From an animal's tusk, it was worked into a small personal hygiene tool, inscribed with a modest wish, and eventually, ...

A familiar story about the evolution of alphabets is that individual letters originated in iconic representations of real things. Over time, these naturalistic pictures became simplified into abstract ...

they undergo evolution at a deeper level, too. That is, changes affect the "letters" (four different types of chemical units) in the genetic blueprints -- the genes-- that are carried in their cells.