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Monday, October 22, 2007Pregnant DinosaursDinosaurs probably did not enjoy many carefree teenage years, since most were parents before they reached adulthood, according to recently announced research. The find puts dinosaurs on the list of animals that had teenage pregnancies. Others on the list include crocodiles, lizards and humans. The discovery, announced in Austin at the Society of Vertebrate Paleontology's annual meeting, also suggests why evolution favors early births in these groups. "Dinosaurs did pretty much what we do and what most other vertebrates do," explained co-presenter Andrew Lee. "If these species had waited until full size to reproduce, they would have had very few years in which to produce offspring." Lee, a microanatomy instructor and post-doctoral fellow at Ohio University, and colleague Sarah Werning extracted bone tissue from three types of dinosaurs: Tyrannosaurus rex, Allosaurus and Tenontosaurus. The latter was a medium sized, plant-eating cousin of duck-billed dinos, while the former two were big carnivores, so the sampling represented a broad spectrum. Three of the examined dinos possessed a special type of bone tissue called medullary that was used as temporary calcium storage before eggshells were made. Lee explained to Discovery News that living birds possess this same tissue, which they form a few weeks before they are ready to create eggs. This means the analyzed dinosaurs were females that were ready to lay eggs just before they died. Their cause of death remains unknown. Based on the growth stages of the dinosaurs, the scientists determined that T. rex was laying eggs by the age of 18, Allosaurus by age 10 and Tenontosaurus by the very young age of 8. Individuals within all three species would have reached full adult size between their 17th and 21st years. Their lifespan was from 25-30 years. Since smaller animals tend to reach sexual maturity earlier than larger animals, the smallest of the three dinosaurs studied, Tenontosaurus, was on a slightly faster track. Florida State University paleontologist Gregory Erickson and his team recently came to similar conclusions using a different technique. Instead of extracting bone tissue, Erickson and his colleagues counted growth rings in the bones of T. rex and other related dinosaurs, all of which had been found buried with brooding eggs. Erickson and his group also concluded that T. rex gave birth before it reached full maturity. "We now know that T. rex lived fast and died young," he said. While birds are the modern descendants of dinosaurs, birds never give birth as teens. They finish growing and then may wait a year, or even longer, before reproducing. Lee thinks several factors caused birds to change from their dino birthing ways. "Flight is definitely part of the answer," he said. "Most birds need to be able to fly when they fledge, so they have to reach adult size." Birds also now require a steep learning curve for survival, and the learning process takes time. Additionally, he said, "If birds matured early, their offspring might be born during the late summer or fall when food for growth is more scarce." As for future humans losing their ability to produce as teens, Lee believes that's unlikely. He said, "There is little benefit to delay sexual maturity in humans, so I can't imagine that selection might operate to delay sexual maturity before reaching adult size."  
Dinosaurs probably did not enjoy many carefree teenage years, since most were parents before they reached adulthood, according to recently announced research. The find puts dinosaurs on the list of animals that had teenage pregnancies. Others on the list include crocodiles, lizards and humans. The discovery, announced in Austin at the Society of Vertebrate Paleontology's annual meeting, also suggests why evolution favors early births in these groups. "Dinosaurs did pretty much what we do and what most other vertebrates do," explained co-presenter Andrew Lee. "If these species had waited until full size to reproduce, they would have had very few years in which to produce offspring." Lee, a microanatomy instructor and post-doctoral fellow at Ohio University, and colleague Sarah Werning extracted bone tissue from three types of dinosaurs: Tyrannosaurus rex, Allosaurus and Tenontosaurus. The latter was a medium sized, plant-eating cousin of duck-billed dinos, while the former two were big carnivores, so the sampling represented a broad spectrum. Three of the examined dinos possessed a special type of bone tissue called medullary that was used as temporary calcium storage before eggshells were made. Lee explained to Discovery News that living birds possess this same tissue, which they form a few weeks before they are ready to create eggs. This means the analyzed dinosaurs were females that were ready to lay eggs just before they died. Their cause of death remains unknown. Based on the growth stages of the dinosaurs, the scientists determined that T. rex was laying eggs by the age of 18, Allosaurus by age 10 and Tenontosaurus by the very young age of 8. Individuals within all three species would have reached full adult size between their 17th and 21st years. Their lifespan was from 25-30 years. Since smaller animals tend to reach sexual maturity earlier than larger animals, the smallest of the three dinosaurs studied, Tenontosaurus, was on a slightly faster track. Florida State University paleontologist Gregory Erickson and his team recently came to similar conclusions using a different technique. Instead of extracting bone tissue, Erickson and his colleagues counted growth rings in the bones of T. rex and other related dinosaurs, all of which had been found buried with brooding eggs. Erickson and his group also concluded that T. rex gave birth before it reached full maturity. "We now know that T. rex lived fast and died young," he said. While birds are the modern descendants of dinosaurs, birds never give birth as teens. They finish growing and then may wait a year, or even longer, before reproducing. Lee thinks several factors caused birds to change from their dino birthing ways. "Flight is definitely part of the answer," he said. "Most birds need to be able to fly when they fledge, so they have to reach adult size." Birds also now require a steep learning curve for survival, and the learning process takes time. Additionally, he said, "If birds matured early, their offspring might be born during the late summer or fall when food for growth is more scarce." As for future humans losing their ability to produce as teens, Lee believes that's unlikely. He said, "There is little benefit to delay sexual maturity in humans, so I can't imagine that selection might operate to delay sexual maturity before reaching adult size."
A New Jersey second-grader's drawing of a stick figure shooting a gun has earned him a one-day school suspension. Seven-year-old Kyle Walker's mom told an The Press newspaper of Atlantic City that her son was suspended for violating the district's zero-tolerance policy on guns. She said her son told her he'd drawn a water pistol. Kyle gave the picture to another child on the school bus, and that child's parents complained about it to school officials. The case is not the first in New Jersey in which students were suspended for depictions of weapons. Four kindergarten boys were suspended in 2000 for playing cops and robbers, even though they were using their fingers as guns.
She just flew in from New Zealand and boy are her wings tired. Early last month, a female Bar-tailed Godwit, a type of shorebird, completed an epic journey from New Zealand to Alaska and back, a trip that included the longest flight ever recorded for a land bird, according to the U.S. Geological Survey (USGS). The bird logged a flight that lasted for more than eight days and covered a distance of 7,200 miles (11,600 kilometers), the equivalent of flying roundtrip from New York to San Francisco, and then back to San Francsico. The USGS tracked the migrating bird and its travel mates via satellite. Bar-tailed Godwits (Limosa lapponica) spend their summers breeding in western and northern Alaska, and in the fall gather on the Alaska Peninsula to make the long flight across the Pacific Ocean to their winter homes in New Zealand and southeastern Australia. The 18,000-mile (29,000-kilometer) roundtrip journey is the longest known non-stop migration for any shorebird species, though the birds sometimes fly it in several legs. The conservation status of Bar-tailed Godwits is listed as of High Concern in the United States, mostly because of the birds' low population size (there are only an estimated 100,000 to 150,000 breeding birds in Alaska) and habitat threats to some of their migratory .
A few years ago, an obesity researcher at the University of Washington named Adam Drewnowski ventured into the supermarket to solve a mystery. He wanted to figure out why it is that the most reliable predictor of obesity in America today is a person’s wealth. For most of history, after all, the poor have typically suffered from a shortage of calories, not a surfeit. So how is it that today the people with the least amount of money to spend on food are the ones most likely to be overweight? Drewnowski gave himself a hypothetical dollar to spend, using it to purchase as many calories as he possibly could. He discovered that he could buy the most calories per dollar in the middle aisles of the supermarket, among the towering canyons of processed food and soft drink. (In the typical American supermarket, the fresh foods — dairy, meat, fish and produce — line the perimeter walls, while the imperishable packaged goods dominate the center.) Drewnowski found that a dollar could buy 1,200 calories of cookies or potato chips but only 250 calories of carrots. Looking for something to wash down those chips, he discovered that his dollar bought 875 calories of soda but only 170 calories of orange juice. As a rule, processed foods are more “energy dense” than fresh foods: they contain less water and fiber but more added fat and sugar, which makes them both less filling and more fattening. These particular calories also happen to be the least healthful ones in the marketplace, which is why we call the foods that contain them “junk.” Drewnowski concluded that the rules of the food game in America are organized in such a way that if you are eating on a budget, the most rational economic strategy is to eat badly — and get fat. This perverse state of affairs is not, as you might think, the inevitable result of the free market. Compared with a bunch of carrots, a package of Twinkies, to take one iconic processed foodlike substance as an example, is a highly complicated, high-tech piece of manufacture, involving no fewer than 39 ingredients, many themselves elaborately manufactured, as well as the packaging and a hefty marketing budget. So how can the supermarket possibly sell a pair of these synthetic cream-filled pseudocakes for less than a bunch of roots? For the answer, you need look no farther than the farm bill. This resolutely unglamorous and head-hurtingly complicated piece of legislation, which comes around roughly every five years and is about to do so again, sets the rules for the American food system — indeed, to a considerable extent, for the world’s food system. Among other things, it determines which crops will be subsidized and which will not, and in the case of the carrot and the Twinkie, the farm bill as currently written offers a lot more support to the cake than to the root. Like most processed foods, the Twinkie is basically a clever arrangement of carbohydrates and fats teased out of corn, soybeans and wheat — three of the five commodity crops that the farm bill supports, to the tune of some $25 billion a year. (Rice and cotton are the others.) For the last several decades — indeed, for about as long as the American waistline has been ballooning — U.S. agricultural policy has been designed in such a way as to promote the overproduction of these five commodities, especially corn and soy. That’s because the current farm bill helps commodity farmers by cutting them a check based on how many bushels they can grow, rather than, say, by supporting prices and limiting production, as farm bills once did. The result? A food system awash in added sugars (derived from corn) and added fats (derived mainly from soy), as well as dirt-cheap meat and milk (derived from both). By comparison, the farm bill does almost nothing to support farmers growing fresh produce. A result of these policy choices is on stark display in your supermarket, where the real price of fruits and vegetables between 1985 and 2000 increased by nearly 40 percent while the real price of soft drinks (a k a liquid corn) declined by 23 percent. The reason the least healthful calories in the supermarket are the cheapest is that those are the ones the farm bill encourages farmers to grow. More at:http://www.nytimes.com/2007/04/22/magazine/22wwlnlede.t.html?_r=1&oref=slogin
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