In a fitting celebration of a man whose ideas revolutionized science, Harvard marked Charles Darwin’s 200th birthday in style yesterday.

There was a campuswide read-a-thon of “The Origin of Species,” a roving gorilla, three bushy-bearded Darwin imitators, an afternoon symposium, and a nighttime birthday blast at the Cambridge Queen’s Head Pub rocked by science-themed bands.

But the keynote event was “Darwin at 200: Rethinking the Revolution,” Janet Browne’s evening talk at the Geological Lecture Hall on Oxford Street. Mobbed by well over 400 people, it was the kickoff lecture in a series called “Evolution Matters,” sponsored by the Harvard Museum of Natural History.

Browne, Aramont Professor of the History of Science, is a British-trained zoologist-turned-historian. She’s the author of a two-volume Darwin biography and helped edit his voluminous correspondence. (She found some of it still stuffed into a picnic basket and tucked away at the University of Cambridge.)

Browne sees Darwin as a transformative figure, whose system of thought has propelled scientific transformations in two centuries, and now a third.

Museum executive director Elisabeth Werby introduced Browne. “This is the day and this is the moment we’ve all been waiting for,” she said, arms spread wide. “Happy birthday, Darwin!” The crowd went wild.

In a far-ranging and humorous lecture, Browne explained how the shy, modest Charles Robert Darwin prompted such durable celebrity.

“Darwin isn’t a ghost to us,” she said. “We only have to think what we’ve been enjoying today. … He’s more than real to us. He’s as present in our modern lives as he ever was when he was alive.”

For one, Darwin’s fame has cast a wide net over popular culture, forming a durable part of modern consciousness. His name is on a city in Australia, Browne noted, a university college at Cambridge; it’s a Dutch rock band, and a popular beer, Darwin’s Downfall. (A line of apelike figures pictured on the label show evolution in reverse.)

Then there are the Darwin Awards, said Browne, dedicated “to those people who have inadvertently contributed to natural selection.”

And Darwin still flourishes as a cartoon image, a blend of satire and admiration that has persisted since Victorian times. Browne flashed a New Yorker illustration onto the screen. A Kong-like Darwin stands atop the Empire State Building, gripping an ape in one hand, and being buzzed, “we imagine, by planes piloted by creationists.”

Darwin’s image also appears on the British 10-pound note, the only scientist on UK currency, said Browne — though the hummingbird pictured alongside him should rightly be a finch.

In all these images, “Darwin evidently is being used to represent far more than the man himself,” she said. “He’s come to embody not only the theory of evolution but many of the ideals of modern science.”

Above all there is the theory, “the central organizing concept of modern biology,” said Browne — the idea that evolution occurs through natural selection, and provides a logical explanation of the diversity of life.     The “clarity and impact” of his 1859 volume, now titled “The Origin of Species,” has “explanatory power” that still resonates 150 years later, she said, and its “key principles remain intact.”

In Darwin’s own day, praise was immediate, too. Browne quoted Alfred Russel Wallace, who had independently come to the same idea of evolution and in 1858 published a joint paper with Darwin: “Mr. Darwin has given the world a new science,” he said, and “… the force of admiration can no further go.”

Browne eased through Darwin’s earlier life — from the “Bobby” raised by his older sisters after his mother’s death, his famous grandfathers (natural philosopher Erasmus Darwin, pottery magnate Josiah Wedgwood), and his frustrations with university training.

Darwin bristled at medical studies at Edinburgh and his studies for the Anglican clergy at Cambridge, where he graduated in 1831. But he came out of both places well-versed in what he loved: natural history, botany, marine biology, chemistry, and geology. At Cambridge, Darwin was famous for his obsession with beetles.

Then of course there was the formative voyage on H.M.S. Beagle, the British frigate on which Darwin served as naturalist from 1831 to 1836. (He nearly didn’t go. His physician father considered it “a wild scheme” and — a modern laugh line — “a useless undertaking.”)

It was not aboard the Beagle that Darwin formulated the idea of natural selection, but he had already embraced a motif from Charles Lyell’s “Principles of Geology” that was to inform his lifetime in science: the idea that “many small and gradual changes accumulate into large effects,” said Browne, “over many, many epochs.”

Most and best of all, the voyage on the Beagle impressed on the young scientist the importance of keeping notes. “Darwin became a man who wrote,” said Browne. Add to that, she said, that “Darwin was a devil for work.”

During a long and fruitful marriage to his cousin Emma Wedgwood, Darwin dug into the details, delaying the publication of his theory from 1844 to 1859 because he wanted proof for an idea he saw was “a difficult, dangerous, hard theory to understand,” said Browne.

He started a voluminous scientific correspondence, and in his own back yard tried to work out proofs of natural selection. He bred pigeons and for eight years labored over a taxonomy of barnacles.

Wallace’s parallel ideas hurried Darwin into an early synthesis of his work — the famous “On the Origin of Species” published in November 1859. By Christmastime that year, Asa Gray, James Russell Lowell, and others at Harvard gathered in Boylston Hall to read the first copy in America.

Gray became Darwin’s American champion, and Harvard’s Louis Agassiz was one of Darwin’s prominent critics.

Since 1859, Darwin and his ideas have risen and fallen in favor, said Browne. His stock fell around 1900 with the fervor over new genetics, and again in the 1950s with the rise of molecular biology.

But resurgence of interest in Darwin often come in anniversary years, said Browne, “to re-establish the relevance of natural selection.” She started with Darwin’s 1882 funeral, a covert message from his surviving friends, including the irreligious Thomas Huxley – “Darwin’s bulldog” — that the great man was not irreligious, and the science was still important.

In 1885, the Natural History Museum gave Darwin’s stature a boost with a grand statute — a plea for science of the old-fashioned kind (observe, collect, write) in an age when universities were beginning to dominate and question the old model.

In 1929, the restoration of Darwin’s home made a point, too, said Browne: that British science still had weight, and that as modern science raced forward there was still a place for Darwin’s simple tools – “eyes,” said, Browne, “and a pencil and paper.”

In 1959, the main Darwin anniversary celebration shifted to America, where at the University of Chicago a sort of League of Nations of scientists (Browne’s image) gathered to make peace, agreeing that Darwin was the glue that bound all — and that his ideas even had a place in understanding the science of brain and behavior.

Harvard evolutionary biologist Ernst Mayr delivered a paper at the 1959 conference. Around the same time, said Browne, he told his Harvard classes that “opposition to evolutionary theory had died down almost completely.”

Today, she said, we “live in a different world” with Darwin’s theories under fire from creationists, especially in the United States.

So Browne urged her listeners to use the 200th anniversary of Darwin’s birth to confront these anxieties, confirm a “collective identity” of faith in Darwin, and to reaffirm him his place as a pre-eminent “figurehead of rational science.”

Darwin’s transformative idea of evolution through natural selection has now been part of culture for 150 years, said Browne. “We should go out there and explain it to people.”

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