In 1837, Charles Darwin sketched a stick-figure tree in a page of Notebook B, one of many private notebooks in which he worked out the details of a new theory he was developing. The tree had spindly branches and a single root labeled with the number "1." Scrawled at the top of the page, in Darwin's cursive handwriting, are the words "I think."

Notebook B will be one of many items on display in "Darwin," a new exhibit opening on Nov. 19 at the American Museum of Natural History (AMNH) in New York. "Darwin" will be the most comprehensive exhibit ever mounted on the British naturalist, whose ideas transformed biology and sparked a religious debate that is playing out in courtrooms, statehouses and school board meetings across the United States.

The exhibit begins with Darwin's voyage upon the H.M.S. Beagle, the ship that carried him to the Galapagos and South America. On display will be a mini-menagerie of animals seen by Darwin during his voyage, including two live Galapagos tortoises, a five-foot long green Iguana and six horned toads.

The exhibit then turns to the Down House, a small farmhouse on the outskirts of London where the naturalist spent the last 40 years of his life. The exhibit includes a faithful reconstruction of the study where Darwin churned out more than 7,500 letters and wrote "The Origins of Species," the book in which he described his theory of natural selection.

The exhibit will also contain a section devoted to Darwin's daughter, Anne, who died at age 10 after an illness. Darwin buried his religious faith when he buried Anne, and he was an agnostic when he died in 1882.

Films and interactive displays will be on hand to help illustrate the importance of Darwin's theory in modern biology and to show how scientists rely on evolution in everything from decoding the human genome to understanding diseases like HIV/AIDS and avian bird flu.