Drawing on evidence from a range of sciences—from genetics to geology—they are searching for answers to a host of pressing questions: Where did the earliest Americans come from?
When exactly did they arrive, and what route did they take into the New World? For the first time in decades there is a heady whiff of discovery in the air.
Adovasio, an archaeologist at Mercyhurst College. Over the past decade, however, geneticists have taken the search for the first Americans to the molecular level, finding new clues to where they hailed from and when they left their homeland in the DNA of indigenous peoples. In more than a dozen studies geneticists examined modern and ancient DNA samples from Native Americans, looking for telltale genetic mutations or markers that define major human lineages known as haplogroups. They found that native peoples in the Americas stemmed from four major founding maternal haplogroups—A, B, C and D—and two major founding paternal haplogroups—C and Q.
To find the probable source of these haplogroups, the teams then searched for human populations in the Old World whose genetic diversity encompassed all the lineages. Only the modern inhabitants of southern Siberia matched this genetic profile, a finding that strongly indicates that the ancestors of the first Americans came from an East Asian homeland. This evidence confirmed what most archaeologists suspected about the location of this homeland. It also strongly suggested that the timing proposed in the Clovis First scenario was wrong.
Geneticists now calculate, based on mutation rates in human DNA, that the ancestors of the Native Americans parted from their kin in their East Asian homeland sometime between 25, and 15, years ago—a difficult time for a great northern migration. Huge glaciers capped the mountain valleys of northeastern Asia, at the same time massive ice sheets mantled most of Canada, New England and several northern states.
Indeed, reconstructions of past climate based on data preserved in ice cores from Greenland and on measurements of past global sea levels show that these ice sheets reached their maximum extent in the last glacial period between at least 22, and 19, years ago. They had a toolbox of tactics and strategies.
Dressed in warm, tailored hide garments stitched together with sinew and bone needles and armed with an expert knowledge of nature, the ancestors of the Paleo-Americans entered an Arctic world without parallel today. The ice sheets in northern Europe and North America had locked up vast quantities of water, lowering sea level by more than meters and exposing the continental shelves of northeastern Asia and Alaska. These newly revealed lands, together with adjacent regions in Siberia, Alaska and northern Canada, formed a landmass that joined the Old World seamlessly to the New.
Known today as Beringia, this landmass would have made a welcoming way station for pre-Clovis migrants. The air masses that swept over it were so dry they brought little snowfall, preventing the growth of ice sheets.
As a result, grasses, sedges and other cold-adapted plants thrived there, as shown by plant remains found preserved under a layer of volcanic ash in northwestern Alaska and in the frozen intestines of large herbivores that once grazed in Beringia.
These plants formed an arid tundra-grassland, and there woolly mammoths weighing as much as nine tons grazed, as did giant ground sloths, steppe bison, musk ox and caribou. Genetic studies of modern Steller's sea lion populations suggest that this sea mammal likely hauled out on the rocks along Beringia's island-studded south shore.
So the migrants may have had their pick not only of terrestrial mammals but also of seafaring ones. Received wisdom holds that the trailblazers hurried across Beringia to reach warmer, more hospitable lands. Some researchers, however, think the journey could have been a more leisurely affair. The major genetic lineages of Native Americans possess many widespread founding haplotypes—combinations of closely linked DNA sequences on individual chromosomes that are often inherited together—that their closest Asian kin lack.
This suggests the earliest Americans paused somewhere en route to the New World, evolving in isolation for thousands of years before entering the Americas. The most likely spot for this genetic incubator is Beringia. There the migrants could conceivably have been cut off from their Asian kin as the climate cooled some 22, years ago, forcing Siberian bands to retreat south.
Whether the migrants cooled their heels in Beringia, however, or somewhere else in northeastern Asia, people eventually began striking off farther east and south. A warming trend began slowly shrinking North America's ice sheets some 19, years ago, gradually creating two passable routes to the south and opening the possibility of multiple early migrations.
According to several studies conducted over the past decade on the geographical distribution of genetic diversity in modern indigenous Americans, the earliest of these migrants started colonizing the New World between 18, and 15, years ago—a date that fits well with emerging archaeological evidence of pre-Clovis colonists. Archaeologists take up the tale of the earliest Americans as these travelers pushed southward, exploring a wilderness untouched by humans.
In an office decorated with prints and pictures of sharks and a poster of a traditional Chumash wood canoe, Jon M. Erlandson, an archaeologist at the University of Oregon, mulls over new evidence of their journey. Reed-thin, tousled and in his mid-fifties, Erlandson has spent much of his career digging at sites along the coast of California, becoming one of the foremost proponents of what is often called the coastal route theory.
Whereas supporters of the Clovis First model envisioned humans reaching the Americas by trekking overland, Erlandson thinks the earliest travelers arrived by sea, paddling small boats from East Asia to southern Beringia and down the western coast of the Americas. Now he and his colleague Todd J. Braje of San Diego State University have uncovered key new evidence of ancient mariners who set out in East Asia and ended their journey in Chile.
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Save Back. An Overview of Native American History. Grades 3—5 , 6—8 , 9— View not found. Download the PDF from here. Related Subjects. Appears in This Collection. Both ideas have now fallen from grace.
The multiple-waves theory has failed as a model because the linguistic similarities used to show patterns of migration are just not that convincing. And the second theory fails because of timing. Cultures are often named and known by the technology that they left behind. In New Mexico there is a small town called Clovis, population 37, In the s, projectile points resembling spearheads and other hunting paraphernalia were found in an archaeological site nearby, dating from around 13, years ago.
These were knapped on both sides—bifaced with fluted tips. It had been thought that it was the inventors of these tools who had been the first people to spread up and down the continents. These people are too far away to show a direct link between them and the Clovis in such a way that indicates the Clovis being the aboriginals of South America.
Today, the emerging theory is that the people up in the Bluefish Caves some 24, years ago were the founders, and that they represent a culture that was isolated for thousands of years up in the cold north, incubating a population that would eventually seed everywhere else. This idea has become known as Beringian Standstill. Those founders had split from known populations in Siberian Asia some 40, years ago, come across Beringia, and stayed put until around 16, years ago.
Analysis of the genomes of indigenous people show 15 founding mitochondrial types not found in Asia. This suggests a time when genetic diversification occurred, an incubation lasting maybe 10, years. New gene variants spread across the American lands, but not back into Asia, as the waters had cut them off. Nowadays, we see lower levels of genetic diversity in modern Native Americans—derived from just those original 15—than in the rest of the world. Again, this supports the idea of a single, small population seeding the continents, and—unlike in Europe or Asia—these people being cut off, with little admixture from new populations for thousands of years, at least until Columbus.
In Montana, 20 miles or so off Highway 90, lies the minuscule conurbation of Wilsall, population as of Though stacks of material culture in the Clovis tradition have been recovered throughout North America, only one person from this time and culture has risen from his grave. He was a toddler, probably less than two years old, judging from the unfused sutures in his skull. He was laid to rest surrounded by at least stone tools, and 15 ivory ones.
Some of these were covered in red ochre, and together they suggest Anzick was a very special child who had been ceremonially buried in splendor. While attending a hydroplane race in , two locals of Kennewick, Washington, discovered a broad-faced skull inching its way out of the bank of the Columbia River. Over the weeks and years, more than fragments of bone and teeth were eked out of this 8,year-old grave, all belonging to a middle-aged man, maybe in his 40s, deliberately buried, with some signs of injuries that had healed over his life—a cracked rib, an incision from a spear, a minor depression fracture on his forehead.
There were academic squabbles about his facial morphology, with some saying it was most similar to Japanese skulls, some arguing for a link with Polynesians, and some asserting he must have been European. With all the toing and froing about his morphology, DNA should be a rich source of conclusive data for this man.
But the political controversies about his body have severely hampered his value to science for 20 years. Scientists sued the government to prevent his reburial, some claiming that his bones suggested he was European, and therefore not connected with Native Americans. To add an absurd cherry on top of this already distasteful cake, a Californian pagan group called the Asatru Folk Assembly put in a bid for the body, claiming Kennewick Man might have a Norse tribal identity, and if science could establish that the body was European, then he should be given a ceremony in honor of Odin, ruler of the mythical Asgard, though what that ritual entails is not clear.
His reburial was successfully blocked in , when a judge ruled that his facial bones suggested he was European, and therefore NAGPRA guidelines could not be invoked. The issue was batted back and forth for years, in a manner in which no one came out looking good.
Nineteen years after this important body was found, the genome analysis was finally published. A fragment of material was used to sequence his DNA, and it showed that lo and behold, Kennewick Man—the Ancient One—was closely related to the Anzick baby. And as for the living, he was more closely related to Native Americans than to anyone else on Earth, and within that group, most closely related to the Colville tribes. Anzick is firm and final proof that North and South America were populated by the same people.
Yet no matter when or how they made the trek, the coast of what is now Canada was on their itinerary.
The rugged shoreline of British Columbia is carved by countless coves and inlets and dotted with tens of thousands of islands. On a cool August morning, I arrived on Quadra Island, about miles northwest of Vancouver, to join a group of researchers from the University of Victoria and the nonprofit Hakai Institute.
The site was located on a tranquil cove whose shores were thick with hemlock and cedar. When I arrived, the team was just finishing several days of digging, the latest in a series of excavations along the British Columbia coast that had unearthed artifacts from as far back as 14, years ago—among the oldest in North America. On a cobble beach and in a nearby forest pit that was about six feet deep and four feet square, Fedje and his colleagues had discovered more than 1, artifacts, mostly stone flakes, a few as old as 12, years.
All testified to a rich maritime-adapted culture: rock scrapers, spear points, simple flake knives, gravers and goose egg-size stones used as hammers. Fedje reckoned that the cove site was most likely a base camp that was ideally situated to exploit the fish, waterfowl, shellfish and marine mammals from the frigid sea.
For Mackie, the archaeological riches of the British Columbian coast reveal a key flaw in the original Bering Land Bridge theory: its bias toward an inland, rather than a marine, route. These were the same people as us, with the same brains. And we know that in Japan people routinely moved back and forth from the mainland to the outer islands by boat as long ago as 30, to 35, years.
Several recent studies show that as the last ice age began to loosen its grip, portions of the coastline of British Columbia and Southeastern Alaska were becoming ice-free as far back as 17, to 18, years ago. Fedje and others note that humans walking across the Bering Land Bridge from Asia could have traveled by boat down these shorelines after the ice retreated. Today, the coast of the Pacific Northwest bears little resemblance to the world the first Americans would have encountered.
The lushly forested shoreline I saw would have been bare rock following the retreat of the ice sheets. And in the last 15, to 20, years, sea levels have risen some feet. But Fedje and his colleagues have developed elaborate techniques to find ancient shorelines that were not drowned by rising seas. Their success has hinged on solving a geological puzzle dating back to the end of the last ice age.
As the world warmed, the vast ice sheets that covered much of North America—to a depth of two miles in some places—began to melt. This thawing, coupled with the melting of glaciers and ice sheets worldwide, sent global sea levels surging upwards. In some places, Fedje says, the coast of British Columbia rebounded more than feet in a few thousand years.
The changes were happening so rapidly that they would have been noticeable on an almost year-to-year basis. But this is a very dynamic landscape. In order to track ancient shorelines, Fedje and his colleagues took hundreds of samples of sediment cores from freshwater lakes, wetlands and intertidal zones.
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