What Darwin Saw Out Back—by Cornelia Dean (NYT)

NYT Published: April 25, 2008

In 1860, while studying primroses in the garden of Down House, his home in Kent, England, Charles Darwin noticed something odd about their blooms.

 

While all the flowers had both male and female parts—anthers and pistils—in some the anthers were prominent and in others the pistils were longer. So he experimented in his home laboratory and greenhouses, cross-pollinating some plants with their anatomical opposites. The results were striking.

 

“He determined that if they cross-pollinate, they produce more seed and more vigorous seedlings,” said Margaret Falk, a horticulturalist and associate vice president at the New York Botanical Garden. The variation is evolution’s way of increasing cross-pollination, she said.

 

Now the Botanical Garden is replicating this work, and more of Darwin’s Down House experiments, in a stunning, multipart exhibition called “Darwin’s Garden: An Evolutionary Adventure.”

 

In all, the tour is 33 stops, spread throughout about half of the garden’s 250 acres. Visitors who enter the exhibition through the Enid A Haupt Conservatory will encounter a replica of a room in Darwin’s house, designed so they can look through the window, as he did, to a profusion of plants and bright flowers: hollyhocks, flax and of course primroses, what Todd Forrest, the garden’s vice president for horticulture, calls “a typical British garden.” On a table stands a tray holding quills, brushes, sealing wax and tweezers, the kinds of simple tools Darwin used to conduct his world-shaking research.

 

Darwin grew the flowers not just for their own sake, Mr. Forrest said, but as subjects for observation and experiment, work he carried out in his home laboratory and greenhouses, on workbenches like those in the exhibition. The work displayed on the benches is typical of studies Darwin made of pollination, how plants grow, even what happens when a carnivorous plant devours an insect. Orchids on display remind visitors of the varieties Darwin studied, and how his observations and dissections of their blooms led him to conclude that particular species were pollinated by particular species of insects, a conclusion later research confirmed.

 

The exhibition also includes a “tree of life” map that guides visitors to the garden’s plants and describes where they fit in the natural scheme of things; books, drawings and notes, some in Darwin’s own hand; and an interactive exhibit for children.

 

It anticipates two Darwin anniversaries next year—his 200th birthday and the 150th of his world-changing book, The Origin of Species.

 

Though most people associate that book and Darwin’s ideas generally with his voyage to the Galápagos and his study of finches there, his work with plants was far more central to his thinking, said David Kohn, a Darwin expert and science historian who is a curator of the exhibition.

 

Even in the Galapágos he focused on plants, said Dr. Kohn, who is general editor of the Darwin Digital Library of Evolution at the American Museum of Natural History. “He did not even label the finches,” he said. “He was fascinated by plants,” particularly the way their variation and sexual reproduction challenged the idea that species were stable, a key idea in botany at the time.

 

As Dr Kohn writes in the exhibition catalogue, “plants were the one group of organisms that he studied with most consistency and depth over the course of a long scientific career” of collecting, observing, experimenting and theorizing. But Darwin studied more than flowers. He was intrigued by what Dr Kohn calls the “behavior” of plants—how they move, respond to light, consume insects and otherwise act in the world.

 

So another exhibit in the Garden conservatory replicates Darwin’s studies of climbing plants. Mr. Forrest said Darwin studied plants whose roots move along walls, whose stems twine, whose tendrils curl around other plants and which climb as their leaves grow into tendrils. Visitors who stop to ponder this display will also be able to see, in the garden library, the wispy, primitive drawings Darwin made as he studied plant movement and insect eating. Dr Kohn said the drawings, which remind him of time-lapse photography, are among his favorite items here even though, as he noted, “Darwin was a terrible drawer.”

 

In his orchard at Down House, Darwin established a “weed garden” by clearing a patch of sod and tracking the germination and growth of every seed that sprouted there. The Botanical Garden has done much the same thing with a small patch in the conservatory.

 

Most seedlings in Darwin’s weed garden vanished, Ms. Falk said, losses he attributed to slugs. (“That’s a gardener for you,” Mr. Forrest said, “always complaining about something.”)

 

The work Darwin carried out in his gardens, greenhouses and home laboratory is particularly impressive, Ms Falk said, given that he was limited to a simple microscope and equipment like “quills, matchsticks, bits of wire.”

 

“It was really in his own garden that many of his ideas came together,” she added.

 

As visitors walk through the Botanical Garden they will be able to follow an illustrated maps of the tree of life—the plant part of it, anyway—that tell them where the plants they can see fit in the evolutionary framework.

 

In the garden’s LuEsther T Mertz Library, they will encounter what Jane Dorfman, its exhibitions coordinator, calls “treasures”: some on loan from Cambridge University, where Darwin studied, some from Harvard and some the fruit of what Dr Kohn called “rummaging” in the garden’s extensive collection of Darwiniana. Among them are Darwin’s notes from university botany class, a plant specimen he collected on the Galápagos and his preliminary sketch of the tree of life with his note, “I think,” at the top.

 

The gallery also displays his “Experiment Book” with notes and drawings of experiments he carried out in his garden, and studies of flowers that led him to predict—accurately—what kind of bird or insect would pollinate them.

 

Nearby is Darwin’s 1857 letter to Asa Gray, the American botanist who was a major supporter, in which he laid out, one by one, the ideas he would shortly turn into “The Origin of Species.” Among other things, Dr Kohn said, the letter is notable because it “proves Darwin’s priority” by demonstrating that it was he, and not his fellow naturalist Alfred Russel Wallace, who developed the theory first.

 

“It shows he’s got it,” Dr Kohn said.

 

The tree of life exhibits, comprising an unusual mix of living plants, laboratory expertise and historical documents, show that many plants are surprisingly close relatives of others that seem quite different, a concept that helps botanists when they look for likely sources of useful plant chemicals or worry about maintaining biodiversity.

 

For example, “squashes and oaks are related,” said Dennis W Stevenson, the garden’s vice president for laboratory science. “Who’d a think it?”

 

But while many branches move off simply and neatly in ways botanists understand—they are “totally resolved,” Dr Stevenson said—other evolutionary branchings occur in clumps called polytomies, areas where the family history of plants is still unknown.

 

One major polytomy involves cycads and conifers. Dr Stevenson is among researchers working with the support of the National Science Foundation to unravel this evolutionary mystery. So far, he said, researchers have come up with two possible explanations. Although they contradict each other, “I like them both,” Dr Stevenson said.

 

Garden officials recognize that there are those who challenge Darwin’s ideas, but for them there is nothing controversial about them. “Our whole science is based on evolution,” Gregory Long, the Botanical Garden’s president, said, as he surveyed the team of horticulturalists installing the flowers that replicate Darwin’s experiments.

 

“It’s the heart of our science,” he said. “We wouldn’t be here if it hadn’t been for Darwin.”

 

 

 

Darwin’s legacy—Editorial the Hindu

12 February 2008

On February 12, 2009, most of the world will celebrate the 200th birth anniversary of a great scientist whose theory—based on incredibly laborious empirical observation and once-in-a-millennium insights—forever changed humankind’s perceptions of itself and of the natural world around. Next year will also mark the 150th anniversary of the publication of Charles Darwin’s great work On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. The five years (December 27, 1831-October 2, 1836) the English naturalist spent on board H.M.S. Beagle in a round-the-world voyage gave him the opportunity to study and compare the fauna, flora, and geology of many distant lands. It led him to wonder about the diversity of life forms he found and why creatures occupying similar environments in places around the globe could be so vastly different. The idea that biological species were not immutable but were capable of change was in itself not new at the time. Darwin would have been familiar with the speculations of his own grandfather, Erasmus Darwin, and the French zoologist, Jean-Baptiste Lamarck. But within a couple of years following the Beagle voyage, Darwin was going much further. He was thinking about a common origin for all life on the planet when he sketched in his notebook a ‘tree of life,’ implying that all species had diversified from a common stalk.

 

However, Darwin was not the only one thinking along such lines. In 1858, he received a letter suggesting ideas remarkably like his own; it was from Alfred Russel Wallace, who was collecting biological specimens in south-east Asia. Papers putting forth both points of view were duly presented at a meeting of the Linnean Society of London. The Origin of Species (as Darwin’s 1859 magnum opus came to be titled in 1872, in the sixth edition) marshalled a vast body of evidence and presented his arguments in favour of evolution driven by a process of natural selection that allowed traits best suited to a particular environment to spread in a population. Evolution and a common origin for all life lie at the heart of biology. In an essay strikingly titled ‘nothing in biology makes sense except in the light of revolution,’ the geneticist and evolutionary biologist Theodosius Dobzhansky declared: “Without that light [biology] becomes a pile of sundry facts—some of them interesting or curious but making no meaningful picture as a whole.” The elucidation of the structure of DNA, the unravelling of the genetic code, and the ability to sequence the entire genome of even complex organisms have served only to lay bare the processes that produce life, which all living organisms share, and show how evolutionary pressures act on those processes. As though this were not enough, Darwin’s ideas have inspired, over the past century-and-a-half, “powerful images and insights in science, humanities and the arts,” as an essay in Nature reminds us.

 

 

 

How Darwin’s ideas evolved—by James Randerson

©Guardian Newspapers Limited, 2008

 http://www.hindu.com/2008/04/18/stories/2008041855091400.htm

Two computer screens display images of the first edition copy of Charles Darwin’s On the Origin of Species in London on Thursday.

 

About 90,000 pages of manuscripts, field notes, photographs, and sketches connected with Charles Darwin are being placed online, where they can be viewed free.

 

Among the gems are his first formulation of the theory of natural selection, his first written doubts that species were fixed and touching correspondence from his wife on religious faith.

 

The huge set of documents and images is part of the Darwin Online project, based in Cambridge, England, which claims to be the largest Darwin bibliography and manuscript catalogue created.

 

Many of items were previously available only to scholars with access to the Cambridge University Library.

 

The project began in 2002 and this is the last major set of additions. Dr John van Wyhe, Darwin Online’s director, said: “[The documents] have been known to scholars, but for the first time they are available to everyone for free online.”

 

One set of pages that is likely to attract considerable interest is Darwin’s scrawled first draft of his theory of evolution from 1842. The scribbled argument is crammed with afterthoughts, footnotes and crossed-out text. A transcript of the text has been published previously, but few will have seen the original facsimile of Darwin’s unpolished thought process.

 

“There is a kind of fascination about it having all the original handwriting and the places where he was making changes and was struggling with issues,” said Dr. Paul White, part of the Darwin Correspondence Project, a separate effort to catalogue Darwin’s letters.

 

The collection also touches on Darwin’s views on religion. Although he shook the foundations of religious faith with his scientific work, scholars know only a limited amount about Darwin’s personal views.

 

In a memo written by his wife, Emma, in 1839, she expresses her concerns about Darwin’s declining faith. “May not the habit in scientific pursuits of believing nothing till it is proved, influence your mind too much in other things which cannot be proved in the same way?” she wrote.