HUMAN BRAIN
HUMAN BLOOD*.
HUMAN BONES
Why isn't it the same with our skin color?
THE SCIENCE BEHIND SKIN COLOR
Source: Dept. of human evolutionary biology
Different wavelengths of light are reflected or absorbed by a pigment on the top layer of our skin Melanocyte Melanin MELANIN
Eumelanin Pheomelanin Melanocyte Melanin The more the Eumelanin, the darker the skin
North Pole Arctic Circle 60 N Low Angle of Lin Incoming Sunlight 30 N Tropic of Cancer Equator Sunlight Strikes Sun Most Directly Tropic of Capricorn 30 S 60 S Antarctic Circle Low Angle of Sun Incoming Sunlight Atmosphere South Pole
Arctic Circle 60 N Low Angle of Lin Incoming Sunlight 30 N Tropic of Cancer 50,000 years ago Equator Sunlight Strikes Sun Most Directly Tropic of Capricorn 30 S 60 S Antarctic Circle Low Angle of Sun Incoming Sunlight Atmosphere South Pole
Before After: Incoming UV photon Damage to DNA when skin is overexposed
UVA UVB UVA UVB The melanin in skin determines how protected you will be from the sun
Some of our ancestors who were adapted to the tropic spread to other parts of the world
What happened in the north?
Vitamin In
Risk of Vit D deficiency due to lack of optimal UV exposure