13 Modern Homo sapiens

Keith Chan, Ph.D., Grossmont-Cuyamaca Community College District and MiraCosta College

Student contributors to this chapter: Lily Berruyer, Lyn Loytchenko, and Sarah Cupidio

This chapter is a revision from “Chapter 12: Modern Homo sapiens” by Keith Chan. In Explorations: An Open Invitation to Biological Anthropology, first edition, edited by Beth Shook, Katie Nelson, Kelsie Aguilera, and Lara Braff, which is licensed under CC BY-NC 4.0. 

The walls of a pink limestone cave in the hillside of Jebel Irhoud jutted out of the otherwise barren landscape of the Moroccan desert (Figure 13.1). Miners had excavated the cave in the 1960s, revealing some fossils. In 2007, a re-excavation of the site became a momentous occasion for science. A fossil cranium unearthed by a team of researchers was barely visible to the untrained eye. Just the fossil’s robust brows were peering out of the rock. This research team from the Max Planck Institute for Evolutionary Anthropology was the latest to explore the ancient human presence in this part of North Africa after a find by miners in 1960. Excavating near the first discovery, the researchers wanted to learn more about how Homo sapiens lived far from East Africa, where we thought our species originated.

The scientists were surprised when they analyzed the cranium, named Irhoud 10, and other fossils. Statistical comparisons with other human crania concluded that the Irhoud face shapes were typical of recent modern humans while the braincases matched ancient modern humans. Based on the findings of other scientists, the team expected these modern Homo sapiens fossils to be around 200,000 years old. Instead, dating revealed that the cranium had been buried for around 315,000 years.

Together, the modern-looking facial dimensions and the older date reshaped the interpretation of our species: modern Homo sapiens. Some key evolutionary changes from the archaic Homo sapiens (described in Chapter 11) to our species today happened 100,000 years earlier than we had thought and across the vast African continent rather than concentrated in its eastern region.

This revelation in the study of modern Homo sapiens is just one of the latest in this continually advancing area of biological anthropology. Researchers today are still discovering amazing fossils and ingenious ways to collect data and test hypotheses about our past. Through the collective work of many scientists, we are building an overall theory of modern human origins.

Defining Modernity

What defines modern Homo sapiens when compared to archaic Homo sapiens? Modern humans, like you and me, have a set of derived traits that are not seen in archaic humans or any other hominin. As with other transitions in hominin evolution, such as increasing brain size and bipedal ability, modern traits do not appear fully formed or all at once. In other words, the first modern Homo sapiens was not just born one day from archaic parents. The traits common to modern Homo sapiens appeared in a mosaic manner: gradually and out of sync with one another. There are two areas to consider when tracking the complex evolution of modern human traits. One is the physical change in the skeleton. The other is behavior inferred from the size and shape of the cranium and material culture evidence.

Skeletal Traits

The skeleton of modern Homo sapiens is less robust than that of archaic Homo sapiens. In other words, the modern skeleton is gracile, meaning that the structures are thinner and smoother. Differences related to gracility in the cranium are seen in the braincase, the face, and the mandible. There are also broad differences in the rest of the skeleton.

Cranial Traits

Several elements of the braincase differ between modern and archaic Homo sapiens. Overall, the shape is much rounder, or more globular, on a modern skull (Lieberman, McBratney, and Krovitz 2002; Neubauer, Hublin, and Gunz 2018; Pearson 2008; Figure 13.2). You can feel the globularity of your own modern human skull. Feel the height of your forehead with the palm of your hand. Viewed from the side, the tall vertical forehead of a modern Homo sapiens stands out when compared to the sloping archaic version. This is because the frontal lobe of the modern human brain is larger than the one in archaic humans, and the skull has to accommodate the expansion. The vertical forehead reduces a trait that is common to all other hominins: the brow ridge or supraorbital torus. The parietal lobes of the brain and the matching parietal bones on either side of the skull both bulge outward more in modern humans. At the back of the skull, the archaic occipital bun is no longer present. Instead, the occipital region of the modern human cranium has a derived tall and smooth curve, again reflecting the globular brain inside.

The trend of shrinking face size across hominins reaches its extreme with our species as well. The facial bones of a modern Homo sapiens are extremely gracile compared to all other hominins (Lieberman, McBratney, and Krovitz 2002). Continuing a trend in hominin evolution, technological innovations kept reducing the importance of teeth in reproductive success (Lucas 2007). As natural selection favored smaller and smaller teeth, the surrounding bone holding these teeth also shrank.

Related to smaller teeth, the mandible is also gracile in modern humans when compared to archaic humans and other hominins. Interestingly, our mandibles have pulled back so far from the prognathism of earlier hominins that we gained an extra structure at the most anterior point, called the mental eminence. You know this structure as the chin. At the skeletal level, it resembles an upside-down “T” at the centerline of the mandible (Pearson 2008). Looking back at archaic humans, you will see that they all lack a chin. Instead, their mandibles curve straight back without a forward point. What is the chin for and how did it develop? Flora Gröning and colleagues (2011) found evidence of the chin’s importance by simulating physical forces on computer models of different mandible shapes. Their results showed that the chin acts as structural support to withstand strain on the otherwise gracile mandible.

Postcranial Gracility

The rest of the modern human skeleton is also more gracile than its archaic counterpart. The differences are clear when comparing a modern Homo sapiens with a cold-adapted Neanderthal (Sawyer and Maley 2005), but the trends are still present when comparing modern and archaic humans within Africa (Pearson 2000). Overall, a modern Homo sapiens postcranial skeleton has thinner cortical bone, smoother features, and more slender shapes when compared to archaic Homo sapiens (Figure 13.3). Comparing whole skeletons, modern humans have longer limb proportions relative to the length and width of the torso, giving us lankier outlines.

Why is our skeleton so gracile compared to those of other hominins? Natural selection can drive the gracilization of skeletons in several ways (Lieberman 2015). A slender frame is believed to be adapted for the efficient long-distance running ability that started with Homo erectus. Furthermore, it is argued that slenderness is a genetic adaptation for cooling an active body in hotter climates, which aligns with the ample evidence that Africa was the home continent of our species.

Behavioral Modernity

Aside from physical differences in the skeleton, researchers have also uncovered evidence of behavioral changes associated with increased cultural complexity from archaic to modern humans. How did cultural complexity develop? Two investigations into this question are archaeology and the analysis of reconstructed brains.

Archaeology tells us much about the behavioral complexity of past humans by interpreting the significance of material culture. In terms of advanced culture, items created with an artistic flair, or as decoration, speak of abstract thought processes (Figure 13.4). The demonstration of difficult artistic techniques and technological complexity hints at social learning and cooperation as well. According to paleoanthropologist John Shea (2011), one way to track the complexity of past behavior through artifacts is by measuring the variety of tools found together. The more types of tools constructed with different techniques and for different purposes, the more modern the behavior. Researchers are still working on an archaeological way to measure cultural complexity that is useful across time and place.

The interpretation of brain anatomy is another promising approach to studying the evolution of human behavior. When looking at investigations on this topic in modern Homo sapiens brains, researchers found a weak association between brain size and test-measured intelligence (Pietschnig et al. 2015). Additionally, they found no association between intelligence and biological sex. These findings mean that there are more significant factors that affect tested intelligence than just brain size. Since the sheer size of the brain is not useful for weighing intelligence within a species, paleoanthropologists are instead investigating the differences in certain brain structures. The differences in organization between modern Homo sapiens brains and archaic Homo sapiens brains may reflect different cognitive priorities that account for modern human culture. As with the archaeological approach, new discoveries will refine what we know about the human brain and apply that knowledge to studying the distant past.

Taken together, the cognitive abilities in modern humans may have translated into an adept use of tools to enhance survival. Researchers Patrick Roberts and Brian A. Stewart (2018) call this concept the generalist-specialist niche: our species is an expert at living in a wide array of environments, with populations culturally specializing in their own particular surroundings. The next section tracks how far around the world these skeletal and behavioral traits have taken us.

First Africa, Then the World

What enabled modern Homo sapiens to expand its range further in 300,000 years than Homo erectus did in 1.5 million years? The key is the set of derived biological traits from the last section. It is theorized that the gracile frame and neurological anatomy allowed modern humans to survive and even flourish in the vastly different environments they encountered. Based on multiple types of evidence, the source of all of these modern humans was Africa. Instead of originating from just one location, evidence shows that modern Homo sapiens evolution occurred in a complex gene flow network across Africa, a concept called African multiregionalism (Scerri et al. 2018).

This section traces the origin of modern Homo sapiens and the massive expansion of our species across all of the continents (except Antarctica) by 12,000 years ago. While modern Homo sapiens first shared geography with archaic humans, modern humans eventually spread into lands where no human had gone before. Figure 13.5 shows the broad routes that our species took expanding around the world. I encourage you to make your own timeline with the dates in this part to see the overall trends.

Modern Homo sapiens Biology and Culture in Africa

We start with the ample fossil evidence supporting the theory that modern humans originated in Africa during the Middle Pleistocene, having evolved from African archaic Homo sapiens. The earliest dated fossils considered to be modern actually have a mosaic of archaic and modern traits, showing the complex changes from one type to the other. Experts have various names for these transitional fossils, such as Early Modern Homo sapiens  or Early Anatomically Modern Humans. However they are labeled, the presence of some modern traits means that they illustrate the origin of the modern type. Three particularly informative sites with fossils of the earliest modern Homo sapiens are Jebel Irhoud, Omo, and Herto.

Recall from the start of the chapter that the most recent finds at Jebel Irhoud are now the oldest dated fossils that exhibit some facial traits of modern Homo sapiens. Besides Irhoud 10, the cranium that was dated to 315,000 years ago (Hublin et al. 2017; Richter et al. 2017), there were other fossils found in the same deposit that we now know are from the same time period. In total there are at least five individuals, representing life stages from childhood to adulthood. These fossils form an image of high variation in skeletal traits. For example, the skull named Irhoud 1 has a primitive brow ridge, while Irhoud 2 and Irhoud 10 do not (Figure 13.6). The braincases are lower than what is seen in the modern humans of today but higher than in archaic Homo sapiens. The teeth also have a mix of archaic and modern traits that defy clear categorization into either group.

Research separated by nearly four decades uncovered fossils and artifacts from the Kibish Formation in the Lower Omo Valley in Ethiopia. These Omo Kibish hominins were represented by braincases and fragmented postcranial bones of three individuals found kilometers apart, dating back to around 233,000 years ago (Day 1969; McDougall, Brown, and Fleagle 2005; Vidal et al. 2022). One interesting finding was the variation in braincase size between the two more-complete specimens: while the individual named Omo I had a more globular dome, Omo II had an archaic-style long and low cranium.

Also in Ethiopia, a team led by Tim White (2003) excavated numerous fossils at Herto. There were fossilized crania of two adults and a child, along with fragments of more individuals. The dates ranged between 160,000 and 154,000 years ago. The skeletal traits and stone-tool assemblage were both intermediate between the archaic and modern types. Features reminiscent of modern humans included a tall braincase and thinner zygomatic (cheek) bones than those of archaic humans (Figure 13.7). Still, some archaic traits persisted in the Herto fossils, such as the supraorbital tori. Statistical analysis by other research teams concluded that at least some cranial measurements fit just within the modern human range (McCarthy and Lucas 2014), favoring categorization with our own species.

The timeline of material culture suggests a long period of relying on similar tools before a noticeable diversification of artifacts types. Researchers label the time of stable technology shared with archaic types the Middle Stone Age, while the subsequent time of diversification in material culture is called the Later Stone Age.

In the Middle Stone Age, the sites of Jebel Irhoud, Omo, and Herto all bore tools of the same flaked style as archaic assemblages, even though they were separated by almost 150,000 years. The consistency in technology may be evidence that behavioral modernity was not so developed. No clear signs of art dating back this far have been found either. Other hypotheses not related to behavioral modernity could explain these observations. The tool set may have been suitable for thriving in Africa without further innovation. Maybe works of art from that time were made with media that deteriorated or perhaps such art was removed by later humans.

Evidence of what Homo sapiens did in Africa from the end of the Middle Stone Age to the Later Stone Age is concentrated in South African cave sites that reveal the complexity of human behavior at the time. For example, Blombos Cave, located along the present shore of the Cape of Africa facing the Indian Ocean, is notable for having a wide variety of artifacts. The material culture shows that toolmaking and artistry were more complex than previously thought for the Middle Stone Age. In a layer dated to 100,000 years ago, researchers found two intact ochre-processing kits made of abalone shells and grinding stones (Henshilwood et al. 2011). Marine snail shell beads from 75,000 years ago were also excavated (Figure 13.8; d’Errico et al. 2005). Together, the evidence shows that the Middle Stone Age occupation at Blombos Cave incorporated resources from a variety of local environments into their culture, from caves (ochre), open land (animal bones and fat), and the sea (abalone and snail shells). This complexity shows a deep knowledge of the region’s resources and their use—not just for survival but also for symbolic purposes.

On the eastern coast of South Africa, Border Cave shows new African cultural developments at the start of the Later Stone Age. Paola Villa and colleagues (2012) identified several changes in technology around 43,000 years ago. Stone-tool production transitioned from a slower process to one that was faster and made many microliths, small and precise stone tools. Changes in decorations were also found across the Later Stone Age transition. Beads were made from a new resource: fragments of ostrich eggs shaped into circular forms resembling present-day breakfast cereal O’s (d’Errico et al. 2012). These beads show a higher level of altering one’s own surroundings and a move from the natural to the abstract in terms of design.

Expansion into the Middle East and Asia

While modern Homo sapiens lived across Africa, some members eventually left the continent. These pioneers could have used two connections to the Middle East or West Asia. From North Africa, they could have crossed the Sinai Peninsula and moved north to the Levant, or eastern Mediterranean. Finds in that region show an early modern human presence. Other finds support the Southern Dispersal model, with a crossing from East Africa to the southern Arabian Peninsula through the Straits of Bab-el-Mandeb. It is tempting to think of one momentous event in which people stepped off Africa and into the Middle East, never to look back. In reality, there were likely multiple waves of movement producing gene flow back and forth across these regions as the overall range pushed east. The expanding modern human population could have thrived by using resources along the southern coast of the Arabian Peninsula to South Asia, with side routes moving north along rivers. The maximum range of the species then grew across Asia.

Modern Homo sapiens in the Middle East

Geographically, the Middle East is the ideal place for the African modern Homo sapiens population to inhabit upon expanding out of their home continent. In the Eastern Mediterranean coast of the Levant, there is a wealth of skeletal and material culture linked to modern Homo sapiens. Recent discoveries from Saudi Arabia further add to our view of human life just beyond Africa.

The Caves of Mount Carmel in present-day Israel have preserved skeletal remains and artifacts of modern Homo sapiens, the first-known group living outside Africa. The skeletal presence at Misliya Cave is represented by just part of the left upper jaw of one individual, but it is notable for being dated to a very early time, between 194,000 and 177,000 years ago (Hershkovitz et al. 2018). Later, from 120,000 to 90,000 years ago, fossils of multiple individuals across life stages were found in the caves of Es-Skhul and Qafzeh (Shea and Bar-Yosef 2005). The skeletons had many modern Homo sapiens traits, such as globular crania and more gracile postcranial bones when compared to Neanderthals. Still, there were some archaic traits. For example, the adult male Skhul V also possessed what researchers Daniel Lieberman, Osbjorn Pearson, and Kenneth Mowbray (2000) called marked or clear occipital bunning. Also, compared to later modern humans, the Mount Carmel people were more robust. Skhul V had a particularly impressive brow ridge that was short in height but sharply jutted forward above the eyes (Figure 13.9). The high level of preservation is due to the intentional burial of some of these people. Besides skeletal material, there are signs of artistic or symbolic behavior. For example, the adult male Skhul V had a boar’s jaw on his chest. Similarly, Qafzeh 11, a juvenile with healed cranial trauma, had an impressive deer antler rack placed over his torso (Figure 13.10; Coqueugniot et al. 2014). Perforated seashells colored with ochre, mineral-based pigment, were also found in Qafzeh (Bar-Yosef Mayer, Vandermeersch, and Bar-Yosef 2009).

 

 

One remaining question is, what happened to the modern humans of the Levant after 90,000 years ago? Another site attributed to our species did not appear in the region until 47,000 years ago. Competition with Neanderthals may have accounted for the disappearance of modern human occupation since the Neanderthal presence in the Levant lasted longer than the dates of the early modern Homo sapiens. John Shea and Ofer Bar-Yosef (2005) hypothesized that the Mount Carmel modern humans were an initial expansion from Africa that failed. Perhaps they could not succeed due to competition with the Neanderthals who had been there longer and had both cultural and biological adaptations to that environment.

Modern Homo sapiens of China

A long history of paleoanthropology in China has found ample evidence of modern human presence. Four notable sites are the caves at Fuyan, Liujiang, Tianyuan, and Zhoukoudian. In the distant past, these caves would have been at least seasonal shelters that unintentionally preserved evidence of human presence for modern researchers to discover.

At Fuyan Cave in Southern China, paleoanthropologists found 47 adult teeth associated with cave formations dated to between 120,000 and 80,000 years ago (Liu et al. 2015). It is currently the oldest-known modern human site in China, though other researchers question the validity of the date range (Michel et al. 2016). The teeth have the small size and gracile features of modern Homo sapiens dentition.

The fossil Liujiang (or Liukiang) hominin (67,000 years ago) has derived traits that classified it as a modern Homo sapiens, though primitive archaic traits were also present. In the skull, which was found nearly complete, the Liujiang hominin had a taller forehead than archaic Homo sapiens but also had an enlarged occipital region (Figure 13.11; Brown 1999; Wu et al. 2008). Other parts of the skeleton also had a mix of modern and archaic traits: for example, the femur fragments suggested a slender length but with thick bone walls (Woo 1959).

 

Another Chinese site to describe here is the one that has been studied the longest. In the Zhoukoudian Cave system (Figure 13.12), where Homo erectus and archaic Homo sapiens have also been found, there were three crania of modern Homo sapiens. These crania, which date to between 34,000 and 10,000 years ago, were all more globular than those of archaic humans but still lower and longer than those of later modern humans (Brown 1999; Harvati 2009). When compared to one another, the crania showed significant differences from one another. Comparison of cranial measurements to other populations past and present found no connection with modern East Asians, again showing that human variation was very different from what we see today.

 

Crossing to Australia

Expansion of the first modern human Asians, still following the coast, eventually entered an area that researchers call Sunda before continuing on to modern Australia. Sunda was a landmass made up of the modern-day Malay Peninsula, Sumatra, Java, and Borneo. Lowered sea levels connected these places with land bridges, making them easier to traverse. Proceeding past Sunda meant navigating Wallacea, the archipelago that includes the Indonesian islands east of Borneo. In the distant past, there were many megafauna, large animals that migrating humans would have used for food and materials (such as utilizing animals’ hides and bones). Further southeast was another landmass called Sahul, which included New Guinea and Australia as one contiguous continent. Based on fossil evidence, this land had never seen hominins or any other primates before modern Homo sapiens arrived. Sites along this path offer clues about how our species handled the new environment to live successfully as foragers.

The skeletal remains at Lake Mungo, land traditionally owned by Mutthi Mutthi, Ngiampaa, and Paakantji peoples, are the oldest known in the continent. The now-dry lake was one of a series located along the southern coast of Australia in New South Wales, far from where the first people entered from the north (Barbetti and Allen 1972; Bowler et al. 1970). Two individuals dating to around 40,000 years ago show signs of artistic and symbolic behavior, including intentional burial. The bones of Lake Mungo 1 (LM1), an adult female, were crushed repeatedly, colored with red ochre, and cremated (Bowler et al. 1970). Lake Mungo 3 (LM3), a tall, older male with a gracile cranium but robust postcranial bones, had his fingers interlocked over his pelvic region (Brown 2000).

Kow Swamp, within traditional Yorta Yorta land also in southern Australia, contained human crania that looked distinctly different from the ones at Lake Mungo (Durband 2014; Thorne and Macumber 1972). The crania, dated between 9,000 and 20,000 years ago, had extremely robust brow ridges and thick bone walls, but these were paired with globular features on the braincase (Figure 13.13).

While no fossil humans have been found at the Madjedbebe rock shelter in the North Territory of Australia, more than 10,000 artifacts found there show both behavioral modernity and variability (Clarkson et al. 2017). They include a diverse array of stone tools and different shades of ochre for rock art, including mica-based reflective pigment (similar to glitter). These impressive artifacts are as far back as 56,000 years old, providing the date for the earliest-known presence of humans in Australia.

From the Levant to Europe

The first modern human expansion into Europe occurred after other members of our species settled in East Asia and Australia. As the evidence from the Levant suggests, modern human movement to Europe may have been hampered by the presence of Neanderthals. It is suggested that another obstacle was the colder climate, which was incompatible with the biology of modern Homo sapiens from Africa, as they were adapted to high temperatures and ultraviolet radiation. Still, by 40,000 years ago, modern Homo sapiens had a detectable presence. This time was also the start of the Later Stone Age or Upper Paleolithic, when there was an expansion in cultural complexity. There is a wealth of evidence from this region due to a Western bias in research, the proximity of these findings to Western scientific institutions, and the desire of Western scientists to explore their own past.

In Romania, the site of Peștera cu Oase (Cave of Bones) had the oldest-known remains of modern Homo sapiens in Europe, dated to around 40,000 years ago (Trinkaus et al. 2003a). Among the bones and teeth of many animals were the fragmented cranium of one person and the mandible of another (the two bones did not fit each other). Both bones have modern human traits similar to the fossils from the Middle East, but they also had Neanderthal traits. Oase 1, the mandible, had a mental eminence but also extremely large molars (Trinkaus et al. 2003b). This mandible has yielded DNA that surprisingly is equally similar to DNA from present-day Europeans and Asians (Fu et al. 2015). This means that Oase 1 was not the direct ancestor of modern Europeans. The Oase 2 cranium has the derived traits of reduced brow ridges along with archaic wide zygomatic cheekbones and an occipital bun (Figure 13.14; Rougier et al. 2007).

Dating to around 26,000 years ago, Předmostí near Přerov in the Czech Republic was a site where people buried over 30 individuals along with many artifacts. Eighteen individuals were found in one mass burial area, a few covered by the scapulae of woolly mammoths (Germonpré, Lázničková-Galetová, and Sablin 2012). The Předmostí crania were more globular than those of archaic humans but tended to be longer and lower than in later modern humans (Figure 13.15; Velemínská et al. 2008). The height of the face was in line with modern residents of Central Europe. There was also skeletal evidence of dog domestication, such as the presence of dog skulls with shorter snouts than in wild wolves (Germonpré, Lázničková-Galetová, and Sablin et al. 2012). In total, Předmostí could have been a settlement dependent on mammoths for subsistence and the artificial selection of early domesticated dogs.

The sequence of modern Homo sapiens technological change in the Later Stone Age has been thoroughly dated and labeled by researchers working in Europe. Among them, the Gravettian tradition of 33,000 years to 21,000 years ago is associated with most of the known curvy female figurines, often assumed to be “Venus” figures. Hunting technology also advanced in this time with the first known boomerang, atlatl (spear thrower), and archery. The Magdalenian tradition spread from 17,000 to 12,000 years ago. This culture further expanded on fine bone tool work, including barbed spearheads and fishhooks (Figure 13.16).

Among the many European sites dating to the Later Stone Age, the famous cave art sites deserve mention. Chauvet-Pont-d’Arc Cave in southern France dates to separate Aurignacian occupations 31,000 years ago and 26,000 years ago. Over a hundred art pieces representing 13 animal species are preserved, from commonly depicted deer and horses to rarer rhinos and owls. Another French cave with art is Lascaux, which is several thousand years younger at 17,000 years ago in the Magdalenian period. At this site, there are over 6,000 painted figures on the walls and ceiling (Figure 13.17). Scaffolding and lighting must have been used to make the paintings on the walls and ceiling deep in the cave. Overall, visiting Lascaux as a contemporary must have been an awesome experience: trekking deeper in the cave lit only by torches giving glimpses of animals all around as mysterious sounds echoed through the galleries.

 

Peopling of the Americas

By 25,000 years ago, our species was the only member of Homo left on Earth. Gone were the Neanderthals, Denisovans, Homo naledi, and Homo floresiensis. The range of modern Homo sapiens kept expanding eastward into—using the name given to this area by Europeans much later—the Western Hemisphere. This section will address what we know about the peopling of the Americas, from the first entry to these continents to the rapid spread of Indigenous Americans across its varied environments.

While evidence points to an ancient land bridge called Beringia that allowed people to cross from what is now northeastern Siberia into modern-day Alaska, what people did to cross this land bridge is still being investigated. For most of the 20th century, the accepted theory was the Ice-Free Corridor model. It stated that northeast Asians (East Asians and Siberians) first expanded across Beringia inland through a passage between glaciers that opened into the western Great Plains of the United States, just east of the Rocky Mountains, around 13,000 years ago (Swisher et al. 2013). While life up north in the cold environment would have been harsh, migrating birds and an emerging forest might have provided sustenance as generations expanded through this land (Potter et al. 2018).

However, in recent decades, researchers have accumulated evidence against the Ice-Free Corridor model. Archaeologist K. R. Fladmark (1979) brought the alternate Coastal Route model into the archaeological spotlight; researcher Jon M. Erlandson has been at the forefront of compiling support for this theory (Erlandson et al. 2015). The new focus is the southern edge of the land bridge instead of its center: About 16,000 years ago, members of our species expanded along the coastline from northeast Asia, east through Beringia, and south down the Pacific Coast of North America while the inland was still sealed off by ice. The coast would have been free of ice at least part of the year, and many resources would have been found there, such as fish (e.g., salmon), mammals (e.g., whales, seals, and otters), and plants (e.g., seaweed).

South through the Americas

When the first modern Homo sapiens reached the Western Hemisphere, the spread through the Americas was rapid. Multiple migration waves crossed from North to South America (Posth et al. 2018). Our species took advantage of the lack of hominin competition and the bountiful resources both along the coasts and inland. The Americas had their own wide array of megafauna, which included woolly mammoths (Figure 13.20), mastodons, camels, horses, ground sloths, giant tortoises, and—a favorite of researchers—a two-meter-tall beaver. The reason we cannot see these amazing animals today may be that resources gained from these fauna were crucial to the survival for people over 12,000 years ago (Araujo et al. 2017). Several sites are notable for what they add to our understanding of the distant past in the Americas, including interactions with megafauna and other elements of the environment.

A 2019 discovery may allow researchers to improve theories about the peopling of the Americas. In White Sands National Park, New Mexico, 60 human footprints have been astonishingly dated to around 22,000 years ago (Bennett et al. 2021). This date and location do not match either the Ice-Free Corridor or Coastal Route models. Researchers are now working to verify the find and adjust previous models to account for the new evidence. This groundbreaking find is sparking new theories; it is another example of the fast pace of research performed on our past.

Monte Verde is a landmark site that shows that the human population had expanded down the whole vertical stretch of the Americas to Chile by 14,600 years ago. The site has been excavated by archaeologist Tom D. Dillehay and his team (2015). The remains of nine distinct edible species of seaweed at the site shows familiarity with coastal resources and relates to the Coastal Route model by showing a connection between the inland people and the sea.

Named after the town in New Mexico, the Clovis stone-tool style is the first example of a widespread culture across much of North America, between 13,400 and 12,700 years ago (Miller, Holliday, and Bright 2013). Clovis points were fluted with two small projections, one on each end of the base, facing away from the head (Figure 13.21). The stone points found at this site match those found as far as the Canadian border and northern Mexico, and from the west coast to the east coast of the United States. Fourteen Clovis sites also contained the remains of mammoths or mastodons, suggesting that hunting megafauna with these points was an important part of life for the Clovis people. After the spread of the Clovis style, it diversified into several regional styles, keeping some of the Clovis form but also developing their own unique touches.

The Big Picture: The Assimilation Hypothesis

How do researchers make sense of all of these modern Homo sapiens discoveries that cover over 300,000 years of time and stretch across every continent except Antarctica? How was modern Homo sapiens related to archaic Homo sapiens?

The Assimilation hypothesis proposes that modern Homo sapiens evolved in Africa first and expanded out but also interbred with the archaic Homo sapiens they encountered outside Africa (Figure 13.22). This hypothesis is powerful since it explains why Africa has the oldest modern human fossils, why early modern humans found in Europe and Asia bear a resemblance to the regional archaics, and why traces of archaic DNA can be found in our genomes today (Dannemann and Racimo 2018; Reich et al. 2010; Reich et al. 2011; Slatkin and Racimo 2016; Smith et al. 2017; Wall and Yoshihara Caldeira Brandt 2016).

While researchers have produced a model that satisfies the data, there are still a lot of questions for paleoanthropologists to answer regarding our origins. What were the patterns of migration in each part of the world? Why did the archaic humans go extinct? In what ways did archaic and modern humans interact? The definitive explanation of how our species started and what our ancestors did is still out there to be found. You are now in a great place to welcome the next discovery about our distant past—maybe you’ll even contribute to our understanding as well.

The Chain Reaction of Agriculture

While it may be hard to imagine today, for most of our species’ existence we were nomadic: moving through the landscape without a singular home. Instead of a refrigerator or pantry stocked with food, we procured nutrition and other resources as needed based on what was available in the environment. This section gives an overview of how the foraging lifestyle enabled the expansion of our species and how the invention of a new way of life caused a chain reaction of cultural change.

The Foraging Tradition

There are a variety of possible subsistence strategies, or methods of finding sustenance and resources. To understand our species is to understand the subsistence strategy of foraging, or the search for resources in the environment. While most (but not all) humans today live in cultures that practice agriculture (whereby we greatly shape the environment to mass produce what we need), we have spent far more time as nomadic foragers than as settled agriculturalists. As such, it has been suggested that our traits have evolved to be primarily geared toward foraging. For instance, our efficient bipedalism allows persistence-hunting across long distances as well as movement from resource to resource.

How does human foraging, also known as hunting and gathering, work? Anthropologists have used all four fields to answer this question (see Ember n.d.). Typically, people formed bands, or kin-based groups of around 50 people or less (rarely over 100). A band’s organization would be egalitarian, with a flexible hierarchy based on an individual’s age, level of experience, and relationship with others. Everyone would have a general knowledge of the skills assigned to their gender roles, rather than specializing in different occupations. A band would be able to move from place to place in the environment, using knowledge of the area to forage (Figure 13.23). In varied environments—from savannas to tropical forests, deserts, coasts, and the Arctic circle—people found sustenance needed for survival.

 

Humans made extensive use of the foraging subsistence strategy, but this lifestyle did have limitations. The ease of foraging depended on the richness of the environment. Due to the lack of storage, resources had to be dependably found when needed. While a bountiful environment would require just a few hours of foraging a day and could lead to a focus on one location, the level and duration of labor increased greatly in poor or unreliable environments. Labor was also needed to process the acquired resources, which contributed to the foragers’ daily schedule (Crittenden and Schnorr 2017).

The adaptations to foraging found in modern Homo sapiens may explain why our species became so successful both within Africa and in the rapid expansion around the world. Overcoming the limitations, each generation at the edge of our species’s range would have found it beneficial to expand a little further, keeping contact with other bands but moving into unexplored territory where resources were more plentiful. The cumulative effect would have been the spread of modern Homo sapiens across continents and hemispheres.

Why Agriculture?

After hundreds of thousands of years of foraging, some groups of people around 12,000 years ago started to practice agriculture. This transition, called the Neolithic Revolution, occurred at the start of the Holocene epoch. While the reasons for this global change are still being investigated, two likely co-occurring causes are a growing human population and natural global climate change.

Overcrowding could have affected the success of foraging in the environment, leading to the development of a more productive subsistence strategy (Cohen 1977). Foraging works best with low population densities since each band needs a lot of space to support itself. If too many people occupy the same environment, they deplete the area faster. The high population could exceed the carrying capacity, or number of people a location can reliably support. Reaching carrying capacity on a global level due to growing population and limited areas of expansion would have been an increasingly pressing issue after the expansion through the major continents by 14,600 years ago.

A changing global climate immediately preceded the transition to agriculture, so researchers have also explored a connection between the two events. Since the Last Glacial Maximum of 23,000 years ago, the Earth slowly warmed. Then, from 13,000 to 11,700 years ago, the temperature in most of the Northern Hemisphere dropped suddenly in a phenomenon called the Younger Dryas. Glaciers returned in Europe, Asia, and North America. In Mesopotamia, which includes the Levant, the climate changed from warm and humid to cool and dry. The change would have occurred over decades, disrupting the usual nomadic patterns and subsistence of foragers around the world. The disruption to foragers due to the temperature shift could have been a factor in spurring a transition to agriculture. Researchers Gregory K. Dow and colleagues (2009) believe that foraging bands would have clustered in the new resource-rich places where people started to direct their labor to farming the limited area. After the Younger Dryas ended, people expanded out of the clusters with their agricultural knowledge (Figure 13.24).

The double threat of the limitation of human continental expansion and the sudden global climate change may have placed bands in peril as more populations outpaced their environment’s carrying capacity. Not only had a growing population led to increased competition with other bands, but environments worldwide had shifted to create more uncertainty. As such, it has been proposed that as people in different areas around the world faced this unpredictable situation, they became the independent inventors of agriculture.

Agriculture around the World

Due to global changes to the human experience starting from 12,000 years ago, it has been suggested that cultures with no knowledge of each other turned toward intensely farming their local resources (see Figure 13.24).  It is proposed that the first farmers engaged in artificial selection of their domesticates to enhance useful traits over generations. The switch to agriculture took time and effort with no guarantee of success and constant challenges (e.g. fires, droughts, diseases, and pests). The regions with the most widespread impact in the face of these obstacles became the primary centers of agriculture (Figure 13.25; Fuller 2010):

• Mesopotamia: The Fertile Crescent from the Tigris and Euphrates rivers through the Levant was where bands started to domesticate plants and animals around 12,000 years ago. The connection between the development of agriculture and the Younger Dryas was especially strong here. Farmed crops included wheat, barley, peas, and lentils. This was also where cattle, pigs, sheep, and goats were domesticated.
• South and East Asia: Multiple regions across this land had varieties of rice, millet, and soybeans by 10,000 years ago. Pigs were farmed with no connection to Mesopotamia. Chickens were also originally from this region, bred for fighting first and food second.
• New Guinea: Agriculture started here 10,000 years ago. Bananas, sugarcane, and taro were native to this island. Sweet potatoes were brought back from voyages to South America around the year C.E. 1000. No known animal farming occurred here.
• Mesoamerica: Agriculture from Central Mexico to northern South America also occurred from 10,000 years ago; it was also only plant based. Maize was a crop bred from teosinte grass, which has become one of the global staples. Beans, squash, and avocados were also grown in this region.
• The Andes: Starting around 8,000 years ago, local domesticated plants started with squash but later included potatoes, tomatoes, beans, and quinoa. Maize was brought down from Mesoamerica. The main farm animals were llamas, alpacas, and guinea pigs.
• Sub-Saharan Africa: This region went through a change 5,000 years ago called the Bantu expansion. The Bantu agriculturalists were established in West Central Africa and then expanded south and east. Native varieties of rice, yams, millet, and sorghum were grown across this area. Cattle were also domesticated here.
• Eastern North America: This region was the last major independent agriculture center, from 4,000 years ago. Squash and sunflower are the produce from this region that are most known today, though sumpweed and pitseed goosefoot were also farmed. Hunting was still the main source of animal products.

By 5,000 years ago, our species was well within the Neolithic Revolution. Agriculturalists spread to neighboring parts of the world with their domesticates, further expanding the use of this subsistence strategy. From this point, the human species changed from being primarily foragers to primarily agriculturalists with skilled control of their environments. The planet changed from mostly unaffected by human presence to being greatly transformed by humans. The revolution took millennia, but it was a true revolution as our species’ lifestyle was dramatically reshaped.

Cultural Effects of Agriculture

The worldwide adoption of agriculture altered the course of human culture and history forever. The core change in human culture due to agriculture is the move toward not moving: rather than live a nomadic lifestyle, farmers had to remain in one area to tend to their crops and livestock. The term for living bound to a certain location is sedentarism. This led to new aspects of life that were uncommon among foragers: the construction of permanent shelters and agricultural infrastructure, such as fields and irrigation, plus the development of storage technology, such as pottery, to preserve extra resources in case of future instability.

The high productivity of successful agriculture sparked further changes (Smith 2009). It is argued that since successful agriculture produced a much greater amount of food and other resources per unit of land compared to foraging, the population growth rate skyrocketed. The surplus of a bountiful harvest also provided insurance for harder times, reducing the risk of famine. Changes happened to society as well. With a few farming households producing enough food to feed many others, other people could focus on other tasks. So began specialization into different occupations such as craftspeople, traders, religious figures, and artists, spurring innovation in these areas as people could now devote time and effort toward specific skills. These interdependent people would settle an area together for convenience. The growth of these settlements led to urbanization, the founding of cities that became the foci of human interaction (Figure 13.26).

The formation of cities led to new issues that sparked the growth of further specializations, called institutions. These are cultural constructs that exist beyond the individual and have wide control over a population. Leadership of these cities became hierarchical with different levels of rank and control. The stratification of society increased social inequality between those with more or less power over others. Under leadership, people built impressive monumental architecture, such as pyramids and palaces, that embodied the wealth and power of these early cities. Alliances could unite cities, forming the earliest states. In several regions of the world, state organization expanded into empires, wide-ranging political entities that covered a variety of cultures.

Urbanization brought new challenges as well. The concentration of sedentary peoples was ideal for infectious diseases to thrive since they could jump from person to person and even from livestock to person (Armelagos, Brown, and Turner 2005). While successful agriculture provided a large surplus of food to thwart famine, the food produced offered less diverse food sources than foragers’ diets (Cohen and Armelagos 1984; Cohen and Crane-Kramer 2007). This shift in nutrition caused other diseases to flourish among those who adopted farming, such as dental cavities and malocclusion (the misalignment of teeth caused by soft, agricultural diets). The need to extract “wisdom teeth” or third molars seen in agricultural cultures today stems from this misalignment between the environment our ancestors adapted to and our lifestyles today.

As the new disease trends show, the adoption of agriculture and the ensuing cultural changes were not entirely positive. It is also important to note that this is not an absolutely linear progression of human culture from simple to complex. In many cases, empires have collapsed and, in some cases, cities dispersed to low-density bands that rejected institutions. However, a global trend has emerged since the adoption of agriculture, wherein population and social inequality have increased, leading to the massive and influential nation-states of today.

The rise of states in Europe has a direct impact on many of this book’s topics. Science started as a European cultural practice by the upper class that became a standardized way to study the world. Education became an institution to provide a standardized path toward producing and gaining knowledge. The scientific study of human diversity, embroiled in the race concept that still haunts us today, was connected to the European slave trade and colonialism.

Also starting in Europe, the Industrial Revolution of the 19th century turned cities into centers of mass manufacturing and spurred the rapid development of inventions (Figure 13.27). In the technologically interconnected world of today, human society has reached a new level of complexity with globalization. In this system, goods are mass-produced and consumed in different parts of the world, weakening the reliance on local farms and factories. The imbalanced relationship between consumers and producers of goods further increases economic inequality.

 

As states based on agriculture and industry keep exerting influence on humanity today, there are people, like the Hadzabe of Tanzania, who continue to live a lifestyle centered on foraging. Due to the overwhelming force that agricultural societies exert, foragers today have been marginalized to live in the least habitable parts of the world—the areas that are not conducive to farming, such as tropical rainforests, deserts, and the Arctic (Headland et al. 1989). Foragers can no longer live in the abundant environments that humans would have enjoyed before the Neolithic Revolution. Interactions with agriculturalists are typically imbalanced, with trade and other exchanges heavily favoring the larger group. One of anthropology’s important roles today is to intelligently and humanely manage equitable interactions between people of different backgrounds and levels of influence.

The Future of Humanity

A common question stemming from understanding human evolution is: What will the genetic and biological traits of our species be hundreds of thousands of years in the future? When faced with this question, people tend to think of directional selection. Maybe our braincases will be even larger, resembling the large-headed and small-bodied aliens of science fiction (Figure 13.28). Or, our hands could be specialized for interacting with our touch-based technology with less risk of repetitive injury. These ideas do not stand up to scrutiny. Since natural selection is based on adaptations that increase reproductive success, any directional change must be due to a higher rate of producing successful offspring compared to other alleles. Larger brains and more agile fingers would be convenient to possess, but they do not translate into an increase in the underlying allele frequencies.

Scientists are hesitant to professionally speculate on the unknowable, and we will never know what is in store for our species one thousand or one million years from now, but there are two trends in human evolution that may carry on into the future: increased genetic variation and a reduction in regional differences.

Rather than a directional change, genetic variation in our species could expand. Our technology can protect us from extreme environments and pathogens, even if our biological traits are not tuned to handle these stressors. The rapid pace of technological advancement means that biological adaptations will become less and less relevant to reproductive success, so nonbeneficial genetic traits will be more likely to remain in the gene pool. Biological anthropologist Jay T. Stock (2008) views environmental stress as needing to defeat two layers of protection before affecting our genetics. The first layer is our cultural adaptations. Our technology and knowledge can reduce pressure on one’s genotype to be “just right” to pass to the next generation. The second defense is our flexible physiology, such as our acclimatory responses. Only stressors not handled by these powerful responses would then cause natural selection on our alleles. These shields are already substantial, and cultural adaptations will only keep increasing in strength.

The increasing ability to travel far from one’s home region means that there will be a mixing of genetic variation on a global level in the future of our species. In recent centuries, gene flow of people around the world has increased, creating admixture in populations that had been separated for tens of thousands of years. For skin color, this means that populations all around the world could exhibit the whole range of skin colors, rather than the current pattern of decreasing melanin pigment farther from the equator. The same trend of intermixing would apply to all other traits, such as blood types. While our genetics will become more varied, the variation will be more intermixed instead of regionally isolated.

Our distant descendants will not likely be dextrous ultraintellectuals; more likely, they will be a highly variable and mobile species supported by novel cultural adaptations that make up for any inherited biological limitations. Technology may even enable the editing of DNA directly, changing these trends. With the uncertainty of our future, these are just the best-educated guesses for now. Our future is open and will be shaped little by little by the environment, our actions, and the actions of our descendants.

Summary

Modern Homo sapiens is the species that took the hominin lifestyle the furthest to become the only living member of that lineage. The largest factor that allowed us to persist while other hominins went extinct was likely our advanced ability to culturally adapt to a wide variety of environments. Our species, with its skeletal and behavioral traits, was well-suited to be generalist-specialists who successfully foraged across most of the world’s environments. The biological basis of this adaptation was our reorganized brain that facilitated innovation in cultural adaptations and intelligence for leveraging our social ties and finding ways to acquire resources from the environment. As the brain’s ability increased, it shaped the skull by reducing the evolutionary pressure to have large teeth and robust cranial bones to produce the modern Homo sapiens face.

Our ability to be generalist-specialists is seen in the geographical range that modern Homo sapiens covered in 300,000 years. In Africa, our species formed from multiregional gene flow that loosely connected archaic humans across the continent. People then expanded out to the rest of the continental Eurasia and even further to the Americas.

For most of our species’s existence, foraging was the general subsistence strategy within which people specialized to culturally adapt to their local environment. With omnivorousness and mobility, people found ways to extract and process resources, shaping the environment in return. When resource uncertainty hit the species, people around the world focused on agriculture to have a firmer control of sustenance. The new strategy shifted human history toward exponential growth and innovation, leading to our high dependence on cultural adaptations today.

While a cohesive image of our species has formed in recent years, there is still much to learn about our past. The work of many driven researchers shows that there are amazing new discoveries made all the time that refine our knowledge of human evolution. Technological innovations such as DNA analysis enable scientists to approach lingering questions from new angles. The answers we get allow us to ask even more insightful questions that will lead us to the next revelation. Like the pink limestone strata at Jebel Irhoud, previous effort has taken us so far and you are now ready to see what the next layer of discovery holds.

Hominin Species Summary

African multiregionalism: The idea that modern Homo sapiens evolved as a complex web of small regional populations with sporadic gene flow among them.

Agriculture: The mass production of resources through farming and domestication.

Aquaculture: The farming of fish using techniques such as trapping, channels, and artificial ponds.

Assimilation hypothesis: Current theory of modern human origins stating that the species evolved first in Africa and interbred with archaic humans of Europe and Asia.

Atlatl: A handheld spear thrower that increased the force of thrown projectiles.

Band: A small group of people living together as foragers.

Beringia: Ancient landmass that connected Siberia and Alaska. The ancestors of Indigenous Americans would have crossed this area to reach the Americas.

Carrying capacity: The amount of organisms that an environment can reliably support.

Coastal Route model: Theory that the first Paleoindians crossed to the Americas by following the southern coast of Beringia.

Early Modern Homo sapiens, Early Anatomically Modern Human: Terms used to refer to transitional fossils between archaic and modern Homo sapiens that have a mosaic of traits. Humans like ourselves, who mostly lack archaic traits, are referred to as Late Modern Homo sapiens and simply Anatomically Modern Humans.

Egalitarian: Human organization without strict ranks. Foraging societies tend to be more egalitarian than those based on other subsistence strategies.

Foraging: Lifestyle consisting of frequent movement through the landscape and acquiring resources with minimal storage capacity.

Generalist-specialist niche: The ability to survive in a variety of environments by developing local expertise. Evolution toward this niche may have been what allowed modern Homo sapiens to expand past the geographical range of other human species.

Globalization: A recent increase in the interconnectedness and interdependence of people that is facilitated with long-distance networks.

Globular: Having a rounded appearance. Increased globularity of the braincase is a trait of modern Homo sapiens.

Gracile: Having a smooth and slender quality; the opposite of robust.

Holocene: The epoch of the Cenozoic Era starting around 12,000 years ago and lasting arguably through the present.

Ice-Free Corridor model: Theory that the first Native Americans crossed to the Americas through a passage between glaciers.

Institutions: Long-lasting and influential cultural constructs. Examples include government, organized religion, academia, and the economy.

Last Glacial Maximum: The time 23,000 years ago when the most recent ice age was the most intense.

Later Stone Age: Time period following the Middle Stone Age with a diversification in tool types, starting around 50,000 years ago.

Levant: The eastern coast of the Mediterranean. The site of early modern human expansion from Africa and later one of the centers of agriculture.

Megafauna: Large ancient animals that may have been hunted to extinction by people around the world.

Mental eminence: The chin on the mandible of modern H. sapiens. One of the defining traits of our species.

Microlith: Small stone tool found in the Later Stone Age; also called a bladelet.

Middle Stone Age: Time period known for Mousterian lithics that connects African archaic to modern Homo sapiens.

Monumental architecture: Large and labor-intensive constructions that signify the power of the elite in a sedentary society. A common type is the pyramid, a raised crafted structure topped with a point or platform.

Mosaic: Composed from a mix or composite of traits.

Neolithic Revolution: Time of rapid change to human cultures due to the invention of agriculture, starting around 12,000 years ago.

Ochre: Iron-based mineral pigment that can be a variety of yellows, reds, and browns. Used by modern human cultures worldwide since at least 80,000 years ago.

Sahul: Ancient landmass connecting New Guinea and Australia.

Sedentarism: Lifestyle based on having a stable home area; the opposite of nomadism.

Southern Dispersal model: Theory that modern H. sapiens expanded from East Africa by crossing the Red Sea and following the coast east across Asia.

Subsistence strategy: The method an organism uses to find nourishment and other resources.

Sunda: Ancient Asian landmass that incorporated modern Southeast Asia.

Supraorbital torus: The bony brow ridge across the top of the eye orbits on many hominin crania.

Upper Paleolithic: Time period considered synonymous with the Later Stone Age.

Urbanization: The increase of population density as people settled together in cities.

Wallacea: Archipelago southeast of Sunda with different biodiversity than Asia.

Younger Dryas: The rapid change in global climate—notably a cooling of the Northern Hemisphere—13,000 years ago.

For Further Exploration

Websites

First-person virtual tour of Lascaux cave with annotated cave art: Ministère de la Culture and Musée d’Archéologie Nationale. “Visit the cave” Lascaux website.

Online anthropology magazine articles related to paleoanthropology and human evolution: SAPIENS. “Evolution.” SAPIENS website.

Various presentations of information about hominin evolution: Smithsonian Institution. “What does it mean to be human?” Smithsonian National Museum of Natural History website.

Magazine-style articles on archaeology and paleoanthropology: ThoughtCo. “Archaeology.” ThoughtCo. Website.

Database of comparisons across hominins and primates: University of California, San Diego. “MOCA Domains.” Center for Academic Research & Training in Anthropogeny website.

Books

Engaging book that covers human-made changes to the environment with industrialization and globalization: Kolbert, Elizabeth. 2014. The Sixth Extinction: An Unnatural History. New York: Bloomsbury.

Overview of what human life was like among the environmental shifts of the Ice Age: Woodward, Jamie. 2014. The Ice Age: A Very Short Introduction. Oxford: OUP Press.

Articles

Recent review paper about the current state of paleoanthropology research: Stringer, C. 2016. “The Origin and Evolution of Homo sapiens.” Philosophical Transactions of the Royal Society B 371 (1698).

Overview of the history of American paleoanthropology and the many debates that have occurred over the years: Trinkaus, E. 2018. “One Hundred Years of Paleoanthropology: An American Perspective.” American Journal of Physical Anthropology 165 (4): 638–651.

Amazing magazine article that synthesizes hominin evolution and why it is important to study this subject: Wheelwright, Jeff. 2015. “Days of Dysevolution.” Discover 36 (4): 33–39.

Fascinating research on Ötzi, a mummy from 5,000 years ago: Wierer, Ursula, Simona Arrighi, Stefano Bertola, Günther Kaufmann, Benno Baumgarten, Annaluisa Pedrotti, Patrizia Pernter, and Jacques Pelegrin. 2018. “The Iceman’s Lithic Toolkit: Raw Material, Technology, Typology and Use.” PLOS One 13 (6): e0198292. https://doi.org/10.1371/journal.pone.0198292.

Documentaries

PBS NOVA series covering the expansion of modern Homo sapiens and interbreeding with archaic humans: Brown, Nicholas, dir. 2015. First Peoples. Edmonton: Wall to Wall Television. Amazon Prime Video.

PBS NOVA special featuring the footprints found in White Sands National Park: Falk, Bella, dir. 2016. Ice Age Footprints. Boston: Windfall Films. https://www.pbs.org/wgbh/nova/video/ice-age-footprints/.

PBS NOVA special about how modern humans evolved adaptations to different environments. Shows how present-day people live around the world: Thompson, Niobe, dir. 2016. Great Human Odyssey. Edmonton: Clearwater Documentary. https://www.pbs.org/wgbh/nova/evolution/great-human-odyssey.html.

Araujo, Bernardo B. A., Luiz Gustavo R. Oliveira-Santos, Matheus S. Lima-Ribeiro, José Alexandre F. Diniz-Filho, and Fernando A. S. Fernandez. 2017. “Bigger Kill Than Chill: The Uneven Roles of Humans and Climate on Late Quaternary Megafaunal Extinctions.” Quaternary International 431: 216–222.

Armelagos, George J., Peter J. Brown, and Bethany Turner. 2005. “Evolutionary, Historical, and Political Economic Perspectives on Health and Disease.” Social Science & Medicine 61 (4): 755–765.

Armstrong, C. G., J. E. D. Miller, A. C. McAlvay, P. M. Ritchie, and D. Lepofsky. 2021. “Historical Indigenous Land-Use Explains Plant Functional Trait Diversity. Ecology and Society 26 (2): 6.

Bar-Yosef Mayer, Daniella E., Bernard Vandermeersch, and Ofer Bar-Yosef. 2009. “Shells and Ochre in Middle Paleolithic Qafzeh Cave, Israel: Indications for Modern Behavior.” Journal of Human Evolution 56 (3): 307–314.

Barbetti, M., and H. Allen. 1972. “Prehistoric Man at Lake Mungo, Australia, by 32,000 Years Bp.” Nature 240 (5375): 46–48.

Bennett, M. R., D. Bustos, J. S. Pigati, K. B. Springer, T. M. Urban, V. T. Holliday, Sally C. Reynolds, et al. (2021). “Evidence of Humans in North America during the Last Glacial Maximum.” Science 373 (6562): 1528–1531.

Bowler, J. M., Rhys Jones, Harry Allen, and A. G. Thorne. 1970. “Pleistocene Human Remains from Australia: A Living Site and Human Cremation from Lake Mungo, Western New South Wales.” World Archaeology 2 (1): 39–60.

Brown, Peter. 1999. “The First Modern East Asians? Another Look at Upper Cave 101, Liujiang and Minatogawa 1.” In Interdisciplinary Perspectives on the Origins of the Japanese, edited by K. Omoto, 105–131. Kyoto: International Research Center for Japanese Studies.

Brown, Peter. 2000. “Australian Pleistocene Variation and the Sex of Lake Mungo 3.” Journal of Human Evolution 38 (5): 743–749.

Clarkson, Chris, Zenobia Jacobs, Ben Marwick, Richard Fullagar, Lynley Wallis, Mike Smith, Richard G. Roberts, et al. 2017. “Human Occupation of Northern Australia by 65,000 Years Ago.” Nature 547 (7663): 306–310.

Cohen, Mark Nathan. 1977. The Food Crisis in Prehistory: Overpopulation and the Origins of Agriculture. New Haven, CT: Yale University Press.

Cohen, Mark Nathan, and George J. Armelagos, eds. 1984. Paleopathology at the Origins of Agriculture. Orlando, FL: Academic Press.

Cohen, Mark Nathan, and Gillian M. M. Crane-Kramer, eds. 2007. Ancient Health: Skeletal Indicators of Agricultural and Economic Intensification. Gainesville, FL: University Press of Florida.

Copes-Gerbitz, K., S. Hagerman, and L. Daniels. 2021. “Situating Indigenous Knowledge for Resilience in Fire-Dependent Social-Ecological Systems.” Ecology and Society 26(4): 25. https://www.ecologyandsociety.org/vol26/iss4/art25/.

Coqueugniot, Hélène, Olivier Dutour, Baruch Arensburg, Henri Duday, Bernard Vandermeersch, and Anne-Marie Tillier. 2014. “Earliest Cranio-Encephalic Trauma from the Levantine Middle Palaeolithic: 3-D Reappraisal of the Qafzeh 11 Skull, Consequences of Pediatric Brain Damage on Individual Life Condition and Social Care.” PLOS ONE 9 (7): e102822.

Crittenden, Alyssa N., and Stephanie L. Schnorr. 2017. “Current Views on Hunter‐Gatherer Nutrition and the Evolution of the Human Diet.” American Journal of Physical Anthropology 162 (S63): 84–109.

d’Errico, Francesco, Lucinda Backwell, Paola Villa, Ilaria Degano, Jeannette J. Lucejko, Marion K. Bamford, Thomas F. G. Higham, Maria Perla Colombini, and Peter B. Beaumont. 2012. “Early Evidence of San Material Culture Represented by Organic Artifacts from Border Cave, South Africa.” Proceedings of the National Academy of Sciences 109 (33): 13214–13219.

d’Errico, Francesco, Christopher Henshilwood, Marian Vanhaeren, and Karen Van Niekerk. 2005. “Nassarius Kraussianus Shell Beads from Blombos Cave: Evidence for Symbolic Behaviour in the Middle Stone Age.” Journal of Human Evolution 48 (1): 3–24.

Dannemann, Michael, and Fernando Racimo. 2018. “Something Old, Something Borrowed: Admixture and Adaptation in Human Evolution.” Current Opinion in Genetics & Development 53: 1–8.

Day, M. H. 1969. “Omo Human Skeletal Remains.” Nature 222: 1135–1138.

Dillehay, Tom D., Carlos Ocampo, José Saavedra, Andre Oliveira Sawakuchi, Rodrigo M. Vega, Mario Pino, Michael B. Collins, et al. 2015. “New Archaeological Evidence for an Early Human Presence at Monte Verde, Chile.” PLOS ONE 10 (11): e0141923. doi:10.1371/journal.pone.0141923.

Dow, Gregory K., Clyde G. Reed, and Nancy Olewiler. 2009. “Climate Reversals and the Transition to Agriculture.” Journal of Economic Growth 14 (1): 27–53.

Durband, Arthur C. 2014. “Brief Communication: Artificial Cranial Modification in Kow Swamp and Cohuna.” American Journal of Physical Anthropology 155 (1): 173–178.

Ember, Carol R. N.d. “Hunter-Gatherers.” Explaining Human Culture. Human Relations Area Files. Accessed March 4, 2023. https://hraf.yale.edu/ehc/summaries/hunter-gatherers.

Erlandson, Jon M., Todd J. Braje, Kristina M. Gill, and Michael H. Graham. 2015. “Ecology of the Kelp Highway: Did Marine Resources Facilitate Human Dispersal from Northeast Asia to the Americas?” The Journal of Island and Coastal Archaeology 10 (3): 392–411.

Fladmark, K. R. 1979. “Routes: Alternate Migration Corridors for Early Man in North America.” American Antiquity 44 (1): 55–69.

Fletcher, M. S., T. Hall, and A. N. Alexandra. 2021. “The Loss of an Indigenous Constructed Landscape Following British Invasion of Australia: An Insight into the Deep Human Imprint on the Australian Landscape.” Ambio 50(1): 138–149.

Fu, Qiaomei, Mateja Hajdinjak, Oana Teodora Moldovan, Silviu Constantin, Swapan Mallick, Pontus Skoglund, Nick Patterson, et al. 2015. “An Early Modern Human from Romania with a Recent Neanderthal Ancestor.” Nature 524 (7564): 216–219.

Fuller, Dorian Q. 2010. “An Emerging Paradigm Shift in the Origins of Agriculture.” General Anthropology 17 (2): 1, 8–11.

Gammage, B. 2008. “Plain Facts: Tasmania under Aboriginal Management.” Landscape Research 33 (2): 241–254.

Germonpré, Mietje, Martina Lázničková-Galetová, and Mikhail V. Sablin. 2012. “Palaeolithic Dog Skulls at the Gravettian Předmostí Site, the Czech Republic.” Journal of Archaeological Science 39 (1): 184–202.

Gröning, Flora, Jia Liu, Michael J. Fagan, and Paul O’Higgins. 2011. “Why Do Humans Have Chins? Testing the Mechanical Significance of Modern Human Symphyseal Morphology with Finite Element Analysis.” American Journal of Physical Anthropology 144 (4): 593–606.

Harvati, Katerina. 2009. “Into Eurasia: A Geometric Morphometric Reassessment of the Upper Cave (Zhoukoudian) Specimens.” Journal of Human Evolution 57 (6): 751–762.

Headland, Thomas N., Lawrence A. Reid, M. G. Bicchieri, Charles A. Bishop, Robert Blust, Nicholas E. Flanders, Peter M. Gardner, Karl L. Hutterer, Arkadiusz Marciniak, and Robert F. Schroeder. 1989. “Hunter-Gatherers and Their Neighbors from Prehistory to the Present.” Current Anthropology 30 (1): 43–66.

Henshilwood, Christopher S., Francesco d’Errico, Karen L. van Niekerk, Yvan Coquinot, Zenobia Jacobs, Stein-Erik Lauritzen, Michel Menu, and Renata García-Moreno. 2011. “A 100,000-Year-Old Ochre-Processing Workshop at Blombos Cave, South Africa.” Science 334 (6053): 219–222.

Hershkovitz, Israel, Gerhard W. Weber, Rolf Quam, Mathieu Duval, Rainer Grün, Leslie Kinsley, Avner Ayalon, et al. 2018. “The Earliest Modern Humans Outside Africa.” Science 359 (6374): 456–459.

Hublin, Jean-Jacques, Abdelouahed Ben-Ncer, Shara E. Bailey, Sarah E. Freidline, Simon Neubauer, Matthew M. Skinner, Inga Bergmann, et al. 2017. “New Fossils from Jebel Irhoud, Morocco, and the Pan-African Origin of Homo sapiens.” Nature 546 (7657): 289–292.

Lepofsky, D., N. F. Smith, N. Cardinal, J. Harper, M. Morris, M., Gitla (Elroy White), Randy Bouchard, et al. 2015. “Ancient Shellfish Mariculture on the Northwest Coast of North America.” American Antiquity 80 (2): 236–259.

Lieberman, Daniel E. 2015. “Human Locomotion and Heat Loss: An Evolutionary Perspective.” Comprehensive Physiology 5 (1): 99–117.

Lieberman, Daniel E., Brandeis M. McBratney, and Gail Krovitz. 2002. “The Evolution and Development of Cranial Form in Homo sapiens.” Proceedings of the National Academy of Sciences 99 (3): 1134–1139.

Lieberman, Daniel E., Osbjorn M. Pearson, and Kenneth M. Mowbray. 2000. “Basicranial Influence on Overall Cranial Shape.” Journal of Human Evolution 38 (2): 291–315.

Liu, Wu, María Martinón-Torres, Yan-jun Cai, Song Xing, Hao-wen Tong, Shu-wen Pei, Mark Jan Sier, Xiao-hong Wu, R. Lawrence Edwards, and Hai Cheng. 2015. “The Earliest Unequivocally Modern Humans in Southern China.” Nature 526 (7575): 696-699.

Lucas, Peter W. 2007. “The Evolution of the Hominin Diet from a Dental Functional Perspective.” In Evolution of the Human Diet: The Known, the Unknown, and the Unknowable, edited by Peter S. Ungar, 31–38 Oxford, UK: Oxford University Press.

Marsh, W. A. & Bello, S. (2023). Cannibalism and burial in the late Upper Palaeolithic: Combining archaeological and genetic evidence. Quaternary Science Reviews, 319, 108309. https://doi.org/10.1016/j.quascirev.2023.108309

McCarthy, Robert C., and Lynn Lucas. 2014. “A Morphometric Reassessment of Bou-Vp-16/1 from Herto, Ethiopia.” Journal of Human Evolution 74: 114–117.

McDougall, Ian, Francis H. Brown, and John G. Fleagle. 2005. “Stratigraphic Placement and Age of Modern Humans from Kibish, Ethiopia.” Nature 433 (7027): 733–736.

McNiven, I. J., J. Crouch, T. Richards, N. Dolby, and G. Jacobsen. 2012. “Dating Aboriginal Stone-Walled Fishtraps at Lake Condah, Southeast Australia.” Journal of Archaeological Science 39 (2): 268–286.

McNiven, I., J. Crouch, T. Richards, K. Sniderman, N. Dolby, and G. Mirring. 2015. “Phased Redevelopment of an Ancient Gunditjmara Fish Trap over the Past 800 Years: Muldoons Trap Complex, Lake Condah, Southwestern Victoria.” Australian Archaeology 81 (1): 44–58.

Michel, Véronique, Hélène Valladas, Guanjun Shen, Wei Wang, Jian-xin Zhao, Chuan-Chou Shen, Patricia Valensi, and Christopher J. Bae. 2016. “The Earliest Modern Homo sapiens in China?” Journal of Human Evolution 101: 101–104.

Miller, D. Shane, Vance T. Holliday, and Jordon Bright. 2013. “Clovis across the Continent.” In Paleoamerican Odyssey, edited by Kelly E. Graf, Caroline V. Ketron, and Michael R. Waters, 207–220. College Station: Texas A&M University Press.

Neubauer, Simon, Jean-Jacques Hublin, and Philipp Gunz. 2018. “The Evolution of Modern Human Brain Shape.” Science Advances 4 (1): eaao5961. https://doi.org/10.1126/sciadv.aao5961.

Pearson, Osbjorn M. 2000. “Postcranial Remains and the Origin of Modern Humans.” Evolutionary Anthropology 9: 229–247.

Pearson, Osbjorn M. 2008. “Statistical and Biological Definitions of ‘Anatomically Modern’ Humans: Suggestions for a Unified Approach to Modern Morphology.” Evolutionary Anthropology: Issues, News, and Reviews 17 (1): 38–48.

Pobiner, B., Pante, M. & Keevil, T. (2023). Early Pleistocene cut marked hominin fossil from Koobi Fora, Kenya. Sci Rep, 13, 9896. https://doi.org/10.1038/s41598-023-35702-7

Pietschnig, Jakob, Lars Penke, Jelte M. Wicherts, Michael Zeiler, and Martin Voracek. 2015. “Meta-Analysis of Associations between Human Brain Volume and Intelligence Differences: How Strong Are They and What Do They Mean?” Neuroscience & Biobehavioral Reviews 57: 411–432.

Posth, Cosimo, Nathan Nakatsuka, Iosif Lazaridis, Pontus Skoglund, Swapan Mallick, Thiseas C. Lamnidis, Nadin Rohland, et al. 2018. “Reconstructing the Deep Population History of Central and South America.” Cell 175 (5): 1185–1197.

Potter, Ben A., James F. Baichtal, Alwynne B. Beaudoin, Lars Fehren-Schmitz, C. Vance Haynes, Vance T. Holliday, Charles E. Holmes, et al. 2018. “Current Evidence Allows Multiple Models for the Peopling of the Americas.” Science Advances 4 (8): eaat5473. https://doi.org/10.1126/sciadv.aat5473.

Reich, David, Richard E. Green, Martin Kircher, Johannes Krause, Nick Patterson, Eric Y. Durand, Bence Viola, et al. 2010. “Genetic History of an Archaic Hominin Group from Denisova Cave in Siberia.” Nature 468 (7327): 1053–1060.

Reich, David, Nick Patterson, Martin Kircher, Frederick Delfin, Madhusudan R. Nandineni, Irina Pugach, Albert Min-Shan Ko, et al. 2011. “Denisova Admixture and the First Modern Human Dispersals into Southeast Asia and Oceania.” American Journal of Human Genetics 89 (4): 516–528.

Richter, Daniel, Rainer Grün, Renaud Joannes-Boyau, Teresa E. Steele, Fethi Amani, Mathieu Rué, Paul Fernandes, et al. 2017. “The Age of the Hominin Fossils from Jebel Irhoud, Morocco, and the Origins of the Middle Stone Age.” Nature 546 (7657): 293–296.

Roberts, Patrick, and Brian A. Stewart. 2018. “Defining the ‘Generalist-Specialist’ Niche for Pleistocene Homo sapiens.” Nature Human Behaviour 2: 542–550.

Rougier, Helene, Ştefan Milota, Ricardo Rodrigo, Mircea Gherase, Laurenţiu Sarcinǎ, Oana Moldovan, João Zilhão, et al. 2007. “Peştera Cu Oase 2 and the Cranial Morphology of Early Modern Europeans.” Proceedings of the National Academy of Sciences 104 (4): 1165–1170.

Sahlins, Marshall. 1968. “Notes on the Original Affluent Society.” In Man the Hunter, edited by R. B. Lee and I. DeVore, 85–89. New York: Aldine Publishing Company.

Saladié, P. & Rodríguez-Hidalgo, A. (2017). Archaeological Evidence for Cannibalism in Prehistoric Western Europe: from Homo antecessor to the Bronze Age. Journal of Archaeological Method and Theory 24, 1034–1071. https://doi.org/10.1007/s10816-016-9306-y

Sawyer, G. J., and Blaine Maley. 2005. “Neanderthal Reconstructed.” The Anatomical Record (Part B: New Anat.) 283 (1): 23–31.

Scerri, Eleanor M. L., Mark G. Thomas, Andrea Manica, Philipp Gunz, Jay T. Stock, Chris Stringer, Matt Grove, et al. 2018. “Did Our Species Evolve in Subdivided Populations Across Africa, and Why Does It Matter?” Trends in Ecology & Evolution 33 (8): 582–594.

Shea, John J. 2011. “Refuting a Myth about Human Origins.” American Scientist 99 (2): 128–135.

Shea, John J., and Ofer Bar-Yosef. 2005. “Who Were the Skhul/Qafzeh People? An Archaeological Perspective on Eurasia’s Oldest Modern Humans.” Journal of the Israel Prehistoric Society 35: 451–468.

Slatkin, Montgomery, and Fernando Racimo. 2016. “Ancient DNA and Human History.” Proceedings of the National Academy of Sciences 113 (23): 6380–6387.

Smithsonian Institution. (2023, June 26). Humans’ evolutionary relatives butchered one another 1.45 million years ago. Smithsonian Institution. https://www.si.edu/newsdesk/releases/humans-evolutionary-relatives-butchered-one-another-145-million-years-ago

Smith, Fred H., James C. M. Ahern, Ivor Janković, and Ivor Karavanić. 2017. “The Assimilation Model of Modern Human Origins in Light of Current Genetic and Genomic Knowledge.” Quaternary International 450: 126–136.

Smith, Michael. 2009. “V. Gordon Childe and the Urban Revolution: A Historical Perspective on a Revolution in Urban Studies.” Town Planning Review 80 (1): 3–29.

Spence, M., & Jackson, L. J. (2014). The Bioarchaeology of Cannibalism at the Charity Site. Journal of The Ontario Archaeological Society , 94, 65–80. https://www.academia.edu/14371786/The_Bioarchaeology_of_Cannibalism_at_the_Charity_Site

Stock, Jay T. 2008. “Are Humans Still Evolving?” EMBO Reports 9 (Suppl 1): S51–S54.

Swisher, Mark E., Dennis L. Jenkins, Lionel E. Jackson Jr., and Fred M. Phillips. 2013. “A Reassessment of the Role of the Canadian Ice-Free Corridor in Light of New Geological Evidence.” Poster Symposium 5B: Geology, Geochronology and Paleoenvironments of the First Americans at the Paleoamerican Odyssey Conference, Santa Fe, New Mexico, October 16–19.

Thorne, A. G., and P. G. Macumber. 1972. “Discoveries of Late Pleistocene Man at Kow Swamp, Australia.” Nature 238 (5363): 316–319.

Trinkaus, Erik, Ştefan Milota, Ricardo Rodrigo, Gherase Mircea, and Oana Moldovan. 2003a. “Early Modern Human Cranial Remains from the Peştera Cu Oase, Romania.” Journal of Human Evolution 45 (3): 245–253.

Trinkaus, Erik, Oana Moldovan, Adrian Bîlgăr, Laurenţiu Sarcina, Sheela Athreya, Shara E Bailey, Ricardo Rodrigo, Gherase Mircea, Thomas Higham, and Christopher Bronk Ramsey. 2003b. “An Early Modern Human from the Peştera Cu Oase, Romania.” Proceedings of the National Academy of Sciences 100 (20): 11231–11236.

Ullrich, H. (2005). Cannibalistic rites within mortuary practices from the palaeolithic to middle aged in Europe. Anthropologie (1962-), 43(2/3), 249–261. http://www.jstor.org/stable/26292739

Velemínská, J., J. Brůzek, P. Velemínský, L. Bigoni, A. Sefcáková, and S. Katina. 2008. “Variability of the Upper-Palaeolithic Skulls from Predmostí Near Prerov (Czech Republic): Craniometric Comparison with Recent Human Standards.” Homo 59 (1): 1–26.

Vidal, Céline M., Christine S. Lane, Asfawossen Asrat, Dan N. Barfod, Darren F. Mark, Emma L. Tomlinson, Ambdemichael Zafu Tadesse, et al. (2022). “Age of the Oldest Known Homo sapiens from Eastern Africa. Nature 601 (7894): 579–583.

Villa, P., Bouville, C., Courtin, J., Helmer, D., Mahieu, E., Shipman, P., Belluomini, G. & Branca, M. (1986). Cannibalism in the Neolithic. Science, 233(4762), 431–437. doi:10.1126/science.233.4762.431

Villa, Paola, Sylvain Soriano, Tsenka Tsanova, Ilaria Degano, Thomas F. G. Higham, Francesco d’Errico, Lucinda Backwell, Jeannette J. Lucejko, Maria Perla Colombini, and Peter B. Beaumont. 2012. “Border Cave and the Beginning of the Later Stone Age in South Africa.” Proceedings of the National Academy of Sciences 109 (33): 13208–13213.

Wall, Jeffrey D., and Deborah Yoshihara Caldeira Brandt. 2016. “Archaic Admixture in Human History.” Current Opinion in Genetics & Development 41: 93–97.

White, Tim D., Berhane Asfaw, David DeGusta, Henry Gilbert, Gary D. Richards, Gen Suwa, and F. Clark Howell. 2003. “Pleistocene Homo sapiens from Middle Awash, Ethiopia.” Nature 423 (6941): 742–747.

Woo, Ju-Kang. 1959. “Human Fossils Found in Liukiang, Kwangsi, China.” Vertebrata PalAsiatica 3 (3): 109–118.

Wu, XiuJie, Wu Liu, Wei Dong, JieMin Que, and YanFang Wang. 2008. “The Brain Morphology of Homo Liujiang Cranium Fossil by Three-Dimensional Computed Tomography.” Chinese Science Bulletin 53 (16): 2513–2519.

Acknowledgments

I could not have undertaken this project without the help of many who got me to where I am today. I extend sincere thank yous to the many colleagues and former students who have inspired me to keep learning and talking about anthropology. Thank you also to all who are involved in this textbook project. The anonymous reviewers truly sparked improvements to the chapter. Lastly, the staff of Starbucks #5772 also contributed immensely to this text.