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MIT Technology Review

Anthropology: What we have learned over the last decade

Modern humans not only produced offspring with now-extinct human species such as Neanderthals, but much of today’s human population shares genes with these ancestors.

Paleoanthropology studies the origin and evolution of man and tries to reconstruct the history of biological and cultural changes experienced by our ancestors since the lines that have led to humans and chimpanzees split some six million years ago. One of the main bodies of evidence on which the study of human evolution draws is fossils of extinct hominid species.

María Martinón-Torres is director of the National Research Center on Human Evolution in Spain.

This frequently leads to the erroneous idea that paleoanthropology is an area of study cloistered in the past. In fact, research into human evolution over the last decade has invalidated that paradigm in both the methodological and conceptual sense with research on the very horizon of knowledge that has contributed previously unknown knowledge about our own species. The past is now uncovered using technology of the future. The need “to make the dead talk” and to maximize the information that can be extracted from cherished and rare fossils and archeological finds has led paleontologists and archeologists to perfect and fully exploit current methods—sometimes to define new lines of investigation. 

Over the last decade, the analysis of ancient DNA has emerged as cutting-edge research that uses methods (genetics) and concepts (hybridization) not previously common in the field of anthropology. Today, we are the only human species on the planet, but we now know that we had offspring with others that no longer exist and have inherited some of their genes. Both genetic and fossil evidence gathered over the last decade offer a more diverse and dynamic image of our origins. Many of the keys to Homo sapiens’ success at adapting may possibly lie in this miscegenation that not only does not harm our identity, but probably constitutes a part of our species’ hallmark and idiosyncrasies.

Anthropology: What we have learned over the last decade
Today, we are the only human species on the planet, but we now know that we had offspring with others that no longer exist and have inherited some of their genes. Both genetic and fossil evidence gathered over the last decade offer a more diverse and dynamic image of our origins.

Privileged with a variety of advanced physical and intellectual capacities, modern humans would have spread to all of the continents no more than 50,000 years ago. That is the essence of the “Out of Africa” theory, which suggests that in its expansion across the planet Homo sapiens would have replaced all archaic human groups without any crossbreeding at all. Molecular analyses have now dismantled that paradigm, revealing that modern humans not only interbred and produced fertile offspring with now-extinct human species such as Neanderthals, but also that the genetic makeup of today’s non-African human population contains between two and four percent of their genes. 

Both genetic studies and fossil evidence from the last 10 years offer a more diverse, rich, and dynamic view of our own species. Many of the keys to our successful adaptation as we conquered ever-wider territories and changing environments may well be the result of precisely the cosmopolitan miscegenation that has characterized us for at least the last 200,000 years. This mixture not only does not weaken our identity as a species; it is probably part and parcel of our idiosyncrasy. Human evolution rests precisely on biological diversity, an advantageous and versatile body of resources on which nature can draw when circumstances require adaptive flexibility. Endogamic and homogeneous species are more given to damaging mutations, and it is even possible that the Neanderthals’ prolonged isolation in Europe over the course of the Ice Age may have made them more vulnerable in the genetic sense.

Part of the flexibility that characterizes humans today came from other humans who no longer exist.

Part of the flexibility that characterizes us today came from other humans who no longer exist. We are the present and the future, but we are also the legacy of those who are no longer among us. Despite being from species who probably recognized each other as different, humans and others now extinct crossbred, producing offspring and caring for them. This inevitably leads us to reflect on current society and its fondness for establishing borders and marking limits among individuals of the same species that are far more insurmountable than those dictated by biology itself.

What is our level of tolerance toward biological and cultural diversity? We continue to evolve. Natural selection continues to function, but we have altered selective pressures. Social pressure now has greater weight than environmental pressure. With the rise of genetic editing techniques, humans now enjoy a “superpower” that we have yet to really control. Society must therefore engage in a mature and consensual debate about where we want to go, but that debate must also consider our own evolutionary history, including our species’ peculiarities and the keys to our success.

By any measure, what made us strong was not uniformity, but diversity. Today, more than ever, humanity holds the key to its own destiny. We boast about our intelligence as a species, but what we do from now on will determine how much insight we really possess. In 10, 20, or 100 years, our past will speak for us, and it will be that past that issues the true verdict on our intelligence.

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