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Palaeoanthropology > Origins of Homo > Flashcards

Origins of Homo Flashcards

1
Q

s.l. and s.s.

A

Homo habilis sensu lato (s.l., broad sense)

Homo habilis sensu stricto (s.s., narrow sense) + Homo rudolfensis + other specimens without clear attribution

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2
Q

Major evolutionary trends at 2.5mya - Paranthropus

A

Hypermasticatory complex
Increase in cheek tooth size
Body size similar to Australopithecus

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3
Q

Major evolutionary trends at 2.5mya - Homo

A

Increase in brain size and capacity for tool making
Decrease in prognathism, and postcanine tooth size

Increase in body size

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4
Q

Earliest Homo fossil

A

Ledi-Geraru left hemimandible, discovered 2015

2.8mya, Ethiopia

Smaller third molar and other traits indicate affinity with Homo. Assigned to Homo genus but no particular species.

Affinity with Homo has been contested based on alleged similarity with Au. sediba.

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5
Q

Homo habilis - temporal range, holotype, sites

A

2.4-1.4mya

OH 7 mandible, parietals, and hand bones

Sites:
Olduvai, Tanzania
Koobi Fora, Kenya
Omo, Ethiopia
Hadar, Ethiopia
Sterkfontein, South Africa
Swartkrans, South Africa
Drimolen, South Africa
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6
Q

Homo derived traits vs. Australopithecus - cranium

A 
Rounded cranial vault
Vertical forehead
Reduced cranial crests
More anterior foramen magnum
Reduced prognathism
Increased brain size both absolutely and relativel to body size
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7
Q

Homo derived traits vs. Australopithecus - dental

A

Reduction in postcranine tooth size
Smaller canines
Parabolic dental arcade

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8
Q

OH 7

A

Homo habilis, Olduvai, Tanzania
2 parietals, juvenile mandible, finger bones
U shaped dental arcade
730-830cc
-> brain enlargement and dental reduction were not linked in hominin evolution

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9
Q

Meets Le Gros Clark’s criteria for Homo

A 
Larger brain - 687cc
Capable of language
Relatively small teeth
Capacity for precision grip
Associated with stone tools
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10
Q

Homo habilis vs. australopiths

A 
Similarly small brain size
Less projected face
Narrow lower face
Incipient supraorbital ridge
Bell-shaped vault from rear
Smaller molars
Parabolic dental arcade
Flexed basicranium
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11
Q

Homo habilis vs Homo ergaster

A 
Smaller brain
Vertical face in both
Narrow lower face
Less developed supraorbital ridge
No bell shape in H. ergaster
Similarly small molars
Parabolic dental arcade
Flexed basicranium
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12
Q

OH 62

A

Olduvai, Tanzania, 1.8mya

Individual with a reliable association of cranial and postcranial remains.

Craniodental anatomy similar to other H. habilis

Body size and proportions similar to Australopithecus

Derived H. erectus skeleton 1.6mya -> 
rapid postcranial evolution?
OH62 not H. habilis?
H. habilis not ancestral to H. erectus?
H. habilis and H. erectus overlap and fill different niches?
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13
Q

KNM-ER 1813

A

Homo habilis, Koobi Fora, Kenya

Small brain - 510cc - below alleged limit for Homo
Small teeth
Narrower face
Homo-like face

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14
Q

SK 847, SK 15, Stw 53

A

Homo habilis, South Africa

<2mya

Small teeth and general gracility

Traditionally put into H. habilis, but taxonomic affinities are uncertain

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15
Q

AL 666-1

A

Homo habilis, Hadar, Ethiopia

2.33mya

With stone tools

Similar to Olduvai material

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16
Q

KNM-ER 1470

A

H. rudolfensis (H. habilis s.l.), Koobi Fora, Kenya

Australopithecus-like face
Homo-sized brain

17
Q

KNM-ER 1813 (H. habilis s.s.) vs KNM-ER 1470 (H. rudolfensis)

A

KNM-ER 1470 has:

  • bigger brain - 775cc
  • more facial projection
  • broad midface - Au.-like
  • bigger molars
  • slight browridge
  • well developed mandible for chewing muscles

KNM-ER 1813 has:

  • incipient supraorbital ridge
  • relatively smaller brain size - 612cc
  • broader upper face than midface
  • smaller molars
  • less robust mandible
18
Q

Variation between H. habilis s.s. and H. rudolfensis

A

Extreme forms are easy to differentiate but intermediate forms are not easily classifiable.

Co-efficient of variation (CV) - measures variation in a sample.
CV = standard deviation/mean x100

H. habilis s.l. - 12.4
Compared to:
Gorilla 10.9
H. sapiens 10.1
Bonobo 9.5
Chimpanzee 8.9

Greater than gorillas - an extremely dimorphic group. H. habilis unlikely to have been as dimorphic as gorillas = two different species.

19
Q

Homo rudolfensis - temporal range, holotype, sites

A

2.4-1.6mya

Holotype - KNM-ER 1470

Sites:
Koobi Fora, Kenya
Uraha, Malawi

20
Q

Homo rudolfensis - morphology

A

Face is widest in its midpart (compared to superiorly in H. habilis)

Larger absolute brain size

Robust jaws, large postcanine teeth, complex premolar root systems

Body size ~45kg

21
Q

KNM-ER 1470

A

H. rudolfensis, ~1.9mya

Large, rounded brain case

Initially placed into H. habilis

22
Q

UR 501

A

Malawi, 2.5-2.3mya

Very robust mandible

Connects East African and South African Homo

Possibly H. rudolfensis

23
Q

Homo or Australopithecus habilis?

A

Brain size = 650cc, between Australopithecus 400-550cc & H. ergaster 730-1070cc.

Body weight - M 52kg, F 32kg
Whereas:
A. afarensis - M 45kg, F 29kg
H. erectus - M 63kg, F 52kg
H sapiens - M 68kg, F 62kg

Australopithecus-like features e.g. body size, shape, locomotion, jaws & teeth, development, brain size (Wood & Collard 1999)

OH 7 hand & OH 62 skeleton show climbing features = different adaptive niche to later Homo

24
Q

Encephalisation Quotient

A

Measure of relative brain size. Ratio of actual brain mass and predicted brain mass.

Pan troglodytes 2.8-3.1
Australopithecus 2.4-3.3
H. habilis 4.3
H. erectus 4.4
H. sapiens 7.2
25
Q

Why are OH fossils placed within the genus Homo?

A

Slightly larger brain than Australopithecus

Slightly smaller posterior teeth

Habitual erect posture and bipedal gait

H. sapiens-like foot bones

Different affinities in hand bones, but capable of making tools

26
Q

Differences between Australopithecus and Homo

A 
Homo has:
Increased cranial capacity
Reduced prognathism
Reduced teeth and parabolic arcade
Obliged and modern bipedalism
Sophisticated and more committed use of stone tools
More complex social behaviour
Increased meat consumption
27
Q

Brain size and diet

A

~2mya - substantial increase in brain size begins
Systematic hunting & increased meat consumption

Advantages of meat:
Higher energetic contents
Easier digestion (expensive tissue hypothesis)

Disadvantages of meat:
Harder to get & competition
Requires planning, co-operation, complex social networks

28
Q

Expensive tissue hypothesis

A

Aiello & Wheeler 1995 -> humans cannot afford having a big brain together with other ‘expensive tissues’

Trade-off = brain size increases and gut size decreases

Associated with higher quality diet (more meat, perhaps cooked)

HOWEVER:
sample of 100 mammalian species -> no significant relationship between brain size and gut size

Brain size is negatively correlated only with the size of adipose deposits

Encephalisation and fat storage are alternative strategies to buffer against starvation

29
Q

H. habilis and stone tools

A

Oldowan industry - thought to be the most primitive human technology for many years. Associated with OH 7 at 1.8mya

Concoidal fractures

Manuports - rocks moved by hominins but not worked
Hammerstones - used to remove flakes from other rocks
Core forms - pebbles which flakes were removed or used as tools themselves
Flakes

Demonstrate advanced knowledge of the mechanical properties of stone

30
Q

Pre-Oldowan stone tools

A

Tools in Gona, Afar, Ethiopia at 2.6mya

Cutmarks in Bouri at 2.5mya - association with Au. garhi? Lack of associated lithics suggests curation of tools

Cutmarks in Dikika, Ethiopia at 3.39mya - Dominguez-Rodrigo et al 2010 “In a less contentious context, the marks would likely be accepted as genuine cutmarks.”

Stone tools at Lake Turkana, Kenya, at 3.3mya

31
Q

Lomekwian stone tools

A

West Turkana, Kenya, 3.3mya

Same location as Kenyanthropus platyops

Predates Oldowan by 700,000 years - possibly the oldest human technology

Simplest mode to make stone tools

Very large and crude

Human-like dexterity is not required

32
Q

Tool use in non-human primates

A

Chimpanzees, macaques, capuchins use stones to open nuts and crabs

Therefore tool use is NOT a defining trait of the genus Homo - not surprising that Australopithecus used tools as well

33
Q

Did other hominins make or use stone tools?

A

OH 5 (P. boisei) found in layers with stone tools

Stone tools found at SK Mbr 3, only with P. robustus

P. robustus hand bones capable of a modern human-like precision grip

34
Q

Co-operative hunting

A

Hunting in groups = division of labour and role specialisation

Implies higher cognitive abilities and communication

80-95% of carnivores are solitary

Exceptions: lions, wild dogs, spotted hyenas, chimpanzees, humans

35
Q

OH 8

A

Homo habilis foot

Adducted hallux
Straight - not curved - metatarsals
Evidence for transverse and longitudinal arch

Could also belong to P. boisei
Modern features have been contested

36
Q

Palaeolithic era

A

2.3mya to 12,000 years ago

Divided into:
Lower Palaeolithic 2.3mya to 125,000 years ago
Middle Palaeolithic 125,000 to 35,000 years ago
Upper palaeolithic 35,000 to 12,000 years ago

37
Q

Lower Palaeolithic stone tools

A

Oldowan and Acheulean

Oldowan: opportunistic flaking. Associated with hunting behaviours, but likely useful for other activities e.g. digging, woodwork, defence.

Acheulean: first appeared 1.4mya. Characteristic tool is the hand axe, plus tool types specific to certain regions. Evidence for preconceived notion of what the tool should look like = greater intellectual capacity.

38
Q

Homo naledi

A

Rising Star cave system near Johannesburg, South Africa. 1,500 fossils (Berger et al., 2015)

Combination of primitive and derived characteristics:
Curved fingers
Primitive shoulders
465-560cc brain size
Premolar asymmetry
Increased size of teeth towards the back of the tooth row

Palaeoanthropology (9 decks)

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