A team of researchers made a discovery that disputes the long-lasting theory of how humans arrived in America. It would have been biologically-unviable for people to come through the land bridge between Siberia and Alaska, a recent study suggests.
For decades, archaeologists and scientists have defended the theory of humans populating the Americas through a corridor that opened between two large ice sheets. According to the corridor-theory, the first people that populated North America were the Clovis clan. Nonetheless, there has been supporting evidence of ancient populations living in the continent from about 13,500 years ago.
The recent study claims it was unviable for any human to have passed the corridor at the time because of biological reasons and timing, arguing the passage was biologically stable 12,600 years ago.
The international team of researchers, including a team from the University of Copenhagen, performed a fieldwork investigation. Researchers studied sediment cores from the Charlie Lake in British Columbia and the Spring Lake in Alberta, all part of modern Canada and the ancient passage.
The recent investigation published Wednesday in the journal Nature was led by Professor Eske Willerslev, an evolutionary geneticist from the GeoGenetics center at the University of Copenhagen.
Disputing a long-lasting theory
Experts have affirmed the corridor approach for several years, which claims the first people to populate the Americas arrived in the continent via a land bridge between Siberia and Alaska.
However, due to climate conditions at the time, researchers from the GeoGenetics Center respectfully disagree with the theory. Considering that two ice sheets covered modern-day Canada, ancient populations had to wait thousands of years for those ice sheets to melt and create the corridor.
Professor Willerslev and his team performed a ground investigation to dispute the previous theory, proving the ancient flora and fauna didn’t match the timing and wouldn’t have allowed the ancient populations to survive.
The team concluded the corridor would have been unviable earlier than 12,600 years ago, after performing a “bottleneck” investigation. Said examination focuses on investigating sediments of ground to re-create a particular environment.
After gathering land evidence, the team studied all the ingredients on the soil, including macrofossils, DNA on the lake, pollen and other components. The investigation was performed during the winter so that the sediments would be more preserved thanks to the ice.
Thanks to a technique called “shotgun sequencing” the team was able to re-create the ancient environment and determine all the flora and fauna that used to be in the famous corridor.
“It’s amazing what you can get, we found evidence of fish, eagles, mammals and plants,” said lead-author Willerslev in a statement for the University of Copenhagen.
The investigation allowed researchers to observe the evolution of the climate in the ancient passage, which paved the way to determining it would have been impossible for early Americans to travel earlier than 12,600 years ago.
Researchers concluded that before 12,600 years ago, the corridor had no signs of plants nor animals, which means ancient Americans would have had to pass 1,500 kilometers without access to food nor water.
“The bottom line is that even though the physical corridor was one by 13,000 years ago, it was several hundred years before it was possible to use it,” said lead-author Willerslev.
The hall started to see evidence of vegetation around 12 to 13,00o years ago when animals such as jackrabbits, voles, bisons, wooly and mammoth appeared in the ecosystem. As for the lakes, they started to show a population of fish in them, such as perch and pike.The passage also evolved and became populated by large trees and
The passage also developed and became filled by large trees and bald eagles, becoming more human-friendly. The recent discovery is also supported by a previous study published in the Proceedings of the National Academy of Sciences in June. The study found evidence of Bisons populations in the corridor area, according to the journal Nature. The animals appeared at least 13,000 years ago, the study notes.
Discovering a different route
The fact that science shows evidence of the Clovis people in the continent long before the corridor was biologically stable means that the ancient people had to find a different way to enter the Americas.
The presence of another civilization previous to the Clovis clan has been a research target for many scientists, as it would mean the tribe’s predecessors arrived at the continent by sea or another part of the land.
Researchers have also questioned the Clovis theory since evidence of ancient civilizations has been found in the south of Chile. The data found dates back thousands of year before the Clovis clan appeared.
Theories claim Americans traveled through the Pacific Coast by sea and land to arrive at the continent. More investigations need to be made to determine a new and accurate traveling method for early American civilizations.
Source: University of Copenhagen