Anthropology

Arboreal Hypothesis

Hypothesis that primates evolved as a niche adaptation to life in the trees

Visual Predation Hypothesis

Proposes that primates first adapted to shrubby forest undergrowth and many of their adaptations are for catching insects and other small prey

Angiosperm Radiation Hypothesis

Proposes that primates evolved alongside angiosperms (flowering plants) that began 140 million years ago

Epochs

Geologic division of time related to stratigraphy

Where did Platyrrhine ancestors come from?

Miocene

When did hominins split from chimpanzee and bonobo lineage?

6 - 8 million years ago

When did humans, bonobo and chimpanzee lineage split from the gorilla lineage?

9 million years ago

Hominini

Humans and human ancestors after split between Chimpanzee ancestral line and human ancestral line (6 - 8) million years ago

Trais that appeared later in Homo species

• ~2 million years ago - Significant brain size increase

• ~2 million years ago - Speech (proto-speech)

• ~2 million years ago - Hunting

• ~2.6 million years ago - Complex material culture & tools

Traits of pre-Homo

• Bipedal locomotion

• Non-honing chewing complex

Mosaic Evolution

Different features evolved at different times

Dental Arcade

Curve of the row of teeth in each jaw

Humans have a __________ shaped dental arcade

Parabolic

Honing Complex (CP3 Complex)

Dental structure in which the upper canine and lower premolar rubs against each other to stay sharp

__________ allows humans to eat harder foods

Enamel thickness

Do humans have a sagittal crest?

No

Bipedal organisms have a ____________ foramen magnum

anterior

Pre-Australopothecines

Early hominins that bridge the previous gap between hominid (chimpanzees and bonobos) and hominin (humans)

When did Pre-Australopothecines emerge?

6 -7 million years ago

Which species are the first evidence of hominin ancestors found in wooded habitats?

Pre-Australopothecines

What species were considered gracile?

A anamensis

A. afarensis

A. platyops

A. garhi

What species were considered robust?

A africanus

A robustus

A. sediba

A. aesthiopicus

A. boisei

Differences between gracile and robust australopithecines

Robust australopithecines have bone markers that indicate very large chewing muscles

Gracile - More prominent Prognathism

Megadontia Quotient (MQ)

- How big the molars are compared to front teeth

Which Australopithecines had more sexual dimorphism?

Robust

Dietary Hypothesis

- Different foods produce different microwear patterns on teeth

Australopithecus anamensis

• Fossils found in East Africa (1995)

  • Kenya

  • Ethiopia

  • 4 million years ago

  • Woodland habitat

• Oldest and most primitive confirmed australopithecine (so far)

• Probably a descendant of Ardipithecus ramidus

Traits of Australopithecus anamensis

Ancestral Traits

• Large canines

• Parallel tooth rows

  • U-shaped

Derived Traits

• Thick enamel

• Flexible elbow joint

• Thickened tibial plateu

  • Weight-bearing tibia

Australopithecus afarensis

• Fossils found in East Africa (1974)

  • Hadar, Ethiopia

  • Laetoli, Tanzania

  • 3.6 - 3 million years ago

• Most well-known australopithecine

• Dikika child

  • 3 year old child

• Lucy

  • Discovered by Donald Johanson

  • 40% complete adult female

Traits of Australopithecus afarensis

Cranial Characteristics

• Brain size —> 430 cc

• Prognathic face

• Large canines

• Parabolic tooth rows

  • Derived trait

  • Less u-shaped

Post-cranial characteristics

• Bipedal

  • Thickfemur - Fast runner

• Intermediate curved phalanges

• Short legs relative to arms

Who did the Laetoli Footprints likely belong to?

Australopithecus afarensis

Who were the first tool makers?

Australopithecus afarensis

Lomekwian Tools

• First appeared 3.5 - 3.2 million years ago

• Used by A. afarensis?

• Basic rock-smashing technology

Australopithecus platyops

• Fossils found in East Africa

  • Kenya

  • 3.5 million years old

    • Same time as A. afarensis

Traits of Australopithecus platyops

Primitive Traits

• Small brain size

  • Similar to A. afarensis

Derived Traits

• Flat face

Australopithecus garhi

• Fossils found in East Africa

  • Ethiopia

  • 2.5 million years old

• Combination of primitive and derived traits

• Likely ancestral to early Homo

Traits of Australopithecus garhi

Primitive Traits

• Large teeth compared to earlier Australopithecines

• Prognathic face

• Small brain (450 cc)

Derived Traits

• Arm/length ratio is similar

  • More human-like than ape-like

    • Less arboreal than earlier australopithecines

Oldowan Complex

• Lower Paleolithic stone tool culture

• Uses one stone to knock flakes of a core stone

• Earliest stone tool industry

  • ~2.3 - 1.7 million years ago

Could have been used by australopithecines or by Homo habilis

Traits of A. aethiopicus

Primitive Traits

• Small brain - 410 cc

• Prognathic face

Derived Traits

• Hyper-robust features

• Flaring zygomatic processes

• ‘Dished’ face

• Large sagittal crest

• Huge molars

• Thick enamel

Traits of A. Paranthopus boisei

• Small brain - 510 cc

• Hyper-robust

• Sagittal crest

• Massive premolars and molars

• Thick enamel

• Very specialized diet

Taung child

First australopithecine found ever

Traits of A. robustus

• Small brain - 530 cc

• Massive, flat face

• Large molars, small incisors

• Isotopic studies = Large quantities of meat in diet

• Thick enamel

  • Harder/tougher diet than A. africanus

A. sediba

• 2 - 1.8 million years ago

• Discovered in 2008

  • Malapa Cave, South Africa

A. robustus

• Fossils found in South Africa

  • 2 - 1.5 million years ago

• Descendant species of A. africanus

• Found at South African sites only

  • First discovery in 1938

  • Second australopithecine discovered

When did robusts go extinct?

1 million years ago

Traits of Homo

• Increased brain size

  • Especially EQ (brain/body size proportion)

• Brain sits higher in cranium

  • Round, high forehand

  • Reduced prognathism

• Smaller teeth, thicker enamel

• Increased body size

  • But less sexual dimorphism (pair bonding)

  • Longer stride, shorter arms

• Clear tool use/evidence of culture

Homo habilis

• “Handy man” (1964)

  • First makers of stone tools

• One of the earliest members of the genus Homo

• 2.5 - 1.8 million years ago

• Same time as australopithecines

• Found at similar locations as australopithecines

  • Mainly East Africa, some South Africa

    • Olduvai Gorge, Tanzania

    • Lake Turkana, Kenya

    • Middle Awash, Ethiopia

Pros of brain expansion

• More behavioral flexibility

  • Adapting to the environment; increases chances of survival

• Higher problem-solving skills

• Improved communication (eventually)

• Improved social networking

Cons of brain expansion

• Slower development

• Difficult birth

• High energetic cost

• Increased parental investment

Killer Ape Hypothesis

• Posed by Raymond Dart (found Taung Child)

  • Says violence is innate to hominins and ancestors are savage and bloodthirsty

  • Possible tools found in South African caves

Man, The Hunter Hypothesis

• Symposium and book in 1966

  • Says genus Homo hunted meat and used tools to do it

  • Supposedly based on modern hunter/gatherer groups

  • Huge emphasis on male hunting

Problems with Man, The Hunter Hypothesis

• No evidence of hunting until H. erectus, but brain increase happens in H. habilis

• Women

Problems with Killer Ape Hypothesis

• No evidence of active hunting until H. erectus

• Violence is not a widespread primate or human trait

• “Tools” found are just bone fragments - Not even killed by A. africanus

Scavenging Hypothesis

• Hominins were scavenging for meat rather than hunting

• Can look at who ate the bone first with specialized microscopes

  • Tool marks frequently appear on top of teeth marks

Did Australopithecus and early Homo hunt?

No

Tools used by Homo habilis

Oldowan tool complex

• Chopper - Cutting, chopping, scraping

• Hammerstone - Cracks open bone to get marrow

• Blades - Cuts tubers/meat

Homo rudolfensis

• Found on eastern side of Lake Turkana, Kenya

  • 2.4 - 1.6 million years old

    • Contemporaneous with Homo habilis

• Larger than H. habilis but with same general body plan and overall morphology

• More than one species?

Homo erectus

• 1.8 - 0.3 million years ago (longest time span of any Hominin)

• Different from previous hominins:

  • Bigger bodies

  • Bigger brains

  • More advanced tools

  • Many features approximate modern human traits

  • Found outside of Africa

Traits of Homo erectus

Primitive

• Large brow ridge

• Receding forehead

• No chin

• Thick cranial vault bone

Derived

• Bigger brain

  • Range - 750cc - 1,2500cc

  • Higher EQ than H. habilis

• Sagittal keel (less intense than a crest - no muscle attachment)

• Less prognathic than H. habilis

Nariokotome/Turkana Boy

• 1.6 million years ago at Lake Turkana, Kenya (found 1984)

• 5’3” tall, 106lbs

• 8 - 11 years old

• Cranial capacity - 880cc

  • Might have reached 909cc as an adult

• Most complete early hominin skeleton ever found

Did Homo erectus speak?

Likely not

Where was potential evidence of controlled fire use found?

Zhoukoudian, China

Acheulian Tool Complex

• Earliest found ~1.5mya

• Likely coincided with actual hunting

• More complex than Oldowan

• Wider variety of stone (indication of choice)

• Hand-axe shape can be found in the fossil record until 130,000 years ago

Why were H. erectus the first hominid to become so widespread?

• Anatomy —> Body size, stature, larger brain

• Culture —> Controlled use of fire and hunting/tools

• Adaptability to changing climatic and environmental conditions

• Reproductive success

H. heidelbergensis/Archaic Homo sapiens

H. heidelbergensis/Archaic Homo sapiens

Late Archaic Homo sapiens

• Primarily referring to Neanderthals

  • Skeletal, archaeological, aDNA evidence

• Denisovans

  • Very little evidence

  • Several teeth, finger bone, aDNA

Homo neanderthalensis

• 130,000 - 30,000 yBP

• Europe/West Asia

• Increased brain size

• Reduced tooth size

• Cold-adapted?

• Increased tool use and signs of higher cognition

Anatomically Modern Humans species

• Homo sapiens

Late Archaic Homo sapiens

• Homo neanderthalensis

• Homo sapiens neanderthalensis

Neanderthal characteristics (physical)

• Extremely robust

• Heavy muscle markings

• Short and stocky

• Barrel-shaped rib cage

• Even fingers are more heavily built than AMH

• Large nasal aperture - Big nose to help warm and humidify cold air

• Large infraorbital foramina - More blood-flow and nerves to the face

  • Warming

• Shorter and more robust than AMH

  • Follows Bergman and Allen’s rules

Bergman’s Rule

Populations in colder environments have larger mass and populations with smaller masses are found in warmer regions

Allen’s Rule

Populations in colder environments have shorter limbs and populations in warmer environments have longer limbs

Levallois Technique

• Middle Paleolithic

• 300,000 - 250,000 yBP

• Chip edges off a core

• Strike the tool from the core

Mousterian Tool Complex

• ~300,000 - 30,000 yBP

• Involved Levallois technique as well as more advanced tools (spears)

• Requires pre-planning tool shape = More advanced cognitive ability & dexterity

Denisovans

• From Denisova Cave, Siberia (2010)

• ~300,000 - 15,000 yBP (?)

• Homo subspecies?

  • Homo sapiens denisova

• Very little fossil evidence

• aDNA shows they were more closely related to Neanderthals but interbred with humans as well

When did Neanderthals go extinct?

40,000 years ago

Potential reasons for Neanderthal extinction

• Completely inbred into human populations (possibly little breeding amongst themselves) - A recent, more likely explanation

• Humans brought new diseases

• Humans were more violent and killed them all

• Too specialized

• Humans were better at adapting and taking advantage of resources (trade, better tools/technology)

Homo naledi

• 236,000 - 335,000 years old

15 individuals; > 150 teeth

• Small body; small brain; arboreal and bipedal

• Baffling combination of traits

Homo florensiensis

• Flores, Indonesia

  • 190,000 - 18,000 years BP (maybe older)

• 9 - 12 individuals

• Nicknamed “The Hobbit”

• Small brain (~400cc)

  • Microcephaly?

• Small body size

  • Island effect?

yBP referes to?

Years before present

What year does “present” in yBP refer to?

1950

Homo sapiens

• First appeared ~250,000 years ago in Africa

• Anatomically modern humans (AMH)

• The only hominin species alive today

Out of Africa Model

• “Population replacement model”

• Homo sapiens evolved within Africa, migrated to Asia/Europe and replaced the archaic Homo living there

• Limited admixture (interbreeding)

Multiregional Continuity Model

• Populations living in Africa, Europe, and Asia all evolved into AMH in those areas

• Emphasis on gene flow (admixture) between African European, and Asian populations

• No replacement

Expectations of the Out of Africa Model

• The earliest AMH was only in Africa and nowhere else

• Genetic ancestry rooted in Africa and nowhere else

• Sudden arrival in Europe and Asia of:

  • Anatomical differences

  • Genetic differences

  • Artifacts

Expectations of the Multiregional Continuity Model

• Early AMH found in all regions

• Intermediate forms (admixture) found in all regions

• Genetic continuity in all regions

• Gradual transition in all regions of:

  • Anatomy

  • Genetics

  • Artifacts

Assimilation Model

• “Partial Replacement Model”

• “Hybridization Model”

• Homo sapiens evolved within Africa, migrated to Asia/Europe

• Then extensive admixture between AMH from Africa and European/Asian archaic Homo

Expectations of the Assimilation Model

Intermediate between Multiregional and Replacement model

Aurignacian Culture

• First blade industry

  • Long, narrow flakes

  • Use of bone/antler for flakes

• Beads and jewelry

  • Mammal bones and teeth

  • Shells

  • Symbolic portable goods

  • Travel/trade?

• Bone needles and awls

• Suggest tailored clothing

• Helps with colder climate

Gravettian Culture

• 30,000 - 20,000 yBP

• Known specifically for Venus figurines

• Potentially more sedentary - More evidence of houses

• The earliest evidence of ceramics and pottery in both Europe and Asia

  • Ceramic kiln in the Czech Republic

  • Xianrendong Cave, China(~20,000 yBP)

Solutrean Culture

• 21,000 - 17,000 yBP

• Extremely refined blade technology

• Highpoint of stone tools during the Upper Paleolithic in Europe (very hard to make)

• Small regional distribution

Magdalenian Culture

• 17,000 - 12,000 yBP

• Large scale climate change

• Extreme cold, high-altitude areas in Europe were abandoned

• Signs of increased sedentism

• Evidence of use of marine resources

• New hunting techniques

  • Fishing, bow and arrow

• Bone harpoons

• Advanced bone sewing needles

• Arrow shafts (debated)

Major reasons for modern human migration (mass movement)

• Population increase

• Disappearance of food resources

• Increased competition with neighboring populations

• Cimate deterioration

  • Glacial maximum/ice age

The first AMH lived ____________ years ago, restricted to _______

250,000 - 100,000, Africa