6 - intro to paleoanthropology Flashcards

1
Q

hominids

A

collective name for modern and fossil species of humans

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2
Q

hominid African ape lineage split

A

6-8 million years ago, likely in east Africa
evidence:
- comparative anatomy
- fossil evidence
- genetic evidence

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3
Q

what two parts is the skull made up of

A

cranium and mandible

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4
Q

cranial bones

A

frontal
maxilla
zygomatic x2
sphenoid
parietal x2
temporal x2
occipital

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5
Q

axial skeleton

A

vertebrae, sternum, ribs

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6
Q

upper limbs

A

clavicle, scapula, humerus, radius, ulma

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7
Q

lower limbs

A

pelvis, femur, tibia and fibula

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8
Q

hand and feet

A

phalanges, metacarpals, metatarsals, carpals, tarsals

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9
Q

hominins characteristics

A

bipedalism, large brain for body size, advanced dentition with rotary chewing

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10
Q

bipedalism

A
  • primary mode of locomotion only in humans and our ancestors.
  • human primates use a striding gait where weight is alternatively placed on a single full extended hind limb
  • non humans walk bipedal with hips and knees bent
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11
Q

formamen magnum bipedalism adaptations

A
  • situation towards back of cranium in non human apes
  • repositioned underneath cranium in humans
  • head is balanced on spine
  • requires less robust neck muscles to hold head upright
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12
Q

spine bipedalism adaptations

A
  • assists balance when we walk upright
    -quadrupedal primate spine has a ‘c’ curve, humans have ‘s’ to absorb shock as we walk
  • weight transmitted down through body centre
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13
Q

pelvis adaptations to bipedalism

A
  • quadrupedal animal - pelvis bones elongation and positioned along beachside of the lower portion of spine
  • humans - pelvis shorter and broader and extends around to the side
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14
Q

hind limbs bipedalism adaptations

A
  • lower limbs elongated proportional to thighs
    -femur angled inward to keep legs directly under body
  • modified knee anatomy so leg held straight and locks at knee
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15
Q

feet adaptations to bipedalism

A
  • non human ate feet used as a grasping limb
  • hallux (big toe) enlarged and non divergent
  • longitudinal arch in foot absorbs shock and adds propulsive spring
  • “toe-off” walking
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16
Q

some genera of early hominins

A

sahelanthropus, orrorin, ardipithecus, paranthropus, australopithecus, homo

17
Q

how to recognise a fossil hominin when its lots of small parts

A
  • evidence of bipedalism
  • teeth (smaller canines)
  • thickness of enamel (thin in living African apes, thicker in humans)
  • decrease in facial size
18
Q

earliest possible hominins

A
  • orrrorin tugenensis
  • sahelanthropus tchadensis
  • ardipithecus ramidus

(NOTE: hominid status of orrorin and sahelanthropus debated)

19
Q

sahelanthropus tchadensis

A

2001 - Chad
6-7 mya
- only cranium and dentition:
- forward positioning of foramen magnum
- brain c 320 - 380cc
- very large supra-orbital torus

20
Q

origin tugenensis

A

tugen hills, Kenya, 2000
c 6.0 mya
- Bipedal:
- attachment on femoral neck
- no cranium
- partial mandible

21
Q

ardipithecus ramidus “ardi”

A

1994 - Aramis, Ethiopia
c 4.4 mya
Mosaic of ape and incipient hominid features:
- forward position of foramen magnum
- long muscled arms
- no knuckle walking features
- opposable big toe
- brain c300-350cc

22
Q

ardipithecus cranium

A
  • cranium found in 5000 pieces
  • brain c300-500cc
  • small face with projecting muzzle (like apes but less projecting than chimps)
23
Q

ardipithecus pelvis

A

mosaic of characteristics for bipedality and climbing
- short iliac blades like hominins
- lower pelvis more non-human ape like due to large thigh muscles for climbing

24
Q

ardipithecus feet

A
  • opposable big toe but different from extant great apes
  • feet unlike extant apes
  • has an os peroneum - used to draw in big toe when foot is grasping (found in gibbons but not extant great apes)