While UV rays can cause skin cancer, because skin cancer usually affects people after they have had children, it likely had little effect on the evolution of skin color because evolution favors changes that improve reproductive success.
The only problem was that I couldn't remember where I had heard that. In fact, I wasn't all that sure that I was right. I know that the Roman Empire lasted rougly 500 years but how about the Egyptians, the Chinese, the Ottomons, etc. I thought that it would be interesting to explore different empires and see how long they lasted. In another article, I talk about the definition of civilization..
The period known as the Pax Romana was a span of time that lasted  about 200 years in the Roman Empire. During this time, there was  peace and prosperity in this empire. It â¦ was established by  Augustus, and it began in 27 B.C. and ended about 180 A.D. There  were five good emperors associated with this period.