Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for d
arker skin in these environments. On what evidence did she base this hypothesis? Darker skin is more prevalent in high-UV areas. Dr. Nina Jablonski proposed a hypothesis to explain the selective pressure for darker skin in these environments. On what evidence did she base this hypothesis? the melanin in darkly pigmented skin protects circulating folate from being destroyed by UV radiation, and folate is important in human reproduction the melanin in darkly pigmented skin protects DNA from UV radiation, and UV radiation can cause skin cancer people of African descent all have the same version of the MC1R gene, indicating that this gene was under selection she discovered that people of African descent have less folate circulating in their blood and that folate is important for human reproduction
The answer is; the melanin in darkly pigmented skin protects DNA from UV radiation, and UV radiation can cause skin cancer
In Africa, due to its equatorial latitude location, receives direct sunlight at more or less 90 degrees most of the year. These highly concentrated rays increase the UV radiation exposure that can cause damage to cell DNA. Selection pressure, therefore, favored individuals with high melanin concentrations that protect against UV. Therefore population evolved towards high melanin densities in the skin.
Bacteria have either DNA or RNA as genetic material. This genetic material must be able to replicate efficiently and accurately in order to make sure that offspring inherit the same genotype as the parent organism. This is possible because of genetic information.
Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
