The Origin & Dispersal of Modern Humans Chapter 15 The Origin & Dispersal of Modern Humans

Anatomically Modern Homo sapiens (AMH) Earliest evidence of AMH are the remains of the Omo I skull from Omo, Ethiopia. Date to 195 kya.

AMH Skull Characteristics High, well-rounded skull Rounded back, no occipital bun Small brow ridges Face protrudes little Chin Vertical forehead Border Cave, South Africa, at least 100 kya

Homo sapiens All contemporary populations are placed within H. sapiens.

Why did AMHs Evolve? Language Some argue a recent and sudden evolution of language ability (although Neanderthals may also have had language). Others suggest there was little difference in linguistic ability between archaics and moderns. We are not sure then if language abilities were the reason for why AMH evolved.

Why did AMHs Evolve? Biological Change Why the change from large teeth, faces, and bones? Structural characteristics of archaics may have been the result of stresses generated by the use of front teeth as tools.

Why did AMHs Evolve? Biological Change As cultural behaviors were relied upon, these larger features were no longer adaptive. Evidence indicates that large teeth would have been maladaptive once technology advanced, and so they were selected against

Models of AMH Origins What was the nature of the transition from archaic to modern humans? Cladogenesis (branching speciation) Anagenesis (change within a species) If AMH arose through cladogenesis, in what part of the world did modern humans arise as a new species?

African Replacement Model (ARM) Proposes that modern humans emerged as a new species (cladogenesis) in Africa between 200 and 150 kya. Some populations left Africa around 100 kya and spread throughout the Old World. Neanderthals and all other archaic populations outside of Africa became extinct and are not part of our ancestry.

African Replacement Model (ARM) (Fig. 13.16)

African Replacement Model

Multiregional Model (MRM) (“Regional Continuity Model” in Stein) Proposes that human evolution over the past two million years occurred within a single evolving lineage (anagenesis), from Homo erectus to archaic humans to modern humans. AMH started in Africa as H. erectus, later spread into Asia and Europe, continuing to evolve over time and kept coherent by GF among the groups.

The Origins of Homo sapiens The regional continuity model (per Stein; =MRM, not AM): Assumes multiple origins of H. sapiens from existing local populations. For example, Neandertals would have given rise to modern Europeans. Gene flow would have maintained existing hominin species as a single species, H. sapiens.

The Origins of Modern Humans [Stein Figure 15-5]

Assimilation Model (AM) (not in Stein) Proposes that the initial change from archaic to modern anatomy took place in Africa (like ARM); these changes then spread to other populations outside of Africa through GF (anagenesis, like MRM). This model claims that interbreeding occurred between emigrating Africans and resident premodern populations.

Comparison of the 3 Models

Review Assignment: Evaluating the Models Break into small groups and discuss three types of evidence Morphology in time and space Genetics Archaeological What patterns do you think would support each of the three models just profiled?

ARM vs MRM vs AM: Expectations ARM: expect modern humans to appear in Africa first and then replace the archaics (no evidence of GF or regional continuity) MRM: expect AMH to appear around the same time around the Old World. AM: expect the earliest evidence of AMH in Africa, but also evidence of GF (including regional continuity) with archaics in Africa, Asia, and Europe

Time Line of Modern Homo Sapiens Discoveries: What do the Data Say?

Herto Cranium From Ethiopia, dated 160,000–154,000 ya. Adult Mosaic of modern and premodern traits Very large, and extremely long cranial vault Large, arching browridge and projecting occipital bun

Specimens From Israel Skhül 5. (Earliest evidence of AMH outside of Africa) 130,000-100,000 ya Qafzeh 6 (b) 120,000-92,000 ya The vault height, forehead, and lack of prognathism are modern traits. Contemporary with Neandertals in Region

Mladec and Dolní Crania The Mladec (a) and Dolní Věstonice (b) crania from the Czech Republic, is a good example of early modern Homo sapiens in central Europe. Along with Oase in Romania, the evidence for early modern H. sapiens appears first in central Europe, then later in western Europe.

Cro-Magnon I Cro-Magnon I (France). In this specimen, modern traits are quite clear. (a) Lateral view, (b) Frontal view

Geography of Modern Humans in East Asia and Australia

Australia 50,000 ya modern humans inhabited Sahul, area including New Guinea and Australia Lake Mungo, SE Australia (60,000?) 30,000-25,000 ya Kow Swamp 14,000-9,000 ya fossils with archaic features, including receding foreheads, heavy brow ridges, and thick bones; some of the archaic ‘strangeness’ of these is now attributed to cultural deformation

Kow Swamp 1

Anatomically Modern Homo sapiens (AMH) Distribution in Time and Space: Africa: 195-160 kya (thousand years ago) Near East: 92 kya Australia (by boat): 60-46 kya Europe: 40-30 kya N. and S. America (via the Bering Land Bridge and/or boat): 20-15 kya

Migrations of AMH

Origins: Fossil Evidence Fossil evidence is compatible with the ARM and the AM. It shows modern humans first appeared in Africa then later outside of Africa. The data so far show that AMH first appeared in Africa, then in the Middle East, then in Europe.

Origins: Regional Continuity Regional continuity of many traits within regions is predicted by the AM. If AMHs spread and mixed with different archaic populations that had evolved variations (NS and GD)… the resulting mixed populations would retain some of the variations inherited from their archaic ancestors.

Abrigo do Lagar Velho Child Possible AMH-Neanderthal “hybrid”

GENETIC EVIDENCE FOR OUT OF AFRICA II Researchers from Berkeley generated a computerized model of Homo evolution Based upon the average rate of mutation in known samples of mtDNA Everyone alive today has mtDNA that descends from a woman (“Eve”) who lived in sub-Saharan Africa around 200,000 years ago

THE NEANDERTHALS In 1997, DNA extracted showed that the Neandertal Y-chromosome differs significantly from modern humans 27 differences between modern humans and Neandertal Samples of DNA from modern populations worldwide show only 5 to 8 differences

THE NEANDERTHALS Pääbo: 2.5% of Neanderthal genome more similar to the DNA of living Europeans and Asians than to African DNA Suggests Neandertals interbred with AMHs soon after the latter emerged in Africa

THE DENISOVANS Denisovans distant cousins to Neandertals Lived in Asia from 400,000 to 50,000 years ago Split between ancestral Neandertals and Denisovans around 400,000 years ago

Recent Genetic Evidence Modern human populations outside of Africa possess1-4% of distinctive Neandertal DNA Melanesian populations contain 4-5% of distinctive Denisovan DNA Suggests interbreeding of premodern and modern populations (AM)

Neanderthals: DNA and Variation A 2007 international study of Neanderthal DNA found that they may have varied as much as modern humans in terms of skin and hair color. The remains of 2 individuals suggest at least 1% of Neanderthals were likely redheads.

Origins: Consensus? The ARM and the AM have some support from fossil and genetic evidence. Fossil evidence for regional continuity outside of Africa points to the AM. Our recent origins can be considered mostly, but not exclusively, out of Africa.

Real Hobbits?

Location of the Flores Site, Indonesia

Homo floresiensis Discovered in 2003. 8 nearly complete skeletons (but only one skull) dated between 94 and 12 kya. Adults were only ~3.5 ft tall AND had cranial capacity of ~417 cc (smaller than H. habilis!). Associated tools were found suggesting intelligence and culture.

Homo floresiensis Either a new species evolved from H. erectus through founder effect and island dwarfism …OR AMHs with a pathological disease. Fossils of other species, including a miniature elephant, were found on Flores. It is also unlikely that this was caused by disease because all of the fossils are the same general size.

Homo floresiensis There is still much debate and more research to carry out. If these fossils represent a separate species, it means that another hominid co-existed alongside AMH more recently than 20 kya. H. floresiensis and H. sapiens sapiens

Homo Tools: Time Frame General terms for stone tool technologies: Lower Palaeolithic: H. habilis, H. rudolfensis, and erectus. Middle Palaeolithic (≅Middle Pleistocene): H. heidelbergensis and neanderthalensis Upper Palaeolithic: AMH. This lasted until the Mesolithic in Europe (c. 12 kya).

Upper Palaeolithic Tools More precisely made, more diverse functions and styles. Blades (2x as long as wide). Burins- special tools to make other bone tools (needles, awls, points, knives, harpoons) and art or decorative objects.

Upper Palaeolithic Tools A burin (a) and a blade (b)

Technological Innovations

Upper Palaeolithic Tools: Blades

Upper Palaeolithic Tools: Blades and Other Tools

Upper Palaeolithic Tools Bone, ivory and antler become more widely used raw materials Bone Awl

Upper Palaeolithic Shelter Caves and rock shelters like archaic hominids. First evidence of constructed shelters: huts of wood and bones of large mammals, such as mammoth, and animal hides. What would be the great advantage of having the technology to construct shelters?

Upper Palaeolithic Shelter Mal’ta, Russia shelter: 18 kya (Fig. 13.12); made of mammoth bone, other animal bones and hides, antler, wood, and boulders. Mezhirich, Ukraine shelters: 15 kya; 4 shelters made almost entirely of mammoth bones.

Reconstructed Shelter, Mezhirich, Ukraine

Innovations in Symbols More investment in grave offerings Variable social status reflected in grave offerings

Upper Palaeolithic Symbolism Symbolic expression emerged in Africa ~77 kya, then increased in frequency in across the Old World. Engravings and drilled shells are first documented at Blombos Cave, South Africa dated to 77-73 kya.

Earliest Symbolism: Blombos Cave, South Africa Shell beads (above), engraved ochre (below)

2nd Earliest Symbolism: Katanda, Republic of Congo Decorated bone harpoon point (88-78 kya)

Upper Palaeolithic Symbolism Cave paintings: Lascaux Cave, France (~17 kya), Altamira, Spain (~16.5-14 kya), and the Trois Frères, France (~13 kya). It began c. 30 kya in Europe, Africa, and Australia. Most are scenes of hunting and animals that would have been central to UP life.

Earliest Symbolism: Lascaux Cave, France The site is a long, complex system of chambers that has no natural light.

Lascaux Cave, France

Lascaux Cave, France

Altamira Cave, Spain

The Trois Frères Cave, France The “Sorcerer”

Aboriginal Bradshaw Rock Art between 26,500 and 20,000 years ago

Upper Palaeolithic Symbolism Several interpretations for this ‘non-functional’ activity: Sympathetic magic. Cultural expression. Transmission of cultural ideas (i.e., teaching). All of these may have been functions served by this early art.

Upper Palaeolithic Symbolism There also were engravings, beads, pendants, and sculptures. “Venuses” are engraved statuettes found from east-central Russia to northern Spain. They were made of soft stone, bone, ivory, or fired clay. They ranged from 4-25 cm in height.

Venus Figurines

Upper Palaeolithic Symbolism The Venus figurines often show large-breasted and large-hipped females, possibly representing goddesses, abstract fertility, and/or actual women.

Upper Palaeolithic Symbolism It is unlikely that they represent women because cultural anthropological data suggest women would rarely be so large, whereas later fertility goddess statues often highlight large breasts and hips.

Venus Figurines

Upper Palaeolithic Symbolism There have only been a few UP phalli found. The oldest is from Hohle Fels Cave, Germany and is dated to 28 kya. It is 20x3 cm.

Recent Biological and Cultural Evolution in Homo sapiens Human evolution continues! Most of the major changes in the recent past (~10-15 kya) have been cultural. Agriculture and other manipulations of environment have led to many changes. Industrialization and recent technological changes have led to an incredibly rapid rate of cultural change.