Many students have difficulty understanding and explaining how evolution operates. In search of better ways to teach the subject, researchers at Michigan State University developed complete evolutionary case studies spanning the gamut from the molecular changes underlying an evolving characteristic to their genetic consequences and effects in populations. The researchers, Peter J. T. White, Merle K. Heidemann, and James J. Smith, then incorporated two of the scenarios into a cellular and molecular biology course taught to undergraduates at the university's Lyman Briggs College.
When the students' understanding was tested, the results showed that students who had understood an integrated evolutionary scenario were better at explaining and describing how evolution works in general.
The results of the research, described in the July issue of BioScience, are significant because evolution is not usually taught in this comprehensive, soup-to-nuts way. Rather, instructors teach examples of parts of the evolutionary process, such as the ecological effects of natural selection or the rules of genetic inheritance, separately. It appears that this fragmentation makes it harder for students to understand the process as a whole.
White and his colleagues note that "surprisingly few" comprehensive evolutionary study systems have been described, although the number is growing. The two employed in the BioScience study were about the evolution of sweet taste and wrinkled skin in domestic garden peas, and the evolution of light or dark coat color in beach mice living on light or dark sand. Students were tested on the beach mouse coat color scenario as well as on evolutionary principles in general. Understanding the beach mouse example was a better predictor of good responses to questions about evolution in general than was performance on the course as a whole. This suggests that improvements in evolutionary understanding came mostly from studying the integrated evolution scenarios.
From Science Daily
Jun 15, 2013
Huge Earth-Passing Asteroid 'Entirely New Beast'
Asteroid 1998 QE2 and its moon sailed within 3.6 million miles (5.8 million kilometers) of Earth on May 31, making their closest approach to our planet for at least the next two centuries. New radar images captured by the Arecibo Observatory in Puerto Rico are revealing just how unique this binary asteroid is, researchers say.
“Asteroid QE2 is dark, red, and primitive — that is, it hasn’t been heated or melted as much as other asteroids," Arecibo's Ellen Howell said in a statement. "QE2 is nothing like any asteroid we've visited with a spacecraft, or plan to, or that we have meteorites from. It's an entirely new beast in the menagerie of asteroids near Earth."
The 1,000-foot-wide (305 meters) Arecibo dish and NASA's 230-foot (70 m) Deep Space Network antenna in Goldstone, Calif., tracked 1998 QE2 as it approached Earth last month, then kept following the near-Earth asteroid as it receded into the depths of space.
The resulting radar images have helped researchers take 1998 QE2's measure. The dark, cratered main asteroid is 1.9 miles (3 km) wide, and it has a 2,500-foot (750 m) moon that orbits it once every 32 hours.
"QE2's moon is roughly one-quarter the size of the main asteroid," Patrick Taylor, also of Arecibo, said in a statement. "Similarly, our moon is also approximately one-fourth the size of our planet."
Studying the moon and its orbit should help scientists determine the mass of the main asteroid, which in turn will shed light on the object's composition, researchers said.
Asteroid 1998 QE2 was discovered in August 1998 by astronomers working with MIT's Lincoln Near Earth Asteroid Research program in New Mexico. The space rock completes one lap around the sun every 3.8 years.
There was never any danger of 1998 QE2 hitting Earth during last month's flyby, scientists say. If it had hit us, the damage would have been severe; researchers think that any asteroid bigger than 0.6 miles (1 km) is capable of inflicting damage on a global scale, primarily by altering the planet's climate.
Read more at Discovery News
Jun 14, 2013
Prehistoric-Looking Horses Roaming China's Plains Again
The horses -- named after a Russian officer and explorer who spotted them around 1880 -- bear a striking resemblance to those depicted in European cave paintings, with short necks, spiky manes and a yellow hue.
They graze calmly on a few strands of straw as the wind whips across the vast, open landscape.
"These ones here, they can be approached. The others will run away as soon as you get within 300 yards of them," says Sun Zhicheng, an official at the 1.6-million-acre West Lake national nature reserve.
According to the International Union for Conservation of Nature, Przewalski's horses once roamed as far as Western Europe.
But as the centuries passed, climatic change reduced their habitat and the remainder were so widely hunted, mainly for food, that they were classified as extinct in the wild in 1960 -- although a living specimen was later found in Mongolia.
But a few survived in European zoos, and now efforts are under way to reintroduce them to the wild.
The Chinese project near Xihu in Gansu province faces daunting challenges -- freezing winters, sweltering summers and limited supplies of food and water.
According to Chinese legend, Sun says, the animals were discovered two millennia ago by an exiled criminal around the oasis of Dunhuang, a crossroads on the Silk Road.
"A man had been convicted and banished from Dunhuang. While he was walking near a lake he saw one of these horses.
"He made a mannequin and put it on a path the horse would follow. One day he took the place of the mannequin, and he was able to catch the horse to offer it to the emperor.
"The man then lied to the emperor Han Wudi, saying the horse had sprung out of a spring. And he called it a heavenly horse. The emperor loved the horse so much that he wrote a poem about it."
In 1986 China purchased 18 of the horses from the United States, Britain and Germany and has since bred them in captivity, with their numbers growing to more than 70.
Starting in 2010, carefully selected batches have been released into the reserve.
"Now there are 27, 16 females and 11 males," says Sun. "We even registered the birth of a foal in July 2011, a new success in our reintroduction process."
But very few animals can endure an environment as hard and dry as Gansu's desert steppe.
Przewalski's horses require daily access to water that is within a 30-kilometre (20-mile) range and does not freeze in winter. They also need 22 pounds of dry food per day, relatively close to the water.
In a region that receives less than 1.5 inches of rain per year, many of these conditions could become problems, says Sun.
The reserve is taking back-up measures to improve the horses' chances.
"We have increased the water supply by expanding 10 wells. At a later point we are thinking of bringing water from the river.
"In winter we have to break the ice so that the horses can drink."
The horses eat grasses and certain plant species, says reserve employee Lu Shengrong, but when vegetation becomes sparse in winter-time, they will be fed dry alfalfa, straw, black beans and corn.
Of the 2,000 or so Przewalski's horses that now exist worldwide, about a quarter are part of efforts to reintroduce them to the wild, says Claudia Feh, a biologist doing similar work in Mongolia, where several hundred have been released.
The worst threat they face, she says, are ordinary horses, which can infect them with disease or crossbreed with them, diluting the gene pool.
Read more at Discovery News
Medici Children Suffered From Rickets
Researchers at the University of Pisa made the discovery after analyzing nine skeletons taken from under the floor of the Medici Chapels in the Basilica of San Lorenzo in Florence.
The children’s bones were found in 2004 after the discovery of a secret entrance in the intact tomb of Giangastone (1671–1737), the last Grand Duke of the clan that dominated the Florentine Renaissance.
“The removal of a marble disc in the floor of the chapel, initially considered only a simple floor decoration, displayed a secret opening with a small stone stair leading to a hidden crypt,” palaeopathologist Valentina Giuffra, Gino Fornaciari and colleagues of Pisa and Siena Universities, wrote in the International Journal of Osteoarchaeology.
In the crypt, a large sarcophagus contained the remains of Giangastone, while on the floor lay eight coffins and several scattered bones — the result of the Arno flooding of 1966. The ninth coffin was found in a nearby tomb.
Analysis of the bones revealed that the children’s ages ranged from newborn to about 5 years old. Six out of nine showed the classic signs of rickets, such as curved arms and bow legs — a consequence of trying to crawl or walk on pathologically soft bones.
One of the children clearly identified, Filippo (1577-1582), the seventh child of Francesco I and Giovanna of Austria, also known as Don Filippino, had a slightly deformed skull. According to the researchers, rickets was the culprit.
A skeletal disorder characterized by a lack of vitamin D, rickets is usually associated with poor children living in heavily polluted cities where exposure to sunlight is limited.
“Diagnosis of a metabolic disease linked to vitamin D deficiency would appear unexpected in children brought up at the court of a Renaissance high social class family like the Medici of Florence,” the researchers observed.
Rather than from defects in the metabolism, the disease originated from the Medicis’ desire to protect their offspring, raising them according to the highest social standards for their times.
“During the Renaissance, a common opinion prescribed that children were not to be weaned before the second year of life; for this reason, among the elite classes, wet nursing was a very widespread practice,” the researchers wrote.
Indeed, the Medici princes were never weaned until they were at least 2; starting from eight to nine months, woman’s milk was integrated with paps made of soft bread and apples. Cereals and breast milk are known to supply little vitamin D, while fruit contains none.
“With prolonged breast-feeding, vitamin D deficiency is highly expected to rise, in particular if the other main risk factor, inadequate sunlight exposition, is associated with a diet based on maternal milk,” the researchers said.
They added that two hours per week is the required minimum period of exposure to sunlight for infants if only the face is exposed — something the Medici children did not enjoy.
At that time, skin color was a way to distinguish the upper class from peasants engaged in field work.
“A pale ivory skin was considered a sign of health and elegance,” the researchers wrote.
Kept indoors in large palaces where the opportunity of sunlight exposure was significantly reduced, the Medici children were also wrapped in many heavy layers. In keeping with the Renaissance customs, infants were heavily swaddled, leaving very little skin exposed.
Even two newborns showed signs of rickets, although they should have received vitamin D from their mothers through the placenta.
Rickets may have been the cause of death for these children or may have contributed to worsening other problems present at birth.
According to the researchers, the mothers also had a vitamin D deficiency. Heavy makeup, to prevent skin exposure to sunlight, and repeated childbearing — Eleanor of Toledo bore 11 children in 14 years — might have been the cause for their low-level vitamin D.
Read more at Discovery News
Fab Abs? Ancient Fossil Fish Had Em!
Mapping the oldest fossilized vertebrate muscles ever seen -- in Gogo fish thought to be 380 million years old -- researchers worked out the position of the muscles and the orientation of the muscle fibers.
The fossil fish, found in the Kimberley region of Western Australia, are enclosed in limestone nodules and are known for their exceptional preservation.
"The muscles in the abdomen cavity that we found weren't expected because even in living fish their main mode of propulsion is of course to flap their tails to left and right so all the muscles are sitting on the side of the body," said Gavin Young from Australian National University's Research School of Earth Sciences.
"What's interesting is when we found these muscles and did some comparisons, the only comparable muscles are in... land animals," he added to AFP.
He said the question now was whether these muscles had the same function as abdominals seen in land animals.
In the study published in Science, the researchers prepared and analyzed the muscles in a small number of specimens from three different species.
"(The ancient fish) have already revealed soft tissues such as nerve and muscle cells, the oldest known vertebrate embryos, and even a preserved umbilical cord," Young said.
The latest study went further and mapped the musculature of the ancient fish for the first time, possible after researchers realized that soft tissues had been preserved in some of the specimens, though it was being destroyed in the earlier process of acid etching the skeletons.
Curtin University associate professor Kate Trinajstic, a chief investigator on the ANU-based research into early vertebrate evolution, said the team had been "stunned to find that our ancient fossil fishes had abs!"
"Abdominal muscles were thought to be an invention of animals that first walked onto the land but this discovery shows that these muscles appeared much earlier in our evolutionary history," she said.
Read more at Discovery News
Radioactive Mountain Yields Rare-Earth Digs
Green technologies such as electric cars, wind turbines, solar panels and fluorescent light bulbs rely on rare-earth metals. The military depends on rare earths for guided missile systems, satellites and unmanned drones. NASA's spacecraft carry powerful rare earth magnets to Mars and outer space. The magnets also miniaturized iPads, computers and high-tech headphones.
China controls 95 percent of the world's rare-earth supply. The key to this monopoly isn't an abundance of rare-earth deposits, but its expertise in processing ore into oxides and pure metal. The ore tends to carry uranium and thorium, the most radioactive element on the planet, and extracting the metal is typically a long, multistage process involving toxic chemicals.
"We know where the deposits are. Having them end up in your iPhone is not a straight or simple process," said Brad Van Gosen, a geologist with the U.S. Geological Survey (USGS) in Denver.
A few years ago, China showed its power, and cut the supply of rare earths to a trickle. The move sent the United States and other countries scrambling to end their reliance on China. Prices soared, drawing new investors and mining companies into the rare earth market. Now, the United States has one new mine nearly finished and two more in the permitting stages. But the crucial element in escaping China's rare-earth rule isn't new mines, it's rebuilding the expertise and infrastructure to process the finicky metals, experts say.
Price war
In 2010, China spiked the cost of rare-earth elements when it started restricting exports and charging foreign companies higher prices. The price bubble sparked a worldwide frenzy to escape China's control. A new Australian-owned processing plant just opened in Malaysia. Others are planned in Canada, Europe and Africa. Several companies are also trying to develop an American supply for rare earths, some with support from the Department of Defense.
"The rare earths are very much strategic metals, and particularly very much of strategic importance to the defense industry," said Curt Freeman, president of Avalon Development Corp. in Fairbanks, Alaska, a mining consulting firm. "There's a queasy feeling in Congress and the Department of Defense," he said.
In the United States, California's Mountain Pass mine reopened in 2010 and is expected to start producing light rare-earth elements this year. The mine was once the world's biggest producers of rare earths, but shut down in 2002 because of environmental problems and falling prices. Another mine is proposed in Wyoming, by Canadian company Rare Element Resources, but faces opposition from local residents.
Despite their name, rare earths are actually common in Earth's crust, though in low concentrations. The moniker is a holdover from the 19th century, when researchers discovered the oddly named elements in rarely found minerals. The 17 elements share a close affinity, with similar chemical properties and atomic weights. Bokan Mountain is one of the few spots on Earth with a bounty of heavy rare-earth elements, which have higher atomic weights. It's especially elevated in yttrium, which appears in everything from cubic zirconia and car pollution sensors to lasers, rockets and jet engines.
Because rare earths are often all mixed together in one rock, separating the heavy rare earths usually requires removing the lighter ones first. This is typically done with a series of chemical tanks and solvents. Plus, there's the radioactive uranium to dispose of. But mine owner Ucore says it has a new solid-extraction technology that greatly simplifies this process. The technique relies on nanotechnology to remove impurities and concentrate the heavy rare earths into oxides, according to Ucore. The Department of Defense funded Ucore's ore extraction research with a contract in October 2012.
But a USGS-funded study found Bokan Mountain's vein system is very complex, with a mix of at least two dozen ore minerals, the agency's Van Gosen said. The study was published Jan. 22 in the Canadian Journal of Earth Sciences.
"It's getting more and more complicated the more we look at it," Van Gosen said.
"Processing is the key challenge for deposits that particularly are skewed toward the middle and heavy rare earths, because they have some unusual minerals that haven't been processed before," said Hatch, founding principal of Technology Metals Research. Hatch is helping develop a rare earth processing company in Canada.
The USGS has several ongoing projects examining the geology of Bokan Mountain, to better understand how the minerals appeared.
"The idea is to develop a fundamental understanding of how these deposits get started in the first place in Earth's crust, and use it to go look for resources that the U.S. public needs," said Susan Karl, a USGS geologist based in Anchorage.
Ucore board member Jaroslav Dostal, an emeritus professor at Saint Mary's University in Halifax, Nova Scotia, was lead author of the Bokan Mountain study. The grant program that provided funding for the study, the USGS Mineral Resources External Research Program, has awarded projects to private industry and foreign recipients in the past.
Investing in processing
The USGS also has projects exploring the geology of other rare-earth deposits. Since 2010, the House of Representatives has introduced legislation to curb mining regulations and fund rare-earth research and development, which have yet to pass the Senate. Recycling of rare-earth metals, which is not always made possible with high-tech gadgetry, is another way to reduce dependency on China's supply. Earlier this year, the Department of Defense recommended stockpiling $120 million of critical heavy rare-earth elements. But industry experts say money would be better spent on building American expertise and infrastructure in processing rare earths. [The Common Elements of Innovation]
Read more at Discovery News
Jun 13, 2013
Dead Daddy Guppies Keep Making Babies
Storing sperm could allow these guppy gals to be pioneers, settling new waters and giving birth to genetically diverse offspring. Females swim better than males, so the females can colonize new territory more easily.
“Populations that are too small can go extinct because close relatives end up breeding with each other and offspring suffer from inbreeding,” David Reznick, professor of biology at the University of California, Riverside and leader of the guppy study published in Proceedings of the Royal Society B, said in a press release. “If there are stored sperm, then the real population size is bigger than the number of animals you see. Also, stored sperm can increase genetic variation in other ways.”
Females live for up to two years, compared to the three to four month lifespan of a male. Keeping dead dads’ sperm on tap could allow females to give birth to a blast from the past male color pattern that will have all the other guppy girls going gaga. Female guppies are attracted to males with unusual patterns.
“In addition to learning about sperm storage, this is the first time we are learning about the huge differences in lifespan between males and females,” Reznick said. “If we were to use males to estimate generation time, then these differences mean that lucky females live for three generations. A human equivalent would be for us to have women around who were 90 years old and still very fertile.”
Read more at Discovery News
Are Languages Shaped By Geography?
A study of more than 550 languages around the world found that tongues spoken in high-altitude regions contain more sounds called ejective consonants, made with a burst of air, than languages closer to sea level.
Ejectives may be more common in these regions because the sounds are easier to produce there, or possibly because they minimize water loss from the mouth in dry, high-altitude environments, said study author Caleb Everett, an anthropological linguist at the University of Miami.
Traditionally, linguists have assumed that geography doesn't play a role in shaping languages, with the exception of vocabulary specific to certain environments or wildlife. A handful of small studies have suggested that languages in warm climates use more vowels than languages in cold climates, but the findings are controversial.
Everett set out to investigate how other aspects of geography, namely altitude, might be linked to certain sounds, or phonemes, in a language. Specifically, he looks at ejectives, a class of sounds (not present in English) produced by puffs of air in the mouth as opposed to the lungs. Everett suspected these sounds might be more common at high altitudes, where the lower air pressure would make them easier to produce.
To test this hypothesis, Everett analyzed phoneme data on 567 languages from the World Atlas of Linguistic Structures Online. He compared the data to the altitudes where the languages were spoken, obtained using geographic mapping software.
Languages containing ejective sounds were found to occur at or near five of the six major inhabited high-altitude regions, including in North and South America, southern Africa and Eurasia, Everett found.
The one exception to this pattern was the Himalayan Plateau — that region was not home to any languages containing ejectives. "It is not particularly surprising that one region should present such an exception," Everett wrote in his paper, "and in fact it strikes us as remarkable that only one region presents an exception."
Languages at high altitudes may have evolved to have ejective sounds because less effort is required to produce these bursts of air in thinner atmospheres, Everett speculates. His basic calculations of the air pressure needed to make these sounds support this explanation.
Read more at Discovery News
The Hunt is on for Habitable Exomoons
The Hunt for Exomoons with Kepler (HEK) is an astronomy project intended to try and find exomoons. And not just any exomoons; the kind of moons that could be a haven for life. While the Kepler telescope has, sadly, been forced into retirement, the data it collected lives on. And there’s a lot of data still to sift though.
The idea of habitable moons is already well known to fans of science fiction. From Star Wars to Prometheus, the idea of a habitable world orbiting a gas giant is quite well ingrained on our collective subconscious. Perhaps this is what inspired the idea back in 2009 that we could look for exomoons with Kepler.
Since then, the idea has come forward in leaps and bounds, and we know of several gas giants within their parent stars’ habitable zones. Some even expect that exomoons may even be the best place to start looking for extrasolar life. The latest development in this story saw a team of astronomers, lead by Harvard-Smithsonian‘s David Kipping, take a closer look at Kepler-22b to try and hone their techniques.
Kepler-22b is a planet with a 95 percent probability of being in its parent star’s habitable zone. Around 620 light-years away from us, it has a radius about 2.4 times as large as Earth, and is about 10 percent as massive as Jupiter. With that size, it’s most likely to be a gas giant.
Unfortunately, no moon was found around Kepler-22b. If it has any moons at all, they must be smaller than half Earth’s mass. Nonetheless, this was far from a wasted exercise. Planet hunters now have a small arsenal of tools and techniques at their disposal — enough for Kipping and his colleagues to draw the conclusion that if any Earth-like moon is there to be found around similar planets, they will find it.
Planet Kepler-22b was chosen for this search for several reasons. As well as being comfortably in the habitable zone and having been confirmed by Kepler observations, this planet also had radial velocity data available for it, and the observations contain very low noise (take it from me, noise in observations is the bane of an astronomer’s life!).
While no Earth-like exomoons could be found around Kepler-22b, the fact that moons should be very easy to see if they’re there is heartening. What’s more, it’s worth bearing in mind that this does not mean that Kepler-22b has no moons at all. For example, Titan, Saturn’s giant moon, has only 2 percent the mass of Earth.
Read more at Discovery News
Andromeda: My God, It's Full of Black Holes
It might not sound like a lot compared to the size of an entire galaxy, but it’s many more than have been found so far in our own galaxy’s center and indicates the presence of even more that can’t be seen.
“While we are excited to find so many black holes in Andromeda, we think it’s just the tip of the iceberg,” said Robin Barnard of Harvard-Smithsonian Center for Astrophysics (CfA), lead author of a new paper describing these results. “Most black holes won’t have close companions and will be invisible to us.”
Using data from Chandra and the European Space Agency’s XMM-Newton X-ray Observatory, astronomers were able to spot these otherwise invisible objects by the energy released by superheated material they draw in from nearby stars.
More than 150 Chandra observations, spread over 13 years, were used to identify the 26 new black holes.
The image above combines optical data from the Warner and Swansey Observatory on Kitt Peak in Arizona with an inset of X-ray observations of the central region. The new black hole candidates are circled in yellow.
While neutron stars would have exhibited a certain level of X-ray emission and wavelength, these sources were more energetic and brighter, indicating that they are very likely stellar-mass black holes — the collapsed remains of stars five to ten times the mass of our sun.
Because the Andromeda galaxy’s central bulge is bigger than the Milky Way’s, more black holes can form there — a scenario that was expected by astronomers and now supported by these Chandra results.
Read more at Discovery News
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