Description: Human skin color can change in response to environmental changes (i.e. getting a sunburn or a suntan). However the root cause of our skin color is genetic and comes from our ancestors. UV radiation causes damage to the DNA in our cells and can lead to various forms of cancer. If your ancestors lived in an area that received large amounts of UV radiation (i.e. closer to the equator) humans evolved darker skin for protection through the process of natural selection. However light is also important since it allows humans to synthesize vitamin D. Therefore if your ancestors lived in an area that receives little light (i.e. near the poles) they evolved lighter skin.
Web Resources: Human Skin Color - Wikipedia, The Biology of Skin Color - HHMI
