06 November, 2007

Ancient Mammal Had Modern Teeth

LiveScience Staff

LiveScience.com Wed Oct 31, 5:40 PM ET

The fossils of an ancient creature resembling a small opossum and equipped with modern-looking teeth suggest our furry ancestors were far more diverse in the age of dinosaurs than previously thought.

"The story of the earliest mammals is a story of their teeth," said study team member Zhe-Xi Luo, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh. "By tracing their evolution in the rich fossil record of the Mesozoic, we can understand how these cutting and grinding teeth evolved over and over again."

Dubbed Pseudotribos robustus , the creature was discovered in 165 million-year-old lakebeds corresponding to the Jurassic Period in Northern China. It measured about 5 inches (12 centimeters) in length and weighed between 20 to 30 grams (.04 to .07 pounds). The animal likely fed on worms and insects and lived above ground, although it had strong limbs and would have been capable of "power digging," scientists say.

What surprised scientists, however, were the animal's teeth. They resembled the "tribosphenic" teeth of modern mammals, which can both slice and grind. Psuedotribos had "pseudo-tribosphenic" teeth that are superficially similar to tribosphenic teeth except that the positions of the cutter and grinder are flipped.

Paleontologists previously thought tribosphenic teeth evolved once before spreading to all mammals. But a 2001 study by Luo and colleagues suggested tribosphenic molars in monotremes, whose living descendents include the platypus, evolved separately from those of marsupial and placental mammals.

The new fossil lends further support to the idea that similar dental structures for cutting and grinding evolved several times in mammalian evolution. belt deep

Under natural selection, organisms descending from different ancestors can evolve similar structures and similar adaptations to suit a common purpose. This is called convergent evolution.

"The pseudo-tribosphenic teeth and the true tribosphenic teeth are great examples of convergent evolution and a great manifestation of how dental and feeding adapationa can be achieved by different lineages of mammals," Luo said.

Original Story: Ancient Mammal Had Modern Teeth

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06 November, 2007

Experts discover rare amphibian imprints

By CATHERINE TSAI, Associated Press Writer Wed Oct 31, 5:45 PM ET

DENVER - A rock that sat untouched in a Pennsylvania museum's fossil collection for years has rare full-body imprints of not just one, but three, ancient amphibians.

Researchers found the imprints in sandstone rocks collected in eastern Pennsylvania decades ago and stored in the museum in Reading, Pa. The body impressions of the salamander-like creatures are estimated to be 330 million years old, or about 100 million years before the first dinosaurs appeared.attku begin

Many ancient footprints have been found, but a full-body animal impression is unusual. The three impressions show the foot-long temnospondyls had webbed feet and smooth skin similar to modern-day amphibians, rather than armored bodies.

"The most remarkable thing about these is they exist at all. This is a very rare preservation," said John Bolt, curator of fossil amphibians and reptiles at The Field Museum in Chicago.

Details were being presented Tuesday in Denver at the annual meeting of the Geological Society of America.

"They're really some of the oldest body imprints of land-living amphibians," said Spencer G. Lucas of the New Mexico Museum of Natural History and Science, who was making the presentation.

"They show you what the shape of the body was, they show you what the texture of the skin was like," Lucas said. "These are things we don't know from bones. They're giving us new information about the anatomy of these long-extinct amphibians."

The fossil could indicate social behavior or even courtship, Lucas speculated, or the impressions also could have been made at different times.

"The real question is why do you have three close together on a rock," he said.

David Fillmore, who was doing postgraduate work with Kutztown University geology professor Edward Simpson, found the impressions two years ago when the two were studying Mauch Chunk Formation footprints in a fossil collection at Pennsylvania's Reading Public Museum.

"We looked at each other and were speechless. It's way beyond anything we could imagine finding," Fillmore said.

25 October, 2007

Obesity ads too soft on fat, critics say

ATLANTA - Drunks swimming in gin, smokers in body bags and dopers living with their parents deep into adulthood. Those are among the public service ads shown in the past. But the government's new batch of obesity spots declines even to show a fat person, let alone wag a finger for gluttony or sloth.

No one is advocating public service announcements that ridicule fat people; experts say such spots would do more harm than good. But critics complain that the three new spots premiering this month are a wimpy attack on the costly and deadly explosion of obesity in America.

"It's so namby-pamby I think people will shrug it off," said Michael Jacobson of the Center for Science in the Public Interest, a Washington-based advocacy organization.

The three new spots are the latest in a series created by the Ad Council and the U.S. Department of Health and Human Services, which try to tackle the nation's obesity problem with ads that encourage healthy snacking and taking the stairs.

Creators of the "Small Steps" campaign, funded by the government at more than $1.5 million a year, cite survey data for 467 adults which showed those who saw the ads did more walking and adopted some other healthy habits than those who didn't see the ads.

But critics say such a survey is hardly proof of success, and the nation's fat problem is clearly getting worse — more than one in three U.S. children are overweight or obese, and two in three adults are.

"I think 'Small Steps' is a euphemism for small vision," said Kelly Brownell, director of Yale University's Center for Eating and Weight Disorders.

The "Small Steps" campaign began in 2004. It was created for free by McCann Erickson New York, the ad agency that created the MasterCard "Priceless" campaign. Six TV spots have aired so far, all professionally produced and humorous, highlighting tips to healthier living.

This month, three more spots joined the rotation, along with a multimedia campaign focusing on exercise. The new anti-obesity TV spots show trim or slightly pudgy people noticing blobs of fat on a hotel room floor or in a theater. They comment that someone must have lost it by eating healthy snacks.

The spots' creators say they learned in focus groups that many people are intimidated — hopeless, even — about the sustained changes needed to slim down.

"So many people, when they think about losing weight, see it as a Sisyphean task — 'I have to lose weight but I can't fit it into my busy schedule,'" said Peggy Conlon, president of the Ad Council.

The ads offer easily achievable tips that empower people to make positive changes, she added.

The ads targeting smoking aren't as tame. A recent one by the New York City Department of Health and Mental Hygiene shows smokers' decayed and tumored bodies.

Young viewers pay more attention to ads that evoke feelings of personal loss, sadness, anger, disgust or fear, according to an analysis by the Centers for Disease Control and Prevention. Kids also tend to remember such ads longer.

That drama is lacking in the obesity spots — for example, none have offered a surgeon's view of fat, or dramatized a death from Type 2 diabetes, or shown a person complaining about how a fat neighbor's medical bills are costing taxpayers.

In the past, the vegan advocacy group, Physicians Committee for Responsible Medicine, has taken a somewhat confrontational approach.

In 2005, the group put out a spot in which doctors yank a pizza and jumbo-sized soda away from an intently eating fat boy and toss him an apple. They put out another in which the same doctors haul away fatty foods from a restaurant called Chubby's.

The group has no data on whether the ads are working, but the government ads "don't address the obesity problem in a vivid enough way to get people's attention," said Patrick Sullivan, the group's communications director.

That raises a second complaint with the government's campaign: It sidesteps what some feel are the real causes of the obesity epidemic, the abundance of cheap and large portions of sugary and high-calorie foods.

"The U.S. government doesn't have the guts to go after junk food producers," Jacobson said.

Tied in with the "Small Steps" campaign, the Ad Council and federal health department are part of the "Coalition for Healthy Children," whose members include Coca Cola, PepsiCo, the Hershey Co. and the National Confectioners Association. Critics say the partnership suggests a conflict of interest that might dissuade efforts to discourage soft drinks or candy bars.

Food and soda companies did not alter what was said in spots, said Ellyn Fisher, an Ad Council spokeswoman. The content was shaped by advertising research, which concluded the spots were humorous and motivating, she said.