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Modern Humans

Modern Humans. Homo sapiens Origin Theories Evidence. Time Line. Homo sapiens (ca. 200 kya…). Fully modern humans Upper Paleolithic tool technology Elaborate Cave Art. Homo sapiens sites in Europe. Transformation. Reduced robusticity Everything gets smaller

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Modern Humans

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  1. Modern Humans Homo sapiens Origin Theories Evidence

  2. Time Line

  3. Homo sapiens(ca. 200 kya…) • Fully modern humans • Upper Paleolithic tool technology • Elaborate Cave Art

  4. Homo sapiens sites in Europe

  5. Transformation • Reduced robusticity • Everything gets smaller • Back teeth continue to reduce, so do front teeth • Cranial buttresses much less in evidence • loss of brow ridge • development of chin • Skeletal robusticity markedly less • Sexual dimorphism reduces to modern levels

  6. Homo sapiens

  7. What causes this overall reduction? • Teeth and cranial buttresses: food processing • Especially cooking technology • Earth ovens maybe during late Neanderthal times • Reduced selection for big molars • Skel. robust. & sex. dimorph.: projectiles & string • With a.m. humans, first projectile weapons • Atlatl (spear-thrower) & bow and arrow • No close quarter killing of big-game • Selection reduced for maintaining big bones • Sex. dimorph: males get relatively smaller

  8. Cro Magnon http://www.mnh.si.edu/anthro/humanorigins/ha/cromagnon.html

  9. Cro Magnon • During construction for a railroad in 1868, a rock shelter in a limestone cliff was uncovered. • Near the back of the shelter, an occupation floor was recognized, and when excavated, it revealed the remains of four adult skeletons, one infant, and some fragmentary bones. • Cro-Magnon 1 preserved the skeleton of an adult male. • The individual was probably middle-aged (less than 50 years old) at his death on the basis of the pattern of closure of cranial sutures. • The bones in his face are noticeably pitted from a fungal infection. http://www.mnh.si.edu/anthro/humanorigins/ha/cromagnon.html

  10. Cro Magnon without teeth reconstruction. http://www.modernhumanorigins.net/cromagnon1.html

  11. Skuhl 5 http://www.mnh.si.edu/anthro/humanorigins/ha/skhul.html

  12. Skuhl 5 • The remains of this male individual, known as Skhul V, were recovered from the Skhul Cave near Mount Carmel, Israel, along with the skeletons of nine other adults and children. • The anatomical features of this skull are reminiscent of earlier, "archaic" humans. One notable example is the bony torus over the orbits. • It has a high forehead and an expanded frontal portion of the braincase. These are features typical of modern human skulls. http://www.mnh.si.edu/anthro/humanorigins/ha/skhul.html

  13. Wadjak 1 http://www.mnh.si.edu/anthro/humanorigins/ha/wadjak.html

  14. Wadjak 1 • This cranium was discovered in a rock shelter by miners near Wadjak, Java, in 1888 • The cranium shows an expanded forehead that rises near vertically from above the orbits. • This is associated with either a repackaging of brain tissue in the cranial braincase or an actual expansion of the frontal lobe of the brain.

  15. Omo 1& 2 Herto, Ethiopia http://www.sciencedaily.com/releases/2005/02/050223122209.htm

  16. Omo 1 & 2

  17. Omo 1 & 2 • Two early humans were found in 1967 near Kibish, Ethiopia, they were thought to be 130,000 years old. A few years ago, researchers found 154,000- to 160,000-year-old human bones at Herto, Ethiopia. • Now, a new study of the 1967 site indicates the earliest known members of our species, Homo sapiens, roamed Africa about 195,000 years ago. (The fossils were closer to a layer dated to 195 kya, than the upper layer dated to 130 kya). http://www.sciencedaily.com/releases/2005/02/050223122209.htm

  18. Modern Human Origin Theories • Multiregional Evolution Model • Wolpoff • Replacement Model • Stringer and Andrews • “Mostly” Out of Africa Model • Relethford

  19. Multiregional Theory • After H. erectus left Africa, spread to other areas of the world, and evolved into modern humans. • Human populations linked throughout the world were linked by gene flow. • Caused modern humans to evolve as a single species from H. erectus to Archaic H. sapiens to H. sapiens all over the world. • Also separated by distance and environment so had considerable regional variation in morphology. • All genes arose in many parts of the world and were mingled together as people from different regions mated.

  20. Replacement Theory (Eve Hypothesis) • Hominid populations genetically separated during the Middle Pleistocene (before 200,000 B.P.), evolving independently. • Between 150,000 and 200,000 years ago modern humans evolved in Africa and spread out, replacing archaic H. sapiens. • Little or no gene flow as modern humans replaced local populations, all genes necessary for moderns assembled in Africa.

  21. “Mostly” Out of Africa • Modern Humans evolved in Africa around 150,000-195,000 years ago. • Spread to Asia, Middle East and Europe and replaced earlier settlers. • In Europe, with Neanderthals, this may have been complicated by absorption of Neanderthals into the Modern gene pool. • This allowed a very few Neanderthal traits to persist in living populations in very small percentages.

  22. Evidence: Fossils • Evidence from Europe and Middle East is inconsistent with Multiregional model. • long period of overlap between Neanderthal and moderns in this area. • anatomically modern people appeared 60,000 years before Neanderthals disappeared. • Most recent Neanderthal found at St. Cesaire ca. 30 kya, earliest anatomically Modern in Europe dates to 60,000. http://www.actionbioscience.org/evolution/johanson.html

  23. Evidence: Archaeological • Cave sites in Israel, most notably Qafzeh and Skhul date to nearly 100,000 years and contain skeletons of anatomically modern humans. • Furthermore, Neanderthal remains are known from sites such as the 110,000-year-old Tabun cave, which predates the earliest Homo sapiens by about 10,000 years in the region.  • The presence of Neanderthals at two other caves in Israel, Amud and Kebara, dated to roughly 55,000 years means that Neanderthals and Homo sapiens overlapped in this region. • Therefore, if Homo sapiens were in this region prior to the disappearance of the Neanderthals, there is no reason to assume that Neanderthals evolved into modern humans. http://www.actionbioscience.org/evolution/johanson.html

  24. Evidence: Archaeological • Archaeological evidence from Europe suggests that Neanderthals may have survived in the Iberian Peninsula until perhaps as recently as 28,000 to 35,000 years ago. • Fully modern humans first appear in Europe, bringing with them an Upper Paleolithic tool tradition referred to as the Aurignacian. • Hence, Neanderthals and fully modern humans may have overlapped in Europe. • Again, with fully modern humans on the scene, it is not necessary to have Neanderthals evolve into modern humans, further bolstering the view that humans replaced Neanderthals.  http://www.actionbioscience.org/evolution/johanson.html

  25. Evidence: Tools • Tools associated with moderns are not found with Neanderthals. • Overlap of tools suggest that the modern morphology arrived in Europe due to the movement of people, not of genes. • A remarkable diversity in stone tool types  • tool types showed significant change over time and space  • artifacts were regularly fashioned out of bone, antler and ivory, in addition to stone  • stone artifacts were made primarily on blades and were easily classified into discrete categories, presumably reflecting specialized use  • Burials were accompanied by ritual or ceremony and contained a rich diversity of grave goods  • Living structures and well-designed fireplaces were constructed • Hunting of dangerous animal species and fishing occurred regularly  • Higher population densities  • Raw materials such as flint and shells were traded over some distances  http://www.actionbioscience.org/evolution/johanson.html

  26. Paleolithic Tool Traditions In Europe http://anthro.palomar.edu/homo2/mod_homo_5.htm

  27. Evidence: Biological Distance • In plots of cranial measurements, modern European forms at ca. 15-25 kya look more similar to early modern African forms at 100-130 kya. • In contrast, Neanderthals are considerably distant from both.

  28. Evidence: Genetic • Contemporary patterns of genetic variation provide clues to origins of modern humans mtDNA, mitochondrial DNA passed from mother to her children, an exact copy of genetic material. • Humans are less genetically variable than other populations-suggests population explosion. • Studies of contemporary DNA, especially mitochondrial DNA (mtDNA) which occurs only in the cellular organelles called mitochondria, reveal that humans are astonishingly homogeneous, with relatively little genetic variation. 

  29. Evidence: Genetic • In support of an African origin for Homo sapiens the work of Cann and Wilson has demonstrated that the highest level of genetic variation in mtDNA occurs in African populations. • This implies that Homo sapiens arose first in Africa and has therefore had a longer period of time to accumulate genetic diversity. • Using the genetic distance between African populations and others as a measure of time, they furthermore suggested that Homo sapiens arose between 100,000 and 400,000 years ago in Africa. 

  30. Evidence: Genetic • Scientists recently succeeded in extracting DNA from several Neanderthal skeletons. • After careful analysis of particularly the mtDNA, but now also some nuclear DNA, it is apparent that Neanderthal DNA is very distinct from our own but not entirely different. • Genetic data suggests that Neandertals may have been absorbed by the larger population of Moderns coming into Europe, with the Neandertal “type” disappearing around 28 kya. 

  31. Lagar Velho 1 Skeleton

  32. Neandertal/Human Hybrid?? • Analysis of the skeletal remains of this four-year-old boy has revealed that he may be a Neandertal-Cro-Magnon hybrid. • Found in a Portuguese rock-shelter and dating to 25,000 to 24,500 years ago has yielded startling evidence that early modern humans and Neandertals may have interbred. • While the boy's prominent chin, tooth size, and pelvic measurements marked him as a Cro-Magnon, or fully modern human, his stocky body and short legs indicate Neandertal heritage, according to Erik Trinkaus, a paleoanthropologist at Washington University in St. Louis.

  33. Lagar Velho 1 Skeleton

  34. Chin-on Lagar Velho Specimen, not on Neandertals Lagar Velho 1

  35. Implications • Suggestions from mtDNA • Human populations spread out across the globe well before any major population expansion took place. • Size of pop before expansion was between 10 and 50,000 people. • Major expansion of people beginning around 100,000 years ago in Africa and 50,000 years ago in the rest of the world.

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