Ontogeny

In interview: Richard Dawkins and Craig Venter

2009-07-08T05:46:00.000-07:00

This is a wonderful video: it's Richard Dawkins interviewing Craig Venter and getting a tour of his amazing sequencing facility. It also reveals how much the technology is changing.

How the Food Makers Captured Our Brains

2009-07-08T05:39:00.000-07:00

[Via: NYT] As head of the Food and Drug Administration, Dr. David A. Kessler served two presidents and battled Congress and Big Tobacco. But the Harvard-educated pediatrician discovered he was helpless against the forces of a chocolate chip cookie.

In an experiment of one, Dr. Kessler tested his willpower by buying two gooey chocolate chip cookies that he didn’t plan to eat. At home, he found himself staring at the cookies, and even distracted by memories of the chocolate chunks and doughy peaks as he left the room. He left the house, and the cookies remained uneaten. Feeling triumphant, he stopped for coffee, saw cookies on the counter and gobbled one down. “Why does that chocolate chip cookie have such power over me?” Dr. Kessler asked in an interview. “Is it the cookie, the representation of the cookie in my brain? I spent seven years trying to figure out the answer.”

The result of Dr. Kessler’s quest is a fascinating new book, “The End of Overeating: Taking Control of the Insatiable American Appetite” (Rodale).

During his time at the Food and Drug Administration, Dr. Kessler maintained a high profile, streamlining the agency, pushing for faster approval of drugs and overseeing the creation of the standardized nutrition label on food packaging. But Dr. Kessler is perhaps best known for his efforts to investigate and regulate the tobacco industry, and his accusation that cigarette makers intentionally manipulated nicotine content to make their products more addictive.

In “The End of Overeating,” Dr. Kessler finds some similarities in the food industry, which has combined and created foods in a way that taps into our brain circuitry and stimulates our desire for more.

When it comes to stimulating our brains, Dr. Kessler noted, individual ingredients aren’t particularly potent. But by combining fats, sugar and salt in innumerable ways, food makers have essentially tapped into the brain’s reward system, creating a feedback loop that stimulates our desire to eat and leaves us wanting more and more even when we’re full.

Dr. Kessler isn’t convinced that food makers fully understand the neuroscience of the forces they have unleashed, but food companies certainly understand human behavior, taste preferences and desire. In fact, he offers descriptions of how restaurants and food makers manipulate ingredients to reach the aptly named “bliss point.” Foods that contain too little or too much sugar, fat or salt are either bland or overwhelming. But food scientists work hard to reach the precise point at which we derive the greatest pleasure from fat, sugar and salt.

The result is that chain restaurants like Chili’s cook up “hyper-palatable food that requires little chewing and goes down easily,” he notes. And Dr. Kessler reports that the Snickers bar, for instance, is “extraordinarily well engineered.” As we chew it, the sugar dissolves, the fat melts and the caramel traps the peanuts so the entire combination of flavors is blissfully experienced in the mouth at the same time.

Foods rich in sugar and fat are relatively recent arrivals on the food landscape, Dr. Kessler noted. But today, foods are more than just a combination of ingredients. They are highly complex creations, loaded up with layer upon layer of stimulating tastes that result in a multisensory experience for the brain. Food companies “design food for irresistibility,” Dr. Kessler noted. “It’s been part of their business plans.”

But this book is less an exposé about the food industry and more an exploration of us. “My real goal is, How do you explain to people what’s going on with them?” Dr. Kessler said. “Nobody has ever explained to people how their brains have been captured.”

The book, a New York Times best seller, includes Dr. Kessler’s own candid admission that he struggles with overeating.

“I wouldn’t have been as interested in the question of why we can’t resist food if I didn’t have it myself,” he said. “I gained and lost my body weight several times over. I have suits in every size.”

This is not a diet book, but Dr. Kessler devotes a sizable section to “food rehab,” offering practical advice for using the science of overeating to our advantage, so that we begin to think differently about food and take back control of our eating habits.

One of his main messages is that overeating is not due to an absence of willpower, but a biological challenge made more difficult by the overstimulating food environment that surrounds us. “Conditioned hypereating” is a chronic problem that is made worse by dieting and needs to be managed rather than cured, he said. And while lapses are inevitable, Dr. Kessler outlines several strategies that address the behavioral, cognitive and nutritional factors that fuel overeating.

Planned and structured eating and understanding your personal food triggers are essential. In addition, educating yourself about food can help alter your perceptions about what types of food are desirable. Just as many of us now find cigarettes repulsive, Dr. Kessler argues that we can also undergo similar “perceptual shifts” about large portion sizes and processed foods. For instance, he notes that when people who once loved to eat steak become vegetarians, they typically begin to view animal protein as disgusting.

The advice is certainly not a quick fix or a guarantee, but Dr. Kessler said that educating himself in the course of writing the book had helped him gain control over his eating.

“For the first time in my life, I can keep my weight relatively stable,” he said. “Now, if you stress me and fatigue me and put me in an airport and the plane is seven hours late — I’m still going to grab those chocolate-covered pretzels. The old circuitry will still show its head.”

Doctor rescued from Antarctica in 1999 dies at 57

2009-07-07T05:12:00.000-07:00

[Via: CNN] Nearly a decade after she was rescued from a remote Antarctic research station after diagnosing herself with breast cancer, Dr. Jerri Nielsen died early Tuesday, her brother said. She was 57.

Nielsen had been fighting the latest round of cancer for the past five years, brother Eric Cahill said. She died just before 4 a.m. in Massachusetts, surrounded by her family, he said.

"She would want to be remembered for the adventure and, you know, living every day, and not just the sickness," said sister-in-law Diana Cahill. "She was very much active and still even doing talks as late as March of this year. Then the last month or so, she was pretty sick."

Nielsen caught the nation's attention in 1999, when she found a lump in her breast as a 47-year-old physician stationed at the Amundsen-Scott South Pole Research Station.

After finding the lump in June, she diagnosed herself with breast cancer and began treating herself using chemotherapy agents that the U.S. Air Force parachuted to the station the next month.

It was later revealed, according to a March 2009 article in the Detroit Free Press newspaper, that Nielsen -- an emergency room doctor from Cleveland, Ohio -- performed a biopsy on herself with the help of non-medical crew, who practiced using needles on a raw chicken.

While treating herself, Nielsen carried on her duties as the sole doctor for the 41-person research group. She consulted with her doctors in the United States by e-mail and teleconference. They recommended that she return as soon as possible for treatment.

Although flights in support of the South Pole program don't usually begin until late October or early November, the start of Antarctic spring, it was October 6 when two planes set out on what was dubbed Operation Deep Freeze.

Ten days and a handful of stops later -- California, Hawaii, Pago Pago, New Zealand and then Antarctica -- rescuers braved temperatures of nearly minus 60 degrees Fahrenheit to land a ski-equipped plane at the pole, drop off a replacement doctor and pick up Nielsen. It was the earliest such flight attempted.

Once she returned home and was treated, Nielsen's cancer went into remission, and she wrote about her experience in a best-selling book, "Icebound." She married and became a public speaker, Diana Cahill said.

But in 2005, Nielsen's cancer returned in her bones and liver, later spreading to her brain.

"My experience at the pole had to do with accepting things that most people fear most deeply and coming to feel that they need not be feared," Nielsen told Psychology Today magazine in 2006. "It certainly had far more to do with peace and surrender than it did with courage. Being 'on the ice' was a great good fortune: It created a much greater clarity for me about what was essential in life.

"I'm not afraid of death. I've come to accept it as being part of life, and I think I've come to accept it earlier than my years because of what's happened to me."

She said that after learning her cancer had returned, "after about three weeks of going through a kind of terror, I felt the most incredible peace come over me. Now I am very happy and excited about going forward with my life. The metastatic disease is now just another part of me, another thing that has happened to me."

"She was always upbeat," Diana Cahill said. "She never really dwelled upon her illness. She told people to live every day, and it was about what kind of life you lived. She was really inspirational to a lot of people around the world."

In October 2008, Nielsen spoke at the University of Toledo College of Medicine, formerly her alma mater the Medical College of Ohio, according to the Free Press. She took off her wig to show students her bald head, the newspaper said, and told them not to be discouraged: "There is no end of life until your last breath. We can all do something to help someone."

She told the Free Press in March that the cancer had spread to her brain but still displayed her inspiring grit.

"I'm not as smart a girl as I used to be," she told the newspaper. "I'm not as hard a worker, that's for sure. But I'm still doing everything, I'm writing a book and giving speeches, and I'm really having a beautiful winter."

Nielsen told Psychology Today, "The things that make you strong, and make you feel as though you've accomplished something, are not the easy ones; it's the things you had to work and struggle through. Those are what give us our depth -- that make us not gray and plain and nothing but give us depth and texture and longing.

"I believe you're always much better off knowing what the real truth is. I think it's only then that you can come to grips with your illness, or with any difficult situation. Some people call this process 'mourning.' I prefer to call it tiring of the fear and the depression and the denial, and the fake optimism and the irritation of it all -- and just saying, 'Hey, I'm tired of feeling bad about this. Now I go on.' "

How Darwin Shaped Art

2009-07-07T05:07:00.000-07:00

[Via: Seed] Surrealist artists claimed Freud, the cubists looked to Einstein, but Charles Darwin’s influence on his 19th century artistic contemporaries has rarely been fully appreciated. In celebration of his bicentennial birthday this year, Connecticut’s Yale Center for British Art (YCBA) and the UK’s Fitzwilliam Museum—the art museum to which Darwin would escape from college classes at Cambridge—have launched Endless Forms: Charles Darwin, Natural Science, and the Visual Arts [Get info], a traveling exhibit that properly takes stock of the impact Darwin’s evolutionary theories had on the visual arts. The exhibit moves from Yale to Cambridge on June 16.

It’s hard to exaggerate just how widely Darwin’s ideas on natural selection and the evolution of human kind traveled in the cultural milieu of his day, even in the age of stagecoaches and month-long journeys across the Atlantic. Artists of all shades reacted to his revolutionary theories, and this exhibit attempts to capture their range of responses in all sorts of mediums, including paintings, photographs, sketches, and sculptures. Sprinkled amidst 200 works of art are historical collections of natural wonders like beetles, fossils, gems, stuffed birds, and plated flowers. These items give visitors a distinctly visual sense of what artists—and Darwin himself—grappled with during the Victorian era, as academic science began to challenge the subjective nature of romantic art.

The exhibit categorizes Darwin’s artistic influence into tidy themes like the Darwinian “struggle for existence,” the ancient history of earth, the kinship with other animals, the origin of man, and the nature of beauty as a product of sexual selection. But perhaps the most eye-opening aspect of Endless Forms—an allusion to the ending of his 1859 masterpiece On the Origin of Species—is the revelation of how art influenced Darwin. Just as Darwin introduced Victorian sculptors and French impressionists to scientific order, artists helped the young naturalist draw a connection between details in nature and his bubbling ideas on evolution.

Take for instance, the astoundingly thorough 17th century engraving of a gnat’s eye or the intricate drawing of the common milkwort flower by Darwin’s mentor at Cambridge, the botanist John Stevens Henslow. According to curators at YCBA, these depictions of adaptation and complexity in part inspired Darwin’s thoughts on natural selection. Most famously, his thesis that the beaks of Galapagos finches were uniquely adapted to each island stemmed from a series of lithographs drawn by the ornithologist John Gould and are on display in the exhibit near a case of stuffed birds of paradise.

But the biggest draw—both for audiences of his time and museumgoers today—may be the depictions of apes. With the publication of The Descent of Man in 1871, Darwinian became synonymous with simian; the exhibit in fact includes Victorian political cartoons that caricature Darwin as a foolish chimp. Near the exhibit entrance are two sculptures that reflect the conflicting societal views of human evolution: One is Hugo Rheinhold’s iconic pose of an ape holding a human skull, deep in thought, juxtaposed next to Emmanuel Frémiet’s shocking Gorilla Abducting a Woman.

Some of the other displays are more subtle. It’s revealed that Edgar Degas, best known for his miniature ballerinas, drew inspiration for his careful sculpting of facial expressions from Darwin’s Expression of the Emotions in Man and Animals. And though it’s hard to tie Cezanne’s painting of a cistern to evolutionary theory, the curators give it their best shot: They point to the rock in the background as evidence of a new curiosity about geology. Monet’s 30 successive paintings of the Rouen Cathedral in northwestern France are seen through the lens of natural selection. This nuance bleeds a bit into head-scratching subjectivity.

A modest drawing of the Andes holds an indisputable place of honor in the gallery—it’s one of the only known drawings by Darwin himself. In contrasting the majestic strokes of the impressionist masters with Darwin’s childish squiggles and uneven shading, the exhibit makes clear that Darwin was brilliant, but also very self-aware. He knew to leave art to the artists..

Peter and Rosemary Grant win Kyoto Prize

2009-07-06T05:01:00.001-07:00

[Via: The Scientist] Peter and Rosemary Grant, emeritus professors at Princeton University who were the first to document natural selection in action, have won the 2009 Kyoto Prize in the category of Basic Sciences for their work on evolutionary adaptations in response to environmental flux. "I can't think of any other scientists who deserve it more," said Kenneth Petren, a former postdoc of Peter Grant and now a professor at the University of Cincinnati in Ohio, citing "their long term commitment to unraveling some very complex problems" in evolutionary biology.

Following in Darwin's footsteps, the Grants have spent 35 years studying the finches he discovered on the Galápagos Islands during his Beagle tour. In perhaps their most famous contribution to the evolutionary literature, the Grants demonstrated how, in just a few short generations, the beak size and shape of ground finches (genus Geospiza) transformed as a consequence of the availability of different sized seeds, which fluctuates with the varying levels of rainfall caused by the El Nino-Southern Oscillation. That study, published in Ecology in 1996, was cited more than 85 times, according to ISI.

"The Grants' empirical research has made the most important contribution since Darwin toward making evolutionary biology a science in which proof is possible," stated a press release from the Inamori Foundation, which sponsors the award.

The Grants still travel every year to Daphne Major of the Galápagos archipelago, where they continue to study rapid changes in morphology and behavior of finches in response to changing environmental conditions. "The kind of data they collected was very challenging," Petren said. In addition to the rough terrain of the Galápagos the researchers must traverse to find their study subjects, he explained, decisively demonstrating that these changes were caused by shifts in the environment takes a lot of detailed data over an extended period of time. "And they do this as if it were walking in the park," he said.

And after nearly four decades of following the finch populations, the couple now knows every bird on the island, Rosemary Grant said in a statement released by Princeton University this morning.

The Grants met in 1960 at the University of British Columbia in Vancouver, where she was a research associate and he was just starting his PhD. They came to Princeton in 1985. Throughout their career, they have published more than 200 papers. "They're exceptionally good at pinching off very broadly appealing, scientifically rigorous snippets of what's happening over that long term study," Petren said. "It's part of why they're so successful."

In 2008, they also published a book entitled How and Why Species Multiply: The Radiation of Darwin's Finches, in which they describe their experiences in the field while detailing the evolutionary history of the fourteen finch species that currently inhabit the Galápagos. "They're great naturalists with endless amounts of information about the islands," Petren said.

The Grants are the first husband-and-wife team to ever receive the Kyoto Prize. "They really do operate as a pair at all times," Petren said. "They are a complete team, and they have been ever since they started the work on Daphne with their family."

The Kyoto Prize was founded in 1985 by the Inamori Foundation of Japan and honors lifetime achievements in basic science, advanced technology, and arts and philosophy. Isamu Akasaki of Nagoya University and Meijo University in Japan will receive the prize for his work on the development of blue light emitting devices. Pierre Boulez, honorary director of the Institute for Research and Coordination Acoustic/Music in France, will receive the prize for his innovation as a composer and conductor.

The award includes a cash prize of 50 million yen (approximately $500,000). The recipient are invited to Kyoto to receive the award this November as well as to San Diego in April 2010 for the ninth annual Kyoto Prize Symposium.

Great White Sharks Hunt Like Serial Killers

2009-07-06T04:56:00.001-07:00

[Via: Discovery News] Sharks may only kill for food, but they share similar strategies with human serial killers: They lurk out of sight, stalking their victims. Sharks and human serial killers can both be tracked using geographic profiling, according to a new study that applied this investigative technique to the hunting patterns of great white sharks, the world's largest known predatory fish.

The study, published in the latest Journal of Zoology, marks the first time geographic profiling has ever been used on a marine species. "As predators, they must get close enough to check out prey and figure out their movements, but they also must be far enough way so that they themselves won't be easily tracked," said co-author Neil Hammerschlag. "They must use known traveling routes," added Hammerschlag, a University of Miami researcher in the Rosenstiel School of Marine and Atmospheric Sciences. "For human killers, these would be things like subways, buses and freeways. For great whites, these would include channels, reef edges and other topographical features."

For the study, Hammerschlag worked with shark expert Aidan Martin and former Canadian beat cop Kim Rossmo, who developed the geographic profiling technique and is now at Texas State University. The researchers observed and recorded 340 great white shark attacks on Cape fur seals in the waters off of Seal Island in South Africa's False Bay. They plotted these attack sites, using a radar chart to examine the distribution of the encounters and noting where the sharks began and ended their attacks.

All else being equal, attack frequency should be directly related to prey density, with sharks lurking where the most seals gather. Surprisingly, that wasn't the case. The scientists determined sharks instead positioned themselves about 328 feet from the island at a water depth of around 82 feet. Hammerschlag thinks this might provide the optimal balance of being close enough for attack, yet not close enough for detection. A deep water starting point permits momentum, "allowing the shark to build up enough speed to initiate the attack."
The researchers also found that big adult sharks had very focused anchor points from which they repeatedly launched their offensives. Smaller, younger sharks were less focused.
"This could be because sharks learn to refine their hunting skills over time and know the best spots, or they could dominate smaller sharks and exclude them from the best areas," Hammerschlag explained, adding that cleverness at all attack stages is critical, since seals can do serious damage to sharks.

"A seal can rip a shark's eyes out and they have a lot of bacteria in their mouths that can cause infections when they bite," he said. "Many sharks have face gashes caused by seals."
Nevertheless, it's a shark-eat-seal world, and top predators like sharks play an important role in structuring communities and maintaining ecosystem health. The new findings help to solve mysteries about great white hunting behavior and can help to identify areas for protection -- of both humans and sharks. "I wouldn't recommend holding a swim meet in known shark attack areas," Hammerschlag deadpanned, adding that boating, oil drilling and other human marine activities should be moved away from the regions for the sake of human and shark safety.
Steven Le Comber, an expert on geographic profiling at the School of Biological and Chemical Sciences at Queen Mary, University of London, believes the investigative technique "is an interesting way to study patterns of animal foraging, and especially predation." He concluded, "Shark hunting patterns are extremely difficult to study and the work here will have important implications for our understanding of the ways in which predators hunt their prey."

Tungara Frog Calling: BCI Panama

2009-06-25T10:38:00.000-07:00

H/t Drawing the Motmot

The plant that pretends to be ill

2009-06-25T07:30:00.000-07:00

Figure: A leaf damaged by mining moths (left) compared to one faking it (right).

[Via: BBC Science] A plant that pretends to be ill has been found growing in the rainforests of Ecuador. The plants feigns sickness to stop it being attacked by insect pests known as mining moths, which would otherwise eat its healthy leaves. It is the first known example of a plant that mimics being ill, and could also explain a common pattern seen on plant leaves known as variegation.

Variegation is familiar to gardeners and affects many species of plant. Variegated plants have different coloured patterns on the leaf surface, produced by a variety of causes. One of the most common is when cells in the leaf lose chlorophyll and their ability to photosynthesis, appearing white. In theory, plants with variegated leaves should be at a disadvantage, because of this restricted ability to photosynthesis. But a chance discovery by a team of botanists suggests this may not be true after all. Instead, some variegated plants may be mimicking illness to avoid being eaten, putting themselves at an advantage. Sigrid Liede-Schumann and colleagues Ulf Soltau and Stefan Dotterl of the University of Bayreuth in Germany were studying understory plants in the forest of southern Ecuador, when they noticed that the plain green leaves of a plant known as Caladium steudneriifolium were far more frequently damaged by mining moths than those of variegated leaves of the same species nearby. Mining moths lay larvae into the leaves, and the caterpillars then munch through the leaf surface, leaving a white trail of damage behind. "The similarity of the variegation patterns with the criss-cross munching traces of the larvae led to the idea that maybe they deter the mining moth from laying its eggs," says Liede-Schumann. To test the idea, the researchers used white correction fluid to mimic the appearance of variegation on hundreds of healthy leaves. After three months, they then counted the number of leaves affected by the mining moth caterpillars, comparing green leaves, variegated leaves and those painted white to appear variegated. "The results were the same," says Liede-Schumann. "Visibly variegated leaves were significantly less frequently damaged by mining moth larvae than plain green ones." While moths infested almost 8% of green leaves, they infested 1.6% of variegated ones and just 0.4% of those painted to look like they were variegated. "I was quite surprised," says Liede-Schumann. She believes that the plant essentially fakes being ill, producing variegated leaves that mimic those that have already been damaged by mining moth larvae. That deters the moths from laying any further larvae on the leaves, as the insects assume the previous caterpillars have already eaten most of the leaves' nutrients. "The fact that there are both plain green and variegated leaves in the population indicates to me that both are useful in the long-term success of the species," says Liede-Schumann. The reduction in a variegated leaf's ability to photosynthesise is likely to be more than offset by the benefits of not being eaten, the researchers believe, suggesting that variegation survives in wild plants because it confers a selective advantage.

Watching Arachnids Evolve

2009-06-25T07:26:00.000-07:00

A thoroughly enjoyable presentation.

H/t Alex Wild over at the Myrmecos blog

Teen diagnoses her own disease in science class

2009-06-25T07:22:00.000-07:00

[Via: CNN] For eight years, Jessica Terry suffered from stomach pain so horrible, it brought her to her knees. The pain, along with diarrhea, vomiting and fever, made her so sick, she lost weight and often had to miss school. Her doctors, no matter how hard they tried, couldn't figure out the cause of Jessica's abdominal distress. Then one day in January, Terry, 18, figured it out on her own.

In her Advanced Placement high school science class, she was looking under the microscope at slides of her own intestinal tissue -- slides her pathologist had said were completely normal -- and spotted an area of inflamed tissue called a granuloma, a clear indication that she had Crohn's disease.

"It's weird I had to solve my own medical problem," Terry told CNN affiliate KOMO in Seattle, Washington. "There were just no answers anywhere. ... I was always sick."

Terry, who graduated from Eastside Catholic School in Sammamish, Washington, this month, is now being treated for Crohn's, says her science teacher, MaryMargaret Welch.

"She was pretty excited about finding the granuloma," Welch said. "She said, 'Ms. Welch! Ms. Welch! Come over here. I think I've got something!' "

Welch, who has taught the Biomedical Problems class at Eastside for 17 years, immediately went on the Internet to see whether Terry had indeed spotted a granuloma.

"I said, 'Jeez, it certainly looks like one to me,' " Welch remembered. "I snapped a picture of it on the microscope and e-mailed it to the pathologist. Within 24 hours, he sent back an e-mail saying yes, this is a granuloma."

Although Terry was relieved to finally get a diagnosis, it was also tough for her to hear that she has such a serious disease.

There are treatments, but there is no cure for Crohn's, a condition in which the digestive tract becomes inflamed. It can lead to ulcers, malnutrition and other health problems.

"As I get older, the disease can get worse," Terry told KOMO.

Crohn's disease is often misdiagnosed or diagnosed very late, says Dr. Corey Siegel, director of the Inflammatory Bowel Disease Center at Dartmouth-Hitchcock Medical Center in Lebanon, New Hampshire.

"Granulomas are oftentimes very hard to find and not always even present at all," Siegel said. "I commend Jessica for her meticulous work."

Pathologists also sometimes miss important findings for other diseases, says Dr. Mark Graber, chief of the medical service at the Northport VA Medical Center in New York.

"This story carries a valuable lesson about how errors are found. It's very often by 'fresh eyes,' just like in Jessica's case," he said. "Some specialty centers, recognizing the reality of perceptual error and the power of a second independent reading, are now requiring second reviews on certain types of smears and pathology specimens."

Welch credits Terry's "fresh eyes" but also local pathologists who volunteered to train her and her classmates on how to view specimens under the microscope.

"We've been lucky to have that partnership. It allowed Jessica to think of herself as a scientist," she said. "The class empowered Jessica to think of herself as being a partner in her own health care."

As for Terry's future, she'll start nursing school in the fall. She's written a book for children about Crohn's disease, which she hopes to have published. In the meantime, she's grateful for her science class and for the pathologist for giving her her slides.

"This has been the highlight of my high school career, for sure," Terry told the Sammamish Reporter newspaper. "It's been amazing."

A new dinosaur species looks set to solve an old evolutionary puzzle

2009-06-19T07:02:00.000-07:00

[Via: Nature News] Birds are generally considered to be the living descendants of dinosaurs, yet differences between bird wings and dinosaur hands have long left palaeontologists struggling to explain how birds would have evolved from their dinosaur ancestors.

Birds' wings are thought to form from the fusion of the second, third and fourth digits on their hands as the embryo develops. Theropods, the predominantly carnivorous dinosaurs that included tyrannosaurids such as Tyrannosaurus rex and dromaeosaurids such as Velociraptor mongoliensis, also only had three long fingers.

But palaeontologists had thought that these were the first, second and third digits because in early theropod fossils, such as that of Dilophosaurus, these three fingers were elongated, with a seemingly semi-vestigial fourth digit and a nearly absent fifth.

Based on this species, it looked very much like theropod dinosaurs lost their fifth digit early on then, around the time of Dilophosaurus, started to lose their fourth digit too.

But this evolutionary explanation left researchers wondering how birds' wings could have developed from digits 2, 3 and 4. The prevailing explanation was that theropods lost their fourth and fifth digits, then birds lost their first digits and regrew their fourth digits.

Mistaken identity

Now, a team led by Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing and James Clark from The George Washington University in Washington DC is proposing a simpler answer based on a new dinosaur species found in Jurassic rocks formed 156 million to 161 million years ago in the Junggar Basin in western China.

The species, a ceratosaur named Limusaurus inextricabilis, is a beaked and herbivorous early theropod with two remarkable characteristics: a reduced first digit and a metacarpal (lower finger bone) at the base of the second digit that matches those found at the base of the first digits in tyrannosaurids and dromaeosaurids (Ref. 1). These two features suggest that the first digits in late theropods are in fact the second digits, the researchers report today in Nature. We believe that late theropod dinosaurs "had digits 2, 3 and 4, but that these have long been misidentified as digits 1, 2 and 3", says Xu.

On the basis of this evidence, the team argue that early theropods lost their first and fifth digits once and that these digits remained lost in late theropods, an explanation that vastly simplifies the current convoluted evolutionary story. "When birds are considered to [have digits] 2, 3 and 4 it is far simpler for most theropods to [have] 2, 3 and 4 as well," says Clark.

This fossil "can be viewed as a kind of 'missing link' that shows an intermediate digital morphology between living birds and more primitive theropods", says Paul Barrett, a palaeontologist at the Natural History Museum in London.

Evolutionary oddity

However, some researchers are concerned about how the new fossil is being interpreted. "A lot of the arguments depend on bird wings being formed from the second, third and fourth digits and it is possible that they are not," explains evolutionary geneticist Günter Wagner from Yale University.During development, digits are identified by what embryonic tissue forms them, where they grow and what genes shape them as they grow.

If the tissue that forms the second digit is bombarded by genes telling it to form in the shape of a first digit, it will appear to be a first digit - but growing in the location where a second digit normally forms. And experimental evidence suggests this is happening inside modern bird wings, Wagner says.

"The ceratosaur fossil may be showing us a species in the midst of a digit identity shift, but whether the digits that we see in later theropods are the actual second, third and fourth digits or the first, second and third digits in the second, third and fourth positions, altered by gene bombardment to look like the second, third and fourth digits, is difficult to determine," he says.

It is also possible that the ceratosaur does not play a part in the larger evolutionary story and evolved its unusual hands in response to a lifestyle that, because it was beaked and herbivorous rather than toothed and carnivorous, was quite different from that of other theropods. "I think it far more likely that this new animal just has an oddly reduced hand," says Kevin Padian, an palaeontologist at the University of California, Berkeley. "It is equally reasonable that we are just dealing with another odd possibility of evolution," he says.

References
1. Xu, X. et al. Nature 459, 940-944 (2009). | Article |

Friday Ant Zen

2009-06-19T04:49:00.000-07:00

Myrmecia pilosula - Jack Jumper Ant

Victoria, Australia

Myrmecia ants from neighboring nests, engaged in battle.

Photo courtesy of Alex Wild @ Myrmecos

A Conversation with Bert Holldobler

2009-06-18T19:24:00.001-07:00

(Via: NY Times) At 72, Bert Hölldobler, a professor of life sciences at Arizona State University and a professor emeritus at the University of Würzburg in Germany, is one of the world’s great ant experts. Along with his collaborator, E. O. Wilson, Dr. Hölldobler won a Pulitzer Prize in 1991 for “The Ants.” The two wrote a second book in 2008, “The Superorganism: The Beauty, Elegance and Strangeness of Insect Societies.”

Q. HOW DID YOU AND EDWARD O. WILSON BECOME COLLABORATORS?

A. I met Ed Wilson in the 1970s when I first came to Harvard. We’d both been interested in ants since we were young boys, he in Alabama, I in Bavaria. In Germany, there’s a saying, “Every boy goes through a bug phase.” Well, Ed and I, we never grew out of ours! The first time that Ed and I traveled together to Costa Rica, we turned over so many logs together, saw so many new things, that we gathered enough information for six research papers. As for the friendship: that took time. First, we had collegial respect. We’d have lunch. We’d talk about ants. Like every scientist, we gossiped. Scientists gossip a lot! In German, there’s a saying, “You gossip like a washer-woman!” I always say, “No, I gossip like a scientist!” In Ed’s memoir, he said of me — and this touched me very much — “He’s like the younger brother I never had.”

Q. HOW DO TWO ALPHA BIOLOGISTS WRITE BOOKS TOGETHER?

A. We are very different, but we are remarkably complementary. I am basically the experimentalist. Ed is the synthesizer. When Ed reads a paper, he, very quickly, digests it. I read line by line. And sometimes I’ll say, “Ed, this is wrong.” Then we have lunch and we’ll joke around and soon the ball flies quickly. Our friendship was really tested with our last book, “The Superorganism.” We agreed on about 89 percent of it. But we disagreed — and we still do — about sections in the chapter on evolution. He’d written the first draft. I said, “Let me rewrite it.” That took me two months. Later, Ed wrote, “You may have saved us a great deal of embarrassment, but I still don’t agree on several key points. Let me add some footnotes and a dissenting view.” Amazingly, this never affected the friendship. With Ed Wilson, you can have a strong disagreement and still remain good friends.

Q. IN THAT BOOK, YOU AND WILSON WROTE THAT “INSECT SOCIETIES HAVE MUCH TO TEACH US.” LIKE WHAT?

A. Cooperation. The insect societies we study have evolutionary success because they are organized into a division of labor system. Only a relative few species — ants, honeybees, termites — have evolved social systems where you have a few reproductive individuals and hundreds or millions of nonreproductive nest mates. In ant societies, the nonreproductives do particular tasks that benefit “the queens,” who reproduce. This distributed labor system allows the colonies to grow to enormous numbers. There are some species where there’s fierce internal competition to become the reproductives. Their colonies are usually small and less successful. So when we say ants can teach us something, it’s not that we should all aspire to live like an ant. That would be horrible. What ants can teach is that networks of labor distribution, where communications are good and where each group’s work benefits the other, are effective. Economists know this.

Q. So to extrapolate to humans, should we all be happy with our place in the system?

A. We are really a different species. But we learn from nature and see some analogies, even though it has no evolutionary connect. We should value the work of a craftsman carpenter at the same level as we value the work of an academic person. Each part done in humans with expertise and done well has the same value. I’m not saying that everyone should be paid the same. People have tried and it was a dismal failure. Karl Marx was right, but he picked the wrong species. With the ants, he was right. In their world, the individual is nothing, the society is everything.

Q. A LOT OF YOUR RESEARCH IS BASED ON OBSERVING ANT BEHAVIOR IN THE WILD. GIVEN THAT MOST ANTS ARE TINY, HOW DO YOU DO THAT?

A. You just go out and look. Here in Arizona, you don’t have to go very far to find desert ants. You see things. You get ideas. You test them out in the lab. We do a lot of genetic testing. We extract the chemicals that the ants make to learn about their communications systems. One day I was walking in the mountains south of here and I had this lucky discovery. I saw hundreds of honey ants standing on stilt legs, displaying at each other. I had never seen this before. No one had. What was going on? Through much observation, we realized that this was a territorial tournament. The ants come in opposing parties, do these displays, and somehow, a head count. If the numbers were more or less equal, everyone goes home after a while. But if one party proves to be weak, this tournament quickly moves to the nest entrance of the weaker group. Then the stronger group goes in and kills their queen.

Q. IS THIS ANT WARFARE?

A. Yes. And that led to the discovery of what I call ant slavery, which is what I’m working on now. I’m pulling together about 26 years’ worth of observation of it. When the weak group is overrun, the stronger ones capture their pupae and larvae and take them to their own nest. These stolen immature individuals eventually hatch to become workers in the foreign colony. Their lifetime of labor then benefits the raiding group. We’ve been using genetic testing to prove this. We’ve been looking at large ant colonies and we find again and again individuals who belong to foreign mothers. So these workers were definitely stolen. When I discovered this, this was amazing. This was the first example of slavery found where ants exploit foreign labor of their own species.

Q. WHAT FUNCTION DOES IT SERVE?

A. The same function slavery serves in humans. You get others to do your work for you.

Q. WHY DO SO MANY HUMANS HATE ANTS?

A. It’s a mistake to think that people don’t like ants. Many children respond to them. They see that there’s a whole society and that ants behave socially.

Q. SO WHY DO THESE LOVELY CREATURES BITE ME WHEN I’M SITTING AT THE BEACH?

A. Because they don’t like you to sit where perhaps they have their trail and they want to forage. They want you to move away. It works.

Q. DO YOU CALL AN EXTERMINATOR WHEN ANTS INFEST YOUR KITCHEN?

A. No, I don’t mind them. Listen, if you have ants in the house, you take a wet towel and detergent and you wipe over their trail. Do this a couple of times and they’ll stay out. People come up after speeches and say, “But what can we do, we have ants?” I say, “Buy a magnifying glass and enjoy watching them.”

NASA Orbiter on Way to Explore Moon

2009-06-18T16:43:00.000-07:00

[Via: CNN] Story here.

NASA's return to the Moon is off and running. The Lunar Reconnaissance Orbiter and Lunar Crater Observation and Sensing Satellite both rode into the sky over Cape Canaveral, Florida,aboard an Atlas V rocket on 18 June. The threat of thunderstorms had the launch in question right up until the very end, but conditions were declared 'green' with less than 30 minutes remaining.

LRO is now heading directly to the moon, and expected to reach it on Tuesday. LCROSS is in a looping orbit around Earth that will send it plunging into a crater near the moon's south pole on 9 October, to look for water ice. If you can't wait until then for your lunar south pole action, check out a gorgeous new composite map of the south pole craters available here.

The Purpose of Purpose

2009-06-16T17:06:00.001-07:00

Ah, back in business. I had a bit of a blog hiccup some months ago (some would call it catastrophic failure) and if you're familiar with previous manifestations of Ontogeny, you'll likely notice things are a bit sparse around here in terms of links and all. No worries--we'll get her up and running in no time (probably over the next two weeks as grad work allows). I thought it was fitting to start the re-inaugural post with something by Dawkins...

The funny thing about the relaunch is that I bet there have been a lot of Ontogeny links out there not working for some time...I wonder if anybody noticed? Probably not.