Modern Humans Homo sapiens Origin Theories

Time Line

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

Homo sapiens sites in Europe

Transformation Reduced robusticity-everything gets smaller Reduced robusticity-everything gets smaller Back teeth continue to reduce, so do front teeth Back teeth continue to reduce, so do front teeth Cranial buttresses much less in evidence Cranial buttresses much less in evidence loss of brow ridgeloss of brow ridge development of chindevelopment of chin Sexual dimorphism reduces to modern levels Sexual dimorphism reduces to modern levels

Homo sapiens

What causes this overall reduction? Teeth and cranial buttresses: food processing Teeth and cranial buttresses: food processing Especially cooking technologyEspecially cooking technology Earth ovensEarth ovens Reduced selection for big molarsReduced selection for big molars

What causes this overall reduction? Skel. robust. & sex. dimorph.: projectiles & string Skel. robust. & sex. dimorph.: projectiles & string With modern humans, first projectile weaponsWith modern humans, first projectile weapons Atlatl (spear-thrower)Atlatl (spear-thrower) No close quarter killing of big-gameNo close quarter killing of big-game Selection reduced for maintaining big bones Selection reduced for maintaining big bones Sex. dimorph: males get relatively smaller Sex. dimorph: males get relatively smaller

Atlatl

Cro Magnon Species:Homo sapiens Age:~30,000 years Date of Discovery: March 1868 Location: Les Eyzies, Dordongne, France Discovered by: Louis Lartet

Skuhl 5 Species:Homo sapiens Age:~ 90,000 years Date of Discovery: May 2, 1932 Location: Mount Carmel, Israel Discovered by: T. McCown and H. Moivus, Jr.

Upper Paleolithic Tools

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

Replacement Theory (Eve Hypothesis) Hominid populations genetically separated during the Middle Pleistocene (before 200,000 B.P.), evolving independently. Hominid populations genetically separated during the Middle Pleistocene (before 200,000 B.P.), evolving independently. Between 100,000 and 200,000 years ago modern humans evolved in Africa and spread out, replacing archaic H. sapiens.Between 100,000 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. Little or no gene flow as modern humans replaced local populations, all genes necessary for moderns assembled in Africa.

“Mostly” Out of Africa Modern Humans evolved in Africa around 150,000 years ago. Modern Humans evolved in Africa around 150,000 years ago. Spread to Asia, Middle East and Europe and replaced earlier settlers. 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. 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.This allowed a very few Neanderthal traits to persist in living populations in very small percentages.

Lagar Velho 1 Skeleton

Neanderthal/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.

Lagar Velho 1 Skeleton Presence of artifacts in burial also a modern trait.

Chin-on Lagar Velho Specimen, not on Neanderthals Lagar Velho 1

Evidence: Fossils Evidence from Europe and Middle East is inconsistent with Multiregional model. Evidence from Europe and Middle East is inconsistent with Multiregional model. long period of overlap between Neanderthal and moderns in this area.long period of overlap between Neanderthal and moderns in this area. anatomically modern people appeared 60,000 years before Neanderthals disappeared.anatomically modern people appeared 60,000 years before Neanderthals disappeared.

Evidence: Archaeological Cave sites in Israel, most notably Qafzeh and Skhul date to nearly 100,000 years and contain skeletons of anatomically modern humans. Cave sites in Israel, most notably Qafzeh and Skhul date to nearly 100,000 years and contain skeletons of anatomically modern humans. Qafzeh Cave

Amud and Kebara 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 for at least 45,000 years. 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 for at least 45,000 years. Therefore, if Homo sapiens were in this region for some 45,000 years prior to the disappearance of the Neanderthals, there is no reason to assume that Neanderthals evolved into modern humans. Therefore, if Homo sapiens were in this region for some 45,000 years prior to the disappearance of the Neanderthals, there is no reason to assume that Neanderthals evolved into modern humans.

Amud Cave, Israel

Evidence: Tools/Culture Tools associated with moderns are not found with Neanderthals. Tools associated with moderns are not found with Neanderthals. A remarkable diversity in stone tool types for moderns. A remarkable diversity in stone tool types for moderns. tool types showed significant change over time and spacetool types showed significant change over time and space artifacts were regularly fashioned out of bone, antler and ivory, in addition to stoneartifacts 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 usestone artifacts were made primarily on blades and were easily classified into discrete categories, presumably reflecting specialized use

Bone Tools

Upper Paleolithic tools Aurignacian blades Dufour bladeletBone point

Tools/Culture con’d Burials were accompanied by ritual or ceremony and contained a rich diversity of grave goods Burials were accompanied by ritual or ceremony and contained a rich diversity of grave goods Living structures and well-designed fireplaces were constructed Living structures and well-designed fireplaces were constructed Raw materials such as flint and shells were traded over some distances Raw materials such as flint and shells were traded over some distances

Double Burial from Skuhl (adult female and young child)

Genetic Evidence Contemporary patterns of genetic variation provide clues to origins of modern humans Contemporary patterns of genetic variation provide clues to origins of modern humans Mitochondrial DNA (mtDNA) passed from mother to her children, an exact copy of genetic material. Mitochondrial DNA (mtDNA) passed from mother to her children, an exact copy of genetic material. Humans are less genetically variable than other populations-suggests population explosion. Humans are less genetically variable than other populations-suggests population explosion.

Genetic Evidence, con’d The high degree of similarity between human populations stands in strong contrast to the condition seen in our closest living relatives, the chimpanzees. The high degree of similarity between human populations stands in strong contrast to the condition seen in our closest living relatives, the chimpanzees. In fact, there is significantly more genetic variation between two individual chimpanzees drawn from the same population than there is between two humans drawn randomly from a single population. In fact, there is significantly more genetic variation between two individual chimpanzees drawn from the same population than there is between two humans drawn randomly from a single population.

Genetic Evidence 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. 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. 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, Homo sapiens arose between 100,000 and 200,000 years ago in Africa. Using the genetic distance between African populations and others as a measure of time, Homo sapiens arose between 100,000 and 200,000 years ago in Africa.

Genetic Evidence The low amount of genetic variation in modern human populations suggests that our origins may reflect a relatively small founding population for Homo sapiens. The low amount of genetic variation in modern human populations suggests that our origins may reflect a relatively small founding population for Homo sapiens. Analysis of mtDNA by Rogers and Harpending supports the view that a small population of Homo sapiens, numbering perhaps only 10,000 to 50,000 people, left Africa somewhere between 100,000 and 200,000 years ago. Analysis of mtDNA by Rogers and Harpending supports the view that a small population of Homo sapiens, numbering perhaps only 10,000 to 50,000 people, left Africa somewhere between 100,000 and 200,000 years ago.

Neanderthal mtDNA Scientists recently succeeded in extracting DNA from several Neanderthal skeletons. 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.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. In assessing the degree of difference between DNA in Neanderthals and modern humans, the authors suggest that these two lineages have been separated for more than 400,000 years.In assessing the degree of difference between DNA in Neanderthals and modern humans, the authors suggest that these two lineages have been separated for more than 400,000 years.

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

Why important? Resolution of this controversy because it affects our view of contemporary human variation. Resolution of this controversy because it affects our view of contemporary human variation. Affects our perspective about the significance of genetic differences and modern human populations. Affects our perspective about the significance of genetic differences and modern human populations. If replacement model correct, then all humans descended from a lineage that arose around 100, ,000 years ago. If replacement model correct, then all humans descended from a lineage that arose around 100, ,000 years ago. If multiregional correct then humans related as long as 1 million years ago and arose separately from there. If multiregional correct then humans related as long as 1 million years ago and arose separately from there.