The Origin of Man Dating a Neanderthal Dating

The Origin of Man: Dating a Neanderthal

Dating Techniques: AMS Carbon Dating • Decay Law: N(t)=N 0(eλt) • Previous Technique – Larger Sample – Measure Activity • Comparison of 14 C/12 C ratio • Accelerator Mass Spectrometry – Smaller Sample • Send atoms through accelerator – Separate Isotopes – Obtain very accurate atom-by-atom count for 14 C/12 C ratio RANGE: Present 40, 000 BP

Dating Techniques: AMS Problems… • Event Horizon: 40, 000 BP – Contamination – Low amounts of remaining 14 C • Fluctuation of 14 C/ 12 C ratio • Correction by dendrochronology

Dating Techniques: Thermoluminescence • Procedure – Crystalline structured material absorbs radiation which is released when heated. – Heating the sample releases the captured energy which can be measured, thus revealing the age. • History RANGE: 2, 000 500, 000 BP

Dating Techniques: Uranium-Series • Measures radioactive decay following uptake of uranium into the carbonate as it forms. • Use decay rates for uranium and thorium. • Useful in European caves. RANGE: 5, 000 350, 000 BP

Our Story: Early Hominids

Our Story: Early Hominids Homo erectus Homo habilis australopithecus

Our Story: Early Hominids A. afarensis 3. 9 -2. 9 mya • Bipedal • “Lucy” 3. 2 mya A. boisei/robustus 2. 3 -1 mya • Larger brain • Huge teeth (gorilla-like) • Discovery led to thoughts of co-existence of two hominid species

Our Story: Early Hominids H. habilis 2 mya • Possibly rudolfensis as well (2. 4 mya) • Larger brain • First to make tools CENSORED H. Erectus 1. 9 mya • Ergaster is early African erectus. • Even Larger brain. Shorter face, arms • Human proportions. CENSORED

Our Story: Who is “Neanderthal”? Basic Characteristics • Short stature • Great muscle mass • Large boned skeleton • Heavy build • Males: 1. 7 m tall 84 kg • Females: 1. 5 m tall 80 kg

Our Story: Neanderthal Traits Skull Description • • Low forehead region Prominent brow ridge Large nasal cavity Forward-projecting cheek and nasal regions • Non-projecting jaw • Space behind third molar • 1500 -1600 cm 3 cranial capacity

Our Story: Dimwitted Brute? Stereotype is wrong! • Walked fully upright • Had some thought of the hereafter – Burial sites/graves • Made own tools – Stone flints – Was human; distinction from animals

Our Story: Theories of Origin • Whence came modern man? • How did Neanderthal and Cro-Magnon interact? • Out of Africa 1 – 1. 7 million BP –Homo erectus leaves Africa and spreads across Eurasia Out of Africa 1

Our Story: Multiregionalism • Modern man: all groups have evolved from Erectus groups spread across the continents. • Gene flow accounts for similarities we observe today. • Favored by racists in the past to account for a “superior race. ”

Our Story: Out of Africa 2 • Modern man developed independently in Africa 200, 000 BP • Neanderthals develop from Erectus population • 2 nd Exodus from Africa 70, 000 BP • Population replacement wipes out other hominids: including Neanderthals

Application: AMS Carbon Dating • When did they disappear? 30, 000 BP • Could Cro-Magnon and Neanderthal have mixed after Out of Africa II? • Evidence of co-existence for up to 10, 000 years in some areas! • 1998: Lagar Velho –Dates to about 25, 000 BP –Skull displays mix of Cro-Magnon and Neanderthal characteristics!

Application: Lagar Velho • Neanderthals (in the full sense) disappeared from Portuguese region 5, 000 years before Lagar Velho was born. • In many places (France, Russia, Balkans) it looks as if Cro-Magnon man wiped out Neanderthal • Lagar Velho shows that in some cases they were not wiped out: they were mixed into Cro-Magnon society! • Big Questions: How many other Lagars are there? Do we have significant Neanderthal heritage?

Application: Thermoluminescence • Hélène Valladas and team • Kebara – Results of TL-dating: flint tools were ~60, 000 years old • Qafzeh – Results: skeleton would be ~92, 000 years old

Application: Thermoluminescence Amud Cave • • • Burnt flints in ash layers 19 were able to be tested 14 in upper two levels – 44, 000 -70, 000 BP – 70% were 50, 000 -60, 000 BP • 5 from lower layer – – 55, 000 -76, 000 BP 4 were 65, 000 -76, 000 • Results/Conclusion – Normal intra-species variation

Application: Uranium-Series Pontnewydd Cave in Whales. – Found bones, teeth, flint, stone axes, scrapers, & arrowheads – Dated to 250, 000 BP Uncovered Neanderthal hunter-gatherer & his children

The End!