The Origin of Man: Dating a Neanderthal Dating Techniques: AMS Carbon Dating Decay Law: N(t)=N 0 (e...

The Origin of Man:

Dating a Neanderthal

Dating Techniques:

AMS Carbon Dating• Decay Law: N(t)=N0(e

λt)

• 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

Dating Techniques:

AMS Problems…• Event Horizon: 40,000 BP

– Contamination

– Low amounts of remaining 14C • Fluctuation of 14C/ 12C ratio• Correction by dendrochronology

• 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

Dating Techniques:

Thermoluminescence

RANGE: 2,000 500,000 BP

• Measures radioactive decay following uptake of uranium into the carbonate as it forms.

• Use decay rates for uranium and thorium.

• Useful in European caves.

Dating Techniques:

Uranium-Series

RANGE: 5,000 350,000 BP

Our Story:

Early Hominids

Our Story:

Early Hominids

australopithecus

Homo erectus

Homo habilis

A. afarensis 3.9-2.9 mya

• Bipedal• “Lucy” 3.2 mya

Our Story:

Early Hominids

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 HominidsH. habilis 2 mya• 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.

CENSORED

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

Skull Description• Low forehead region• Prominent brow

ridge• Large nasal cavity• Forward-projecting

cheek and nasal regions

Our Story:

Neanderthal Traits• Non-projecting jaw•Space behind third molar•1500-1600 cm3 cranial capacity

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:

Dimwitted Brute?

• Whence came modern man?

• How did Neanderthal and Cro-Magnon interact?

Our Story:

Theories of Origin

Out of Africa 1

•Out of Africa 1

–1.7 million BP

–Homo erectus leaves Africa and spreads across Eurasia

• Modern man: all groups have evolved from Erectus groups spread across the continents.

Our Story:

Multiregionalism

                                                              •Gene flow accounts for similarities we observe today.•Favored by racists in the past to account for a “superior race.”

• Neanderthals develop from Erectus population

Our Story:

Out of Africa 2

• 2nd Exodus from Africa 70,000 BP• Population replacement wipes out other hominids: including Neanderthals

• Modern man developed independently in Africa 200,000 BP

Application:

AMS Carbon Dating

•Could Cro-Magnon and Neanderthal have mixed after Out of Africa II?

•When did they disappear?

30,000 BP

•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!

• 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:

Lagar Velho

• 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 CaveAmud Cave• Burnt flints in ash layersBurnt flints in ash layers• 19 were able to be tested 19 were able to be tested • 14 in upper two levels14 in upper two levels

– 44,000-70,000 BP44,000-70,000 BP– 70% were 50,000-60,000 70% were 50,000-60,000

BPBP• 5 from lower layer5 from lower layer

– 55,000-76,000 BP55,000-76,000 BP– 4 were 65,000-76,0004 were 65,000-76,000

• Results/ConclusionResults/Conclusion– Normal intra-species Normal intra-species

variationvariation

Application:

Thermoluminescence

Application:

Uranium-Series

Pontnewydd Cave in Whales.– Found bones, teeth, flint, stone axes, scrapers, &

arrowheads– Dated to 250,000 BPUncovered Neanderthal hunter-gatherer & his

children

The End!