Par trichard le 25 Janvier 2013 à 12:44
The near-complete archive allows the sometimes overlooked 19th-century naturalist to emerge from Darwin's shadow
This portrait of Alfred Russel Wallace (1823–1913) was painted in 1923 by J. W. Beaufort. The Natural History Museum in London took it out of storage and unveiled it on 24 January to celebrate the 100th anniversary of the great naturalist's death. Image: Natural History Museum
Charles Darwin and Alfred Russel Wallace are credited for co-discovering evolution by natural selection in early 1858. But on one morning back in the summer of 1852, as Wallace had just finished his breakfast, evolution nearly went up in smoke.
Wallace was on a ship in the middle of the Atlantic Ocean, relaxing in his cabin, when the captain strolled in and announced, perhaps too calmly: “I am afraid the ship's on fire. Come and see what you think of it."
Within a few hours, the vessel was on its side, engulfed in flames. Sitting in a small lifeboat 1,100 kilometers from land, with minimal supplies, Wallace almost fell victim to the very process he would later uncover — what we would today call survival of the fittest.
Thankfully, after ten days, Wallace was rescued by the Jordeson, a brig running between the West Indies and London. On arriving back home, he was overjoyed, writing to a friend: “Oh! Glorious day! … Beef steaks and damson tart, a paradise for hungry sinners.”
This episode is just one of many to emerge from Wallace Letters Online, launched today on the website of the Natural History Museum in London. It is a project funded by the Andrew W. Mellon Foundation based in New York City to track down and digitize Wallace’s correspondence.
So far, the open-access database contains nearly 4,000 letters sent to and from the famous naturalist, or about 95% of his known surviving correspondence. The database is fully searchable and includes transcripts as well as scans of many of the letters. The launch of this database is part of Wallace100, a series of events celebrating Wallace’s life and work during the centenary of his death.
Darwin is so strongly associated with natural selection that Wallace is sometimes forgotten. However, with the launch of this database, scientists and historians can better understand the personal and scientific relationship between these two men. “This is the first time that all of the Darwin and Wallace correspondence has been published in full,” says George Beccaloni, director of the project.
Shortly after the publication of Darwin’s On the Origin of Species in 1859, scientific debate turned to the problem of animal coloration: could natural selection explain the bright pigments observed in so many species? “It was the test case of the new theory,” says Beccaloni.
Letters in the database address this, as well as topics as diverse as biogeography, socialism and phrenology. Currently, 60% of the letters have viewable images and 36% have transcripts. Over the next three years, the Natural History Museum intends to complete the transcripts, hiring two professional historians to produce scholarly annotations. “The hope is that Wallace Letters Online will lead to a renaissance in research about Wallace,” says Beccaloni.
Par trichard le 24 Janvier 2013 à 12:05
- 00:01 24 January 2013 by Rowan Hooper
- For similar stories, visit the Letters and Evolution Topic Guides
Alfred Russel Wallace discovered natural selection independently of Charles Darwin. Through his letters, available online for the first time, he tells us of his research, expeditions and enduring fascination for nature's mysteries.
You are famously joint author, with Darwin, of the first paper describing the origin of species and natural selection, published in 1858. When did you first get the idea?
I begin [in 1847] to feel rather dissatisfied with a mere local collection – little is to be learnt by it. I sh[ould]d like to take some one family, to study thoroughly – principally with a view to the theory of the origin of species. By that means I am strongly of [the] opinion that some definite results might be arrived at.
This desire led you to Brazil to collect birds, butterflies and beetles to try to discover what drives the evolution of new species. Were there any incidents on the voyage?
On Friday the 6th of August … the Captain (who was the owner of the vessel) came into the cabin & said "I am afraid the ship's on fire. Come & see what you think of it."
Despite that harrowing experience, you next undertook an 8 year expedition to the Malay Archipelago, where you discovered the invisible boundary between the animals of Asia and the Australian region, which would later be called the Wallace Line in your honour. What fascinated you most on that trip?
The Birds have however interested me much more than the insects, they are proportionally much more numerous, and throw great light on the laws of Geographical distribution of Animals in the East… As an instance I may mention the Cockatoos, a group of birds confined to Australia & the Moluccas, but quite unknown in Java Borneo Sumatra & Malacca… Many other species illustrate the same fact.
You have been famously good-natured about sharing the discovery of natural selection with Darwin…
I also look upon it as a most fortunate circumstance that I had a short time ago commenced a correspondence with Mr. Darwin on the subject of "Varieties", since it has led to the earlier publication of a portion of his researches & has secured to him a claim to priority which an independent publication either by myself or some other party might have injuriously effected
What did you and Darwin have in common?
In early life both Darwin and myself became ardent beetle-hunters. Both Darwin and myself had, what he terms "the mere passion of collecting"… Now it is this superficial and almost child-like interest in the outward forms of living things, which, though often despised as unscientific, happened to be the only one which would lead us towards a solution of the problem of species.
Do you feel your contribution has been overlooked?
The idea came to me, as it had come to Darwin, in a sudden flash of insight: it was thought out in a few hours – was written down with such a sketch of its various applications and developments… then copied on thin letter-paper and sent off to Darwin – all within one week.
I should have had no cause for complaint if the respective shares of Darwin and myself in regard to the elucidation of nature's method of organic development had been thenceforth estimated as being, roughly, proportional to the time we had each bestowed upon it when it was thus first given to the world – that is to say, as 20 years is to one week.
You helped Darwin with the puzzle of bright colouration in animals, which led to the concept of warning colours. To ask his question again, why are some caterpillars so brightly coloured?
[Since some]… are protected by a disagreeable taste or odour, it would be a positive advantage to them never to be mistaken for any of the palatable caterpillars… Any gaudy & conspicuous colour therefore, that would plainly distinguish them from the brown & green eatable caterpillars, would enable birds to recognise them easily as a kind not fit for food, & thus they would escape seizure which is as bad as being eaten.
How did you feel looking back on your life's work, at the age of 89?
The wonders of nature have been the delight and solace of… life. Nature has afforded… an ever increasing rapture, and the attempt to solve some of her myriad problems an ever-growing sense of mystery and awe.
Do you have a message for our readers?
I sincerely wish you all some of the delight in the mere contemplation of nature's mysteries and beauties which I have enjoyed.
The correspondence of Alfred Russel Wallace – from which the answers for this interview are mined – is now available online. Wallace (1823–1913) independently discovered the theory of evolution by natural selection and founded the science of evolutionary biogeography.
"I sincerely wish you all some of the delight in the mere contemplation of nature's mysteries and beauties which I have enjoyed" (Image: Natural history Museum, London/SPL)
Par trichard le 24 Janvier 2013 à 12:03
- 24 January 2013
- Magazine issue 2901.
HOW do you spot a fit partridge? Check out the fractals round its neck.
Fractal geometry is used when a pattern is too complex to be described by Euclidean geometry. It has been applied to coastlines, plant structures and animals' foraging patterns. Lorenzo Pérez-Rodríguez at the National Museum of Natural Sciences in Madrid, Spain, and colleagues wanted to see if it could also be helpful when analysing the complex plumage patterns of birds.
Using images fed into software, the team found that red-legged partridges with a more gradual transition between the plain and spotted areas of their bib have a higher fractal dimension (FD) - a measure of a pattern's complexity.
To see if this was linked to the bird's fitness, they compared the bibs of 68 birds of both sexes, half of which were on a restricted diet. After six months, the bibs of undernourished birds had a lower FD than before their food was reduced. Low FD also predicted poorer immune responsiveness.
Pérez-Rodríguez thinks that a fractal-rich bib could be used to advertise the health of the bird to potential mates. "Birds have quite a different visual system to ours," says Thanh-Lan Gluckman at the University of Cambridge, so the work could also help us understand what one bird sees in another.
Fractal bling (Image: Ernie Janes/naturepl.com)
Par trichard le 17 Octobre 2012 à 22:42
October 17, 2012 |
The ancient ocean was a frightening place. But the emergence of the armored placoderm fish would have made it even more terrifying. These fish were no great whites—some weren’t much bigger than a goldfish. But they were some of the firstvertebrates to have jaws, and new research shows that they were probably the first tobrandish teeth as well.
The emergence of pearly whites has been a bit of an evolutionary mystery, with some pointing to these early armored fish, which lived some 430 million to 360 million years ago, and others suggesting that teeth didn’t emerge until later groups of vertebrates.
New analysis of fossil Compagopiscis croucheri placoderm specimens reveals that these ancient jawed fish did indeed already have teeth to gnash. The findings were published online October 17 in Nature (Scientific American is part of Nature Publishing Group). With individual teeth present in these basal vertebrates, it suggests a very early origin of these assets for the rest of us—rather than them developing multiple times in different lineages.
“This is solid evidence for the presence of teeth in these first jawed vertebrates,” study co-author Philip Donoghue of the University of Bristol’s Department of Earth Sciences, said in a prepared statement.
The placoderms examined for this study likely had teeth that developed shallowly in the jaw, like many of today’s boney fish. These toothy fish, however, hadn’t perfected all of the options of modern dentition. For example, they don’t appear to have been able to replace choppers when they wore out.
The researchers used x-ray tomographic microscopy and computational algorithms to generate detailed 3-D models of the ancient fossils. “This technique allows us to obtain a perfect digital model and very detailed insight views of the old fossil without destroying it,” Marco Stampanoni, of the Paul Scherrer Institute in Switzerland and study co-author, said in a prepared statement.
Indeed, much of the reason the origins of teeth has remained so obscured is that few studies have been able to dig into these important fossils. “These wonderfully preserved fossils from Australia yield many secrets of our evolutionary ancestry but research has been held back waiting for the kind of nondestructive technology that we used in this study,” study co-author Zerina Johanson, of London’s Natural History Museum, said in a prepared statement. “Without the collaborations between paleontologists and physicists, our evolutionary history would remain hidden in the rocks.”
Par trichard le 17 Octobre 2012 à 22:41
It began with cooperation. When life first arose, teams of small molecules got together to perform tasks none could manage alone or so the theory goes. For the first time, networks like this have been built in the lab.
The earliest life may have been a primordial soup of RNA molecules, but the first crude self-replicating molecules in this "RNA world" would have faced a big problem. They had to grow to store more information, but that made copying errors more likely. Get big enough and these errors become almost certain, destroying the molecule's information.
In theory, the first replicators could have avoided this "error catastrophe" by splitting their information between several cooperating molecules. Then the network could function as long as copies of each molecule survived.
Repair one for the team
To see if this strategy would work, Niles Lehman of Portland State University in Oregon and colleagues created three RNA molecules that could repair each other – A did B, B did C, and C did A.
When the team put these broken molecules together in a test tube, the collective network worked well. When they pitted the cooperative network against a selfish, self-repairing molecule, the cooperators won out.
Although earlier studies showed that pairs of molecules can cooperate, Lehman is the first to create a network of 3, opening the door to much larger networks. "If you can go from 2 to 3, you can go from 3 to infinity," he says. Lehman repeated the study with 48 different fragments of an RNA molecule. Sure enough, they assembled into a network that eventually included all 48.
Such cooperation may have arisen early in the RNA world and helped to build complexity, says Gerald Joyce of the Scripps Research Institute in San Diego. "It's an experimental demonstration that real molecules can do this," he says.
Cooperating RNA networks might have an even greater advantage if the component molecules could cluster together in space.
To show this, Philip Bevilacqua and colleagues at Penn State University in University Park studied an RNA called a "hammerhead ribozyme" that cuts itself into pieces. They helped the RNAs to cluster by putting them into a solution containing both dextran and polyethylene glycol. These two compounds separate instead of mixing, causing the ribozyme, which is more soluble in the dextran portion, to become more concentrated.
They found this increased the RNA's reaction rate about 70-fold (Nature Chemistry, doi.org/jjk). Something similar – a pore on a rock surface, say, or a slime layer – could have given prebiotic molecules a boost as life got started, says Joyce.
Journal reference: Nature, DOI: 10.1038/nature11549
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