From love letters to a thimble, Darwin on display

NEW YORK -- Charles Darwin, the father of evolutionary theory, was born to pious parents and raised a creationist. Stubborn and strong-headed, he hated school and did poorly, leading his despairing father to deride him as a dilettante who cared only for ''shooting, dogs, and rat catching."

The prodigal son eventually found his way to Cambridge University, where he promised to hunker down and study for the clergy. It was here that he met the Rev. John Stevens Henslow, a renowned professor of science who nurtured Darwin's growing fascination with the natural world. In 1831, Henslow arranged for his charge to fill the post of ''unpaid naturalist" aboard the HMS Beagle, a 90-foot, two-masted Royal Navy ship embarking on a voyage around the world.

The rest is history -- a history on magisterial display through May at the Museum of Natural History in New York and then, from Feb. 18 to April 27, 2007, at the Boston Museum of Science.

The Darwin exhibit is a spicy and enormously satisfying melange of history, science, and human interest -- just the right mix to catch and hold the attention of the most reluctant attendees, who, like my teenage daughter Joanna, anticipate a morning at a museum as a morning wasted.

Even Joanna could not resist the juicy love letters Darwin wrote to his beloved wife, Emma, or the sluggish iguana basking inert as a fossil in the glow of its own personal heat lamp.

We recoiled at the cramped quarters the 22-year-old Darwin shared with another man on his arduous voyage (''He slept in a hammock for five years!") and at the paltry personal effects he stowed on board: a pistol the size of a hummingbird, a worn Bible.

And we gasped, as Darwin himself must have, at the fun house menagerie he encountered on his survey of South America -- the blue footed booby, the Day-Glo orange lightfoot crab, the pillow-shaped horned toad nicknamed a ''mouth on legs" -- all of which served to change his mind about humankind's place on earth.

The collection is ingeniously and artfully arranged to allow visitors to experience for themselves Darwin's fateful journey of discovery. A glass case holding a rock hammer gives evidence of Darwin's deep fascination for geology. Noting that the earth is not static but is subject to violent upheavals through faults and earthquakes helped shape his later ideas of how animals and plants might change over long periods of time.

The exhibit displays swashbuckling scenes from Patagonia, where Darwin galloped across the pampas accompanied by gauchos who fed him a Christmas dinner of spit-roasted rhea, an ostrich-like bird. Subsequently observing rheas of a somewhat different form about 100 miles farther south led Darwin to question why an all-knowing creator would design two varieties of rheas when one seemed more than adequate.

Likewise, in the Galapagos he marveled that tortoises varied from island to island and that natives of the archipelago could tell instantly the provenance of a tortoise just by looking at its shell. Pondering this, and similar effects in other animals and plants, Darwin had the unsettling insight that species, like geological formations, are not fixed but adapt to their environment over time. Those that do not adapt -- like the dinosaurs or the giant sloth -- fade away.

Documents charting the development of Darwin's thinking offer poignant reminders of how painful it was for him to pursue this line of reasoning. In a letter on display, Emma pleads, ''May not the habit of scientific pursuits of believing nothing till it is proven influence your mind too much?" To which Darwin replies, ''When I am dead, know that many times I have kissed and cried over this."

An accompanying film notes the influence on Darwin of Thomas Malthus, the ''gloomy economist" famous for his prediction that populations will always grow faster than their food supply. Malthus's writings on the power of competition to limit growth inspired Darwin to connect evolution with the struggle for survival. Noting that more individuals are born than can survive, he concluded that some species more than others are endowed with variations that better equip them for life and propagation. This thinking grew into Darwin's most radical idea, later expressed as ''the survival of the fittest."

Fearing reprisal by the church, Darwin chose to keep this insight private and moved his family to Down House, a rural sanctuary where he helped raise 10 children, tended his garden, and wrote learned monographs on barnacles and pigeons. Darwin's study, a cozy haven where he did most of his writing and microscopy, is here recreated from photographs. Darwin wrote on a cloth-covered board laid across the arms of a sort of wheelchair, made necessary by a series of mysterious illnesses brought on, many believe, by the guilt he suffered over his personal rejection of biblical creation.

Any vestige of religiosity Darwin harbored was dashed in about 1851 with the death of his 10-year-old daughter, Annie, likely from tuberculosis. A glass case holds Ann's writing box, filled with a selection of childhood treasures heart-rending in their modesty -- a tiny notebook, a miniature set of water colors, a worn thimble, spools of thread. ''We have lost the joy of the household and the solace of our old age," Darwin wrote days after her death.

Fantasies that his own ill health had infected his dear child made Darwin all the more reluctant to publish his theories -- until 1858, when a letter arrived from a young naturalist, Alfred Russel Wallace. The letter outlined a theory much like Darwin's own, even citing a passage from Malthus.

Horrified at the prospect of being scooped by a young upstart, Darwin cranked out his masterwork, ''The Origin of Species," in just over a year.

The Darwin exhibit brings to life a scientist -- and a way of doing science -- that seems out of date in today's competitive and specialized environment. What is perhaps most inspiring is its recreation of a serendipitous series of events that enabled a wondrous theory to evolve from one man's careful observations. Darwin was a geologist, a botanist, an ornithologist, and many other things, yet it is because he was unencumbered by allegiance to any of these specialties that he was able to see the world so clearly.

Ellen Ruppel Shell is codirector of Boston University's graduate program in science journalism.