Human Variation and Race

A high level of solar radiation is an environmental stress that can negatively impact the survival of humans by disturbing homeostasis.  UVA and UVB radiation are dangerous impacts resulting from sun exposure and can penetrate our skin deep into the dermis layer. Although this sounds dangerous some exposure to sun is healthy, it all has to be done in moderation. The pro of UV rays is that it allows our body to produce Vitamin D.  When our bodies are not exposed to these rays in moderation we can experience, what is called, overexposure the cons of this are: sunburns and damage to our skin which can result in skin cancer. On the opposing side, not enough Vitamin D being produced in the body can cause high blood pressure and skeletal deformities (seen in the pelvis).  Skin cancer and deformities are considered damage to our genetics and in result disturbs our homeostasis and negatively impacts the survival of the human species.

Short-Term Adaptation

Unfortunately humans do not have a short term adaptation to overexposure to solar radiation. In result we will burn without proper protection such as sunscreen.

Facultative Adaptation

A facultative adaptation that we have from UV rays is when our skin tans. The tan color of our skin occurs when we are exposed to these rays and sunlight; our bodies produce a protection in our skin with an increase in melanin.  The increase of melanin in our skin may last for a while, but with reduced exposure to the sun and UV rays there too, will be a reduction in melanin. This is why in the winter months everyone’s complexion is much fairer and in the summer much darker.

Developmental Adaptations

A developmental adaptation that has occurred is the natural color of our skin and the levels of melanin that make our skin color.  People with a low concentration of melanin are seen to be of much lighter complexions with those with a higher concentration are seen to be of a much darker complexion.  This difference is apparent and conclusive as we see individuals from Northern Europe with fair skin, blue eyes, and blonde hair; these individuals do not have a melanin protective barrier and thus will burn much easier. Those who live in much harsher sun exposed conditions such as areas in Africa are seen to have a darker complexion to protect them from the sun for much longer a period. Although these individuals have a longer tolerance, they too will burn if overexposed.

Cultural Adaptations

We as a society have come up with many cultural adaptations for protection from solar radiation.  Some of these include shelters, sunscreen, hats, umbrellas, and clothing.  Because of this our culture has seen a reduction for high levels of melanin needing to be produced in our skin.  Today people of all skin pigmentation are populated around the world due to travel and migration over many years.

The benefit of studying human variation across environmental clines allows us to understand and research the environmental stressors on individuals in certain populations depending on where they are or do over periods of time.  If we were to move individuals from their regular surroundings and what they have adapted to into a new environment, they too ‘overtime’ would adapt to their new surroundings.  An example of how this information from explorations can be useful to help us is how people with fair skin who live in the far north have an advantage if their skin ‘has little shielding pigmentation’.  When there is weak ultraviolet radiation the body will produce less melanin, because of this individuals with dark pigmentation will not be able to produce enough vitamin D in their bodies which can cause rickets disease and osteoporosis.  This information can help us understand the benefits and disadvantages of sun exposure and solar radiation on those with varying skin pigmentation; and also allows us to understand how these variations occurred over time.

I would use race to understand the variation of adaptations by distinguishing where in the world a group of people who have experienced very similar adaptations to stressors and where they have originated.  This will help us understand their ancestral traits and see how these traits may have developed over time.

The study of environmental influences on adaptations is a better way to understand human variation than by the use of race because we can see the how individuals have adapted to fit their environment over time.  This allows us to see patterns within people who are in the same environment or very similar ones.  It also allows us to see how humans can inherit and define our genetics whether it is to need a fair complexion or a darker one. It allows us to see that we are all the same and it is only our adaptations to the environment that is allowing us to define each other as different when we should not.