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GEO1009F > homonin evolution > Flashcards

homonin evolution Flashcards

lect 5,6,7,8

1
Q

Sahelanthropus tchadensis

A
  • first entry on chart
  • transitional species
  • 6-7 mya
  • found in Chad
  • Foramen magnum positioned to the rear of the skull
  • Horizontally oriented basicranium
  • Thick supra-orbital torus
  • Long narrow brain case
  • found by??
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2
Q

human and apelike characteristics of Sahelanthropus tchadensis:

A 
some human features: ???
apelike features:
-small brain, 
-projecting face, 
-sloped forehead and 
-large neck muscles.
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3
Q

Ororrin tugenensis

A
  • second entry on chart
  • fount in Tugen Hills of Kenya
  • 6 Ma
  • Small teeth but thick enamel
  • Femur suggests bipedality
  • found by ??
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4
Q

Ardipithecus Kadabba

A
  • third entry on chart
  • found in Ethiopia
  • 5.6 million years ago
  • Known only from teeth and fragments of skeletal bones
  • Originally described as subspecies of Ardipithecus ramidus, now considered a possible ancestor of the latter (based on discovery of additional teeth).
  • found by ??
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5
Q

Ardipithecus ramidus

A

-fourth entry in chart
-found in Ethiopia
-had a small cranium
-Gracile limbs
-Bowl shaped pelvis
-4.4 Ma
-Basal foramen magnum
-Toe bone similar to later
bipedal hominins
- found by??

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6
Q

Australopithecus anamensis

A
  • fifth entry on chart
  • Found at Alia Bay and Kanapoi, Kenya
  • Mosaic of ape and human features
  • Parallel tooth rows
  • Hind limbs suggest bipedality
  • 4.2 to 3.9 Ma
  • found by???
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7
Q

Australopithecus afarensis

A
  • Gracile australopithecine
  • 4.0 to 2.9 Ma
  • Found in Hadar, Ethiopia, -Kenya and Tanzania
  • The most well known hominin
  • Clearly a biped
  • Ape-like limb proportions
  • Large sexual dimorphism
  • Still some arboreal adaptations
  • found by??
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8
Q

Kenyanthropus platyops

A

-3.2 -3.5 Ma
-Western side of Lake Turkana basin in Kenya
-Tall cheek region and flat face
-Small teeth
-Mixture of ape and human traits
-Badly damaged skull
-Bipedal??
- found by ??
controversial fossil - very fragmented

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9
Q

Australopithecus africanus

A
  • Gracile australopithecine
  • 3.2 – 2.1 Ma
  • Southern Ape from Africa
  • Australopithecus africanus
  • Raymond Dart – first described species
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10
Q

Paranthropus aethiopicus

A
  • 2.5 Ma
  • Earliest known robust australopithecine
  • Eastern Africa (Turkana basin of northern Kenya, southern Ethiopia)
  • Black skull
  • Very few remains of this species have been found – still a mystery
  • Strongly protruding face, large megadont teeth, and a -powerful jaw, and a well-developed sagittal crest
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11
Q

Paranthropus robustus

A

found in South Africa

2-1.5 mya

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12
Q

Paranthropus boisei

A

found in east Africa

lived 2.5-1 mya

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13
Q

what does the term “Gracile australopithecines’ mean?

A 
slighter build
prognathic face
smaller teeth
steeper forehead
smaller temporal fossa
longer snout
no crest
face sits below neurocranium
steeper forehead
incisor prognathism
less robust mandible
example: Australopithecus africanus
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14
Q

what does the term robust australopithecines mean?

A 
more robust
sagittal crest
massive teeth
larger temporal fossa
shorter snout
face is hafted, high on neurocranium
flatter forehead
flatter face
more robust madible
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15
Q

Australopithecus garhi

A
  • Found in middle Awash Ethiopia
  • 2.5mya
  • apelike face
  • large teeth
  • small brain
  • associated with tool use - Olduwan type
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16
Q

Australopithecus sediba

A
  • 1.95-1.78 mya
  • found in COHK Joburg
  • mosaic of homo and aus traits
  • Cranial capacity similar to that of Australopithecus, but jaw and teeth are gracile like those of early Homo
  • found by Lee Burger
17
Q

Australopithecus sediba similarities with Homo

A 
front of brain reorganized
projecting nose
smaller teeth and chewing muscles
hips are less flared and similar to humans
longer legs
precision grip
18
Q

Australopithecus sediba similarities with Australopiths

A 
smaller brain size
long and high cheek bones
primitive molar cusps
small body size
longer upper limbs
primitive heel bone
19
Q

what were some of the earliest homo individuals found?

A

homo rudolfensis
homo habilis

found on the eastern shores of Lake Turkana
dated - 2.0-1.9 mya

20
Q

homo rudolfensis

A

more australopith face
larger brain
2.0-1.9 mya
Lake Turkana

21
Q

homo habilis

A

more australopith/smaller brain more human face
2.0-1.9 mya
Lake Turkana

22
Q

homo habilis shared traits with Aus afarensis

A

low body mass
teeth adapted to tough foods
Arboreal and terrestrial adaptation
development stages african apes

23
Q

homo habilis shared traits with erectus

A

stone tools

larger brain

24
Q

homo erectus

A 
first hominin species to leave africa
major anatonical changes
brain size 1000cc
bipedalism is more modern
reduction in sexual dimorphism
association with well made stone tools - Acheulean hand axe
found by ??
found where??
lived 1.5 mya
25
Q

homo heidelbergensis

A

-800k-200kya
-Africa and Europe, possibly Asia
-mixture of sapiens and eretus features
-massive brow ridge
-forwardly projecting face
-robust build
-thick walled skull
-larger brain capacity
-Rear of cranium is more rounded
-reduction in post canine tooth size
found in Heidelberg germany
found by ??
found in ??

26
Q

what is the Sima de los Huesos

A

13m shaft where many remains found
32 individuals dropped down ceremonially or disposing of dead
one reddish handaxe

27
Q

Neanderthals

A 
Neander valley - germany
lived - 150k - 28kya
-retromolar gap
-occipital bun
-projecting mid face
-no chin
-heavily built, short and stocky
-bones are thicker
28
Q

adaptations for colder climates and the rules governing that

A

Bergman and Allen’s rule - heat loss reduction

  • organisms that are shorter and ticker and more robust are built for shorter climates so that less heat is lost
  • animals in colder climates have shorter and stockier limbs
29
Q

homo sapiens

A

Reduced robusticity
everything becomes smaller
back teeth continue to reduce so do front teeth
-cranial buttresses much less in evidence
-loss of brow ridge
-development of chin
-sexual dimorphism reduces to modern levels
-vertical forehead
-canine fossa*
-pyramidal mastoid process*

30
Q

what are the three theories of modern human origins?

A

complete replacement model
regional continuity model
partial replacement model

31
Q

explain the complete replacement model as a theory of modern human evolution

A
  • developed by british paleontologists Christopher Stinger and Archeol. peter Andrews
  • proposes that anatomically modern populations - Sapiens replaced Heidelbergensis in Africa
  • migrated from Africa and completely replaced descendent populations of erectus in europe and Asia- they out competed them
32
Q

problem with the complete replacement model?

A

-doesnt account for the transition from heidelbergensis to sapiens anywhere else other than africa

33
Q

explain the partial replacement model as a theory of modern human evolution

A
  • proposed by Bunter Brauer of the uni of Hamburg
  • Erectus moved out of africa and settled in the of the globed - eventually giving rise to heidelbergensis around 100kya
  • Thes H. sapiens moving into Eurasia, and hybridized with resident groups (non H. sapiens descendants of H. erectus) , eventually replacing them.
  • The disappearance of these archaic humans outside of Africa was due to hybridization (interbreeding and not complete replacement) and replacement.
34
Q

another name for the partial replacement model

A

the assimilation model

35
Q

explain the regional continuity model as a theory of modern human evolution

A
  • Associated with paleoanthropologist Milford Wolpoff of the University of Michigan.
  • H. erectus moved from Africa to Eurasia around 2 mya and gave rise to H. heidelbergensis in the various regions.
  • Human populations in Europe, Asia, and Africa continued evolutionary development from H. heidelbergensis to anatomically modern humans.
  • No en mass migration of H. sapiens from Africa into the rest of the world.
  • However, limited gene flow between regions.
36
Q

what is the most accepted theory?

A

The out of africa hypothesis - replacement

37
Q

what are some predictions that come along with a replacement hypothesis?

A
  • The oldest anatomically modern specimens will be in Africa
  • Transitional forms will be in Africa
  • Co-existence of ancient modern sapiens and archaic forms outside africa
  • archeological evidence for modernity should appear in africa first
38
Q

where was some evidence of modernity found in africa and when was this evidence from?

A

Blombos cave

100k-70kya

GEO1009F (16 decks)

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