NEW YORK - NOVEMBER 15:  A 'Tree of Life' sketch is seen in Darwin's 'B' notebook at a press preview of the new 'Darwin' exhibition at the American Museum of Natural History November 15, 2005 in New York City. The exhibition traces the life and discoveries of Charles Darwin and will be on view from November 19, 2005 through May 29, 2006.  (Photo by Mario Tama/Getty Images)