Modern Humans

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

20. 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.

21. 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.

22. “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.

23. 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

24. 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

25. 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

26. 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

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

28. 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.

29. 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. 

30. 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. 

31. 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. 

32. Lagar Velho 1 Skeleton

33. 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.

34. Lagar Velho 1 Skeleton

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

36. 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.