protective clothing, or seeking shelter to stay protected from the sun's harmful rays. We have all experienced a sunburn at some point in our lives, and know how painful it can be when we fail to stay protected. These adaptations are cultural because they are not passed on through our genes but rather through our behaviors. We can only teach the next generations about the dangers of solar radiation and only hope that they never EVER step foot inside a tanning salon.
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.
   - There are definitely benefits to studying human variation because in studying how solar radiation affects humans across the globe we can further understand why we have evolved the way that we have and where we may be headed in the future. We may come to realize that our homeostasis is becoming increasingly disturbed and if that happens to be the case, our survival may just depend on what we decide to do with that information. Cancer research may help to provide us with clues as to how our environment alters our bodies, and if we find that our own environmental pollution is the cause of these cancers, we may eventually be forced to change the way we use up the Earth's resources, which will help us to ensure human survival in the long-term.
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.
   - If I had to use race in an attempt to understand human variation it would only be discriminatory because race does not really explain human variation at all. Skin color simply correlates with exposure to sunlight and altitude and is not a good way to determine human variation. It turns out we are all more genetically similar than we may appear on the outside. And when studying local “racial” groups we also find more diversity than we would have otherwise expected.