Anthropologie What Does It Mean To Be Human Part 4

FIGURE 4.27 Upper Paleolithic stone-tool industries in Europe were fully developed blade technologies that show considerable stylistic variation over time. Tools a, b, and c are from the Perigordian culture, a variet y of the Gravettian; tool d is from the Aurignacian; and tool e is from the Solutrean. This anatomical change, if it occurred, has left no fossil evidence. However, as knowledge about the genomes of living humans, other primates, and fossil hominins accumulates, it may become increasingly possible to find and date key mu-tations associated with brain expansion or language ability (Klein 2009, 638ff.; Tattersall 2009, 243–44). For the present, such a change must be inferred from the cultural evidence produced by anatomically modern humans after about 40,000 years ago. What Happened to the Neandertals? The first appearance of Upper Paleolithic culture in Europe is important because of what it can tell us about the fate of the Neandertals. If Neandertals gradually evolved into modern human beings, it is argued, then this gradual evolution should be documented in archaeological assemblages. In this search, the Châtelperronian and Aurignacian industries have attracted the most attention. Châtelperronian assemblages from France, 35,000– 30,000 years old, contain a mixture of typical Mousterian backed knives and more advanced pointed cutting tools called “burins.” They also contain bone tools and pierced animal teeth. Other mixed assemblages similar to the Châtelperronian have been found in Italy, central and northern Europe, and southern Russia (Mellars 1996, 417–18). Aurignacian assemblages, 34,000–30,000 years old, are Upper Paleolithic blade assemblages. We know that Neandertals were capable of making Châtelperronian tools because two Neandertal skeletons were found in 32,000-year-old Châtelperronian deposits at St. Césaire, France (Mellars 1996, 412ff.). If Neandertals invented Aurignacian technology as they evolved into anatomically modern human beings, then the Châtelperronian and other mixed assemblages might be transitional between the Mousterian and the Aurignacian. Some archaeologists argue, however, that Neandertals may have borrowed elements of Upper Paleolithic technology from a culturally more advanced population of outsiders. For example, deposits found in some cave sites in southwestern France and northern Spain show Châtelperronian layers on top of some Aurignacian layers, suggesting that two different cultural groups coexisted and occupied the same caves at different times (Mellars 1996, 414). These archaeologists believe that anatomically modern people invented the Aurignacian industry in southwestern Asia and brought it with them when they migrated into central and western Europe 40,000–35,000 years ago. The skeletons of anatomically modern human beings begin to appear at European sites about this time, when the ice sheets had begun to melt and the climate was improving. For many archaeologists, the arrival in Europe of both modern human beings and Aurignacian culture during the same time period seems too well correlated to be an accident. No Aurignacian assemblages have been found in eastern Europe, which suggests that the Upper Paleolithic developed differently there (Klein 2009, 586–88, 605). Even if European Neandertals borrowed Upper Paleolithic technology from southwestern Asian immigrants, they were gone a few thousand years later. What happened to them? There is no evidence that the replacement of Neandertals by modern people involved conquest and extermination, although this has been proposed from time to time. European Neandertals may have disappeared because they evolved into anatomically modern people, developing Aurignacian culture as they did so, in line with the regional continuity model. This hypothesis, however, runs afoul of the fact that Neandertals and moderns apparently originated on different continents and coexisted in southwestern Asia for 45,000 years, both of them making and using Mousterian tools. European Neandertals may have disappeared as they interbred with the in-migrating modern people and as their descendants adopted Aurignacian culture. If this happened, then contemporary European populations might be expected to share morphological traits with their alleged Neandertal ancestors. As we saw earlier, morphological evidence for such inbreeding during the Pleistocene is stronger for populations in eastern Europe and western Asia than for the classic Neandertals of western Europe. Evidence from ancient DNA also shows that Neandertals did interbreed with other non-Neandertal populations during the Pleistocene, and Neandertal genes make up 1% to 4% of our modern nuclear genome. However, Y-chromosome DNA recently extracted from a Neandertal skeleton is distinct from all known modern human Y-chromosome lineages, which suggests that this lineage has gone extinct. If so, its disappearance could be due to genetic drift, but the researchers also suggest another possibility: that genetic incompatibilities in the genomes of male fetuses with Neandertal fathers and anatomically modern human mothers rendered these fetuses unviable or infertile. If this second possibility were the case, it might have contributed to reproductive isolation between Neandertals and anatomically modern humans (Mendez et al. 2016). Neandertals may have retreated as modern people spread throughout Europe, decreasing in number until, around 30,000 years ago, they simply died out. In sum, at this time, the archaeological evidence is no more able than the fossil or genetic evidence to resolve disputes about the fate of the Neandertals. How Many Kinds of Upper Paleolithic/Late Stone Age Cultures Were There? Although blades are the classic tools of Upper Paleolithic/ LSA culture, other tool types appear that are not found in Mousterian/MSA assemblages, such as endscrapers, burins, and numerous artifacts of bone, ivory, and antler (Figure 4.28). Brian Fagan (1990) calls this technological explosion the “Swiss army knife effect”: “like its modern multipurpose counterpart, the core and blade technique was a flexible artifact system, allowing Upper Paleolithic stoneworkers to develop a variety of subsidiary crafts, notably bone and antler working, which likewise gave rise to new weapons systems and tailored clothing” (157). As we saw earlier, the most distinctive Upper Paleolithic artifacts are composite tools, such as spears and arrows, made of several different materials. The oldest undisputed evidence of wooden bows and arrows in Europe dates from 12,000–11,000 years ago; however, bows and arrows may have been used as long as 20,000 years ago in Africa and Eurasia, where researchers have found indirect evidence in the form of stone points, backed bladelets, and bone rods resembling arrow shafts (Klein 2009, 679–80). Archaeologists have also found the skeletons of fur-bearing animals whose remains suggest they were captured for their skins, not for food; pointed bone tools that were probably used to sew skins together (the oldest eyed needles appeared between 35 and 28 Ka years old); and the remains of tailored clothing in Upper Paleolithic burials dating from between 26 and 19 Ka (Klein 2009, 673). Evidence for regular hunting of large game is better at Upper Paleolithic sites than at sites from earlier periods, especially in Europe and Asia. In addition to hunting tools, researchers have found the bones of mammoth, reindeer, bison, horse, and antelope, animals that provided not only meat but also ivory, antler, and bone. Some animals were hunted but not for food. The mammoth, for instance, supplied bones used for building shelters. Fresh bone and animal droppings were also probably burned as fuel. The Upper Paleolithic way of life probably resembled that of contemporary foragers. Consequently, plant foods probably formed a larger part of the diet than meat. Reliance on plant foods was probably greater among those living in warmer areas of Africa and southwestern Asia, whereas those living in the cooler climates of eastern Europe and northern Asia may have relied more on animals for food. The richness and sophistication of Upper Paleolithic culture is documented in many other ways. Upper Paleolithic burials are more elaborate than Mousterian/ MSA burials, and some of them contain several bodies (Klein 2009, 690–91). Some Upper Paleolithic sites have yielded human bones that have been shaped, perforated, or burned or that show cut marks suggesting defleshing. Again, some paleoanthropologists conclude that Upper Paleolithic peoples may have been cannibals. However, the shaped or perforated bones may have been trophies or mementos of individuals who had died for other reasons; the burned bones may be the remains of deliberate cremation or accidental charring under a hearth; and the flesh may have been removed from human bones after death for ritual purposes, a practice documented in modern ethnographic literature. The most striking evidence for a modern human capacity for culture comes from Upper Paleolithic/LSA art. In Africa, ostrich-eggshell beads date to 38,000 years ago, while animal paintings on rocks date to at least 19,000 and possibly 27,500 years ago. Fire-hardened clay objects shaped like animals or human beings, dating to about 28,000–27,000 years ago, were recovered at a Gravettian FIGURE 4.28 Upper Paleolithic stoneworkers developed bone-, antler-, and ivor y-working techniques to a high degree, as shown by these objects from Europe. site in the former Czechoslovakia. This and other Gravettian sites in western and central Europe have yielded human figurines, some of which depict females with exaggerated breasts and bellies, thought to have been made between 27,000 and 20,000 years ago (see Figure 4.28). More than 200 caves in southern France and northern Spain, including Lascaux and Altamira, contain spectacular wall paintings or engravings (Figure 4.29); other painted caves exist in Italy, Portugal, and the former Yugoslavia; spectacular wall art from rock shelters in northern Australia may be especially old (Renfrew and Bahn 2004, 523). The European paintings portray a number of animal species now extinct and were probably painted between 15,000 and 11,000 years ago, during Magdalenian times. Recently, new techniques have permitted archaeologists to analyze the recipes of pigments used to make these wall images, whereas accelerator mass spectrometry can be used to date the charcoal used to make other drawings (Conkey 1993). As a result, archaeologists are increasingly able to determine when images were painted and whether all the images in a particular cave were painted at the same time. Where Did Modern H. sapiens Migrate in Late Pleistocene Times? Upper Paleolithic peoples were more numerous and more widespread than previous hominins. In Europe, according to Richard Klein, Upper Paleolithic sites are more numerous and have richer material remains than do Mousterian sites. Skeletons dating from this period show few injuries and little evidence of disease or violence, and they possess relatively healthy teeth. The IN THEIR OWN WORDS Women’s Art in the Upper Paleolithic? In a 1996 article in American Anthropologist Catherine Hodge McCoid and LeRoy D. McDermott propose that the so-called Venus figures of the early Upper Paleolithic might be more successfully understood as women’s art rather than as sex objects made from a male point of view. Since Édouard Piette (1895) and Salomon Reinach (1898) first described the distinctive small-scale sculptures and engravings of human figures found in the rock shelters and caves of southern France, several hundred more European Upper Paleolithic figures have been identified. The earliest of these, the so-called Stone A ge Venuses or Venus figurines, constitute a distinctive class and are among the most widely known of all Paleolithic ar t objects. A s a group they have frequently been described in the professional and popular literature. Most of the figures are about 150 millimeters in height and depict nude The PKG “lozenge composition.” PKG images routinely women usually described as obese. elevate both the vertical midpoint and greatest width of the In spite of many difficulties in dating , there is a growfemale body, and most make what should be one-half of the ing belief that most of these early sculptures were cre- body closer to one-third. (Figures redrawn and simplified ated during the opening millennia of the Upper Paleolithic based on information in Leroi- Gourhan 1968.) (circa 27,000 –21,000 B .C .) and are stylistically distinc t from those of the later Magdalenian. These first representations of the human figure are centered in the Gravet tian accuracy [see figure]. The characteristic features include or Upper Perigordian assemblages in France and in re- a faceless, usually downturned head; thin arms that lated Eastern Gravettian variants, especially the Pavlov- either disappear under the breasts or cross over them; ian in the former Czechoslovakia, and the Kostenkian in an abnormally thin upper torso; voluminous, pendulous breasts; large fatt y buttocks and/or thighs; a prominent, the former Soviet Union. Most Pavlovian-Kostenkian-Gravet tian (PKG) statu- presumably pregnant abdomen, sometimes with a large et tes are car ved in stone, bone, and ivory, with a few elliptical navel coinciding with the greatest physical width early examples modeled in a form of fired loess ( Van- of the figure; and often oddly bent, unnaturally short diver et al. 1989). Car ved reliefs are also known from four legs that taper to a rounded point or dispropor tionately French Gravettian sites: Laussel, La Mouthe, Abri Pataud, small feet. These deviations produce what M. D. Gvoz- and Terme Pialet. These images show a formal concern dover (1989, 79) has called “ the stylistic deformation of with three-dimensional sculpted masses and have the the natural body.” Yet these apparent distor tions of the most widespread geographical distribution of any form anatomy become apt renderings if we consider the body of prehistoric art. . . . While considerable variation occurs as seen by a woman looking down on herself. Compari- among PKG figurines, claims of true diversit y ignore a son of the figurines with photographs simulating what a central tendenc y that defines the group as a whole. The modern woman sees of herself from this perspec tive re- overwhelming majority of these images reflect a most un- veals striking correspondences. It is possible that since usual anatomical structure, which André Leroi-Gourhan these images were discovered, we have simply been look- (1968) has labeled the “lozenge composition.” What makes ing at them from the wrong angle of view. this struc tural formula so striking is that it consists of a recurring set of apparent departures from anatomical Although it is the center of visual self-awareness, a woman’s face and head are not visible to her without a IN THEIR OWN WORDS reflecting sur face. This may explain why—although there lower body would narrow toward the feet, thus explaining are variations in shape, size, and position in the heads the small size of the feet in these figurines. It is also true of these pieces—vir tually all are rendered without facial that, for a pregnant woman, inspection of the upper body features and most seem to be turned down, as is neces- terminates at the navel with the cur ving silhouette of the sar y to bring the body into view. A woman looking down distended abdomen [see photo on lef t]. Without bending at herself sees a strongly foreshor tened view of the for ward, she cannot see her lower body. Thus for a gravid upper frontal surface of the thorax and abdomen, with female, the visual experience of her body involves two her breasts looming large. Such a perspective helps to separate views whose shared boundar y is the abdomen explain the apparently voluminous size and distinctive at the level of the navel, which is also the widest par t of pendulous elongation routinely obser ved in the breasts the body in the visual field. The apparent misrepresenta- of the figurines. Viewed in this way, the breasts of the tion of height and width in the figurines results from the figurines possess the natural propor tions of the average visual experience of this anatomical necessit y. The loca- modern woman of childbearing age [see photographs]. tion of the eyes means that for an expectant mother the Even pieces such as the one from Lespugue, in which the upper half of the body visually expands toward the abdo- breasts seem unnaturally large, appear naturalistic when men, whereas the lower half presents a narrow, tapering viewed from above. form. Efforts to represent the information contained in Other apparent distortions of the upper body undergo these two views naturally resulted in the lozenge compo- similar optical transformations from this perspec tive. For sitional formulation, which others have seen as anatomi- example, the inabilit y to experience the true thickness of cally “incorrect ” propor tions [see figures]. The idea that women sought to gain and preser ve the upper body may account for the apparently abnormal thinness seen in the torsos of many figurines. Several knowledge about their own bodies provides a direc t figurines also have what seem to be unnaturally large, el- and parsimonious interpretation for general as well as liptical navels located too close to the pubic triangle. In idiosyncratic features found among female representa- a foreshor tened view, however, the circular navel forms tions from the middle European Upper Paleolithic. The just such an ellipse, and when pregnant, a woman cannot needs of health and hygiene, not to mention coitus and easily see the space below the navel. Thus, when viewed childbirth, ensure that feminine self-inspec tion ac tually as women sur vey themselves, the apparent anatomical occurred during the early Upper Paleolithic. Puber t y, distortions of the upper body in these figurines vanish menses, copulation, conception, pregnanc y, childbirth, [see photographs]. and lac tation are regular events in the female c ycle Similarly, as a woman looks down at the lower por tion and involve perceptible alterations in bodily function of her body, those parts far thest away from the eyes look and configuration (Marshack 1972). Mas ter y and con- smallest. A correct representation of the foreshor tened trol of these processes continues to be of fundamental a (a) View of her own upper body by a 26-year-old female who is five months pregnant and of average weight. (b) View of the upper body of the Willendor f figurine from same perspec tive used at left. b IN THEIR OWN WORDS Women’s Art in the Upper Paleolithic? Continued impor tance to women today. It is possible that the emer- improve their understanding of reproduction and thereby gence and reduce infant and maternal mortalit y would clearly have subsequent propagation of these images across Europe occurred precisely because they played contributed to this produc tive and reproductive change. a didac tic function with actual adaptive consequences Perhaps the figurines ser ved as obstetrical aids, the rela- for women. . . . tive sizes of the abdomens helping women to calculate . . . These Upper Paleolithic figurines were proba- the progress of their pregnancies. . . . Theoretically, bly made at a time when there was similarly significant if these figurines were used population increase along with cultural and economic prove reproductive success, keep more women alive and restructuring. The early to middle Upper Paleolithic was healthy, and produce healthier children, then natural se- characterized lection would have been acting directly on the women by produc tive changes that harnessed energy and by reproductive changes that helped make who made and/or used them. If these Upper Paleolithic possible figures the population expansion and technological are naturalistic, accurate to im- self-representations changes that followed in the later European Upper Pa- made by women, then it is reasonable to speculate that leolithic. Could women have made a recognizable con- they might have had such direct, pragmatic purposes. tribution to the fluorescence of ar t and technolog y seen in the opening millennia of this era? Any thing they did to presence of skeletons belonging to older or incapacitated individuals at Upper Paleolithic sites suggests that these people, like the Neandertals, cared for the old and sick. Analysis indicates that the life expectancy of Upper Paleolithic people was greater than that of the Neandertals and little different from that of contemporary foragers (Klein 2009, 695ff.). Archaeologists have found amber, seashells, and even flint in Upper Paleolithic/LSA sites located tens So ur ce: M cC oi d an d McD er m ot t 199 6. to hundreds of kilometers away from the regions where these items occur naturally. They must have been deliberately transported to these sites, suggesting that Upper Paleolithic peoples, like contemporary foragers, participated in trading networks. However, no evidence of such social contacts exists for earlier times. Perhaps the linguistic and cultural capacities of fully modern humans were necessary before they could develop. Eastern Asia and Siberia FIGURE 5. 29 Upper Paleolithic cave paintings, like this one from Lascaux, France, have been dated to between 15,000 and 11,000 years ago. Physically and culturally modern human beings were the first hominins to occupy the coldest, harshest climates in Asia. Upper Paleolithic blade industries developed in central Asia about 40,000–30,000 years ago (Fagan 1990, 195). The oldest reliable dates for human occupation in Siberia are between 35,000 and 20,000 years ago (Klein 2009, 673). Alaskan and Canadian sites with Upper Paleolithic artifacts similar to those of northeast Siberia date to between 15,000 and 12,000 years ago. Artifacts from one of these sites, Bluefish Caves, may even be 20,000 years old. Between 25,000 and 14,000 years ago, land passage south would have been blocked by continuous ice. By 14,000 years ago, conditions for southward migration would have improved considerably. The Americas Genetic studies strongly support an Asian origin for Native American populations (Stringer and Andrews 2005, 198; Klein 2009, 707). The earliest known skeletal remains found in the Americas are between 11,000 and 8,000 years old, and their morphological variation suggests that the Americas may have been colonized more than once (Stringer and Andrews 2005, 198–99; Klein 2009, 707). The strongest archaeological evidence of human presence in the Americas comes after 14,000 years ago. The first anatomically modern human beings in North America, called “Paleoindians,” apparently were successful hunting peoples. The oldest reliable evidence of their presence comes from sites dated between 11,500 and 11,000 years ago, which contain stone tools called Clovis points (Figure 4.30). Meadowcroft Rockshelter in Pennsylvania may represent an early Clovis site (Adovasio et al. 1978; Stringer and Andrews 2005, 197). Clovis points were finely made and probably attached to shafts to make spears. Rapidly following the Clovis culture were a series of different stone-tool cultures, all of which were confined to North America. Some experts believe that Paleoindian hunting coupled with postglacial climatic changes may have brought about the extinction of mammoth, camel, horse, and other big game species in North America, but evidence is inconclusive (Meltzer 2015). FIGURE 4.30 Stone tools made by Paleoindian peoples have been found at sites that provide the oldest reliable dates for human occupation in North America. The Clovis point pictured here was probably haf ted to a shaf t to make a spear. In 1997, the “Clovis barrier” of 11,200 years was finally broken when a group of archaeologists and other scientists formally announced that the South American site of Monte Verde, in Chile, was 12,500 years old (Suplee 1997; Dillehay 2000). Because it was covered by a peat bog shortly after it was inhabited, Monte Verde contained many well-preserved organic remains, including stakes lashed with knotted twine, dwellings with wooden frames, and hundreds of tools made of wood and bone. Thomas Dillehay (2000) argues that evidence from Monte Verde shows that the people who lived there were not big game hunters but, rather, generalized gatherers and hunters. A lower level at the same site, dated to 33,000 years ago, is said to contain crude stone tools. If the 33,000-year-old Monte Verde artifacts are genuine, they remain puzzling. First, these artifacts are few and extremely crude. Second, the dearth of sites in the Americas of such great age suggests that, if human beings were in the Americas 30,000 years ago, they were very thinly scattered compared to populations in Eurasia and Africa at the same period. Finally, blood group and tooth shape evidence supports the idea that the ancestors of indigenous peoples of the Americas migrated into North America from Asia. If the makers of 33,000-year-old Monte Verde artifacts also came from Asia, archaeologists must explain how these people could have reached South America from Siberia by that date. Possibly, they traveled over water and ice, but how they got to South America remains a mystery. In 2011, evidence for pre-Clovis occupations in North America was found at the Debra L. Friedkin site near Austin, Texas: more than 15,000 artifacts assigned to the Buttermilk Creek Complex, dating between 13,200 and 15,000 years ago, were discovered in soil beneath a Clovis assemblage (Waters et al. 2011). The archaeologists who discovered the tools view them as potentially representing the technology from which Clovis was developed; other archaeologists remain unconvinced. Perhaps ancient DNA analysis may help resolve some of these questions, even as it opens up entirely new sets of questions. Ancient mitochondrial DNA and Y chromosome DNA were extracted from the skeleton of a male infant found in association with Clovis artifacts and buried around 12,600 years ago. The DNA evidence showed that this skeleton, known as Anzick-1, belonged to a population more closely related to populations from Central and South America than anywhere else (Rasmussen et al. 2014, 227–28). In 2015, Rasmussen and his colleagues also published results of ancient DNA analysis on skeletal material taken from the controversial 8,500-year-old fossil known as Kennewick Man (or the Ancient One), found in the state of Washington in 1996 (Rasmussen et al. 2015). As we will see in Chapter 6, control over the remains of Kennewick Man had become a focus of sharp debate among archaeologists, members of local indigenous tribes, and the Army Corps of Engineers. After negotiations with all interested parties, Rasmussen and his team performed a DNA analysis that showed Kennewick Man to be closely related to Native American populations from Central and South America, as was the Anzick-1 individual. However, Kennewick Man showed closer affinity than the Anzick-1 individual to geographically closer tribes of the Pacific Northwest of North America. Ancient DNA studies are bound to be controversial, but there is no question that they are forming an important component of scientific efforts to answer questions about ancient human migrations all over the world. Australasia Anatomically modern human beings first arrived in Australia between 60,000 and 40,000 years ago, at a time when lower sea levels had transformed the Malayan Archipelago into a land mass called Sunda and when Australia was linked to New Guinea in a second land mass called Sahul. Nevertheless, the migrants would still have had to cross 30–90 kilometers of open water. Presumably, they used water craft, but finding the remains of boats or the sites where they landed along the now sunken continental shelf is unlikely. Modern people spread throughout the Australian interior by 25,000–20,000 years ago. They may have been connected to widespread extinctions of grass-eating marsupials in Australia between 40,000 and 15,000 years ago (Klein 2009, 714ff.). Two Million Years of Human Evolution By 12,000 years ago, modern human beings had spread to every continent except Antarctica, a fact that we take for granted today but that could not have been predicted 2 mya in Africa, when the first members of the genus Homo walked the earth. In fact, the more we learn about hominins and their primate ancestors, the more zigs and zags we perceive in our own past. Our species’ origin must be regarded as “an unrepeatable particular, not an expected consequence” (Gould 1996, 4). Some paleoecologists have concluded that “human features may not be adaptations to some past environment, but exaptations . . . accidental byproducts of history, functionally disconnected from their origins” (Foley 1995, 47). For example, Rick Potts (1996) argues that, rather than “survival of the fittest” (i.e., of a species narrowly adapted to a specific environment), modern H. sapiens better illustrates “survival of the generalist” (i.e., of a species that had the plasticity, the “weedlike resilience,” to survive the extremes of the rapidly fluctuating climate of the Ice Ages). In other words, our ancestors’ biological capacity to cope with small environmental fluctuations was exapted to cope with larger and larger fluctuations. In Potts’s view, selection for genes favoring open programs of behavior “improve an organism’s versatility and response to novel conditions” (Potts 1996, 239). Archaeologist Clive Gamble (1994) believes that the human social and cognitive skills that allowed our ancestors to survive in novel habitats were exapted by H. sapiens to colonize the world: “We were not adapted for filling up the world. It was instead a consequence of changes in behavior, and exaptive radiation produced by the cooption of existing elements in a new framework of action” (182). Gamble is sensitive to the way humanly constructed niches modified the selection pressures our ancestors faced: he argues that all the environments of Australia could never have been colonized so rapidly without far-flung social networks that enabled colonizers to depend on one another in time of need. He sees the colonization of the Pacific as a deliberate undertaking, showing planning and care (Gamble 1994, 241; see also Dillehay 2000). The role of niche construction is also implicated in the approach of Richard Klein (2009), who lists a series of “related outcomes of the innovative burst behind the out of Africa expansion” (742) that are detectable in the archaeological record after 50,000 years ago, ranging from standardization and elaboration of artifacts to evidence for increasing elaboration of a built environment (with campsites, hearths, dwellings, and graves) to evidence of elaborate trading networks, ritual activity, and successful colonization of challenging cold climates. Paleoanthropologists, archaeologists, and geneticists have assembled many of the pieces of the human evolutionary puzzle, but many questions remain. Experts differ, for example, on how to reconstruct the human family tree. Figure 4.31 shows one recent attempt to summarize what is known (and what remains to be established) about the evolution of human beings. Because new data and interpretations appear in the news almost daily, you may want to find out how much this summary has been modified by the time you read this book! Another knotty problem concerns how we interpret mounting evidence that human biology and human culture evolved at different rates. Finally, within a few thousand years after the glaciers retreated, human groups in Asia and the Americas were settling in villages and domesticating plants and animals. Why they should have done so at this particular time is addressed in Chapter 6. Age Species Behavior (Ma) 1.5 1.7 He (D) 1.9 He Pr As 2.1 1470 group 1813 group Pb 2.3 H sp. 2.5 Ag 2.7 Pa 2.9 A afr FIGURE 4.31 Timelines for hominin evolution. This image shows one recent at tempt to depict the relationships among various groups of hominin fossils, showing the periods in the past for which they are well attested, and placing them alongside the timelines for the best-known early stone-tool traditions. From left to right, the timelines depict the periods when the following fossil groups flourished: (1) P. aethiopicus, P. boisei, and (2) P. robustus (the robust australopiths); (3) the gracile australopith Australopithecus africanus; and (4) Australopithecus sediba. The next four timelines to the right of these represent different subgroups of early members of the genus Homo, which emerge between 2.5 and 2.3 million years ago; this appearance is indicated by the timeline labeled “ H. sp.” This side of the image at tempts to sort different groups of “early Homo ” fossils into distinct subgroups, “1470 group” (AK A Homo habilis) and the “1813 group” (AK A Homo rudolfensis ), on the basis of a new analysis of their distinc tive morphological traits. The rightmost timeline groups together fossils assigned to Homo erectus ; the callout labeled “He-D” indicates the appearance of the H. erectus fossils from Dmanisi, Georgia. The cell to the right of the species timelines juxtaposes timelines associated with the appearance of the two best-attested stone-tool traditions associated with early hominins: Oldowan at the bottom (bet ween 2.5 and 2.7 million years ago) and Acheulean at the top (after about 1.9 million years ago). Jux taposing the timelines for fossils and for stone tools leaves open the question of which earlier hominin species might have given rise to later hominin species, as well as which of these species might have made or used the stone tools. Chapter Summary 1. Bipedal hominoids that appeared in Africa at the end of the Miocene are known as hominins and are placed in the same lineage as living human beings. Bipedalism may have been favored by natural selection in hominoids exploiting food resources on the ground, outside the protection of forests. Their diet was probably omnivorous, and they could carry infants, food, and tools in their newly freed hands. The earliest hominin skeletal fossils are 6–7 million years old. The best-known early hominin fossils are 2–3 million years younger and have been placed in the genus Australopithecus. The earliest direct evidence of hominin bipedalism is a 3.6 million-year-old trail of fossilized footprints found in Laetoli, Tanzania. 2. Hominin adaptations apparently led to changes in dentition. The teeth of australopiths show an evolutionary trend toward smaller front teeth and enormous cheek teeth. This dental pattern is interpreted as an adaptation to diets of coarse vegetable foods that required grinding. Fossils of hominins between 3 and 2 million years old with this dental pattern have been found at southern and eastern African sites and have been classified in two groups: the gracile australopiths and the robust australopiths. Robust australopiths had more rugged jaws, (continued on next page) Chapter Summary (continued) flatter faces, and larger molars than the gracile forms. Apart from differences in dentition, the gracile and robust australopiths had similar postcranial skeletons and chimpanzee-sized cranial capacities. 3. The first members of the genus Homo appeared about 2.5 mya. Many paleontologists believe that more than one species belonging to Homo may have coexisted in eastern Africa in the early Pleistocene alongside the eastern African robust australopiths. 4. Fossils of early Homo disappear about 1.8 mya, by either evolving into or being replaced by Homo ergaster, the first member of the genus Homo to spread out of Africa, giving rise to Homo erectus populations in Asia. The cranium of H. erectus averages around 1,000 cm3, within the lower range of modern human beings. H. erectus may have been, to some extent, capable of speech. Wear patterns on teeth suggest that H. erectus had a diet different from that of previous hominins. The postcranial skeleton of H. erectus is more robust than that of modern humans and shows a marked reduction in sexual dimorphism. H. erectus was probably not primarily a hunter of big game, nor is there any evidence that H. erectus might have practiced cannibalism. 5. The oldest undisputed stone tools, classified in the Oldowan tradition, were found in Ethiopia, date to at least 2.5 mya, and may have been made by early Homo. Acheulean bifaces are associated with H. erectus. In recent years, however, archaeologists have concluded that it is misleading to associate individual stone-tool traditions with only one hominin species. Some archaeologists have suggested that bamboo was available for toolmaking in those areas in Asia where Acheulean bifaces are lacking. Oldowan and Acheulean traditions are usually grouped together in a single period known as the Lower Paleolithic in Europe and the Early Stone Age in Africa. 6. Between 500,000 and 200,000 years ago, H. erectus fossils disappear from the fossil record to be replaced by fossils that show a mosaic of features found in H. erectus and H. sapiens. Many paleoanthropologists classify these fossils as Homo heidelbergensis. A lively debate continues between punctuationists and gradualists about the fate of H. erectus and the origin of H. sapiens. Punctuationists and cladists favor the replacement model; gradualists favor the regional continuity model. 7. Neandertals in Europe flourished between 130,000 and 35,000 years ago. They were shorter and more robust than anatomically modern H. sapiens. Their molars showed taurodontism, their jaws possessed retromolar spaces, and they may have habitually used their incisors as a clamp. Their average cranial capacity was larger than that of modern human populations, although their skull was shaped differently. Neandertal fossils are typically associated in Europe with the Mousterian stone-tool tradition. Similar tools, found in southwestern Asia and Africa, have all been assigned to the Middle Paleolithic/Middle Stone Age, which probably began at least 200,000 years ago. Ancient DNA recovered from hominin fossils in Denisova Cave did not belong to Neandertals, but to a previously unknown population with which Neandertals interbred. 8. During the 1980s, new evidence revealed that anatomically modern H. sapiens appeared in Africa at the same time that Neandertal populations were living in Europe and western Asia. Neandertals and moderns apparently lived side by side in southwestern Asia for at least 45,000 years, and both populations used the same kinds of Mousterian tools. Ancient DNA studies have shown that modern humans share from 1% to 4% of their nuclear genome with Neandertals; what this means is still under discussion. 9. By 40,000 years ago in southwestern Asia and 35,000 years ago in Europe, Mousterian/Middle Stone Age tools are replaced by far more elaborate artifacts that signal the beginning of the Upper Paleolithic/Late Stone Age. Upper Paleolithic people made many different stone tools as well as tools and ornaments out of bone, ivory, and antler; composite tools, such as spears and arrows; and clothing from animal fur. They regularly hunted large game and used bones from animals such as mammoths to construct dwellings and to burn as fuel. Upper Paleolithic burials were far more elaborate than Middle Paleolithic burials. Cave paintings and personal ornaments offer the most striking evidence in the Upper Paleolithic for the modern human capacity for culture. 10. Some Upper Paleolithic assemblages, like the Châtelperronian industry from France, contain a mixture of typical Mousterian tools and more elaborate cutting tools, bone tools, and pierced animal teeth. Paleoanthropologists disagree about what these mixed assemblages represent. Some interpret the Châtelperronian industry as evidence that Neandertals gradually invented Upper Paleolithic tools on their own, which would support the regional continuity model. Others argue that Châtelperronian Neandertals borrowed Upper Paleolithic techniques from in-migrating modern people who already possessed an Upper Paleolithic technology called the Aurignacian. This view is compatible with the replacement model. If Aurignacian moderns did replace Neandertals in Europe, there is no evidence that this was the result of conquest or extermination. 11. Upper Paleolithic peoples show few signs of injury or disease, and their life expectancy was longer than that of Neandertals. Upper Paleolithic peoples apparently constructed niches that allowed them to participate in widespread trading networks. Anatomically modern people with Upper Paleolithic cultures were the first humans to migrate into the northernmost regions of Asia and into the New World, arriving at least 12,000 years ago, possibly earlier. It seems likely that the New World was populated by more than one wave of immigrants from Siberia. Anatomically modern people first arrived in Australia between 60,000 and 40,000 years ago, probably by boat. 12. Until recently, most evolutionists were phyletic gradualists, who thought that microevolutionary anagenesis led to macroevolutionary speciation, given enough time. Gould and Eldredge, however, proposed that most of evolutionary history has consisted of relatively stable species coexisting in equilibrium. Macroevolution occurs, in their view, when this equilibrium is punctuated by a burst of speciation by cladogenesis. They further propose that species selection may operate among variant, related species. Debate between phyletic gradualists and punctuationists has been lively. For Review 1. Define bipedalism and explain its importance in human evolution. 2. What is distinctive about the evolution of dentition in hominins? 3. Explain the differences between robust and gracile australopiths. 4. Summarize the different arguments for explaining the evolutionary transition from early hominins to the genus Homo. 5. List what paleoanthropologists and archaeologists know about early Homo species. 6. Define taphonomy and explain why it is important for paleoanthropologists who study bones and stone tools. 7. Summarize what is known about Homo erectus , morphologically and culturally. 8. Describe the argument that emphasizes the importance of endurance running in human evolution. 9. What is the fossil evidence for the evolutionary transition to modern Homo sapiens? 10. Explain how the origins of Homo sapiens would be accounted for by proponents of evolution by punctuated equilibria. 11. Make a chart of the different Homo species currently identified, including the periods in which they lived, where they were found, and other distinctive anatomical features they display, such as brain size. 12. What is the “mostly out of Africa” model of the origin of modern Homo sapiens? What evidence do biological anthropologists use to defend this model? How does this model contrast with the earlier “replacement” model and the “regional continuity” model? 13. Summarize what biological anthropologists know about the Neandertals. 14. Summarize the features biological anthropologists emphasize in distinguishing anatomically modern humans from other archaic populations of Homo. 15. What happened to the Neandertals? 16. How do archaeology and biological anthropology contribute to our understanding of the evolution of a modern human capacity for culture? 17. Summarize anthropological evidence used to support current arguments concerning the peopling of the Americas. 18. Compare and contrast phyletic gradualism and punctuated equilibria. 19. Define cladogenesis and explain how evolutionary biologists use it to develop taxonomies of species. Key Terms Acheulean tradition 114 anagenesis 96 composite tools 128 cranial capacity 106 Denisovans 127 Middle Stone Age (MSA) 121 mosaic evolution 99 anatomically modern human beings 125 Early Stone Age (ESA) 114 Mousterian tradition 121 archaic Homo sapiens 117 Homo 109 Homo erectus 112 Neandertals 119 Oldowan tradition 110 omnivorous 100 Australopithecus 100 bipedalism 98 blades 127 intrusions 123 macroevolution 96 microevolution 96 phyletic gradualism 97 punctuated equilibrium 97 regional continuity model 119 replacement model 118 species selection 98 taphonomy 110 Upper Paleolithic/Late Stone Age (LSA) 127 Suggested Readings Dahlberg, Frances, ed. 1981. Woman the gatherer. New Haven: Yale University Press. A classic collection of essays challenging the “man the hunter” scenario using bioanthropological data and ethnographic evidence from four different foraging societies. Gamble, Clive. 1994. Timewalkers. Cambridge, MA: Harvard University Press. Gamble argues that our species’ ability to colonize the world was the result of exaptation of attributes we evolved for other purposes. Usefully read in conjunction with the Potts volume below. Kennis and Kennis Reconstructions. http://www .kenniskennis.com. The achievements of the Kennis brothers in reconstructing the appearance of Neandertals and other fossil hominins are extraordinary. The brothers are sticklers for scientific accuracy, yet their imaginative sensibilities allow them to create sculptures that appear plausibly lifelike. Lee, Richard, and Irven DeVore, eds. 1968. Man the hunter. New York: Aldine. The classic collection of articles that undergirded the “man the hunter” scenario of human origins— and paradoxically offered evidence for its critique. Lewin, Roger. 1999. Human evolution: An illustrated introduction, 5th ed. Boston: Blackwell. A highly readable introduction to human evolution. Lewin, a science journalist, has worked closely with Richard Leakey and cowritten three books about human origins with him. Morell, Virginia. 1996. Ancestral passions: The Leakey family and the quest for humankind’s beginnings. New York: Simon & Schuster. A biography of the Leakey family over several generations that brilliantly contextualizes their contributions to paleoanthropology. Pääbo, Svante. 2014. Neanderthal man. New York: Basic Books. Svante Pääbo is the director of the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. This volume is an engaging account of his personal and professional life, centering on how he and his team of scientists succeeded in sequencing Neandertal mitochondrial DNA, the first draft Neanderthal genome, and the Denisovan genome, thereby revolutionizing the study of extinct human populations. Among other things, Pääbo’s professional history illustrates the science-studies point that cutting-edge science within the laboratory depends on the laboratory director’s skills outside the laboratory, securing the necessary funds, staffing, materials, and equipment. In the twenty-first century, these negotiations are global in scope, and Pääbo’s skills have been masterful. Potts, Rick. 1996. Humanity’s descent. New York: William Morrow. A survey of human evolution, in which evidence is presented that the great flexibility of modern Homo sapiens resulted from selection for the ability to survive wide fluctuations in environments, rather than adaptation to any single environment. Usefully read in conjunction with the Gamble volume above. Shreeve, James. 1995. The Neandertal enigma . New York: Avon Books. A science journalist’s account of the controversy between replacement and regional continuity theorists, all of whom we meet in this engaging volume. Stringer, Chris. 2012. Lone survivors. New York: Holt. Stringer is best known for proposing that our species had a recent origin in Africa some 200,000 years ago, after which we moved out of Africa and eventually replaced earlier populations of hominins. This volume contains his current views about evolution of Homo sapiens —the “lone survivors” of millions of years of hominin evolution—and also discusses his involvement with scientists who have developed new and reliable dating methods for the earliest fossils of modern humans.