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CRUISING DOWN THE KELP HIGHWAY
Erlandson has found one more line of evidence that supports the migration theory. While working with a group of marine ecologists, he was startled to learn that there were nearly continuous kelp forests growing just offshore all the way from Japan in the western Pacific to Alaska and down the West Coast to Baja California, then (with a gap in the tropics) off the coast of South America. In a paper presented three weeks ago, he outlined the potential importance to the earliest Americans of what he calls the "kelp highway."
"Most of the early sites on the west coast are found adjacent to kelp forests, even in Peru and Chile," he says. "The thing about kelp forests is they're extremely productive." They not only provide abundant food, from fish, shellfish, seals and otters that thrive there, but they also reduce wave energy, making it easier to navigate offshore waters. By contrast, the inland route along the ice-free corridor would have presented travelers with enormous ecological variability, forcing them to adapt to new conditions and food sources as they traveled.
Unfortunately, the strongest evidence for the coastal theory lies offshore, where ancient settlements would have been submerged by rising seas over the past 10,000 years or so. "Artifacts have been found on the continental shelves," says Dixon, "so I'm quite confident there's material out there." But you need submersible craft to search, and, he says, that type of research is a very hard sell to the people who own and operate that kind of equipment. "The maritime community is interested in shipwrecks and treasures. A little bit of charcoal and some rocks on the ocean floor is not very exciting to them."
MULTIPLE MIGRATIONS
Even if the earliest Americans traveled down the coast, that doesn't mean they couldn't have come through the interior as well. Could there have been multiple waves of migration along a variety of different routes? One way scientists have tried to get a handle on that question is through genetics. Their studies have focused on two different types of evidence extracted from the cells of modern Native Americans: mitochondrial DNA, which resides outside the nuclei of cells and is passed down only through the mother; and the Y chromosome, which is passed down only from father to son. Since DNA changes subtly over the generations, it serves as a sort of molecular clock, and by measuring differences between populations, you can gauge when they were part of the same group.
Or at least you can try. Those molecular clocks are still rather crude. "The mitochondrial DNA signals a migration up to 30,000 years ago," says research geneticist Michael Hammer of the University of Arizona. "But the Y suggests that it occurred within the last 20,000 years." That's quite a discrepancy. Nevertheless, Hammer believes that the evidence is consistent with a single pulse of migration.
Theodore Schurr, director of the University of Pennsylvania's Laboratory of Molecular Anthropology, thinks there could have been many migrations. "It looks like there may have been one primary migration, but certain genetic markers are more prevalent in North America than in South America," Schurr explains, suggesting secondary waves. At this point, there's no definitive proof of either idea, but the evidence and logic lean toward multiple migrations. "If one migration made it over," Dillehay, now at Vanderbilt University, asks rhetorically, "why not more?"
OUT OF SIBERIA?
Genetics also points to an original homeland for the first Americans--or at least it does to some researchers. "Skeletal remains are very rare, but the genetic evidence suggests they came from the Lake Baikal region" of Russia, says anthropologist Ted Goebel of the University of Nevada at Reno, who has worked extensively in that part of southern Siberia. "There is a rich archaeological record there," he says, "beginning about 40,000 years ago." Based on what he and Russian colleagues have found, Goebel speculates that there were two northward migratory pulses, the first between 28,000 and 20,000 years ago and a second sometime after 17,000 years ago. "Either one could have led to the peopling of the Americas," he says.
Like just about everything else about the first Americans, however, this idea is open to vigorous debate. The Clovis-first theory is pretty much dead, and the case for coastal migration appears to be getting stronger all the time. But in a field so recently liberated from a dogma that has kept it in an intellectual straitjacket since Franklin Roosevelt was President, all sorts of ideas are suddenly on the table. Could prehistoric Asians, for example, have sailed directly across the Pacific to South America? That may seem far-fetched, but scientists know that people sailing from Southeast Asia reached Australia some 60,000 years ago. And in 1947 the explorer Thor Heyerdahl showed it was possible to travel across the Pacific by raft in the other direction.
At least a couple of archaeologists, including Dennis Stanford of the Smithsonian, even go so far as to suggest that the earliest Americans came from Europe, not Asia, pointing to similarities between Clovis spear points and blades from France and Spain dating to between 20,500 and 17,000 years B.P. (Meltzer, Goebel and another colleague recently published a paper calling this an "outrageous hypothesis," but Dillehay thinks it's possible.)
All this speculation is spurring a new burst of scholarship about locations all over the Americas. The Topper site in South Carolina, Cactus Hill in Virginia, Pennsylvania's Meadowcroft, the Taima-Taima waterhole in Venezuela and several rock shelters in Brazil all seem to be pre-Clovis. Dillehay has found several sites in Peru that date to between 10,000 and 11,000 years B.P. but have no apparent links to the Clovis culture. "They show a great deal of diversity," he says, "suggesting different early sources of cultural development in the highlands and along the coast."
It's only by studying those sites in detail and continuing to search for more evidence on land and offshore that these questions can be fully answered. And as always, the most valuable evidence will be the earthly remains of the ancient people themselves. In one 10-day session, Kennewick Man has added immeasurably to anthropologists' store of knowledge, and the next round of study is already under way. If scientists treat those bones with respect and Native American groups acknowledge the importance of unlocking their secrets, the mystery of how and when the New World was populated may finally be laid to rest.
In the last post, an overview of the factual findings which contradict the Bering Strait theory...
CRUISING DOWN THE KELP HIGHWAY
Erlandson has found one more line of evidence that supports the migration theory. While working with a group of marine ecologists, he was startled to learn that there were nearly continuous kelp forests growing just offshore all the way from Japan in the western Pacific to Alaska and down the West Coast to Baja California, then (with a gap in the tropics) off the coast of South America. In a paper presented three weeks ago, he outlined the potential importance to the earliest Americans of what he calls the "kelp highway."
"Most of the early sites on the west coast are found adjacent to kelp forests, even in Peru and Chile," he says. "The thing about kelp forests is they're extremely productive." They not only provide abundant food, from fish, shellfish, seals and otters that thrive there, but they also reduce wave energy, making it easier to navigate offshore waters. By contrast, the inland route along the ice-free corridor would have presented travelers with enormous ecological variability, forcing them to adapt to new conditions and food sources as they traveled.
Unfortunately, the strongest evidence for the coastal theory lies offshore, where ancient settlements would have been submerged by rising seas over the past 10,000 years or so. "Artifacts have been found on the continental shelves," says Dixon, "so I'm quite confident there's material out there." But you need submersible craft to search, and, he says, that type of research is a very hard sell to the people who own and operate that kind of equipment. "The maritime community is interested in shipwrecks and treasures. A little bit of charcoal and some rocks on the ocean floor is not very exciting to them."
MULTIPLE MIGRATIONS
Even if the earliest Americans traveled down the coast, that doesn't mean they couldn't have come through the interior as well. Could there have been multiple waves of migration along a variety of different routes? One way scientists have tried to get a handle on that question is through genetics. Their studies have focused on two different types of evidence extracted from the cells of modern Native Americans: mitochondrial DNA, which resides outside the nuclei of cells and is passed down only through the mother; and the Y chromosome, which is passed down only from father to son. Since DNA changes subtly over the generations, it serves as a sort of molecular clock, and by measuring differences between populations, you can gauge when they were part of the same group.
Or at least you can try. Those molecular clocks are still rather crude. "The mitochondrial DNA signals a migration up to 30,000 years ago," says research geneticist Michael Hammer of the University of Arizona. "But the Y suggests that it occurred within the last 20,000 years." That's quite a discrepancy. Nevertheless, Hammer believes that the evidence is consistent with a single pulse of migration.
Theodore Schurr, director of the University of Pennsylvania's Laboratory of Molecular Anthropology, thinks there could have been many migrations. "It looks like there may have been one primary migration, but certain genetic markers are more prevalent in North America than in South America," Schurr explains, suggesting secondary waves. At this point, there's no definitive proof of either idea, but the evidence and logic lean toward multiple migrations. "If one migration made it over," Dillehay, now at Vanderbilt University, asks rhetorically, "why not more?"
OUT OF SIBERIA?
Genetics also points to an original homeland for the first Americans--or at least it does to some researchers. "Skeletal remains are very rare, but the genetic evidence suggests they came from the Lake Baikal region" of Russia, says anthropologist Ted Goebel of the University of Nevada at Reno, who has worked extensively in that part of southern Siberia. "There is a rich archaeological record there," he says, "beginning about 40,000 years ago." Based on what he and Russian colleagues have found, Goebel speculates that there were two northward migratory pulses, the first between 28,000 and 20,000 years ago and a second sometime after 17,000 years ago. "Either one could have led to the peopling of the Americas," he says.
Like just about everything else about the first Americans, however, this idea is open to vigorous debate. The Clovis-first theory is pretty much dead, and the case for coastal migration appears to be getting stronger all the time. But in a field so recently liberated from a dogma that has kept it in an intellectual straitjacket since Franklin Roosevelt was President, all sorts of ideas are suddenly on the table. Could prehistoric Asians, for example, have sailed directly across the Pacific to South America? That may seem far-fetched, but scientists know that people sailing from Southeast Asia reached Australia some 60,000 years ago. And in 1947 the explorer Thor Heyerdahl showed it was possible to travel across the Pacific by raft in the other direction.
At least a couple of archaeologists, including Dennis Stanford of the Smithsonian, even go so far as to suggest that the earliest Americans came from Europe, not Asia, pointing to similarities between Clovis spear points and blades from France and Spain dating to between 20,500 and 17,000 years B.P. (Meltzer, Goebel and another colleague recently published a paper calling this an "outrageous hypothesis," but Dillehay thinks it's possible.)
All this speculation is spurring a new burst of scholarship about locations all over the Americas. The Topper site in South Carolina, Cactus Hill in Virginia, Pennsylvania's Meadowcroft, the Taima-Taima waterhole in Venezuela and several rock shelters in Brazil all seem to be pre-Clovis. Dillehay has found several sites in Peru that date to between 10,000 and 11,000 years B.P. but have no apparent links to the Clovis culture. "They show a great deal of diversity," he says, "suggesting different early sources of cultural development in the highlands and along the coast."
It's only by studying those sites in detail and continuing to search for more evidence on land and offshore that these questions can be fully answered. And as always, the most valuable evidence will be the earthly remains of the ancient people themselves. In one 10-day session, Kennewick Man has added immeasurably to anthropologists' store of knowledge, and the next round of study is already under way. If scientists treat those bones with respect and Native American groups acknowledge the importance of unlocking their secrets, the mystery of how and when the New World was populated may finally be laid to rest.
In the last post, an overview of the factual findings which contradict the Bering Strait theory...
