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The Origin of Man: Dating a Neanderthal

The Origin of Man: Dating a Neanderthal. Dating Techniques: AMS Carbon Dating. Decay Law: N(t)=N 0 (e λt ) Previous Technique Larger Sample Measure Activity Comparison of 14 C/ 12 C ratio Accelerator Mass Spectrometry Smaller Sample Send atoms through accelerator. Separate Isotopes

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The Origin of Man: Dating a Neanderthal

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  1. The Origin of Man:Dating a Neanderthal

  2. Dating Techniques:AMS Carbon Dating • Decay Law: N(t)=N0(eλt) • Previous Technique • Larger Sample • Measure Activity • Comparison of 14C/12C ratio • Accelerator Mass Spectrometry • Smaller Sample • Send atoms through accelerator • Separate Isotopes • Obtain very accurate atom-by-atom count for 14C/12C ratio RANGE: Present  40,000 BP

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

  4. 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

  5. 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

  6. Our Story:Early Hominids

  7. Our Story:Early Hominids Homo erectus australopithecus Homo habilis

  8. 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

  9. Our Story:Early Hominids CENSORED CENSORED • H. habilis 2mya • Possibly rudolfensis as well (2.4 mya) • Larger brain • First to make tools • H. Erectus 1.9 mya • Ergaster is early African erectus. • Even Larger brain. Shorter face, arms • Human proportions.

  10. 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

  11. Our Story:Neanderthal Traits • Non-projecting jaw • Space behind third molar • 1500-1600 cm3 cranial capacity Skull Description • Low forehead region • Prominent brow ridge • Large nasal cavity • Forward-projecting cheek and nasal regions

  12. 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

  13. 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

  14. 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.”

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

  16. 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!

  17. 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?

  18. 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

  19. 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

  20. 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

  21. The End!

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