March 11, 2007, 8:13 PM CT

These legs were made for fighting

Ape-like human ancestors known as australopiths maintained short legs for 2 million years because a squat physique and stance helped the males fight over access to females, a University of Utah study concludes.

"The old argument was that they retained short legs to help them climb trees that still were an important part of their habitat," says David Carrier, a professor of biology. "My argument is that they retained short legs because short legs helped them fight".

The study analyzed leg lengths and indicators of aggression in nine primate species, including human aborigines. It is in the recent issue of the journal Evolution.

Creatures in the genus Australopithecus immediate predecessors of the human genus Homo had heights of about 3 feet 9 inches for females and 4 feet 6 inches for males. They lived from 4 million to 2 million years ago.

"For that entire period, they had relatively short legs longer than chimps' legs but shorter than the legs of humans that came later," Carrier says.

"So the question is, why did australopiths retain short legs for 2 million years? Among experts on primates, the climbing hypothesis is the explanation. Mechanically, it makes sense. If you are walking on a branch high above the ground, stability is important because if you fall and you're big, you are going to die. Short legs would lower your center of mass and make you more stable"......... Posted by: William      Read more         Source

Sun, 11 Mar 2007 18:27:13 GMT

Dinosaur Bone-genomes Surprise Scientists

The new finding of dino bones surprisingly reveals that the genomes of both the birds and the dinosaurs are short, defying the earlier fining that relatively shorter genomes were associated with flight, researchers now say.

The distinction between birds and the dinosaurs from which they evolved is getting even murkier. The genomes (complete DNA sequences) of both groups are short, researchers now say.

According to old finding, birds possess shorter genomes than other vertebrates, or backboned animals with the length of average bird genome being 1.45 billion base pairs. Bats too have short genomes, which is about 2.25 billion base pairs.

But, human genomes are another billion base pairs longer. The flightless birds too generally have long genomes compared to flying birds.

But, according to the new finding, the shorter genomes of birds originated in saurischian dinosaurs. This is the dinosaur-group from which birds evolved which includes Tyrannosaurus rex.

Thus, short genomes should be taken as a characteristic of dinosaurs, and not birds or flying animals. This category of dinosaurs includes the killer theropod dinosaurs. Chris Organ of Harvard University and his colleagues making this thinking complicated, told LiveScience,

Birds just inherit that character like they have inherited other dinosaurian traits, like feathers.

Posted by: Irani      Read more     Source

February 7, 2007, 8:28 PM CT

Collisions Of The Earth's Crust Theory Challenged

New research findings may help refine the accepted models used by earth researchers over the past 30 years to describe the ways in which continents clash to form the Earth's landscape.

Eric Calais, an associate professor of geophysics at Purdue University, in collaboration with Ming Wang and Zenghang Shen from the Institute for Geology and Earthquake Science in China, used global positioning systems to record the precise movements of hundreds of points on the continent of Asia over a 10-year period.

"Previous to this, we had only partial regional views that were sometimes inconsistent with each other," Calais said. "With this work, we addressed a fundamental question that geologists have been debating for the past 40 years: Are continents strong and brittle or weak and viscous?".

The "strong and brittle" theory suggests continents break into pieces during collisions of the tectonic plates, pieces of the Earth's crust into which the continents are embedded. The "weak and viscous" theory suggests, on the contrary, that continents thicken and flow upon collision.

The data collected by Calais and his team, published in the Dec. 30 issue of Geophysical Research Letters, suggests the answer is a combination of both theories. His team observed that the surface of the Asian continent behaves differently in areas of high elevation, such as mountains.........

Posted by: William      Read more         Source

February 7, 2007, 8:23 PM CT

Forensic Photography Brings Color Back

Archaeologists are now turning to forensic crime lab techniques to hunt for dyes, paint, and other decoration in prehistoric textiles.

Eventhough ancient fabrics can offer clues about prehistoric cultures, often their colors are faded, patterns dissolved, and fibers crumbling. Forensic photography can be used as an inexpensive and non-destructive tool to analyze these artifacts more efficiently, as per new Ohio State University.

Forensic photography helps scientists collect information from fragile artifacts before using expensive chemical tests, which cause damage during material sampling. The forensic method also helps scientists narrow areas to sample for colorants, ultimately reducing artifact damage and testing costs.

"Normally when you dig artifacts out of the ground, particularly stone or ceramic ones, you wash them and they look sexy. But you can't do that with textiles," said Christel Baldia, Ohio State University doctoral graduate in textiles and clothing. Baldia conducted the study with Kathryn Jakes, professor of textile sciences in the College of Education and Human Ecology at Ohio State, and published their findings in the April, 2007 issue of Journal of Archaeological Science.

Putting forensic photography to the test, Baldia and Jakes examined textiles from burial mounds built by the Hopewell, a prehistoric Native American people that flourished about 1600 years ago. In their study, the two researchers focused on pieces of fabric recovered from Ohio 's Seip burial mounds in southern Ohio. Experts believe some of the pieces belonged to a canopy of fabric that arched over the remains buried inside the mounds.........

Posted by: William      Read more         Source

January 15, 2007, 5:19 AM CT

Hofmeyr-Skull supports the "Out of Africa"-Theory

Reliably dated fossils are critical to understanding the course of human evolution. A human skull discovered over fifty years ago near the town of Hofmeyr, in the Eastern Cape Province of South Africa, is one such fossil. A study by an international team of researchers led by Frederick Grine of the Departments of Anthropology and Anatomical Sciences at Stony Brook University in New York published recently in Science magazine has dated the skull to 36,000 years ago. This skull provides critical corroboration of genetic evidence indicating that modern humans originated in sub-Saharan Africa and migrated about this time to colonize the Old World. (Science January 12, 2007).

"The Hofmeyr skull gives us the first insights into the morphology of such a sub-Saharan African population, which means the most recent common ancestor of all of us - wherever we come from," said Grine.

Eventhough the skull was found over half a century ago, its significance became apparent only recently. A new approach to dating developed by Grine team member Richard Bailey and colleagues at Oxford University allowed them to determined its age at just over 36,000 years ago by measuring the amount of radiation that had been absorbed by sand grains that filled the inside of the skull's braincase. At this age, the skull fills a significant void in the human fossil record of sub-Saharan Africa from the period between about 70,000 and 15,000 years ago. During this critical period, the archaeological tradition known as the Later Stone Age, with its sophisticated stone and bone tools and artwork appears in sub-Saharan Africa, and anatomically modern people appear for the first time in Europe and western Asia with the equally complex Upper Paleolithic archeological tradition.........

Posted by: William      Read more         Source

January 11, 2007, 9:22 PM CT

Spread Of Modern Humans Occurred Later

The spread of modern humans out of Africa occurred 40,000 to 50,000 years later than previously thought, as per scientists including one Texas A&M University anthropologist.

Ted Goebel, associate director of the Center for the Study of the First Americans at Texas A&M, is the author of the paper titled "The Missing Years for Modern Humans" that appears in the Jan. 12 (Friday) issue of Science.

Goebel's paper is one of three reported in the current issue of Science dealing with the origins and dispersals of modern humans during the Ice Age. A fourth paper appeared in a prior issue of the journal.

The other papers are written by human paleontologist Frederick Grine of Stony Brook University, geneticist Annamaria Olivieri from the University of Pavia in Italy, and archeologists Michael Anikovich and Andre Sinitsyn of the Russian Academy of Science and John Hoffecker of the University of Colorado.

"All of them have one thing in common," says Goebel of the papers. "They are all trying to investigate and demonstrate when it was that modern humans evolved in Africa, left Africa and colonized different areas of the Old World".

Prior theories held that modern humans spread from Africa 100,000 years ago. New data, however, suggest that their migration occurred only 50,000 to 60,000 years ago, Goebel argues. Additionally, the spread of modern humans in eastern Europe and Russia occurred earlier than previously thought notes Goebel.........

Posted by: William      Read more         Source

January 11, 2007, 7:51 PM CT

Fixing The Nitrogen Balance

Scientists in the US have observed that, reassuringly, the global nitrogen cycles can be more easily balanced out than previously thought, as sources and sinks of usable nitrogen are geographically close and respond to each other in rapid feedback.

Conventional wisdom in biogeochemistry suggested that most of the nitrogen fixation in the oceans was going on in the Atlantic, where the supply of iron, mandatory by the nitrogenase enzyme, is more plentiful. However, the evidence also suggested that most of the loss of fixed nitrogen (denitrification) occurred in the Pacific. With such a vast distance between producers and consumers, the equilibrium between the two processes might have taken millennia to adjust to changes in environmental conditions, such as the current climate change.

Curtis Deutsch from the University of Washington at Seattle, together with colleagues from four other institutions across the US, has developed a new way of analysing the existing data on nitrogen cycles, based on the parameter P*, which describes the relative excess or lack of phosphate ions with respect to the predicted ratio between N and P consumption (normally 16:1).

Deutsch and his colleagues now conclude that inhabitants of the Pacific Ocean are responsible for around two thirds of the total nitrogen fixation that occurs annually in the oceans (estimated to be 140 million tons). The Atlantic contributes less than 20 per cent. Thus, the sources and sinks of usable nitrogen are geographically closer than anticipated. Furthermore, the analysis suggests that the supply of iron from the continents is not the limiting factor for nitrogenase activity. Instead, it looks as though nitrogen fixation is encouraged by a shortage of nitrate in a negative feedback loop, which stabilises the overall nitrogen balance of our planet.........

Posted by: William      Read more         Source

January 9, 2007, 8:42 PM CT

Diamonds From Outer Space

If indeed "a diamond is forever," the most primitive origins of Earth's so-called black diamonds were in deep, universal time, geologists have discovered. Black diamonds came from none other than interstellar space.

In a paper published online on December 20, 2006, in the journal Astrophysical Journal Letters, researchers Jozsef Garai and Stephen Haggerty of Florida International University, along with Case Western Reserve University scientists Sandeep Rekhi and Mark Chance, claim an extraterrestrial origin for the unique black diamonds, also called carbonado diamonds.

Infrared synchrotron radiation at Brookhaven National Laboratory was used to discover the diamonds' source.

"Trace elements critical to an 'ET' origin are nitrogen and hydrogen," said Haggerty. The presence of hydrogen in the carbonado diamonds indicates an origin in a hydrogen-rich interstellar space, he and his colleagues believe.

The term carbonado was coined by the Portuguese in Brazil in the mid-18th century; it's derived from its visual similarity to porous charcoal. Black diamonds are found only in Brazil and the Central African Republic.

"Conventional diamonds are mined from explosive volcanic rocks [kimberlites] that transport them from depths in excess of 100 kilometers to the Earth's surface in a very short amount of time," said Sonia Esperanca, program director in the National Science Foundation's Division of Earth Sciences, which funded the research. "This process preserves the unique crystal structure that makes diamonds the hardest natural material known".........

Posted by: Brooke      Read more         Source

December 18, 2006, 9:41 PM CT

Ape-man Skeleton Is 2.2 Million Years Old

Liverpool scientists worked in collaboration with colleagues at the University of Leeds to analyse the skeleton, which was found in 1997 in Sterkfontein cave in South Africa. Known as 'Little Foot', it was known to be between two million and four million years old, but the team has now dated it precisely to 2.2 million years old.

These new findings reveal that the ape-like creature - part of the Australophithecus africanus family - may not be the immediate ancestor of human beings as some experts originally thought. This is because the team observed that 'Little Foot' lived after the arrival of the stone tool makers, Homo habilis, raising the possibility that this family was more of a side branch of the human evolutionary tree.

Dr Alfred Latham, from the University's School of Archaeology, Classics and Egyptology said: "'Little Foot' is known to have stood on two feet, standing approximately 130cm tall and having a brain not much larger than a modern chimpanzee. It was discovered cemented in layers of stalagmites and archaeologists are continuing to extract the skeleton from the hardened deposits. We think that 'Little Foot' either fell down a shaft or somehow got trapped in the cave and died there. The remains were preserved in the stalagmite layers and it is these layers that have helped our team to date the skeleton".........

Posted by: William      Permalink         Source

December 18, 2006, 9:37 PM CT

Tiny Bones Rewrite Textbooks

Small but remarkable fossils found in New Zealand will prompt a major rewrite of prehistory textbooks, showing for the first time that the so-called "land of birds" was once home to mammals as well.

The tiny fossilised bones - part of a jaw and hip - belonged to a unique, mouse-sized land animal unlike any other mammal known and were unearthed from the rich St Bathans fossil bed, in the Otago region of South Island.

But the real shock to researchers was that it was there at all: until now, decades of searching had shown no hint that the furry, warm-blooded animals that thrived and prospered so widely in other lands had ever trodden on New Zealand soil.

The fact that even one land mammal had lived there, at least 16 million years ago, has put paid to the theory that New Zealand's rich bird fauna had evolved there because they had no competition from land mammals.

An international team led by Trevor Worthy, of the University of Adelaide, Alan Tennyson, of the Museum of New Zealand Te Papa Tongarewa, and Mike Archer, of the University of New South Wales, note that New Zealand separated from the ancient supercontinent of Gondwana more than 80 million years ago. The research has been reported in the journal Proceedings of the National Academy of Sciences.........

Posted by: William      Permalink         Source