NPR science 7:43 am Thu September 13, 2012  For How Long Have We
Been Human?  A piece of red ochre with a deliberately engraved
design is pictured here at Cape Town's Iziko/South African
Museum in 2002. The piece was discovered in Blombos Cave near
Stilbaai, about 300 kilometers from Cape Town. Credit Anna
Ziemenski / AFP/Getty Images  Originally published on Thu
September 13, 2012 7:04 am     2.5 mya: First human ancestors in
our own genus, Homo  200,000 years ago: First modern humans,
Homo sapiens  30,000: Cave paintings and rock paintings begin to
emerge on multiple continents  Around 12,000: Onset of
agriculture and human settlements. Up until this period, all
human groups lived by hunting and gathering. (This transition
was neither linear nor simple.)  Does one date, midway in the
pack, snag the eye? 200,000 years ago, Homo sapiens emerged.
That's us.  But can we really affix a date to becoming human?
Here's a question too complex for first-day-of-class lists. I've
written elsewhere that I love my field