Fights hinder certainties about the occupation of America – 11/29/2023 – Science

At the end of the Ice Age, the Americas were the proverbial “final frontier”, the last continent to be colonized from north to south by humans. In recent decades, knowledge about how this process happened has increased dramatically — and yet, uncertainties seem to have grown at the same rate.

This is the great irony of “Admirable New World”, a monumental book-report by scientific journalist Bernardo Esteves.

The work maps in detail the main archaeological sites — from Alaska to Patagonia, passing through Piauí and the interior of Minas Gerais — which are important pieces of the puzzle of the arrival of the Homo sapiens to our continent.

Esteves’ narrative, however, shows that ancient skeletons, stone artifacts and other clues to the remote past often take a backseat to much more complicated and subjective factors.

The geopolitical influence of scientists from developed countries, personal animosities and idiosyncrasies, and the simple difficulty of reconstructing tens of thousands of years of history based on very little evidence hinder the formation of a consensus regarding who they were, where they came from and when they arrived. here the first Americans.

“The scarcity of data in archeology is precisely the key to the beauty of this discipline, at least to the fascination it awakens in me. Because the finds are all subject to interpretation, right?”, ponders Esteves in conversation with Sheet.

“People are forced to work with indirect remains that involve a wide range of contestation. This is behind the temperature of criticism and fights among archaeologists. And, in resolving controversies, the rhetorical dimension of persuasion comes into play very centrally.” , as also happens in other areas of science.”

The portrait of the arrival of our species on the American continent has undergone a series of profound reformulations since the last century, all duly explained in the book.

The granddaddy of the great hypotheses on the subject is the “Clovis First” model (“Clovis first”, a reference to a location with that name in New Mexico). According to this model, the first inhabitants of the Americas came from Siberia around 13 thousand years ago and were hunters of large mammals using, to kill the animals, sophisticated spear points with a channel at the base, the so-called Clovis points.

The people there would have exterminated the giant mammals (the so-called megafauna) and spread across the entire continent in a few hundred years. Formulated by American researchers, the thesis ended up generating the so-called “Clovis police” —archaeologists ready to debunk any proposal of a human presence in the Americas that was older than these valiant hunters.

But, in the 1990s, excavations carried out at the Monte Verde site, in southern Chile, obtained a large body of evidence that there had been human beings since at least 15 thousand years ago, throwing Clovis’ primacy into disarray.

This was possible thanks to the fact that the head of work at Monte Verde was Tom Dillehay — a respected American archaeologist, who managed to convince his counterparts in the United States about the antiquity of the site.

With the arrival on the scene of DNA studies of current indigenous populations and, increasingly, also of the DNA of people who lived on the continent several millennia ago, the possibility of an entry of Homo sapiens in the Americas up to 20 thousand years before the present it became accepted. The date matches calculations, made based on genetics, about the time when the ancestors of all current indigenous people would have separated from the Siberian populations.

This vision, however, has not yet been consolidated as a new consensual paradigm. On the one hand, new excavations at sites such as the Serra da Capivara, in Piauí, Santa Elina, in Mato Grosso, and others in the USA and Mexico threaten to push the date of human presence in the Americas to around 25 thousand years ago or even more. .

Furthermore, ancient and modern DNA data increasingly point to the presence of a modest but significant genetic component in indigenous lineages that reveals a kinship with the present-day aborigines of Australia and Melanesia.

This component, nicknamed “Population Y”, is still of mysterious origin — it could be part of the population heterogeneity of the groups that came from Siberia. Almost no researcher believes in direct travel from the Pacific islands to here.

This trajectory is just a summary of the much more complicated twists and turns described in the book. One constant element, however, is the skepticism and criticism, not always fair, made by US archaeologists of any South American site that seemed to challenge their hypotheses.

“This scientific colonialism, or scientific imperialism, as I prefer to call it, is an important dimension for us to understand the contestation of pre-Clovis sites. A recurring scene in this story is that of scholars from North America coming to South America to learn about and refute the evidence of ancient occupations presented by scientists here”, explains Esteves. Furthermore, a certain cultural prestige ended up becoming part of these scientists’ resistance to new ideas.

“American archaeologists are very proud of the fact that the fluted ends of the Clovis culture are the country’s first invention. As if the people of Clovis had their Steve Jobs from the Ice Age. It’s something that fits well with this pioneering culture and innovation, which is very much the identity of the USA.”

The advancement of genomic research is sometimes sold as the way to resolve once and for all doubts about this chapter in humanity’s expansion. But the author says that expecting this is too simplistic.

He recalls that the ancient skeletons whose DNA can be recovered represent a tiny portion of past populations, and that current indigenous people are survivors of a genocide that may have wiped out 90% or more of their ancestors. As a result, much genetic diversity was lost forever. The discipline that will be responsible for trying to assemble all the data into a new framework is inevitably archeology, argues Esteves.