Human Variation: The Effects Of Solar Radiation

   Solar radiation affects all of Humanity at different levels. The biggest factor in how people are affected by solar radiation is their location. The location of a group of people will affect the pigment of their skin due to the amount and type of melanin they have which is controlled by at least 6 genes. Melanin is produced by cells called melanocytes to detect and produce against ultraviolet rays. Ultra violet rays can be damaging to people in different ways ranging from sunburn to skin cancer.
   Humans have adapted to fight off the damaging effects of solar radiation in many different ways. Developmental adaptations were acquired through natural selection according to the location of a certain group of people. People who live in areas closer to the equator are more exposed to solar radiation and have a darker pigment with more melanin and produce a type called eumelanin, which helps protect them from damaging UV rays. While people in northern parts of the world with less direct exposure to solar radiation produce less melanin in a form called pheomelanin. These people such as European Americans are at ten times the risk of malignant skin cancers than darker pigmented skin people such as African Americans in the United States.
   Some people may have a higher exposure of solar radiation according to the time of year. During the spring and summer months people may be more exposed to solar radiation due to warm weather and longer days. As a short-term adaptation these people may tan and have a darker pigment than they do during the winter and fall seasons due to participating in more outdoor activities and wearing less protective clothing. When these warm seasons disappear or if they are on vacation in a location where solar radiation is greater then return home, their pigmentation and melanin levels will return to normal.
  A person who grew up and was raised in a region where solar radiation is high may have a darker pigmentation and higher melanin levels to help protect them from the danger of radiation exposure. If that individual moves to an area with much lower levels of solar radiation, in time their skin pigmentation will become lighter and their melanin levels may change. They may also become more prone to sun burn when visiting the place they have grown up in after years of adapting to less solar radiation as a kind of facultative adaptation.


Locals in Hawaii (personal pic)

Tourists in Hawaii

    Some cultural adaptations to help supplement the lack of melanin and to prevent damage from solar radiation are the use of items that offer protection against UV rays. Sun screens that contain SPFs offer protection against burns and when exposure to solar radiation is higher and more frequent, the potential for skin cancers. Items like sunglasses and sun hats also help protect against the radiation of the Sun's UV rays. When vacationing in a tropical climate or at your next trip to the beach, take time to notice whether individuals with lighter skin pigments are enlisting the help of items such as hats, and umbrellas more than the individuals who are local to the area and have darker pigments.
   Studying the effects of the adaptation of skin pigment and melanin due to solar radiation can be very useful scientifically and socially. It also allows us to understand why some people are more susceptible to the dangers of solar radiation to help develop ways to lessen the exposure to the threat. It also allows us to make advances in medicine and educate people on the damaging effects of solar radiation. Socially, it breaks down the barrier of misconceptions and the social stigma of race associated with skin color.
   Understanding the variation of adaptation in skin color allows us to see from a scientific standpoint why different people of different regions have the skin pigment that they do. It also allows us to see that color is no more that natures way of protecting people from the elements and not at all a reason for division of class, economic status or opportunity. Rather, it is nature's way of evening things out a bit by giving better survival tools to people in regions who need it most. In a way, skin color naturally makes us more equal rather than racially unequal.