Ultraviolet light can penetrate the skin and damage DNA, and it can also destroy the B vitamin folate needed for bone-marrow maturation and the development of red blood cells. On the other hand, exposure to ultraviolet light is beneficial in the synthesis of vitamin D3, which is important for growth, calcium absorption, and bone development. The amount of ultraviolet light that penetrates the skin depends on the skin's pigmentation: more melanin (skin pigment) means less penetration. Which of the following do you think would BEST describe the pressure of natural selection on human skin pigmentation?

Question

Quizplus · Accepted Answer

Natural selection would favor individuals with darker or lighter skin depending on the intensity of UV in their geographical region. In areas with high levels of UV exposure, natural selection would favor individuals with darker skin to provide more protection against the harmful effects of UV radiation. In areas with low levels of UV exposure, natural selection would favor individuals with lighter skin to allow for the synthesis of vitamin D3. Therefore, there would be a pressure for either darker or lighter skin depending on the environmental factors.

Ultraviolet Light Can Penetrate the Skin and Damage DNA, and It