Human Variation & Race

High levels of solar radiation

1.      High levels of solar radiation are an environmental stress that negatively impacts the survival of humans by disturbing homeostasis. Early hominins lived in the tropics where solar radiation is more intense, they spent their days outdoors, and didn’t wear clothing that would have protected them from the sun. Under these conditions, UV radiation was a powerful agent selecting for maximum levels of melanin production, which protects us from overexposure to UV radiation, in early hominins. However, it was shown that all albinos in dark-skinned populations had either precancerous lesions or skin cancer by the age of twenty. This evidence shows that even in early hominins of reproductive age, less-pigmented skin could have reduced individual reproductive fitness in regions of intense sunlight. Also, some studies have shown that UV radiation rapidly depletes folate serum levels both in laboratory experiments and in light-skinned individuals. These findings have consequences for pregnant women, for children, and for the evolution of dark skin in early hominins.

2.      Humans have adapted to high levels of solar radiation by developing dark skin as a protective response to the damaging effects of UV radiation.

3.      The benefits of studying human variation from this perspective across environmental clines are to show us how we came to be the way we are today.  There are reasons why humans in different areas have certain behaviors and characteristics and it can help us understand how more about ourselves. Information from explorations like this can be useful to help us in many ways such as learning from others’ experiences and perspectives. If one person gets the chance to explore an area while bringing back what they have found and experienced, we have one more way of gaining knowledge about something. This information can be used in a productive way by showing us new developments and cultures, as well as finding out new ways of life.

4.      I would use race to understand the variation of the adaptations by studying physical traits as well as cultural attributes. However, the study of environmental influences on adaptations is a better way to understand human variation than by use of race because instead of thinking of race as a physical attribute, we can think of race as a species. This way seems to be more promising, and gives a clearer and more detailed study.