Category Archives: Biocultural Evolution

Issues and Ideas about Our Intertwined Biological and Cultural Inheritance, Environments, and Identities

Measuring the Beginning of the Upper Paleolithic

by Aaron Jonas Stutz

Research on big issues in human evolution–like how Neandertals contributed to our own genetic diversity and to ancient cultural diversity … before they went extinct–certainly involves a level technical nitty gritty that even specialists in the field get worn down by. But sooner or later, we get back up, ready to geek out on the details again. For those of you interested and with institutional access, please check out our newly published article on radiocarbon dating the earliest Upper Paleolithic in the Levant. This is the first major publication on our work on the Mughr el-Hamamah site–work that has been led my Liv Nilsson Stutz and myself … but which has depended on and succeeded thanks to extensive collaboration (Stutz et al., in press). The article may be viewed here, although–as noted above–full access to this Journal of Human Evolution content requires a subscription, so you may be limited to the abstract:

Liv Nilsson Stutz provides a narrated overview of the article here:

In addition, Emory University’s inimitable Carol Clark has published an great overview of the work here:

In this post, I emphasize the key findings from our collaborative research on the Mughr el-Hamamah site, Jordan, and its importance for understanding the beginning of the Upper Paleolithic. I also offer a brief peek at work to come. Continue reading Measuring the Beginning of the Upper Paleolithic

The Protoaurignacian Didn’t Trigger Anything

Or: It’s All About Evolution, Not Revolution …

by Aaron Jonas Stutz
el-Wad point from the Early Upper Paleolithic site of Mughr el-Hamamah, Jordan (Stutz et al., in press). Photograph by Aaron Jonas Stutz CC-BY 2015.
el-Wad point from the Early Upper Paleolithic site of Mughr el-Hamamah, Jordan (Stutz et al., in press). The stone tools from Mughr el-Hamamah date to between 45 and 39 thousand years ago, including some Protoaurignacian-like technologies employed side by side with Levallois point production and expedient flake and bladelet production technologies. Photograph by Aaron Jonas Stutz CC-BY 2015.

We’re now paying particular attention to research on the Protoaurignacian, including the notable recent report by Benazzi et al. (2015). We’ll get to their report below. Let’s start with the Protoaurignacian fuss in the first place. There’s pretty good scientific reason for it. Around 2006, Paul Mellars and João Zilhão–two prehistoric archaeologists who otherwise don’t agree about much–separately presented very similar suggestions, which have turned out to be very influential. In a series papers they separately argued that the Protoaurignacian archaeological artifact pattern–or technocomplex, which I will describe in a bit more detail below–has a clear relationship to anatomically modern human expansion into western Eurasia around 40,000 years ago.

Mellars (2006) suggested that the Protoaurignacian artifact pattern is actually a key component of a complex archaeological marker that traces anatomically modern human colonization of western Eurasia … and thus, also of Neandertal extinction.

Zilhão (2006) argued the same thing about anatomically modern humans, but he suggested that anatomically distinctive Neandertals–as opposed to some Neandertal features inherited by some Early Upper Paleolithic people with mainly anatomically modern ancestry–persisted in parts of Europe until ca. 30,000 years ago. On the one hand, there’s no clear threshold of how many unique derived Neandertal traits you need to be “distinctively Neandertal.” On the other, Zilhão and others pointed out that in Iberia, there are some quite distinctively Neandertal fossils, for which a series of radiocarbon dates had placed at roughly 30 kya. The problem now is that those C14 dates were made on incompletely chemically cleaned and filtered collagen-like material surviving in those bones (Wood et al., 2013, 2014). It turns out that all of the Iberian Neandertals so far re-analyzed with the collagen ultrafiltration pretreatment are actually closer to 50-45 kya in age, associated with Middle Paleolithic stone tools.

But what’s important for investigating the Protoaurignacian archaeological phenomenon is that Zilhão’s hypothesis overlaps significantly with Mellars’s. And if the joint Mellars-Zilhão version is right, then there are two very important observations we would expect to be able make … leading to more complete understanding of anatomically modern human / Neandertal biological turnover (a.k.a. Neandertal extinction). First, the oldest Protoaurignacian-like artifact assemblages should be found closer to the African geographic origin of anatomically modern human populations–that is to say, in the Near East. Second, hominin fossils associated with Protoaurignacian archaeological deposits should have anatomically modern–rather than Neandertal–features. Continue reading The Protoaurignacian Didn’t Trigger Anything

Learning about the Protoaurignacian

… and about the Biocultural Evolution of Paleolithic Technological Systems in General

by Aaron Jonas Stutz

Human adaptation and niche alike are defined in major part by technology. We use our bodies to shape and transform our material surroundings, fundamentally to extract food resources, but often to create things that we then utilize with our bodies to shape other things, including our own bodies. Technology really changes the way our bodies intertwine with and experience the environment.

Bonobo using a stick as a fishing tool to extract termites in the San Diego Zoo. Photograph by Wikipedia user TacoDeposit, licensed under a CC-BY-SA 3.0 license. It is reshared here under a CC-BY-SA 4.0 International License, acknowledging TacoDeposit’s authorship.

Our tool-using primate relatives–and tool use is quite common in the primate order–mainly employ technologies that are expedient (Bently-Condit & Smith, 2010). Perhaps with the exception of stone hammer-and-anvil nut cracking, observed mainly in some chimpanzee communities (Haslam et al., 2009), primate tool-users do not go out of their way to provision themselves with raw materials or finished, modified tools, as they go about planned foraging tasks over a period of hours. Rather, facing an immediate challenge in extracting food or water, primates take–and sometimes quickly, slightly transform–materials in their immediate vicinity, in order to solve that challenge. This happens in a matter of seconds or minutes. Continue reading Learning about the Protoaurignacian

Why None of Us Are Very Neandertal

… But Most of Us Are a Little

by Aaron Jonas Stutz
The Oase 1 mandible, with some conspicuous anatomically modern human features, like the well-defined mental trigone (i.e. the chin). Along with the Ust-‘Ishim femur (Fu et al., 2015), Oase 1 is the only western Eurasian hominin fossil with anatomically modern features whose surviving bone tissues have been directly dated with the important collagen-ultrafiltration C14 protocol, yielding a likely age older than 39 thousand years. Like the Ust-‘Ishim femur (ca. 45 ky old), the Oase 1 mandible was an isolated find, with no associated archaeological artifacts. Recent reports indicate that ancient bits of DNA from Oase 1 reveal it had a great-great or great-great-great grandparent who was a Neandertal (Callaway, 2015; Gibbons, 2015). Photograph of Oase 1 from Trinkaus et al. (2003).

Every single one of us on Earth today is, by definition, an anatomically modern human. We differ a lot from the Neandertal anatomical pattern that–despite variations among individuals–generally prevailed across western Eurasia some 50,000 years ago. It stands to reason that it would have taken some time for evolution to have shaped the anatomical features that we all now share. It’s reasonable to expect that, going back well into the last Ice Age–which ended 12,000 or so years ago–our ancestors would have also been anatomically modern human, not Neandertal.

The fossil record suggests that the founding anatomically modern human populations were distributed through Africa, extending into the Levant, just outside of Africa, all between 200-100 thousand years ago (see Wolpoff & Lee, 2012, for a scholarly discussion). But bits of intact DNA extracted from ancient Neandertal and anatomically modern human bones alike confirm–with remarkable specifics –what some paleoanthropologists have generally been arguing for decades (Thorne & Wolpoff, 1992). Our ancestry isn’t so simple. Continue reading Why None of Us Are Very Neandertal

Are We in Equilibrium with Our Niche? Are We in Equilibrium with the Wider Ecosystem?

by Aaron Jonas Stutz

At the end of a long semester, my wonderful students in the course Anthropology 200Q: Foundations of Behavior tackled a pretty broad but important set of questions:

1) Are human beings today in equilibrium with our niche?

2) Are human beings–and the niche we occupy–in equilibrium with the wider ecosystem?

Castle in the Air. M.C. Escher (1928).

We’ll have to wait for another question that these inevitably beg: what is the human niche, anyway, even if you can define it?

So, hang on a moment.

These questions about equilibrium were important for my beginning undergraduate students to tackle. This is in part because it is important to develop awareness of how–and therefore, why–we’re integrally part of a globally intertwined biosphere. The resilience of the entire biosphere now depends in no small part on the actions that humans take. But even more basically, with these two questions, there are no foregone conclusions. Sure, it’s clear that something’s out of wack with our relationship to the wider planetary system of which we’re part. Yet, it’s not clear exactly when, how, or why the human-environment relationship has gotten out of wack. Nor is it clear what we can do about it. Thus, what I can tell my students is this. There’s substantial evidence pointing toward a wrong answer that many climate-science-deniers cling to. We’re not in the middle of a natural climatic fluctuation, like the so-called Little Ice Age that lasted from the 14th to the 19th Centuries. But I can’t even begin to tell my students what the right answer is, because interdisciplinary scientific inquiry into sustainability and complex-system resilience is still very much maturing.

Thus, my students (I had 53 in my two sections of the Anthro 200Q course, which is the first core course in Emory’s popular Neuroscience and Behavioral Biology major) are partners in evaluating ideas and information, in order to develop hypotheses–that is, hypotheses that are consistent with available evidence but that can then guide new experiments, field data collection, and analyses. Continue reading Are We in Equilibrium with Our Niche? Are We in Equilibrium with the Wider Ecosystem?