Some Thoughts On The Uniqueness Of Mankind’s Evolution
Posted 14 November 2010 - 03:17 AM
November 5, 2010 Evolutionary divergence of humans from chimpanzees likely occurred some 8 million years ago rather than the 5 million year estimate widely accepted by scientists, a new statistical model suggests.
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Posted 14 November 2010 - 03:18 AM
Researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany have documented species differences in the pattern of brain development after birth that are likely to contribute to cognitive differences between modern humans and Neanderthals.
Posted 14 November 2010 - 03:21 AM
Charles Darwin's theory of gradual evolution is not supported by geological history, New York University Geologist Michael Rampino concludes in an essay in the journal Historical Biology. In fact, Rampino notes that a more accurate theory of gradual evolution, positing that long periods of evolutionary stability are disrupted by catastrophic mass extinctions of life, was put forth by Scottish horticulturalist Patrick Matthew prior to Darwin's published work on the topic.
Posted 06 February 2011 - 06:54 AM
Modern humans may have emerged from Africa up to 50,000 years earlier than previously thought, a study suggests.
Researchers have uncovered stone tools in the Arabian peninsula that they say were made by modern humans about 125,000 years ago.
The tools were unearthed at the site of Jebel Faya in the United Arab Emirates, a team reports in the journal Science.
The results are controversial: genetic data strongly points to an exodus from Africa 60,000-70,000 years ago
Posted 06 February 2011 - 06:57 AM
- Fossilized wrist bones suggest humans switched from trees to a terrestrial lifestyle between 4.2 and 3.5 million years ago.
- Tree dwellers experience more stress on the pinky side of their hands while terrestrial species tend to load more stress on the thumb side.
- The timing of the switch coincides with climate and habitat changes and a shift in diet.
Posted 18 February 2011 - 11:39 PM
A tiny 3.2-million-year-old fossil found in East Africa gives Lucy’s kind an unprecedented toehold on humanlike walking.
Australopithecus afarensis, an ancient hominid species best known for a partial female skeleton called Lucy, had stiff foot arches like those of people today, say anthropologist Carol Ward of the University of Missouri in Columbia and her colleagues. A bone from the fourth toe — the first such A. afarensis fossil unearthed — provides crucial evidence that bends in this species’ feet supported and cushioned a two-legged stride, the scientists report in the Feb. 11 Science.
Posted 18 February 2011 - 11:41 PM
Posted 18 February 2011 - 11:43 PM
BINGHAMTON, NY – Eight small teeth found in a cave near Rosh Haain, central Israel, are raising big questions about the earliest existence of humans and where we may have originated, says Binghamton University anthropologist Rolf Quam. Part of a team of international researchers led by Dr. Israel Hershovitz of Tel Aviv University, Qaum and his colleagues have been examining the dental discovery and recently published their joint findings in the American Journal of Physical Anthropology.
Excavated at Qesem cave, a pre-historic site that was uncovered in 2000, the size and shape of the teeth are very similar to those of modern man, Homo sapiens, which have been found at other sites is Israel, such as Oafzeh and Skhul - but they're a lot older than any previously discovered remains.
"The Qesem teeth come from a time period between 200,000 - 400,000 years ago when human remains from the Middle East are very scarce," Quam said. "We have numerous remains of Neandertals and Homo sapiens from more recent times, that is around 60,00 - 150,000 years ago, but fossils from earlier time periods are rare. So these teeth are providing us with some new information about who the earlier occupants of this region were as well as their potential evolutionary relationships with the later fossils from this same region."
The teeth also present new evidence as to where modern man might have originated. Currently, anthropologists believe that modern humans and Neandertals shared a common ancestor who lived in Africa over 700,000 years ago. Some of the descendants of this common ancestor migrated to Europe and developed into Neandertals. Another group stayed in Africa and evolved into Homo sapiens, who later migrated out of the continent. If the remains from Qesem can be linked directly to the Homo sapiens species, it could mean that modern man either originated in what is now Israel or may have migrated from Africa far earlier that is presently accepted.
But according to Quam, the verdict is still out as to what species is represented by these eight teeth, which poses somewhat of a challenge for any kind of positive identification.
Posted 18 February 2011 - 11:47 PM
Posted 08 January 2012 - 09:20 AM
Scientists studying a unique collection of human skulls have shown that changes to the skull shape thought to have occurred independently through separate evolutionary events may have actually precipitated each other.
Researchers at the Universities of Manchester and Barcelona examined 390 skulls from the Austrian town of Hallstatt and found evidence that the human skull is highly integrated, meaning variation in one part of the skull is linked to changes throughout the skull.
The Austrian skulls are part of a famous collection kept in the Hallstatt Catholic Church ossuary; local tradition dictates that the remains of the town's dead are buried but later exhumed to make space for future burials. The skulls are also decorated with paintings and, crucially, bear the name of the deceased. The Barcelona team made measurements of the skulls and collected genealogical data from the church's records of births, marriages and deaths, allowing them to investigate the inheritance of skull shape.
The team tested whether certain parts of the skull – the face, the cranial base and the skull vault or brain case – changed independently, as anthropologists have always believed, or were in some way linked. The scientists simulated the shift of the foramen magnum (where the spinal cord enters the skull) associated with upright walking; the retraction of the face, thought to be linked to language development and perhaps chewing; and the expansion and rounding of the top of the skull, associated with brain expansion. They found that, rather than being separate evolutionary events, changes in one part of the brain would facilitate and even drive changes in the other parts.
"We found that genetic variation in the skull is highly integrated, so if selection were to favour a shape change in a particular part of the skull, there would be a response involving changes throughout the skull," said Dr Chris Klingenberg, in Manchester's Faculty of Life Sciences
"We were able to use the genetic information to simulate what would happen if selection were to favour particular shape changes in the skull. As those changes, we used the key features that are derived in humans, by comparison with our ancestors: the shift of the foramen magnum associated with the transition to bipedal posture, the retraction of the face, the flexion of the cranial base, and, finally, the expansion of the braincase.
"As much as possible, we simulated each of these changes as a localised shape change limited to a small region of the skull. For each of the simulations, we obtained a predicted response that included not only the change we selected for, but also all the others. All those features of the skull tended to change as a whole package. This means that, in evolutionary history, any of the changes may have facilitated the evolution of the others."
Lead author Dr Neus Martínez-Abadías, from the University of Barcelona's, added: "This study has important implications for inferences on human evolution and suggests the need for a reinterpretation of the evolutionary scenarios of the skull in modern humans."
Posted 14 January 2012 - 09:40 AM
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Posted 14 May 2012 - 03:27 AM
April 30, 2012
New evidence proves humans are continuing to evolve and that significant natural and sexual selection is still taking place in our species in the modern world.
Posted 11 August 2012 - 09:06 AM
In 1972, the skull of an early human – known as KNM-ER 1470 – was found in Koobi Fora in northern Kenya. Homo habilis, an early member of our own genus, was thought to have had the plains of Africa to itself 2 million years ago, but the 1.9-million-year-old skull didn't quite fit with the known remains of that species.
Some were convinced this was a tantalising glimpse of a whole new species, dubbed Homo rudolfensis. Others attributed the differences in shape between this skull and others belonging to Homo habilis to geographical or sexual variation within the species – the unusually large 1470 skull perhaps belonged to a male H. habilis. Without any other specimens to decide either way, the debate rolled on.
Meave Leakey and her colleagues have now discovered three new fossils that share many of the distinctive features of the anomalous skull. The finds finally look set to confirm that the 1470 skull is not an anomalous oddity, but belonged to a distinct species, which will probably continue to be called Homo rudolfensis.
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