Sandro Botticelli, The Birth of Venus, Oil on Canvas, 1484–1486
Venus of Willendorf, Limestone, 28,000 B.C.E – 25,000 B.C.E.
This is going to be a very typical comparison that you may find in every intro art history book. It's simple as this. These two works are distinctive representations of Venus. In Botticelli's Birth of Venus, the goddess of beauty and love is manifested as a female whose body is perfectly proportioned and light skinned. Also she's got that rosy cheeks that make her look as lively and cheery.
The Venus figurine from 22,000 B.C.E., on the other hand, has far different characteristics on its physicality. You can't draw many beauty standards from this particular work, but one thing is clear: she's got huge breasts and hips. Probably that was the parameter of female beauty ideal many centuries ago.
This is just a tiny snippet of what art history can tell us about female beauty ideals. Why don't you start looking around female images (time has changed, but there are still so many! probably in different contexts though) at BBuzzArt and you can point out what is considered gorgeous and beautiful in our time. This could be a fun game!