The pigment in our skin is what makes us urn/tan. You dont see people with dark skin burn or tan, you just cant see it. I am sure they do burn/tan you just dont see it often. hope this helps sheltered whit girl

well anonymous is right, but also the darker your skin the longer it takes for you to burn, there is a vary of diffent skin types, 6 i think. type one is 15 mintes till you burn and 6 i think is an hour in a half.

We burn/tan due to a reaction in the skin. Sunlight partly contains Ultraviolet light, which can cause DNA damage, which can lead to cancer. In intense light the body protects itself by moving 'pockets' of melanin around the nucleus of cells, which is where the DNA is. Melanin is a dark pigment which absorbs the UV light, so protecting the DNA. This is why people tan. However, the amount of melanin that can be produced is dependent on genes (so the DNA itself). If you can produce a reasonable amount of melanin then the skin tans; if you don't have very much then you will burn before it can build up. People with naturally darker skin tend to be from very hot and sunny climates, so it makes sense to be born with plenty of melanin as there is always UV light around that can cause skin damage. White/paler people experience high levels of UV seasonaly, so the body saves energy by only producing a lot of melanin at important times.

Dark-skinned populations have developed darker skin in order to protect themselves from the higher concentration of UV rays in hot equatorial regions. As humans migrated northward into more temperate regions (i.e. Europe and NE Asia), natural selection favored light complexions in order to help people preserve vitamin D that was necessary for survival (or something like that). Therefore, less melanin was produced, and it came to be that in these more seasonal climates, people would produce more melanin when the UV rays were strongest, effectively resulting in tanning. The only people who can't really seem to tan but just burn are NW Europeans, in particular many British, Irish, and Scandinavian people. As you head southward through Europe, then into North Africa, and then finally sub-Saharan Africa (just as an example), skin tones get darker on average. Basically, you go from pale pinkish-white (the Celtic skin type that gets freckles), to generally pale skin that tans minimally (normal in northern and even central Europe), to a brunet white/light olive skin tone that tans well but can still burn (most typical for Italy, Spain, and other southern European countries), to light brown/medium brown (common in North Africa), to medium/dark brown in equatorial sub-Saharan Africa. With all of the above regions, you also have a little bit of overlap between the regions directly adjacent to each other due to the simple nature of human gene flow throughout history. Also to answer part of your question, Asians, particularly from NE Asia, can definitely burn. Many Japanese, Koreans, and N. Chinese are more on the fair-skinned side and can burn. Also some Middle Easterners, particularly those from Turkey, Syria, or Lebanon, are no darker than many southern Europeans and although such people normally tan pretty well, can also get sunburn. Hispanics from Latin America, who are generally a mixed population of European, Native American, and African origins (also depending on the country), will tan or burn according to their respective ancestry. Since most Hispanics in the U.S. are of Mexican origin, most are varying mixes of European (Spanish) and Native American roots. Thus, some are fairer-skinned, and others have the stereotypical light to medium brown complexions that many associate with Mexicans. Hope this helps!

more pigmentation in the skin cells