Re: How did human beings have different skin colors if we evolved the same

	All humans alive today are members of the same species, Homo sapiens. 
Genetically, we are 99% identical (chimps and humans are over 98% 
identical). That other 1% contributes to the differences in size, shape and 
appearance we see in one another. Skin color is determined by the amount of 
melanin in the skin. Melanin is produced by special cells called 
melanocytes. With rare exceptions, we all have a similar number of 
melanocytes. However, those with darker skin have an increased rate of 
melanin deposition. Sun exposure also increases the rate of melanin 
deposition, the process called tanning. Thus, light and dark skinned people 
have the same pigmentation machinery, the only difference is the "speed" at 
which it is running, and that speed is modified by environmental 
circumstances. Darker skin is thought to be protective against the harmful 
UV rays, which would be advantageous in tropical regions.

	For more information regarding the pigmentation process, consult any 
Dermatology textbook. (Dermatology is medical specialty that studies skin.)