Featured Title:
See Your Book Here |
 |
| Hengeworld |
 |
| Login |
|
Don't have an account yet? You can create one. As a registered user you have some advantages like your own home page, fewer ads, and your contributions link to your page. |
| Who's Online |
There are currently, 105 guests and 1 members online.
You are a guest. To join in, please register for free by clicking here |
| |
Moderated by : Andy B , TimPrevett , coldrum , Klingon , MickM , TheCaptain , bat400 , davidmorgan , Runemage , SolarMegalith , sem
The Megalithic Portal and Megalith Map : Index >>
Stones Forum >> Neanderthals
|
 |
| Author |
Neanderthals |
bat400
Joined:
10-04-2006
Messages: 1335
from South Central Indiana, US
 OFF-Line
|  Posted 15-02-2011 at 03:58
Hunting with Neanderthals.
Kenyon researcher launches replica spears to see how ancient humans chased prey 400,000 years ago.
In 1995, researchers uncovered three 400,000-year-old wooden spears near Schoeningen, about 60 miles southeast of Hanover, Germany. Fifteen years have passed since German scientists unearthed the cache of weapons believed to be the hunting tools of long-lost Neanderthals.
The nearly 400,000-year-old spears have shed light on the hunting practices of ancient humans, but scientists can't agree on how the weapons were used. Were they thrown at big game from a distance or thrust into animals at close range?
To find out, Kenyon College paleoanthropologist Bruce Hardy devised a nifty test that relies on another ancient culture for help.
But first, let's go back to 1995, when German researchers found the three spears, each carved from the trunk of a spruce tree. The spears, found at what appeared to be an ancient lake shore hunting ground, were discovered with more than 10,000 animal bones. That told researchers that these hunters perhaps ambushed herds of horses that showed up at the drinking hole.
"These are the oldest hunting tools that we know of," said David Hohl, a third-year anthropology student at Kenyon.
However, the spears are huge - 6 feet to more than 7 feet long.
"The question is, are they too heavy to be thrown effectively?" Hardy said.
Then again, the German researchers reported in a 1997 paper that the spears were shaped to be thickest toward the front, with a long, tapered tail, similar to a modern javelin. That suggests that they were made for throwing rather than jabbing.
To find out, Hardy's team carved replica spears. Then they constructed a ballista to allow each spear to be "thrown" at a precise angle and distance.
For the "prey," Hardy went to a local butcher and picked up a fresh cowhide still soaked in fat and grease. The team wrapped it around a wooden box that contained two tubs of ballistics gel, which would help the researchers measure wound depth. Last month, on a cold, snowy day, the team took its ballista to an empty field on campus and began firing spears. After a few adjustments, they hit their target.
But instead of penetrating and "mortally wounding" the prey, the spears bounced off its hide. Hardy and the others removed the ballistics gel from the tubs and placed it directly against the hide. But the results were the same. At one point, they even ditched the ballista and took turns charging the box with spears in hand.
Nothing worked. They couldn't put so much as a small hole in the hide.
"We're definitely getting a good idea of how difficult it is to penetrate the skin of a large animal," Hohl said.
A week later, the team reloaded the ballista and aimed its spears at sheep hide. Bingo. The spears routinely penetrated the hide from as far as 95 feet away. "We clearly showed that these spears were effective as long-range projectiles for thin-skinned animals and not for thick-skinned," Hardy said.
He said the experiments gave the team a new appreciation for the early humans.
Thanks to coldrum for the link. See more, including photos, at: http://www.dispatch.com/live/content/science/stories/2011/01/09/hunting-with-neanderthals.html?sid=101
 Profile
 Reply
|
bat400
Joined:
10-04-2006
Messages: 1335
from South Central Indiana, US
OFF-Line
| Posted 15-02-2011 at 04:02
Neanderthals and early modern humans had same lifespanA new study by a Washington University in St. Louis suggests life expectancy was probably the same for early modern and late archaic humans and did not factor in the extinction of Neanderthals.
Our species, Homo sapiens, is the only surviving lineage of the genus Homo. Still, there once were many others, all of whom could also be called human. One puzzle was the lack of elderly individuals. It was therefore suggested that early hominins might have had a shorter life expectancy than early modern humans, with our lineage ultimately outnumbering Neanderthals, contributing to their demise.
Erik Trinkaus, PhD, Professor of Anthropology in Arts & Sciences examined the fossil record to assess adult mortality for both groups, which co-existed in different regions for roughly 150,000 years. Trinkaus found that the proportions of 20 to 40 year old adults versus adults older than 40, were about the same for early modern humans and Neanderthals.
Trinkaus admits, “Although biased, probably through a combination of preservation, age assessment, and especially Pleistocene mobility requirements, these adult mortality distributions suggest low life expectancy and demographic instability across these Late Pleistocene human groups.”
“If indeed there was a demographic advantage for early modern humans, at least during transitional phases of Late Pleistocene human evolution, it must have been the result of increased fertility and/or reduced immature mortality,” argues Trinkaus in the paper’s conclusion. He adds, “Neither adult longevity nor proposed modest shifts in developmental rates are likely to have played a role in this demographic transition.”
Thanks to coldrum for the link. See more at,
http://www.pasthorizons.com/index.php/archives/01/2011/longevity-unlikely-to-have-aided-early-modern-humans#ixzz1Aqm3JC7u.
Profile
Reply
|
Andy B
Joined:
13-02-2001
Messages: 7007
from Surrey, UK
OFF-Line
| Posted 22-04-2011 at 01:16
Did Neanderthals Believe in an Afterlife?
A possible Neanderthal burial ground suggests that they practiced funeral rituals and possessed symbolic thought before modern humans.
Evidence for a likely 50,000-year-old Neanderthal burial ground that includes the remains of at least three individuals has been unearthed in Spain, according to a Quaternary International paper.
The deceased appear to have been intentionally buried, with each Neanderthal's arms folded such that the hands were close to the head. Remains of other Neanderthals have been found in this position, suggesting that it held meaning.
Neanderthals therefore may have conducted burials and possessed symbolic thought before modern humans had these abilities. The site, Sima de las Palomas in Murcia, Southeast Spain, may also be the first known Neanderthal burial ground of Mediterranean Europe.
"We cannot say much (about the skeletons) except that we surmise the site was regarded as somehow relevant in regard to the remains of deceased Neanderthals," lead author Michael Walker told Discovery News. "Their tools and food remains, not to mention signs of fires having been lit, which we have excavated indicate they visited the site more than once."
More
http://news.discovery.com/archaeology/neanderthal-burial-ground-afterlife-110420.html#mkcpgn=emnws1
Profile
 Email
Reply
|
Andy B
Joined:
13-02-2001
Messages: 7007
from Surrey, UK
OFF-Line
| Posted 08-05-2011 at 11:53
Ancient Teeth Show Neanderthals Were Righties
Right-handedness reaches back a half million years in the human evolutionary family, at least if scratched-up fossil teeth have anything to say about it.
Stone-tool scratches on the front teeth of Neanderthals and their presumed European ancestors occur at angles denoting right-handedness in most of these Stone Age hominids, just as in human populations today, say anthropologist David Frayer of the University of Kansas in Lawrence and his colleagues.
Scientists have linked prevalent right-handedness in human populations to a left-brain hemisphere that controls right-sided body movements and enables critical language functions. Given the new tooth evidence, populations of largely right-handed Neanderthals and their predecessors must have possessed a gift for gab, Frayer’s team proposes in a paper published online April 14 in Laterality.
“Findings so far suggest that most European hominids were right-handed by at least 500,000 years ago,” Frayer says. “A capacity for language appears to have ancient, not recent, roots.”
Along with widespread right-handedness indicating that these ancient hominids possessed language-ready brains, humanlike inner-ear fossils show that Neanderthals’ ancestors could hear all the sounds employed in modern tongues, Frayer asserts.
Other researchers contend that, based on vocal-tract reconstructions informed by skull and upper-body fossils, Neanderthals were physically incapable of articulating some modern speech sounds. In these scientists’ view, language as spoken today originated in Homo sapiens sometime after 200,000 years ago.
Frayer’s findings coincide with previous reports of right-handed sharpening patterns on 120,000-year-old Neanderthal stone tools (SN: 11/21/09, p. 24), remarks archaeologist Natalie Uomini of the University of Liverpool in England.
“This new study points to a strong right-hand preference at the group level, and very early on among hominids,” Uomini says.
Handedness may exist among chimpanzees and other nonhuman primates (SN: 4/9/11, p. 11), although to a lesser extent than in people.
To discern ancient hand inclinations, Frayer employed a method developed by paleontologists who excavated 500,000-year-old fossils of Neanderthal ancestors in northern Spain.
Experiments conducted by the Spanish team indicate that when using a stone tool to cut a piece of meat by biting down on one end and holding the other end taut, right-handers make accidental scratches that angle in a consistent direction. Similarly, left-handers make scratches angled in the opposite direction.
Magnified images of front teeth from 17 European Neanderthals that lived between 130,000 and 30,000 years ago revealed scratches consistent with right-handedness in 15 cases and left-handedness in two cases.
Comparable scratch data from front teeth of 12 Neanderthal ancestors, previously obtained by Marina Lozano of Universitat Rovira i Virgili in Spain and her colleagues, denoted right-handedness in each individual.
Frayer calculates that between 0.8 percent and 22.8 percent of these Neanderthal and ancestral Neanderthal populations were left-handed. Even at the high end of that range, right-handedness would have been far more common than left-handedness.
Image: Under extreme magnification, stone-tool marks consistent with right-handedness appear on the surface of a 500,000-year-old hominid tooth, left. Most red-highlighted scratches on the outer surface of a 30,000-year-old Neanderthal tooth, right, also signify right-handedness. (M. Lozano et al., D. Frayer)
http://www.wired.com/wiredscience/2011/04/neanderthals-right-handed/
Profile
Email
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:31
Homo sapiens lived in Eretz Yisrael 400,000 years ago
Teeth found near Rosh Ha’ayin older than anything uncovered in Africa.
Talkbacks (4)
Eight human teeth dating back as far as 400,000 years ago and found at the prehistoric Qesem Cave near Rosh Ha’ayin – discovered recently by Tel Aviv University researchers – are “the world’s earliest evidence” of modern man (Homo sapiens).
Until now, remains of humans from only 200,000 years ago have been found in Africa, and the accepted approach has been that modern man originated on that continent.
RELATED:
Scientists to view 1,200 newly discovered sea creatures
Long before the land was called Israel and the residents Jews, Homo sapiens lived here twice as long ago as was previously believed, the researchers wrote in the latest (December) edition of the American Journal of Physical Anthropology.
The cave was uncovered in 2000 by Prof. Avi Gopher and Dr. Ran Barkai of TAU’s Institute of Archeology. Later, Prof. Israel Hershkowitz of the Department of Anatomy and Anthropology at TAU’s Sackler School of Medicine and an international team of scientists performed a morphological analysis on the teeth found in the cave.
The examination included CT scans and X-rays indicating the size and shape of the teeth are very similar to those of modern man. The teeth found in the cave are also very similar to evidence of modern man dated to around 100,000 years ago that had previously been discovered in the Skhul Cave on Mount Carmel and the Qafzeh Cave in the Lower Galilee near Nazareth.
The Qesem Cave is dated between 400,000 and 200,000 years ago, and archeologists working there believe that the findings indicate significant changes in the behavior of ancient man. This period of time was crucial in the history of mankind from cultural and biological perspectives, and the fact that teeth of modern man were discovered indicates that these changes are apparently related to evolutionary changes taking place at that time, they maintained.
Gopher and Barkai noted that the findings that characterize the culture of those who dwelled in the Qesem Cave – the systematic production of flint blades, the habitual use of fire, evidence of hunting, cutting and sharing of animal meat, mining raw materials to produce flint tools from subsurface sources and much more – reinforce the hypothesis that this was, in fact, innovative and pioneering behavior that corresponds with the appearance of modern man.
The specimens, date back to the Middle Pleistocene era, include permanent and deciduous teeth. They were thus placed chronologically earlier than the bulk of fossil hominin specimens previously known from southwest Asia. Although none of the Qesem teeth resemble those of pre-Homo sapiens Neanderthals, a few traits may suggest some affinities with members of the Neanderthal evolutionary lineage, but the balance of the evidence suggests a closer similarity with the Skhul-Qafzeh dental material, said Gopher and Barkai.
According to the researchers, the discoveries made in the Qesem Cave may change the perception that has been widely accepted to date in which modern man originated on the continent of Africa. In recent years, archeological evidence and human skeletons have been discovered in Spain and China that are liable to undermine this perception, but the findings now uncovered at Qesem are significant and invaluable, and their early age is undoubtedly an extraordinary archeological discovery, said Gopher and Barkai.
As excavations at the cave continue, the researchers hope to uncover additional discoveries that will enable them to confirm the findings published up to now and to enhance their understanding of the evolution of mankind and especially the appearance of modern man.
http://www.jpost.com/Sci-Tech/Article.aspx?id=201076
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:32
Unearthing a Neanderthal Madrileña
The discovery of remains in Pinilla del Valle provides scientists with exciting new information about homo sapiens' mysterious predecessor .
The famous paleoarcheological site at Pinilla del Valle can add another valuable find to its list. Known as one of the richest European sites for fauna remains (more than 3,000 fossils of rhinos, lions, bears, hyenas and turtles have been dug up here), it has now offered up important hominid findings that represent a significant step for anthropological research
The discovery in Pinilla del Valle of four dental pieces belonging to a girl who lived more than 40,000 years ago is one of the most important paleontological discoveries of recent decades. That's how it was defined by anthropologist Juan Luis Arsuaga, co-director of Atapuerca; palaeontologist Enrique Baquedano (the driving force behind the excavation at Pinilla) and the top man in Spanish archeology, Alfredo Rérez González, on Monday.
Ignacio González, vice-premier of the regional government, has also announced the acquisition of extra land in order to continue the excavation, which has been carried out by dozens of specialists over ten years as part of a 180,000 euro project financed by the regional department of arts, education and the environment.
Two-and-a-half years old, the child was less than a meter tall and most probably a girl - a redhead. She was part of a Neanderthal community, the forerunner to homo sapiens , the species we all belong to. Her traces were found on August 29 on the Calvero de la Higuerra site in Pinilla del Valle, 90 kilometers from Madrid.
The girl lived with her parents in a stone cave, next to an abundant stream that we now call the Lozoya river, between 70,000 and 40,000 years ago.
On the riverbank lived huge bulls, rhinos and fierce lions. With no knowledge of arrows, her dad lay in wait for them with spears. While he was out hunting, her mom would wean her. And then, for some unknown reason, she died. But the remains of her small body, very intentionally placed away from the hyenas by her parents, were not lost: she had very well formed baby teeth, four of them. Two front teeth, a canine tooth and a molar that made it all the way to us in almost perfect condition, retaining their white gleam.
"It's an extraordinary discovery," says archeo-paleontologist Enrique Baquedano, the main leader of the excavation and director of the Regional Archeology Museum. "Not only because of the enormous quantity of biological and genetic information that the teeth, due to their hardness, provide, but also because the discovery of dental pieces happens in a specific context - that is to say, within a series of elements and references that allow us to generalize the scientific knowledge [the discovery] provides.
"There are no previous examples of similar findings in the Madrid area, it is very important in the Iberian Peninsula and, in truth, relevant for Europe," he adds.
"Thirty thousand years ago this continent saw the extinction of this strong hominid species, endowed with the redhead gene and a skull capacity of up to 1,500 cubic centimeters - 200 more than that of their successors, us, homo sapiens , who had knowledge of spears and also benefited from superior social organization, the reasons they survived and, perhaps, wiped them out."
The girl's teeth were found by a team of archeologists, palaeontologists, geologists and topographers who had been digging in Pinilla del Valle, one of the most promising prehistoric sites in the Iberian Peninsula. With the baby teeth of "The Girl from the Lozoya Valley," the name given to the Neanderthal Madrileña, the specialists have started to sequence her DNA, the key to her genetic code and that of her parents. They will also be able to discover what food she ate, her skull measurement, where her larynx was and what kind of speaking ability she had. They will also be able to ascetain what cerebral capacity she had to formulate abstract ideas or put together a symbolic language.
Paleo-anthropologist Juan Luis Arsuaga, co-director of Atapuerca who manages the Pinilla site with Baquedano and geologist Alfredo Pérez González, on Monday showed his excitement upon learning that the recently discovered remains of the Neanderthal girl would help provide answers to many of these questions.
Regional vice-premier González on Monday announced the acquisition of 3.3 hecatares of land adjoining the site in order to continue the excavations and turn the site into an archaeological park that will eventually be opened to visitors.
http://www.elpais.com/articulo/english/Unearthing/Neanderthal/Madrilena/elpepueng/20110915elpeng_3/Ten?
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:33
Human Ancestors Used Fine-Crafted Tools to Butcher Zebras
Our human ancestors may have been sophisticated tool users 1.76 million years ago.
Newly discovered hand axes from that period are the oldest examples of the complex Acheulean culture, 350,000 years older than the previous record holders. These ancient tools could affect what we know about humanity's departure from Africa. [See images of tools]
"Anthropologists consider the Acheulean hand axes to be the culture of our ancestor Homo erectus, and we know H. erectus first evolved around 1.8 or 2 million years ago," study researcher Christopher Lepre, of Columbia University, told LiveScience. "I think most researchers were anticipating that older stone axes would be found." And now they've found them.
Multiple examples of these Acheulean hand axes, which were made from chipped volcanic rock from a nearby stream, were found at a site on the shore of Lake Turkana in Kenya. The excavation team, led by Hélène Roche from the Université Paris in France, surveyed five sites in the area and found tools from an older culture of tool use, the Oldowan culture, in varying degrees of sophistication.
"There's not a tremendous amount of diligence that goes into making the Oldowan tools, you can say they are kind of haphazardly made," Lepre said. "It's pretty simple in terms of the makers were bashing stones together to make sharp edges."
The Oldowan tools that the researchers discovered were crude stone flakes, sharpened to the edge. The Archeulean hand axes, on the other hand, have a defined teardrop or oval shape to them. Lepre said this indicates that H. erectus had the ability to conceptualize the size and shape of the tool in their minds, and then reproduce it out of stone.
The ax blades were held in the hand (as opposed to wood-handled axes, a later invention) and were probably used to butcher zebras or giraffes, to smash open bones and scrape hides, or as digging tools to reach vegetables like potatoes.
Erectus in Europe
The data indicates that there were at least two tool-using hominids living in Africa 1.76 million years ago. Groups of H. erectus were probably using Acheulean technologies, while the more primitive Homo habilis may have been using the Oldowan tools.
What's still a mystery is how these tools left Africa. Acheulean culture and the tools that go with it don't arrive in Europe until about 1 million years ago. It is widely believed that H. erectus colonized Europe over 1.5 million years ago.
This could indicate one of two things: It's possible that the H. erectus groups that migrated to Europe hadn't developed Acheulean technologies yet, or H. erectus wasn't the species that developed the Acheulean tools. Other hominids living at the time, like H. habilis, could have developed the tools first before the culture eventually spread to H. erectus.
The study will appear in tomorrow's (Sept. 1) issue of the journal Nature.http://www.livescience.com/15851-acheulean-hand-axes-erectus.html
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:34
Australopithecus sediba paves the way for Homo species
Researchers have revealed new details about the brain, pelvis, hands and feet of Australopithecus sediba, a primitive hominin that existed around the same time early Homo species first began to appear on Earth. The new Au. sediba findings make it clear that this ancient relative displayed both primitive characteristics as well as more modern, human-like traits. And due to this “mosaic” nature of the hominin’s features, researchers are now suggesting that Au. sediba is the best candidate for an ancestor to the Homo genus.
New finds challenge previous theories
The discoveries are casting doubt on some long-standing theories about human evolution, including the notion that early human pelvises evolved in response to larger brain sizes. And there is also some new evidence suggesting that Au. sediba may have been a tool-maker.
These new findings, which include the most complete hand ever described in an early hominin, one of the more complete pelvises ever discovered and brand new pieces of the foot and ankle, are detailed in five separate studies. The Au. sediba research also boasts a high-resolution scan of an early hominin’s cranium along with work that refines the date of this early hominin site in Malapa, South Africa, to nearly 2.0 million years ago, close to the emergence of Homo.
The five studies appear in the 9 September issue of the journal Science, which is published by AAAS, the international nonprofit science society.
Lee Berger with Australopithecus sediba hand.
Lee Berger with Australopithecus sediba hand.
Lee Berger, the project leader from the University of the Witwatersrand in Johannesburg, South Africa, explains what these new findings mean for modern humans. “The many advanced features found in the brain and body, along with the earlier date, make it possibly the best candidate ancestor for our genus—the genus Homo—more so than previous discoveries, such as Homo habilis.”
The age of these Au. sediba fossils has been constrained to about 1.977 million years, which predates the earliest appearances of Homo-specific traits in the fossil record. Until now, fossils dated to 1.90 million years ago—and mostly attributed to Homo habilis and Homo rudolfensis—have been considered ancestral to Homo erectus, the earliest undisputed human ancestor. But, the older age of these Au. sediba fossils raises the possibility of a separate, older lineage from which Homo erectus may have evolved.
“Science is pleased to be publishing these papers, which add important new information regarding this species, who lived during an important time in human evolution and was first described in the 9 April 2010 issue,” according to Brooks Hanson, deputy editor of physical sciences. “Well-preserved and complete early human fossils are so rare, and Au. sediba now provides a detailed look at some key parts of the anatomy, such as the hand and foot which are rarely well-preserved.”
The caves of Malapa
The caves of Malapa, nearly 30 miles northwest of Johannesburg, have provided a rich assemblage of early hominin fossils over the years. They are part of the Cradle of Humankind, which has been recognized as a World Heritage Site and set aside for its physical and cultural significance. Last year, Berger and colleagues announced the discovery of the remains of a juvenile male (MH-1) and an adult female (MH-2) Au. sediba that were found together in one of these caves
Malapa site formation
Malapa site formation
Since the fossils are too old to be dated themselves, researchers turned to the calcified sediments that have kept the fossils so well-preserved. The fossils hadn’t moved since they were cemented into place, and researchers were able to identify flowstones above and below them. So, Robyn Pickering from the University of Melbourne in Victoria, Australia, and colleagues used advanced uranium-lead dating techniques and something called palaeo-magnetic dating, which measures how many times the Earth’s magnetic field has reversed, on the surrounding rocks.
“This allowed us to narrow the deposition of the Au. sediba-bearing deposits to one of these short geomagnetic field events, the Pre-Olduvai event at about 1.977 million years ago,” wrote Pickering.
The old age of these fossils somewhat surprised the researchers, given some of the apparently Homo-like features that Au. sediba was already displaying at the time.
A human like brain
Kristian Carlson from the University of the Witwatersrand and colleagues took a look at the partial skull of MH-1 and made an endocast, or a detailed scan, of the space where the juvenile’s brain would have been.
“The actual brain residing within a cranium does not fossilize,” said Carlson. “Rather, by studying the impressions on the inside of a cranium, palaeontologists have an opportunity to estimate what the surface of a brain may have looked like. By quantifying how much volume is contained within a cranium, palaeontologists can estimate the size of a brain.”
According to researchers, the young australopith would have been around 10 to 13 years old, in human developmental terms, at the time of his death.
“The exceptionally well-preserved cranium of MH-1 was scanned at the European Synchrotron Radiation Facility, revealing internal anatomy with the highest achievable precision and contrast,” continued Carlson. “The European Synchrotron Radiation Facility is the most powerful installation worldwide for scanning fossils, setting the standard for what can be achieved during non-destructive studies of internal structures of fossils.”
The cranium of the juvenile skeleton of Australopithecus sediba. Image: Brett Eloff. Picture courtesy of Lee Berger and the University of Witwatersrand
The cranium of the juvenile skeleton of Australopithecus sediba. Image: Brett Eloff. Picture courtesy of Lee Berger and the University of Witwatersrand
The researchers found that the brain of the juvenile was human-like in shape, but still much smaller than the brains seen in Homo species. The orbitofrontal region of the brain, directly behind the eyes, shows some signs of neural reorganization, which perhaps indicates a rewiring toward a more human-like frontal lobe, according to the researchers. Carlson’s results cast doubt upon the long-standing theory of gradual brain enlargement during the transition from Australopithecus to Homo. Instead, their findings corroborate the alternative hypothesis which proposes that a reorganization of the neurons in the orbitofrontal region allowed Au. sediba to evolve while keeping its smaller cranium intact.
A separate study of the partial pelvis of MH-2 echoes that sentiment. Job Kibii from the University of the Witwatersrand and colleagues say that Homo pelvises could not have evolved in response to their expanding cranial capacity. In fact, Au. sediba‘s pelvis was already developing modern, Homo-like features when their brains and skulls were still small.
Pelvis of Australopithecus sediba. Image: Peter Schmid. Picture courtesy of Lee Berger and the University of Witwatersrand
Pelvis of Australopithecus sediba. Image: Peter Schmid. Picture courtesy of Lee Berger and the University of Witwatersrand
“It’s clear there could be two things driving the evolution of the pelvis in our Homo lineage,” said Steven Churchill from Duke University in Durham, North Carolina, a co-author of the paper. “One is bipedal locomotion. Between six and two million years ago, we begin to see a lot of it. The other thing is our big brains.”
“Our brains have to pass through the pelvis, so accommodations must be made,” continued Churchill. “What’s cool about sediba is their pelvises are already different from other australopiths, and yet they’re still small-brained… It’s hard to imagine that there’s no change in locomotion behind all this.”
The hands tell their own story
And like most other aspects of Au. sediba, the hominin’s hands and feet display an interesting mix of both primitive and modern features.
The wrist and hand of MH-2 are only missing a few bones, making them the most complete hand fossils for an early hominin on record. Tracy Kivell from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues analyzed the female Au. sediba‘s hand and found that there was a strong flexor apparatus, which hints at tree-climbing. But, the hand also had a long thumb and short fingers, which is a sign of precision gripping—a grip that just involves the thumb and fingers, but not the palm. It’s even possible that Au. sediba had already started dabbling with tool-making, the researchers say.
The right hand skeleton of the adult female MH2 against a modern human hand. The hand, seen here in palmar view, lacks three wrist bones and four terminal phalanges, but is otherwise complete. Image: Peter Schmid. Picture courtesy of Lee Berger and the University of Witwatersrand
The right hand skeleton of the adult female MH2 against a modern human hand. The hand, seen here in palmar view, lacks three wrist bones and four terminal phalanges, but is otherwise complete. Image: Peter Schmid. Picture courtesy of Lee Berger and the University of Witwatersrand
“The hand is one of the very special features of the human lineage, as it’s very different from the hand of the apes,” said Kivell. “Apes have long fingers for grasping branches or for use in locomotion, and thus relatively short thumbs that make it very difficult for them to grasp like a human.”
“Au. sediba has, in contrast, a more human-like hand that has shortened fingers and a very long thumb,” continued Kivell. “Although at the same time, it appears to have possessed very powerful muscles for grasping. Our team interpreted this as a hand, capable of tool manufacture and use, but still in use for climbing and certainly capable of human-like precision grip.”
The findings don’t mean that Au. sediba was the only hominin around two million years ago who was capable of making stone tools, though. (Homo habilis, or the “handy man,” was on the scene, but this hominin had a very different hand structure.) These latest findings do indicate, however, that different hominins with various hand morphologies may have been around at the same time, fashioning simple tools.
Finally, an analysis of the feet and ankles of MH-1 and MH-2 demonstrate that Au. sediba probably climbed trees sometimes and practised a unique form of bipedal walking. Bernhard Zipfel from the University of the Witwatersrand and colleagues say that the MH-2 ankle is one of the most complete hominin ankles ever found—and at the same time, no ankle has ever been described with so many primitive and advanced features.
“…If the bones had not been found stuck together, the team may have described them as belonging to different species,” said Zipfel.
The ankle joint is largely like a human’s, with some evidence for a human-like arch and a well-defined Achilles tendon, according to the researchers. However, its heel and shin bone appear to be mostly ape-like.
Sorting out the mess
This mix of modern and primitive characteristics evokes the image of a hominin who helped to usher in the various Homo species two million years ago. But, only time (and more research) will tell exactly how MH-1 and MH-2 were related to our own human lineage.
“The fossil record for early Homo is a mess,” said Churchill. “Many fossils are either questionably attributed to various species or their dating is very poor… Au. sediba has a number of derived characteristics, which it shares with the genus Homo. If you were to make a list of these shared traits—including those seen in habilis, rudolfensis and sediba—the list for sediba would be much longer than the other two, which suggests it’s a good ancestor of the first species that everyone recognizes in the Homo genus: H. erectus.”
Read more >> http://www.pasthorizonspr.com/index.php/archives/09/2011/australopithecus-sediba-paves-the-way-for-homo-species#ixzz1YU4WqVCr
Read the Archaeology News - then buy the Trowel at Past Horizons Tools
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:36
Human Ancestor in Indonesia Died Out Earlier Than Once Thought
A 1996 expedition resulted in conclusions that the ancient early human species, Homo erectus, coexisted for a time with modern humans in Indonesia. The most recent expedition suggests otherwise, challenging a widely held hypothesis of human evolution.
Human Ancestor in Indonesia Died Out Earlier Than Once Thought
Homo erectus, an ancient human ancestor that lived 1.8 million - 35,000 years ago, is said by theorists of human evolution to have lived alongside Homo sapiens (modern humans) in Indonesia, surviving most other Homo erectus populations that became extinct in Africa and most of Eurasia by 500,000 B.P. Perhaps not so, according to an international team of researchers, after conducting archaeological investigations and a new dating study at sites on the Solo river in Indonesia.
The work, in progress since 2004, was conducted by a team of scientists (the SoRT, or Solo River Terrace Project) under the direction of anthropologists Etty Indriati of Gadja Mada University, Indonesia, and Susan Antón of New York University. It involved geological surveys, site trenching, archaeological excavations, and analyses of animal remains related to two sites, Ndangong and Jigar, composed of terraces formed by sediment deposits along the Solo river. Historically, the terraces have been a rich source of human and animal fossils since the 1930's. In 1996, scientists dated Homo erectus fossils found at these sites to about 35,000 - 50,000 years ago, based on the dating of associated animal fossil teeth. This dating placed the early human finds contemporaneous with other Homo sapiens finds in Indonesia, suggesting that late-surviving Homo erectus individuals and Homo sapiens (who arrived in Indonesia about 40,000 years ago) shared the same environment at the same time. The SoRT team expedition, however, arrived at different results. Their findings indicate that Homo erectus was extinct in the area by at least 143,000 years ago, and more probably by at least 550,000 years ago, long before the arrival of Homo sapiens.
This is significant because scholarly critics of the earlier (1996) expedition finds have suggested that the sites may have contained a mixture of the fossil remains of younger animals and older homin (early human) fossils, which cast doubt in some minds about the validity of the dates assigned to the homin remains. Mixing often occurs through events, such as water activity or geologic events, that may intermingle older and newer fossils and artifacts into the same stratigraphic relationship. The SoRT Project, in part, was designed to test for this possibility, along with application of additional dating tests and analysis to enhance the data base that has been used for analysis of the sites.
Evidence found from the newer excavations of the sediments indicated that the sediments were actually deposited over a very short time period, and that intermixing of sediments from different time periods, and thus by extension the artifacts and fossils contained within them, did not occur. "Whatever the geological age of the site is, the hominins, animals and sediments at Ngandong and Jigar are all the same age," maintains project co-leader Antón. Moreover, analysis of the animal remains suggested the same conclusion. According to project team expert Briana Pobiner, a paleoanthropologist with the Smithsonian Museum of Natural History in Washington, D.C., "the postmortem damage to the animal remains is consistent and suggests very little movement of the remains by water. This means that it is unlikely that very old remains were mixed into younger ones." To this extent, the SoRT Project finds and interpretation support that of the earlier 1996 expedition.
Regarding actual dates, however, the picture changes. The project team applied three different dating techniques to the finds at the sites. All three depended upon rates of radioactive decay (similar to radio-carbon dating, often used to date organically based materials found within the context of key artifactual or fossil finds). The first two, U-series and ESR (Electron Spin Resonance), applied to fossil teeth as in the earlier 1996 tests, yielded dates approaching 143,000 years. The third methodology, argon-argon, was applied to pumice material, a light, porous volcanic rock found within the sediments. The results of this application yielded relatively precise dates around 550,000 years. Project scientists posit different plausible theories or possibilities that might account for the enormous gap between the dates obtained from the first two techniques and that of the argon-argon, but all agree on one thing -- they provide a minimum and a maximum date for a time range that clearly and significantly predates those suggested by the earlier study. According to SoRT, Homo erectus could not have inhabited Indonesia, or at least these locations in Indonesia, any later than about 143,000 years B.P. "Thus," says Indriati, "Homo erectus probably did not share habitats with modern humans."
The results of the SoRT Project work has implications for current theories about the origins of modern humans. The "Out of Africa" model, perhaps the most widely held theory among evolutionists today, suggests that geographic and time-period overlapping between disparate early human species, and more particularly that of Homo erectus and Homo sapiens, would be predictable. It posits that archaic Homo sapiens (an earlier version of modern humans) evolved to anatomically modern humans solely in Africa between 200,000 and 150,000 years ago, and that members of anatomically modern humans left Africa by between 125,000 and 60,000 years ago, replacing earlier human populations such as Neanderthals and Homo erectus over time. Geographic and time period overlapping would be a natural occurrence under this scenario. The "Muliti-regional Hypothesis", on the other hand, does not predict such an occurrence. It holds that humans first arose near the beginning of the Pleistocene two million years ago and that evolution occurred within a single species, which included a variety of forms such as Homo erectus and Neanderthals. This species evolved into the currently diverse anatomically modern human populations known today by a combination of adaptations within various regions of the world and gene flow between those regions.
The research was sponsored by the National Science Foundation and is reported in the journal, PLoS One. Co-authors of the study include Rusyad Suriyanto and Agus Hascaryo of Gadjah Mada University and Wendy Lees and Maxime Aubert of the Australian National University.
http://popular-archaeology.com/issue/june-2011/article/human-ancestor-in-indonesia-died-out-earlier-than-once-thought?
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:37
Peking man differing from modern humans in brain asymmetry
Paleoanthropologists studying the fossil endocasts of Australopithecus, Homo habilis, Homo erectus, Neanderthals, and Homo sapiens have reported that almost all brain endocasts display distinct cerebral asymmetry. Peking man’s endocasts are good examples of ancestral brains and are useful in studying human evolution. However, studies examining brain asymmetries in fossil hominids are usually limited to scoring of differences in hemisphere protrusion rostrally and caudally, or to comparing the width of the hemispheres.
Dr. WU XiuJie and PAN Lei, one of her graduate students, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), Chinese Academy of Sciences, using 3D laser scanning, examined asymmetries of the hemisphere volumes and surface areas in the Zhoukoudain Homo erectus, well known as Peking man, dated to 0.4–0.8 Ma. They found that Peking man exhibited a greater variation than the modern humans in the relative sizes between the left and right hemispheres, and no differences in the two hemispheres in Peking man, while in the modern endocasts the left hemisphere was significantly greater than the right hemisphere, as reported in the latest issues of Chinese Science Bulletin 56 (21):2215-2220.
Brain evolution is one of the most important aspects of human evolution. For fossil hominids, the soft brain tissue was removed during fossilization. As such, endocasts are the direct material for the study of brain evolution. An endocast is an impression taken from the inside of a cranium that reflects the external features of the brain anatomy in detail.
Six nearly complete crania from Peking man were discovered at Zhoukoudian Locality 1 in the suburbs of Beijing since the official excavation in 1927. From these, six endocasts were reconstructed from the original cranium fossils from Zhoukoudian Homo erectus. Dr. Wu used a 3D laser surface technique to scan the Peking man’s endocasts in order to reconstruct the 3D brain images. Using these methods Wu was able to calculate absolute and relative volumes and surface areas of two hemispheres for this study.
Compared with modern humans, Peking man’s brain casts have small brain size, low height and low position of the greatest breadth, flat frontal and parietal lobes, depressed Sylvian areas, strong posterior projection of the occipital lobes, anterior positioning of the cerebellar lobes relative to the occipital lobes, and relative simplicity of the meningeal vessels.
The study shows that the absolute hemisphere volumes and surface areas exhibited no significant asymmetries in the Peking man or in modern specimens. However, the relative hemisphere volumes against surface areas differed between the two groups, suggesting that brain asymmetries originated from relative brain sizes rather than absolute brain volumes during human evolution. These anatomical changes are likely related to the origin of human brain lateralization.
The anatomical structures of Peking man’s brain maybe differs from the modern human, suggesting that Peking man had no ability to communicate with each other in the form of language. During human evolution, brain anatomical asymmetries experienced marked changes, and certain human abilities including language, intelligence, and cognition are likely related to these asymmetrical changes.
“Although it was suggested that Peking man might exhibit a left hemisphere larger than the right hemisphere, studies restricted to the traditional method of examination were not able to examine these parameters. Using a 3D laser surface technique, we were able to calculate the absolute and relative volumes and surface areas of the two hemispheres”, said Dr. WU, the lead author and research designer.
Provided by Institute of Vertebrae Paleontology and Paleoanthropology
http://www.physorg.com/news/2011-06-peking-differing-modern-humans-brain.html
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:38
Cutting edge training developed the human brain 80 000 years ago
Advanced crafting of stone spearheads contributed to the development of new ways of human thinking and behaving. This is what new findings by archaeologists at Lund University have shown. The technology took a long time to acquire, required step by step planning and increased social interaction across the generations. This led to the human brain developing new abilities.
200 000 years ago, small groups of people wandered across Africa, looking like us anatomically but not thinking the way we do today. Studies of fossils and the rate of mutations in DNA show that the human species to which we all belong – Homo sapiens sapiens – has existed for 200 000 years.
But the archaeological research of recent years has shown that, even though the most ancient traces of modern humans are 200 000 years old, the development of modern cognitive behaviour is probably much younger. For about 100 000 years, there were people who looked like us, but who acted on the basis of cognitive structures in which we would only partially recognise ourselves and which we do not define today as modern behaviour.
It is precisely that period of transformation that the researchers at Lund University in Sweden have studied. In the next issue of the well renowned Journal of Human Evolution, they present their new findings on the early modern humans that existed in what is now South Africa, approximately 80 000 years ago.
The findings show that people at that time used advanced technology for the production of spearheads and that the complicated crafting process developed the working memory and social life of humans.
“When the technology was passed from one generation to the next, from adults to children, it became part of a cultural learning process which created a socially more advanced society than before. This affected the development of the human brain and cognitive ability”, says Anders Högberg, PhD.
The technology led to increased social interaction within and across the generations. This happened because the crafting of stone spearheads took a long time to learn and required a lot of knowledge, both theoretical and practical. Producing a stone spearhead also required the ability to plan in several stages. This social learning contributed to the subsequent development of early modern humans’ cognitive ability to express symbolism and abstract thoughts through their material culture, for example in the form of decorated objects.
“The excavations have been carried out in a small cave; the location we have studied is called Hollow Rock Shelter and lies 250 km north of Cape Town. We are cooperating with the University of Cape Town and the research we have just published is part of a larger research project on this location”, says Professor Lars Larsson.
The article is entitled Lithic technology and behavioural modernity: New results from the Still Bay site, Hollow Rock Shelter, Western Cape Province, South Africa. http://www.lunduniversity.lu.se/o.o.i.s?id=24890&news_item=5626
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:38
Early human fossils unearthed in Ukraine
ncient remains uncovered in Ukraine represent some of the oldest evidence of modern people in Europe, experts have claimed.
Archaeologists found human bones and teeth, tools, ivory ornaments and animal remains at the Buran-Kaya cave site.
The 32,000-year-old fossils bear cut marks suggesting they were defleshed as part of a post-mortem ritual.
Details have been published in the journal PLoS One.
Archaeologist Dr Alexander Yanevich from the National Ukrainian Academy of Science in Kiev discovered the four Buran-Kaya caves in the Crimean mountains in 1991.
Since then, roughly two hundred human bone fragments have been unearthed at the site.
Among the shards of human bones and teeth, archaeologists have found ornaments fashioned from ivory, along with the abundant remains of animals.
The artefacts made by humans at the site allowed archaeologists to tie the ancient people to a cultural tradition known as the Gravettian.
This culture came to span the entire European continent and is named after the site of La Gravette in France, where this stone age culture was first studied.
Researchers were able to directly date the human fossils using radiocarbon techniques. The shape and form of the remains told the scientists they were dealing with modern humans (Homo sapiens sapiens).
Eastern promise
One thing that intrigued researchers was the scarcity of human long bones (bones from the limbs) in the caves.
The site yielded countless limb bones from antelope, foxes and hares.
Cut marks on human bone (L.Crépin/CNRS) Remains at the site bear cut marks where stone tools were used to remove flesh
But the human remains consisted of vertebrae, teeth and skull bones no larger than 12cm.
What is more, the positions of cut marks found on the human fragments were distinct from those found on the animal bones.
And while the bone marrow had been removed from butchered animals, it had been left alone in the case of the human remains at the site, explained co-author Sandrine Prat from the French National Centre for Scientific Research (CNRS) in Paris.
She suspects this demonstrates that human bones were processed differently from those of animals. Human flesh was removed as part of ritual "cleaning", not to be eaten.
Defining culture
Continue reading the main story
“Start Quote
These people had knives, lightweight tools, open air camps, they used mammoth bones to make tents”
End Quote Professor Clive Finlayson Director, Gibraltar Museum
The finds offer anthropologists a glimpse into a very early and important human culture, said Professor Clive Finlayson, an evolutionary ecologist and director of the Gibraltar Museum.
"Gravettian culture is the culture that defines modern humans.
"These people had knives, lightweight tools, open air camps, they used mammoth bones to make tents," he said, adding that this was the earliest example of the Gravettian cultural tradition.
Professor Finlayson said that uncovering evidence of this culture in Ukraine gave weight to the idea that early modern people spread into Europe from the Russian plains, not north through the Balkans from the Middle East.
"What has excited me is that we have found evidence of humans where I would expect them to be, exploiting foods that I would expect them to be exploiting," Professor Finlayson told BBC News. http://www.bbc.co.uk/news/science-environment-13846262
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:40
Undergraduate research fires salvo in simmering scientific controversy
Undergraduate research fires salvo in simmering scientific controversy
Student publishes case for faster, less expensive DNA analysis
PULLMAN, Wash.—A Washington State University student's undergraduate research is challenging a widely held assumption on the best way to analyze old DNA in anthropological and forensic investigations.
Sarah "Misa" Runnells' claim is weighty enough to be published this week in the peer-reviewed, online journal PLoS ONE.
At issue is the best way to sequence "ancient" DNA, bits of genetic code pulled from remains up to 800,000 years old. Such remains tend to be chemically degraded, making it difficult to draw accurate connections between, say a wooly mammoth and modern animals, or Neanderthals and humans.
The techniques are also an issue in forensic investigations where remains, while relatively new, can still be severely compromised.
In 2000, researchers writing in the journal Science recommended a set of standards that emphasized cloning bits of ancient DNA to detect errors and contamination from modern DNA.
"Those rules became gospel," says Brian Kemp, a WSU anthropologist and molecular biologist. In fact, they became so widely adopted that his preferred technique—direct sequencing—is often dismissed by journal reviewers.
"I've had papers outright rejected because they said, 'You did not clone,'" says Kemp.
Kemp wanted to demonstrate that direct sequencing worked just as well by directly comparing it to cloning, but he had a problem: He didn't have experience with cloning.
Then he met Runnells, who had learned to clone while majoring in biotechnology as a WSU undergraduate. The two used both methods to analyze 3,500-year-old northern fur seal bones.
"After five samples with both cloning and direct sequencing, we got the same answer from both methods," says Runnells, who has published under her soon-to-be married name of Winters.
Their findings even held up with one particularly degraded sample. Cloning gave conflicting DNA sequences in the sample, while direct sequencing showed gaps in the code.
"In no case did the results of one method conflict with another," says Kemp.
The PLoS ONE paper is the first published on a $595,000 grant Kemp received from the U.S. Department of Justice. One goal of the grant is to find more cost-effective ways of analyzing degraded DNA.
Direct sequencing can cost a fraction of cloning and be done in less time, says Kemp.
"That's really applicable to the justice system, where you want to save money and time," says Runnells, who is now a second-year Master's student in zoology.
"Everybody wants to save money and time," adds Kemp. "There are more forensic cases than they can work on. There's a backlog of forensic cases."
Direct sequencing can also be increasingly helpful to academic researchers in a time of shrinking budgets, says Kemp.
"If you have an infinite amount of resources and funding, you can do anything," he says. "You can clone everything a thousand times. It doesn't matter. But for the assistant professor at WSU who has a limited budget, we need to make smart choices."
"To clone or not to clone: Method analysis for retrieving consensus sequences in ancient DNA samples" will be available online after 2 p.m. Pacific Time (5 p.m. Eastern) on Monday, June 27, at http://dx.plos.org/10.1371/journal.pone.0021247.
http://www.eurekalert.org/pub_releases/2011-06/wsu-urf062411.php
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:43
Continents influenced human migration, spread of technology
Researchers at Brown University and Stanford University have pieced together ancient human migration in North and South America. Writing in the American Journal of Physical Anthropology, the authors find that technology spread more slowly in the Americas than in Eurasia. Population groups in the Americas have less frequent exchanges than groups that fanned out over Europe and Asia.
PROVIDENCE, R.I. [Brown University] — How modern-day humans dispersed on the planet and the pace of civilization-changing technologies that accompanied their migrations are enduring mysteries. Scholars believe ancient peoples on Europe and Asia moved primarily along east-west routes, taking advantage of the relative sameness in climate, allowing technological advances to spread quickly. But what about in North and South America, with its long, north-south orientation and great variability in climate? How did people move and how quickly did societal innovations follow?
Sohini RamachandranGenetic data carries the signature of ancient migrations.Sohini Ramachandran
Genetic data carries the signature of ancient migrations.Using advanced genetic analysis techniques, evolutionary biologists at Brown University and Stanford University studied nearly 700 locations on human genomes drawn from more than five dozen populations. They say that technology spread more slowly in the Americas than in Eurasia and that the continents’ orientation seems to explain the difference. After humans arrived in the Americas 20,000 to 40,000 years ago, genetic data shows, the migrating populations didn’t interact as frequently as groups in Eurasia.
“If a lack of gene flow between populations is an indication of little cultural interaction,” the authors write in the American Journal of Physical Anthropology, “then a lower latitudinal rate of gene flow suggested for North American populations may partly explain the relatively slower diffusion of crops and technologies through the Americas when compared with the corresponding diffusion in Eurasia.”
“Our understanding of the peopling of the Americas will be refined by archaeological data and additional genetic samples,” added Sohini Ramachandran, assistant professor of biology in the Department of Ecology and Evolutionary Biology at Brown and the paper’s lead author. “But this is the signature of migration we see from genetic data.”
To tease out the migration patterns, Ramachandran and fellow researcher Noah Rosenberg from Stanford gathered genetic markers for 68 indigenous populations from 678 genetic markers in Eurasia and the Americas. The goal was to study the distribution of genetic variation among populations. The similarity or difference in genetic makeup among populations gave the scientists insights about migrations long ago.
To illustrate, when one population breaks off from its parent group, the individuals in the new population take their genomes and any distinct genetic mutations with them. From there, the new population may remain independent of the parent group because of distance or other factors, and over time its genetic makeup diverges from the parent. However, if the new population reunites regularly with its parent population — known as “back migration” — the genetic makeup of the two populations remains relatively close.
“When populations do not share migrants with each other very often,” Rosenberg explained, “their patterns of genetic variation diverge.”
Armed with the genetic background of cultures spanning the Americas and Eurasia, the researchers could test whether the east-west orientation of Eurasia supported a rapid spread of agriculture and other societal innovations, while the dissemination of those advances was slower in the Americas due to the north-south orientation. They found that to be the case: The populations in North and South America are, for the most part, more different from each other than the populations in Eurasia. The reason has to do with the differing climates that migrating peoples in the Americas found when they moved north to south.
“It’s harder to traverse those distances based on climate than it was in Eurasia,” Ramachandran said. “We find greater genetic differences (in the Americas’ populations) because of the difficulty in migration and the increased challenge of reuniting with neighboring populations.”
“Our result that genetic differentiation increases more with latitudinal distance between Native American populations than with longitudinal distance between Eurasian populations supports the hypothesis of a primary influence for continental axes of orientation on the diffusion of technology in Eurasia and the Americas,” the authors write.
The National Institutes of Health, the Burroughs Wellcome Fund and the William F. Milton Fund supported the research.
http://news.brown.edu/pressreleases/2011/09/migration
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:43
Skull points to a more complex human evolution in Africa
Scientists have collected more evidence to suggest that ancient and modern humans interbred in Africa.
Reanalysis of the 13,000-year-old skull from a cave in West Africa reveals a skull more primitive-looking than its age suggests.
The result suggests that the ancestors of early humans did not die out quickly in Africa, but instead lived alongside their descendents and bred with them until comparatively recently.
The results are published in PLoS ONE.
The skull, found in the Iwo Eleru cave in Nigeria in 1965, does not look like a modern human.
It is longer and flatter with a strong brow ridge; features closer to a much older skull from Tanzania, thought to be around 140,000 years old.
Prof Katerina Harvati from the University of Tuebingen in Germany used new digitising techniques to capture the surface of the skull in detail.
The new technique improved upon the original measurements done with callipers by letting researchers see subtler details about the skull's surface.
Iwo eleru skull (Credit: NHM) The cast of the Iwo Eleru skull shows marks of a more ancient ancestor
"[The skull] has got a much more primitive appearance, even though it is only 13,000 years old," said Chris Stringer, from London's Natural History Museum, who was part of the team of researchers.
"This suggests that human evolution in Africa was more complex... the transition to modern humans was not a straight transition and then a cut off."
Prof Stringer thinks that ancient humans did not die away once they had given rise to modern humans.
They may have continued to live alongside their descendants in Africa, perhaps exchanging genes with them, until more recently than had been thought.
The researchers say their findings also underscore a real lack of knowledge of human evolution in the region.
But palaeontologists are not all agreed on precisely what the new analysis is telling us - or, indeed, whether it is telling us anything definitive at all.
"I do not think that these findings add anything new to our view," said Prof Clive Finlayson, director of the Gibraltar Museum, who was not connected to the study.
"We have a few fossils, and no idea of natural variation within populations. That the situation is not simple and is deep and complex is what we would expect.
"In my view, it is the field of genetics that will help us most in clarifying matters," he told BBC News.
Separate research published earlier this month suggests that genetic mixing between hominin species happened in Africa up to 35,000 years ago.
http://www.bbc.co.uk/news/science-environment-14947363
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:44
Human precursors went to sea, team says
A team of researchers that included an North Carolina State University geologist found evidence that our ancestors were crossing open water at least 130,000 years ago. That's more than 100,000 years earlier than scientists had previously thought.
Their evidence is based on stone tools from the island of Crete. Because Crete has been an island for eons, any prehistoric people who left tools behind would have had to cross open water to get there.
The tools the team found are so old that they predate the human species, said Thomas Strasser, an archaeologist from Providence College who led the team. Instead of being made by our species, Homo sapiens, the tools were made by our ancestors, Homo erectus.
The tools are very different from any others found on Crete, Strasser said. They're most similar to early stone-age tools from Africa that are about 700,000 years old, he said.
Initially the team didn't have any way to date the tools. That's where NCSU geologist Karl Wegmann came in.
At the time, Wegmann didn't know much about archaeology, but he did know quite a bit about Crete's geology. He had been figuring out the ages of Crete's rock formations to study earthquakes.
A few of the stone tools the team had discovered were embedded in those same rock formations. Those rocks were formed from ancient beach sands, Wegmann said.
Today, the rocks and the tools embedded in them are hundreds of feet above the shore. The same process that drives the region's strong earthquakes - colliding continents - is pushing Crete upward out of the sea at a rate of less than {0 of an inch every year - more than 35 times more slowly than fingernails grow.
The island's slow rise has preserved beaches from many eras as terraces along the coast.
The lower terraces are the easiest to date. Scientists can measure the age of seashells embedded in the rock using radioactive carbon dating. This method estimates the age of those terraces at about 45,000 and 50,000 years old.
"We know that (the tools) are tens of meters above the terrace we dated at 50,000 years old, so we know right off the bat that they have to be at least that old," Wegmann said.
But 50,000 years ago is carbon dating's limit. Anything older has to be dated using another method.
Crete's rise from the sea gives a fairly simple way of doing that. Once they know the age of lower terraces, geologists can calculate the age of higher terraces just by measuring the difference in the beaches' elevation.
If geologists know how much farther the older terrace traveled upward from the newer, and they know how fast it was going, they can figure out how long it took to get there. Or, in other words, its age, in this case a record-smashing 130,000 years old.
"The thing to me that really makes this unique and exciting is ... these other sister species maybe weren't entirely stupid like we portray them," Wegmann said. "They were capable of really complex things."http://www.physorg.com/news/2011-08-human-precursors-sea-team.html
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:46
Stone Age toe could redraw human family tree
ON THE western fringes of Siberia, the Stone Age Denisova cave has surrendered precious treasure: a toe bone that could shed light on early humans' promiscuous relations with their hominin cousins.
New Scientist has learned that the bone is now in the care of Svante Pääbo at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who revealed the first genetic evidence of interbreeding between ancient humans and other hominins (New Scientist, 30 July, p 34).
There are tantalising hints that the find strengthens the case for a third major group of hominins circulating in Eurasia at the same time as early humans and the Neanderthals. It might possibly even prove all three groups were interbreeding (see diagram).
The Denisova cave had already yielded a fossil tooth and finger bone, in 2000 and 2008. Last year, Pääbo's DNA analysis suggested both belonged to a previously unknown group of hominins, the Denisovans. The new bone, an extremely rare find, looks likely to belong to the same group.
It is a very exciting discovery, says Isabelle De Groote at London's Natural History Museum. "Hominin material from southern Siberia is rare and usually extremely fragmentary."
The primitive morphology of the 30,000 to 50,000-year-old Denisovan finger bone and tooth indicates that Denisovans separated from the Neanderthals roughly 300,000 years ago. At the time of the analysis, Pääbo speculated that they came to occupy large parts of east Asia at a time when Europe and western Asia were dominated by Neanderthals. By 40,000 years ago, Homo sapiens was also moving around much of the region. But the Denisovans remain known only from the finger and tooth fossils - not enough information to formally assign them to their own species.
That may change with analysis of the newly discovered toe bone. It was found in the same layer of the cave floor as the finger bone, by Maria Mednikova at the Russian Academy of Sciences in Moscow (Archaeology, Ethnology and Anthropology of Eurasia, vol 39, p 129).
Mednikova says this suggests it belonged to a contemporary individual, alive roughly 40,000 years ago. But her studies show the finger and toe bones belonged to distinct people. In addition, the toe bone is stocky and its shape is somewhere between that of a modern human and a typical Neanderthal.
Others are less convinced. Erik Trinkaus at Washington University in St Louis, Missouri, who has written extensively on hominin foot bone morphology, says the bone's sturdy appearance is interesting but inconclusive from a taxonomic perspective.
What's needed is DNA evidence. For now, though, Pääbo's team remain very tight-lipped about what, if anything, they have found. "We have no results we are ready to talk about yet," Pääbo told New Scientist. Mednikova saw some of the team's preliminary findings last month and promises a "wonderful result" will be published in the near future - although with the analysis still under review she can say no more.
Her enthusiasm suggests that Pääbo's team has successfully extracted DNA from the toe bone, and hints that it shows that this was no ordinary hominin. At the very least, one can presume it doesn't belong to a human or a Neanderthal.
"The Neanderthals came to the Altai mountains [in Siberia] about 45,000 years ago and were probably assimilated by the native Denisovan population," she says. "It cannot be excluded that the individual was Denisovan, Neanderthal or even a hybrid - why not?"
If the Stone Age toe really did belong to a Neanderthal-Denisovan hybrid, it would be a remarkable find. Pääbo is fast building a reputation for revealing Homo sapiens' promiscuous past. He has shown that humans and Neanderthals interbred, as did humans and Denisovans. Until the latest analysis is published, we can only speculate on what has been found. But the human family tree could be about to get even more complicated. If so, there may be a case for reclassifying all three as members of the same species.http://www.newscientist.com/article/mg21128254.000-stone-age-toe-could-redraw-human-family-tree.html?DCMP=OTC-rss&nsref=online-news
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:47
Neanderthal skull fragment discovered in Nice
Part of a prehistoric skull, dating back 170,000 years, has been discovered during an archaeological dig in Nice. Experts say the discovery could reveal important clues to the evolution of humans.
Paleontologist Marie-Antoinette de Lumley with the Mayor of Nice Christian Estrosi, presenting the latest find at Lazaret Cave.
Paleontologist Marie-Antoinette de Lumley presents the skull fragment of a nordic hunter, discovered at the Lazaret Cave in Nice
Students Ludovic Dolez and Sébastian Lepvraud were working on the excavation site, Lazaret Caves, on 13th August, when they came across the partial remains of a forehead belonging to a Homo Erectus.
Paleontologist Marie-Antoinette de Lumley, who has been in charge of excavation at Lazaret since 1961, said the bone is an important find: "It belonged to a nomad hunter, less than 25 years old. He may be able to teach us more about the evolution of his successor, the Neanderthal man."
The bone was left to dry for a few days where it was discovered, before being removed for a special public announcement attended by Nice Mayor Christian Estrosi.
Archaeologists have been searching this site patiently for 50 years, unveiling more than 20,000 bone fragments from prehistoric animals.
The last human discovery in the cave was in 2009, when the molar tooth of a child was uncovered.http://www.rivieratimes.com/index.php/provence-cote-dazur-article/items/neanderthal-skull-fragment-discovered-in-nice-6698.html
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:47
Svante Paabo: DNA clues to our inner neanderthal
Sharing the results of a massive, worldwide study, geneticist Svante Pääbo shows the DNA proof that early humans mated with Neanderthals after we moved out of Africa. (Yes, many of us have Neanderthal DNA.) He also shows how a tiny bone from a baby finger was enough to identify a whole new humanoid species.
Svante Pääbo explores human genetic evolution by analyzing DNA extracted from ancient sources, including mummies, an Ice Age hunter and the bone fragments of Neanderthals.
http://www.exchangemagazine.com/morningpost/2011/week35/Wednesday/083101.htm
Profile
Reply
|
coldrum
Joined:
17-09-2002
Messages: 780
OFF-Line
| Posted 23-10-2011 at 19:49
Neanderthal man lived on seafood far earlier than previously thought
Neanderthal man lived on a diet of seafood in the caves of southern Spain much longer ago than previously thought, new archaeological findings show.
Much as modern day man enjoys tucking into a plateful of seafood paella when visiting the Costa del Sol, Neanderthals living on the Iberian coast 150,000 years ago supplemented their diet with molluscs and marine animals.
Archaeological examination of a cave in Torremolinos unearthed early tools used to crack open shellfish collected off rocks along the Iberian coast and found fossilised remains of the early meals.
The discovery is the earliest of its kind in northern Europe and shows that early man were fish eaters in Europe some 100,000 years earlier than previously thought.
The findings suggest that early coastal cavemen supplemented their hunter/gatherer diet of nuts, fruits and meat from animals such as antelopes and rabbits with seafood.
A team of archaeologists from Seville University and scientists from the National Council for Scientific Investigation (CSIC) published their research this week after a lengthy investigation involving the scientific dating of fossilised remains from the cave.
The Cueva Bajondillo on Andalusia's southern coast near Malaga contained remains of burned mussel shells and barnacles indicating that Middle Paleolithic hominids had collected and cooked the shellfish for consumption.
The discovery suggests that Neanderthals in Europe and Archaic Homo sapiens in Africa were following parallel behavioural trajectories but with different evolutionary outcomes, the paper claims.
"It provides evidence for the exploitation of coastal resources by Neanderthals at a much earlier time than any of those previously reported," said Miguel Cortés Sánchez who led the Seville University team.
"The use of shellfish resources by Neanderthals in southern Spain started some 150,000 years ago," the paper concluded. "It was almost contemporaneous to Pinnacle Point (in South Africa) when shellfishing is first documented in archaic modern humans."
http://www.telegraph.co.uk/news/worldnews/europe/spain/8765346/Neanderthal-man-lived-on-seafood-far-earlier-than-previously-thought.html
Profile
Reply
| |
|
|
IMPORTANT NOTES: This site uses COOKIES. Please do not use this web site if you do not agree to our Terms and Conditions of use.
If you plan to visit ancient sites in person, please make sure you follow our Charter.
Articles, photographs and comments are the property of their respective authors or contributors, please contact them for permission to reproduce. Site design ©1997-2012 Andy Burnham.
|
Main News