As anyone who has spoken to me more than about forty seconds, I'm a biologist at heart and an evolutionist by inclination. Consequently, I tend to think about things such as marital relationships, love, art, lifespan and nearly everything else within a biological and evolutionary context.
This article came across my desk recently, thanks to Jerry Coyne's blog, why evolution is true.
There are very few things as fundamentally human as our faces. Other animals use scent, sounds, color displays and bodily fluids to exchange personal data with one another. We use the expressions on our faces.
But faces, like everything else about us, came from our forebears and are not completely unique to human beings. Anyone who's ever owned a dog knows that dogs have expressions showing their inner state.
Now we know that our face came from fishes.