Final answer:
Melanin is the main pigment that determines skin color. It is produced by melanocytes and protects against UV ray damage. Skin pigmentation varies across geographical regions as an evolutionary adaptation to different environments.
Step-by-step explanation:
Melanin, carotene, and hemoglobin are the pigments that contribute to the color of human skin. Melanin, produced by melanocytes in the epidermis, is the main pigment that determines skin color. Different amounts and types of melanin result in variations in skin color among individuals. Darker-skinned individuals produce more melanin than those with pale skin. Exposure to UV rays stimulates the production of melanin, which helps protect the DNA of skin cells from UV ray damage. However, excessive melanin can interfere with the production of vitamin D.
The distribution of skin color on Earth is influenced by geography and evolutionary adaptations. Darker skin is believed to be an evolutionary adaptation that helps protect against the damaging effects of UV radiation in sunny regions. On the other hand, lighter skin allows for the production of sufficient vitamin D in regions with less sun exposure. Therefore, skin pigmentation has evolved to help humans thrive in different climates and environments.