High levels of solar radiation can be dangerous to humans state of homeostasis. Melanin, which is a skin pigment responsible for protecting our skin from radiation, has two forms-pheomelanin and eumelanin, which come in different completions and sizes which determine skin color based on geographical location. For example, people who have more pheomelanin and less eumelanin result in having fair skin, putting them more at risk of the damaging UVA and UVB rays which cause various types of skin cancer that can even result in death. Likewise, people with the opposite composition of melanin result in darker skin which can also be negatively impacted by solar radiation. These people can have too much eumelanin which can severely limit their absorption of the nesecary amounts of UVB to produce vitamin A. If such an example should occur, it can result in pelvic deformations that inhibit child birth, rickets which softens bones in kids, and osteoporosis which make bones brittle and prone to breaking in adults.
However, humans are resilient and have found ways to prevent such damage. A short term adaptation, also know as a genetic response which will return to homeostasis shortly, is the appearance of a sunburn. The skin turns red from burning to warn us that we need to get out of the sun or find a remedy for the exposure.
Tanning is a facultative response in that the body temporarily changes its genetic expression so to protect itself from the radiation. This phenotype will return to its normal expression of pale skin when the stressors of intense sun is gone.
A developmental adaptation is the passing down of the eumelanin rich skin to offspring. Tribes in Africa exhibit this trait as it has helped them to survive natural selection this passing down to the current generations.
A cultural adaptation is in that fair skinned humans use sunscreen almost religiously to protect their skin from damage in sunny locations. This would be cultural as sunscreen is a tool and a social practice but not in a persons genetic make up.
Using these adaptations is a better way to understand race as it explains the human species variations as a result of our environments, not as an innate supremacy or marker of biological worthiness. That our visual differences are simply a result of our geography.
*I apologize for it being late, Time Warner had a wifi outage which didn't come back in time for me to submit it so I had to re-type it on my phone which was not fast enough.
