Final answer:
Skin color variation is due to evolutionary adaptations to UV radiation, with dark skin protecting against UV damage in sunny regions and light skin aiding in Vitamin D production in less sunny areas. Latitudinal mismatches in skin tone can arise from human migration and other factors.
Step-by-step explanation:
The variation in skin color among humans can be attributed to evolutionary adaptations to varying levels of ultraviolet (UV) radiation in different regions of the world. Skin color - why does it vary? It does so mainly because of melanin, the pigment that determines skin color, and the process of adaptation to UV radiation exposure. Dark skin is rich in melanin, which protects against the harmful effects of UV radiation and is predominant among populations in areas with high sun exposure, providing an evolutionary advantage. Conversely, in regions with less sunlight, such as northern Europe, light skin offers the advantage of producing adequate amounts of Vitamin D, which is crucial for immune functions and bone health.
Latitudinal mismatches, where skin color does not seem to correlate directly with the level of UV exposure, may occur due to migration, cultural practices, and the interplay of other evolutionary factors. Over time, as humans migrated and adapted to new environments, these variations developed and spread. Today, a spectrum of skin tones can be observed along geographical gradients, though they do not always reflect current UV levels due to historical migrations and modern global movement.