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Early Humans
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Early Humans
Neanderthal DNA
Early Seafarers
Early Humans
The most complete genetic analysis of human origins
bolsters prior conclusions that the human race evolved in Africa and spread later to other parts of the world, according to
a report in this week's issue of the journal Nature. The evidence suggests that the most recent human ancestors lived in Africa
171,500 years ago and began to migrate to Europe and Asia, replacing a more primitive species of humans-just 52,000 years
ago. Previous estimates had modern humans embarking on this exodus between 70,000 and 100,000 years ago. This so-called "Out
of Africa" hypothesis maintains that modern humans evolved first in Africa, rather than separately in already widespread populations.
The latest evidence takes a more in-depth look at mitochondrial DNA than was possible before, according to Ulf Gyllensten
of the University of Uppsala in Sweden. "I think this will be regarded as a landmark study in the sense that it is the first
where complete genomes are used for evolutionary studies of humans," Gyllensten told United Press International. "It will
also be cited as the final proof of the Out of Africa hypothesis." But at least one geneticist, S. Blair Hedges of Pennsylvania
State University, is not convinced. "So far no single study, by itself, has proven one or the other of the two competing hypotheses,"
Hedges told UPI.
HOMO ERECTUS WAS ONE SPECIES
New research suggests that the human ancestor Homo
Erectus ranged from Europe to Africa to Asia in the Pleistocene era, according to a study reported in this week's edition
of the journal Nature. The finding counteracts theories that there was an early split between human ancestors in Eurasia and
Africa. "This says a single species was very widespread in Africa and Eurasia," said Elidabeth Vrba, a professor of paleontology
at Yale University. The conclusions are based on a skull found at a new site in Ethiopia's Afar regional state. The team compared
the new fossil's characteristics with other hominid fossils from Africa, Europe and Asia. The specimens were very difficult
to distinguish. "They show mosaic resemblances," Vrba said. "One does not get one set of character states in each area, which
suggests genetic continuity between them. There was movement and mobility between the populations, and interbreeding, consistent
with a single species which should bear the name Homo Erectus."
OLDEST NEW WORLD SKULLS LOOK LIKE JAPANESE
A new analysis of prehistoric and recent human skulls found in the Americas suggests that
relative newcomers to the continent show more similarities to mainland populations of East Asia than do earlier arrivals.
Researchers from the University of Michigan, University of Wyoming, Chinese Academy of Social Sciences, Chengdu College of
Traditional Chinese Medicine, and Mongolian Academy of Sciences did an analysis of 21 craniofacial measurements made on collections
of human crania from regions of the Europe, Asia, and the Americas. The analysis suggests that the people who inhabited America
15,000 years ago had no close association with any known mainland Asian population, but instead had a closer resemblance to
human populations of modern and prehistoric Japan. On the other hand, the Eskimos, Aleuts, and Na-Dene-speaking people, who
are more recent arrivals, share craniofacial traits with Mongolian, Chinese and, Southeast Asian populations. The data could
impact questions of the earliest settlement of the New World, including the initial date of entry, route of access, and paths
of migration
NEANDERTHALS TOOK CARE OF EACH OTHER
Teeth and jaw fossils found last
year in southeastern France suggest that Neanderthals' social and technological development was much more advanced than previously
documented, according to a report that will appear in the September 25th edition of the Proceedings of the National Academy
of Sciences. The findings suggest that people were taking care of other community members as far back as 175,000 years ago.
The bones include an individual who had massive periodontal inflammation, and all of the teeth had been missing or ineffective
for some time before the individual died. "There had to have been extensive preparation of food -- a combination of cutting
and cooking-before this person could eat. They had good cutting tools and controlled fire, but the absence of real hearths
and tools that would have done more than dice the food suggests that this individual was being given softer food items by
other members of the social group," said Erik Trinkaus, professor of anthropology in arts & sciences at Washington University
in St. Louis.
DID BULLYING
GIVE RISE TO SPEECH?
Prehistoric men showing off to their rivals may have
given rise to the evolution of speech. It had been believed that the human larynx is unique, but researchers have now found
similar 'dropped larynxes' in deer, which use them to make deeper lowing noises to intimidate rivals. Like other mammals,
the human larynx starts out poking up into the nasal passage in a newborn, but at three months of age it 'drops,' opening
up a cavity behind the tongue. "[It makes] speech communication more effective and reliable," Philip Lieberman, who researches
the origins of speech, told New Scientist. "The permanent descent of the larynx may have occurred independently of the evolution
of spoken language," said David Reby of the Large Mammals Research Institute in Castanet, France. Still, not everyone is convinced.
"Deer and humans are so different in behavior that inferring a similar evolutionary history is a stretch," said language expert
Steven Pinker.
UNKNOWN ARCTIC HUNTERS
Almost 40,000 years ago, a band of hunters set
up camp at Mamontovaya Kurya, in the desolate far north of European Russia, close to the Arctic Ocean, according to a report
in this week's edition of the journal Nature. But who were they? John Inge Svendsen of the University of Bergen, Norway, and
colleagues describe stone tools, animal bones and an incised mammoth tusk from the remote site: the oldest documented evidence
for human activity so far north. The discoveries imply either that Neanderthals -- living in Europe and western Asia at the
time, and known to have made tools -- expanded much further north than previously thought; or that modern humans were present
in the Arctic only a few thousand years after their appearance in Europe. If the toolmakers were modern humans, the timing
is significant: the period between around 40,000 and 35,000 years ago marks the transition from the Middle to the Upper Palaeolithic,
a turning point in the history of human evolution in Europe. "The results should also rekindle debate about the effects of
the climate on the movements of early human populations," said John Gowlett of the University of Liverpool, U.K.
Neanderthal DNA
By Steve Sampson
Scientists announced this week that they've discovered
and decoded the oldest human-type DNA yet--a fragment of mitochondrial DNA from a 100,000-year-old tooth. That tooth once
belonged to a Neanderthal, whose remains were found in a Belgian cave in 1993. The find adds to a small but growing store
of genetic information about the Neanderthals, who peopled Europe for most of the last 200,000 years.
Anatomically modern humans--folks like us, but without
cell phones--didn't arrive on the European scene until around 40,000 years ago. A few thousand years after that, the Neanderthals
disappeared. That raises some interesting questions. Who were the Neanderthals? What happened to them? And why do some people
spell it "Neandertal"?
Does the word "Neanderthal" make you think "big, dumb,
slouching brute"? Think again. Neanderthals walked fully upright and had brains at least the size of yours. They created sophisticated
stone tools and weapons, built fires, cared for wounded kin, and buried their dead. Some scientists even think they were capable
of fully articulate speech.
So why the image problem? Well, when anthropologists first
started finding Neanderthal fossils in the 19th century, they reconstructed them as hunching hominids halfway between apes
and modern humans--basically, as "big, dumb, slouching brutes." By the mid-20th century, new finds and better data had taught
scientists the error of their ways. But by then, the image was fixed, and calling someone a "Neanderthal" could get you punched
in the face.
One part of the old image was right. The Neanderthals really
were more muscular, with broad shoulders, large chests, powerful legs, and arms that packed more face-punching power than
we can muster. So why did they die out? There are two answers to that key question.
Neanderthals and anatomically modern humans--the Cro-Magnons--coexisted
in Europe for around 10,000 years. Based on fossil evidence and archaeological finds, some scientists think that the two groups
interbred, and that Neanderthal characteristics were replaced by Cro-Magnon ones. That would make Neanderthals a subspecies
of Homo sapiens--Homo sapiens neanderthalensis--and mean that modern Europeans still carry Neanderthal genes.
Other scientists deny interbreeding and make Neanderthals
a distinct species, Homo neanderthalensis. So far, the genetic evidence (including this week's study) appears to bear
them out. That suggests that competition from Cro-Magnons--who had superior communication skills, tools, and weapons--may
have helped kill off the Neanderthals. Some say direct interspecies battles were key. Others point to competition for resources
in a changing climate. Whatever happened, the Neanderthals were gone by around 30,000 years ago.
The first Neanderthal fossils to be recognized as such
were found in Germany's Neander Valley in 1856. At the time, the locals knew the place as Neanderthal ("thal" being
German for "valley"). German spelling was later regularized to be more consistent with pronunciation--German has no "th" sound--and
Neanderthal became Neandertal.
Since the 1950s, some people have argued that the English
spelling and pronunciation should follow suit. Yet both versions are still acceptable and widely used, even among experts.
So you probably won't be called a Neandertal for saying "Neanderthal."
Steve Sampson
June 9, 2006
Early Seafarers
The first known ocean voyages took place over 800,000 years ago!
Stone tools found on the Indonesian island of Flores have shown
that the human ancestor Homo erectus was capable of seafaring journeys. When the tools were made, the island was 19 kilometers
from the mainland, a significant trip for early hominids.
Before this find, the earliest known ocean voyages were from
40,000 to 60,000 years ago. The new discovery shows that Homo erectus was more advanced than people had thought.
New dates challenge the reputation of early humans
International debate about when humans first gained language,
seafaring skills and the capacity to reach Australia, has been rekindled by new dates from archaeological sites on the Indonesian
island of Flores.
A research team, co-ordinated by UNE archaeologist Dr Mike Morwood,
has dated stone tools on Flores at more than 800,000 years old. The researchers conclude that Homo erectus, an ancestor of
modern humans, was capable of water crossings of up to 19km between Flores and the South East Asian mainland.
"In fact, the evidence suggests that the cognitive capabilities
of this species may be due for re-appraisal," the researchers argue in an article just published in the leading science journal
Nature.
"Homo erectus was clearly not just a glorified chimp," Dr Morwood
said. "This highly successful hominid spread out of Africa about a million years ago. They hunted large animals with well-crafted
spears. "We now know that they made sea crossings to reach Flores and other Indonesian islands. They must have had language
for the collective effort needed to achieve this," he said.
The research team comprises Dr Morwood, Dr Paul O'Sullivan and
Dr Asaf Raza, of La Trobe University, and Dr Fachroel Aziz, of the Indonesian Geological Research and Development Centre.
The extraordinary findings challenge the commonly held view that
humans did not develop the social, organisational and linguistic complexity necessary to make journeys across the sea until
the more recent colonisation of Australia, which occurred between 40,000-60,000 years ago.
The researchers have ruled out the possibility that Flores was
once connected by land to the Asian mainland. Before human intervention, only species that were adapted to water crossing
by swimming, rafting on flotsam, or flight colonised the islands between Java and Australia. In fact, one of the few mammals
to make it to Flores from the Asian mainland was Stegodon, an ancestor of the elephant, which is capable of swimming long
distances. Homo erectus may have made the crossing on bamboo rafts.
"If, as this evidence suggests, hominids had made it to Flores
by 800,000 years ago, then they had the means to continue on through the island chain to Timor and Australia," Dr O'Sullivan
said.
"It's possible that people arrived in Australia much earlier
than currently thought, but we don't have the geology to prove it. For the most part, Australia lacks the volcanic ash deposits
which have provided scientists with ideal dating opportunities in Indonesia and Africa," Dr Raza added.
At the Flores site of Mata Menge, Dr Morwood and Dr Aziz investigated
sandstones and volcanic ash layers deposited in a shallow lake bed. The site has yielded remains of large Stegodon, crocodiles,
giant rats and freshwater molluscs, as well as flaked stone tools.
Mata Menge was dated by Dr O'Sullivan and Dr Raza using fission
track dating, the method used by La Trobe University Professor of Geology Andrew Gleadow to date the famous early hominid
sites found by Richard Leakey in Kenya. This method dates individual zircon grains deposited in volcanic ash.
Dr O'Sullivan and Dr Raza dated a minimum of 50 individual grains
from each of two layers above and below the tools, which resulted in ages of 800,000 and 880,000 years, respectively.
A total of 13 grains from both samples were significantly older
and were therefore rejected by the geochronologists to eliminate the problem of contamination that resulted in the artificially
old ages reported last year at Jinmium rockshelter in the eastern Kimberley. Dr O'Sullivan said that these preliminary results
are being followed up by a more detailed dating program.
New evidence
The findings now establish an 800,000-year cultural sequence
for an East Indonesian island. Since Flores also lies midway along the most likely
route taken by people migrating here from Asia, the archaeological record for the island could provide evidence for the origins
of the first Australians.
"Sites between 100,000 and 200,000 years old would be of particular
interest," Dr Aziz said.
The archaeological excavations on Flores are part of a broader
research project into the origins of the first Australian Aborigines.
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