Human Variation & Race Blog
1. Select only ONE of the following environmental
stresses: high levels of solar radiation Discuss specifically how
this environmental stress negatively impacts the survival of humans by
disturbing homeostasis.
Too much ultraviolet
light can cause irreversible damage to DNA and important photosynthetic
structures, while too much infrared light can cause overheating. DNA damage is
caused by UV-B radiation. While most living cells have adapted and can repair
simple damage, increased exposure to UV radiation can cause cells to mutate
beyond repair, or to die. Overexposure to UVB radiation, which is directly
absorbed by the DNA within cells, can potentially cause genetic damage leading
to skin cancer, it is the more harmful of the two types of UV radiation. This
damage at the genetic level disturbs homeostasis and is life threatening to the
species.
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 adaptation
Facultative adaptation


Developmental adaptation
Nature has selected for
people with darker skin in tropical latitudes, especially in nonforested
regions, where ultraviolet radiation from the sun is usually the most
intense. Melanin acts as a protective biological shield against
ultraviolet radiation. By doing this, it helps to prevent sunburn damage
that could result in DNA changes and, subsequently,several kinds of malignant
skin cancers.
Cultural adaptation
As a result humans have used
sun screen to avoid the amount of radiation that effect their skin. In order to
protect skin from the sun people wear hats and try to avoid the amount of
exposure. This in turn has caused a large amount of the population to be
vitamin D deficient.
3. In my opinion there is
many benefits of studying human variation across environmental clines. By
studying variation across environmental clines we learn how to adapt to the ever
changing enviroment and the negative and positive affects that they have on us.
They help find a solutions to some diseases and help us understand who gets
affected and why.
4. I would use race initially to understand the
variation of the adaptations to try to see who would be more at risk of getting
affected by high levels of solar radiation. The study of environmental
influences on adaptation is a better way to understand human variation than the
use of race. People of a certain race have many different traits within the
same race. Race should not be the only thing considered.