October 30, 2007, 10:13 PM CT

Elusive jellyfish more than 500 million years old

Using recently discovered fossil snapshots found in rocks more than 500 million years old, three University of Kansas scientists have described the oldest definitive jellyfish ever found.

In a paper would be published in PLoS ONE on October 31, the scientists describe four types of cnidarian fossils preserving traits that allow them to be correlation to modern orders and families of jellyfish. The specimens are about 200 million years older than the oldest previously discovered jellyfish fossils.

The fossil record is full of circular shaped blobs, some of which are jellyfish, said Paulyn Cartwright, KU assistant professor of ecology and evolutionary biology and one of the articles authors. Thats one of the reasons the fossils we describe are so interesting, because you can see a distinct bell-shape, tentacles, muscle scars and possibly even the gonads.

The jellyfish left behind a film in fine sediment that resembles a picture of the animal. Most jellyfish do not leave such a clear impression behind because they are often preserved in coarse sand.

Cartwright, Bruce Lieberman, KU professor of geology and senior curator of invertebrate paleontology at the KU Natural History Museum, and Jonathan Hendricks, postdoctoral researcher in geology at KU, collaborated on the article. Their research will be published October 31 in PLoS ONE, an online peer-evaluated journal by the Public Library of Science. Other scientists involved in the discoveries were Susan L. Halgedahl and Richard D. Jarrard, both of the University of Utah, Salt Lake City, Utah; Antonio C. Marques, University of San Paulo, San Paulo, Brazil; and Allen G. Collins, Smithsonian Institution, Washington, D.C......... Posted by: William      Read more         Source

October 25, 2007, 10:26 PM CT

Some Neanderthals were redheads

Ancient DNA retrieved from the bones of two Neanderthals suggests that at least some of them had red hair and pale skin, researchers report this week in the journal Science. The international team says that Neanderthals' pigmentation may even have been as varied as that of modern humans, and that at least 1 percent of Neanderthals were likely redheads.

The researchers -- led by Holger Rmpler of Harvard University and the University of Leipzig, Carles Lalueza-Fox of the University of Barcelona, and Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig -- extracted, amplified, and sequenced a pigmentation gene called MC1R from the bones of a 43,000-year-old Neanderthal from El Sidrn, Spain, and a 50,000-year-old individual from Monti Lessini, Italy.

"Together with other genes, this MC1R gene dictates hair and skin color in humans and other mammals," says Rmpler, a postdoctoral researcher working with Hopi E. Hoekstra in Harvard's Department of Organismic and Evolutionary Biology. "The two Neanderthal individuals we studied showed a point mutation not seen in modern humans. When we induced such a mutation in human cells, we observed that it impaired MC1R activity, a condition that leads to red hair and pale skin in modern humans"......... Posted by: William      Read more         Source

October 17, 2007, 8:20 PM CT

Fossilized cashew nuts reveal Europe was important route

Cashew nut fossils have been identified in 47-million year old lake sediment in Gera number of, revealing that the cashew genus Anacardium was once distributed in Europe, remote from its modern native distribution in Central and South America. It was previously proposed that Anacardium and its African sister genus, Fegimanra, diverged from their common ancestor when the landmasses of Africa and South America separated. However, groundbreaking new data in the recent issue of the International Journal of Plant Sciences indicate that Europe may be an important biogeographic link between Africa and the New World.

The occurrence of cashews in both Europe and tropical America suggests that they were distributed in both North America and Europe during the Tertiary and spread across the North Atlantic landbridge that linked North America and Europe by way of Greenland before the rifting and divergence of these landmasses, explain Steven R. Manchester (University of Florida), Volker Wilde (Forschungsinstitut Senckenberg, Sektion Palaeobotanik, Frankfurt am Main, Gera number of), and Margaret E. Collinson (Royal Holloway University of London, UK). They apparently became extinct in northern latitudes with climatic cooling near the end of the Tertiary and Quaternary but were able to survive at more southerly latitudes......... Posted by: William      Read more         Source

October 11, 2007, 4:09 AM CT

Role Of Climate In Neanderthal Extinction

"Our findings suggest that there was no single climatic event that caused the extinction of the Neanderthals" says palaeoanthro-pologist Katerina Harvati. Only a controversial date for very late Neanderthal survival places their disappearance just before a major environmental shift. "Even in this case" continues Harvati "the role of climate would have been indirect, perhaps promoting competition with other human groups".

"There are three main limitations to understanding the role of climate in the Neanderthal extinction" explains palaeoecologist Chronis Tzedakis: uncertainty over the exact timing of the Neanderthal disappearance; uncertainties in converting radiocarbon dates to actual calendar years; and the chronological imprecision of the ancient climate record. "Our novel method circumvents the last two problems" adds palaeoclimatologist Konrad Hughen. "We were therefore able to provide a much more accurate picture of the climatic background at the time of the Neanderthal disappearance". "More generally," continues Hughen "our approach offers the huge potential to unravel the role of climate in critical events of the recent fossil record as it can be applied to any radiocarbon date from any deposit".

The new method was applied by the scientists to three possible dates for the Neanderthal extinction obtained from Gorham's cave, Gibraltar - a site thought to have been occupied by some of the latest surviving Neanderthals. The first two of these dates (~32 and ~28 thousand radiocarbon years ago) relate to conditions that are not distinct from the general climatic instability of the last glacial period. The much more controversial date of ~24 thousand radiocarbon years ago places the last Neanderthals just before a major environmental shift, with an expansion of ice sheets and onset of cold conditions in northern Europe. Gibraltar's climate, however, remained relatively unaffected "perhaps as a result of warm water from the subtropical Atlantic entering the western Mediterranean" as per palaeoceanographer Isabel Cacho......... Posted by: William      Read more         Source

October 2, 2007, 9:46 PM CT

Ancients engineered sophisticated machines

Move over, Archimedes. A researcher at Harvard University is finding that ancient Greek craftsmen were able to engineer sophisticated machines without necessarily understanding the mathematical theory behind their construction.

Recent analysis of technical treatises and literary sources dating back to the fifth century B.C. reveals that technology flourished among practitioners with limited theoretical knowledge.

Craftsmen had their own kind of knowledge that didnt have to be based on theory, explains Mark Schiefsky, professor of the classics in Harvards Faculty of Arts and Sciences. They didnt all go to Platos Academy to learn geometry, and yet they were able to construct precisely calibrated devices.

The balance, used to measure weight throughout the ancient world, best illustrates Schiefskys findings on the distinction between theoretical and practitioners knowledge. Working with a group led by Jrgen Renn, Director of the Max Planck Institute for the History of Science in Berlin, Schiefsky has observed that the steelyarda balance with unequal armswas in use as early as the fourth and fifth centuries B.C., before Archimedes and other thinkers of the Hellenistic era gave a mathematical demonstration of its theoretical foundations.

People assume that Archimedes was the first to use the steelyard because they suppose you cant create one without knowing the law of the lever. In fact, you canand people did. Craftsmen had their own set of rules for making the scale and calibrating the device, says Schiefsky......... Posted by: William      Read more         Source

September 26, 2007, 8:23 PM CT

Ancient whale fall found from Ano Nuevo Island

A fossilized whale skeleton excavated 20 years ago amid the stench and noise of a seabird and elephant seal rookery on California's Ano Nuevo Island turns out to be the youngest example on the Pacific coast of a fossil whale fall and the first in California, as per University of California, Berkeley, paleontologists.

Whale falls, first recognized in the 1980s, are whale carcasses that fall to the deep-ocean floor where, like an oasis in the desert, they attract a specialized group of clams, crabs and worms that feed for up to decades on the oil-rich bones and tissues.

Some researchers think these random, deep-ocean oases are stepping stones for organisms moving from one ocean floor environment to another - whether a hot vent, a cold seep or a whale carcass - in search of sustenance from energy-rich chemicals.

"The fossil whale fall shows that these deep-sea communities didn't need particularly large whales as a source of nutrients - in fact, the fossil whale from Año Nuevo Island was no longer than a VW bug," said Nick Pyenson, a graduate student in UC Berkeley's Department of Integrative Biology.

Pyenson and museum scientist David M. Haasl, both of UC Berkeley's Museum of Paleontology, published their findings in this week's online edition of the journal Biology Letters......... Posted by: William      Read more         Source

September 24, 2007, 10:08 PM CT

Extraterrestrial impact to blame for Ice Age extinctions

What caused the extinction of mammoths and the decline of Stone Age people about 13,000 years ago remains hotly debated. Overhunting by Paleoindians, climate change and disease lead the list of probable causes. But an idea once considered a little out there is now hitting closer to home.

A team of international researchers, including two Northern Arizona University geologists, reports evidence that a comet or low-density object barreling toward Earth exploded in the upper atmosphere and triggered a devastating swath of destruction that wiped out most of the large animals, their habitat and humans of that period.

The detonation either fried them or compressed them because of the shock wave, said Ted Bunch, NAU adjunct professor of geology and former NASA researcher who specializes in impact craters. It was a mini nuclear winter.

Bunch and Jim Wittke, a geologic materials analyst at NAU, are co-authors of the paper, which fingers an extraterrestrial impact 12,900 years ago for the mass extinctions at the end of the Ice Age. The paper was just released online in the Proceedings of the National Academy of Sciences. The research team includes several members of the U.S. National Academy of Sciences and scientists from Hungary and the Netherlands.

No one has found a giant crater in the Earth that could attest to such a cataclysmic impact 13,000 years ago, but the research team offers evidence of a comet, two and a half to three miles in diameter, that detonated 30 to 60 miles above the earth, triggering a massive shockwave, firestorms and a subsequent drastic cooling effect across most of North America and northern Europe......... Posted by: William      Read more         Source

September 21, 2007, 6:35 AM CT

Human ancestors more primitive that once thought

A team of researchers, including Herman Pontzer, Ph.D., assistant professor of physical anthropology in Arts & Sciences, has determined through analysis of the earliest known hominid fossils outside of Africa, recently discovered in Dmanisi, Georgia, the former Soviet republic, that the first human ancestors to inhabit Eurasia were more primitive than previously thought.

The fossils, dated to 1.8 million years old, show some modern aspects of lower limb morphology, such as long legs and an arched foot, but retain some primitive aspects of morphology in the shoulder and foot. The species had a small stature and brain size more similar to earlier species found in Africa.

"Thus, the earliest known hominins to have lived outside Africa in temperate zones of Eurasia did still not display the full set of derived skeletal features," the scientists conclude.

The findings, published Sept. 20 in the journal "Nature," are a marked step in learning more about the first human ancestors to migrate from Africa.

The lead author of the paper is David Lordpkipanidze, director of the National Museum of Georgia. Collaborators on the study include Pontzer and scientists from Georgia, Switzerland, Italy and Spain.

The new evidence shows how this species had the anatomical and behavioral capacity to be successful across a range of environments and expand out of Africa, said Pontzer, who studies how the musculoskeletal anatomy of an animal reflect its performance, ecological niche and evolutionary history......... Posted by: William      Read more         Source

September 12, 2007, 8:31 PM CT

Emissions targets for 2030 will only be reached by banning cars in London

London Authority (GLA) takes radical steps, one of which could be the removal of all cars from both inner and outer London, as per a report published recently.

The GLA is committed to reducing Londons carbon dioxide emissions by 60% by 20251, but most climate researchers argue that even more rapid reductions will be needed if we are to avoid dangerous climate change2. A team of experts from the London School of Hygiene & Tropical Medicine (LSHTM) and the Transport Studies Unit (Oxford University Centre for the Environment) will today reveal that London is on course to reduce land transport emissions by only 10%-23%3,4.

They do, however, offer a radical vision which could achieve a 72% drop in emissions by 2030 a figure that is 83% lower than the current UK average. The solution involves combining a car-free London with high levels of active transport (for example walking and cycling) and realistic but challenging energy-efficient improvements.

Their findings will be released recently at a press event taking place at LSHTM to launch the Lancet Series on Energy and Health, which looks at access to electricity and energy poverty, transport, agriculture, nuclear and renewable power, and a range of other energy issues, and the effect each has on health. The Series calls for action to be taken at personal, national and global level to address these issues......... Posted by: William      Read more         Source

September 12, 2007, 8:29 PM CT

Role Of Climate In Neanderthal Extinction

THE mystery of what killed the Neanderthals has moved a step closer to resolution after an international study led by the University of Leeds has ruled out one of the competing theories catastrophic climate change as the most likely cause.

The bones of more than 400 Neanderthals have been found since the first discoveries were made in the early 19th century. The finds suggest the Neanderthals, named after the Neander Valley near Dsseldorf, where they were first recognized as an extinct kind of archaic humans, inhabited Europe and parts of western Asia for more than 100,000 years.

The causes of their extinction have puzzled researchers for years with some believing it was due to competition with modern humans, while others blamed deteriorating climatic conditions. But a new study published recently in Nature has shown that the Neanderthal extinction did not coincide with any of the extreme climate events that punctuated the last glacial period.

The research was led by Professor Chronis Tzedakis, a palaeoecologist at the University of Leeds, who explained: Until now, there have been three limitations to understanding the role of climate in the Neanderthal extinction: uncertainty over the exact timing of their disappearance; uncertainties in converting radiocarbon dates to actual calendar years; and the chronological imprecision of the ancient climate record......... Posted by: William      Read more         Source