according to evolutionary biologists, european evolved light skin 18 000 years ago because one individual mutated his genes that gave light skin and spread it. according to the same evolutionary biologists, the european population 18 000 years ago was around 10k. so now here's the part that I don't get, so if the European population was 10 thousand 18k years ago and one of them got the gene for light skin, how come today there are billions upon billions of brown people and not a single one of them have evolved the same gene that gave Europeans light skin? makes no sense