Test 2 Flashcards
What are the overall trends of Australopithecus and Paranthropus?
- Post crania getting larger
- canines and incisors getting smaller
- mixture of attributes
- long faces and small brain: p. aethiopicus
- long faces and larger brains: au. africanus
- shorter faces and larger brains: later paranthropus
Where were australopithecines located and when
ca. 7 to 4.4 Ma in the upper East African Rift Valley
ca. 4.2 to 1 Ma in East African Rift Valley descending all the way to South Africa
What is the East African Rift Valley and why is it so fossil rich
- formed when Africa tried to break from Eur-Asia
- constantly filled with sediments from earthquakes and geological shifts
What is the oldest Australopithecine
Australopithecus anamensis
When and where did anamensis live
4.2-3.9 Ma in Kenya and Ethiopia
What environment did anamensis inhabit and how do we know
- forest ecology
- arboreal animals found at same site (monkeys)
- pollen
- chemical signals from sediments
What are some physical attributes of anamensis
- large canines but trending towards to smaller ones
- vertical palate
- inclined symphysis
- potentially for large teeth
- shorter arms than ardipithecus (similar to pan)
- less tree oriented
- robust knee and tibia
- legs getting longer and heavier…pendulum
- strong sexual dimorphism
- similar to pan
How does anamensis and pan compare (teeth and mandible-maxilla)
- shorter more vertical face
- shorter canines
- large dentin pools
- canine and p3 are about the same size
Describe the cranial features of anamensis
-large zygoma (strong masseter attachment/correlates w/robust mandible and large teeth)
-large front teeth for ape-like chewing (past nasal aperture)
-forward-positioned sagittal crest (separate and give more room for temporalis)
-large face …prognathic lower face
-flared mastoid processes (more space for temporalis and wide mandible)
-long and narrow brain case
-
What is the cranial capacity of anamensis and what is it similar to
365-370 cc
Similar to Sahelanthropus and Ardipithecus
Describe the biomechanics of anamensis joints (proximal tibia, distal tibia, distal humerus)
Proximal Tibia: robust, weight-bearing plateau (polygon) for referral condyle attachment
-modern looking
-for running and jumping…biped
Distal tibia: squared ankle, large malleolus (stable)
-perpendicular condition of join for talus attachment
-prominent medial malleolus
Distal humerus: (elbow) robust suggestion climbing
-large with deep groove
-chimp-like
When and where did Australopithecus afarensis live
- 9-3.0 Ma
- in Hadar (Ethiopia), Laetoli (Tanzania), Kenya
- widely distributed
What environments did afarensis prefer
Mixed forest-open ecology
Describe afarensis mandible
-smaller canines
-larger premolars
-large molars
-long jaws
-large jaws
Brains larger than Pan but smaller than Homo (still overlap)
Compare afarensis cranium to anamensis
- more robust face
- somewhat large size of the back teeth+more powerful chewing muscles
- average size 470cc
- more slender and gracile canine
Describe afarensis post crania
-broad, short, lateral pelvis
-large sacrum
-valgus knee and robust (anamensis too but less)
-shorter arms and forelimbs
-chimp-sized (30-60kg)
-shorter and less curved fingers (away from trees)
-
The Laetoli footprints (who, what)
- afarensis
- addicted toe
- arch
- heel-strike (deep heel impression)
Australopithecus africanus (where, when)
South Africa
3.5-2.5 Ma
africanus environment
- mixed forest-open ecology
- same as africanus
What two Australopithecines are similar sized
africanus+afarensis
What was the first australopithecine found
Taung Child
How does africanus compare to afarensis
- larger molars
- smaller front teeth
- more massive face
- 485cc (a little bigger)
- identical post crania
- obligate biped with climbing abilities
What makes Australopithecus africanus different from Homo
- long femoral necks
- small femoral heads
- flared ilia
- small boy size
Feature different between africanus and Ardipithecus (pelvis)
Shorter ilia and ischia
What two taxa fall under Australopithecines
Australopithecus and Paranthropus
Paranthropus description (when, where, what comparatively)
- Generally later than Australopithecus
- 2.5-1.0Ma
- east and south Africa
- more massive faces with larger chewing muscles
- larger postcanines
- smaller front teeth
- larger brains
- similar in mass, dimorphism, and postcrania morphology with Australopithecus
Where did Paranthropus aethiopicus live
- west turkana and Ethiopia
- 2.5 Ma
Environment of aethiopicus
Lake margin (forest), grassland
Unusual anatomy of aethiopicus
- primitive traits
- small brain (410cc)
- prognathic (most of any human)
- large front teeth
- flat cranial base
- derived traits
- huge back teeth
- huge chewing muscles
- very large face
Describe the cranium of aethiopicus
- huge face
- huge sagittal crest
- strong prognathism
- flat base of cranium (changes in later Paranthropus)
- small brain
- dramatic postorbital gaps
- small brain
- huge chewing muscles
- posterior temporalis
- huge teeth
In what ways is aethiopicus closer to afarensis
- prognathism
- brain size
- basicranium
- temporalis angle
In what ways is aethiopicus similar to boisei
- size of postcanines
- size of face
- size of muscles
In what ways is boisei similar to early Homo
- brain size
- orthognathy
- basicranium (flexed)
- temporalis angle (vertical)
When and where did Paranthropus robustus live
- South Africa (only)
- swartkrans, kromdraai
- 2.0-1.0 Ma
robustus environment and habits
- Mixed forest, grassland
- not slicing teeth but more tubors and roots
- possible tool makers
- Homo erectus other candidate
Paranthropus boisei (when, where)
2.0-1.0 Ma
Kenya, Ethiopia, Malawi, many sites
Boisei environment
Mixed lake margin, river margin forests and open plains
Describe robustus and boisei cranium
- orthognathic
- broad faces
- facial pillars
- flexed cranial bases
- small front teeth
- larger brains (ca 550-600cc)
- massive chewing muscles
- large premolars (look like molars)
- large molars
- flat canines
- Massive mandibles with tall rami
Describe the jaws of boisei and robustus
- massive mandibles
- huge premolars
- tiny front teeth
- canine much smaller than p3
What did Australopithecines do (diet/ecology/social)
-Diet: omnivores, extract challenges resources (digging and cracking), Paranthropus possible folivorous
-Ecology: forest mosaic, sometimes more open, specialized generalists
-Social: dimorphism in body size, reduced canine dimorphism, unlike modern primates
(female selection for larger males)
Describe evidence for Australopithecus tool use
- meat-marrow exploitation
- purposeful cut marks
- marrow extraction
Overall trend in crania
Small brain and bigger faces —->big brain and small face
Time range of Homo rudolfensis
2.5-1.8 Ma
Time scale of Homo habilis
2.8-1.5 Ma
Where were early Homo found?
- East African Rift Valley
- southeastern Europe (Georgia) and Indonesia
- weirdly dispersed unlike Australopithecus
Early evolution of genus Homo
- occupation sites
- tools
- organization
- movement/transport
- distribution range and habitat movement
- hunting/scavenging
- no projectiles
What are the benefits of increased brain size in Homo?
- stone tools
- cut-marked bones
- higher quality, broader diet, protein/fat rich
- better ability to survive shortages
Which Homo has larger body size and what are they comparable to?
- H. Rudolfensis has a larger body size
- about the size of the smallest modern humans
- H.habilis is Australopithecus-like in size
When and where was early Homo?
Name the sites
- 8-1.5 Ma
- east Africa- koobi fora (east turkana), Kenya
- olduvai gorge, Tanzania
- Hadar. Ethiopia
- Ledi-Gerard, Ethiopia
- South Africa (sterkfontein West)
- Malawi
Early Homo environment
River margin settings
- larger ranges
- flood plaines
- more ecological diversity
- diff microclimates
- more open country
- less dependent on trees
What is Kenyanthropus
- from Lomekwi
- 3.3 Ma
- possible cracked Australopithecine
- shares cranial similarities with H.rudolfensis
- broad zygoma
- brain case smaller tho
- more slope in temporal bones
Describe the Homo habilis and it’s mandible
- 2.8 Ma
- Lexi-Geraru, Afar, Ethiopia
- wooded grasslands
- robust and deep mandible
- small premolars (getting smaller)
- Small canines
- long molars
Is habilis prognathic or orthognathic? Less that what
Orthognathic compared to A. afarensis
Describe cranium of habilis
- facial reduction
- brain size increase (close to 600cc)
- smaller temporal fossa
- thus smaller temporalis muscles
- less post orbital constriction
- large brain in frontal region
- greatly reduced mastoid process
- expanded parietals and occipital
Describe post crania of habilis
- long arms
- short legs
- Australopithecine-like
Compare habilis to Australopithecus (skull)
- cranial vault changes
- larger reorganized brain
- complex behaviours (tools)
- smaller jaws and teeth
- less molarized premolars
- more proportionate front and back teeth
- stone tool use
- food preparation
Where and when was the earliest Homo rudolfensis located
- Uraha, Malawi
- 2.5Ma
Describe rudolfensis jaws
- robust jaws and large teeth but less so than Australopiths
- slightly bigger than habilis
- long molars
- small premolars
- deep mandibles
- proportionate anterior teeth
Describe rudolfensis cranium
- tall frontal bone
- overall bigger than habilis but very similar proportions and level of orthognathism
- large face (wide)
- large brain (720/750cc)
- larger brain case bones to adjust
- bigger bodies
Early Homo comparison
habilis:
- small face (larger than Australopithecus)
- Orthognathic
- small teeth
- small brains (530-650cc)
- Australopithecine-like in skeleton
rudolfensis:
- broad, flat, orthognathic face
- large overall
- larger brains (720cc) (relatively the same as habilis)
- more modern skeleton
What are the different sections of the brain? (2) then (5)
Cerebrum and cerebellum
- frontal
- parietal
- temporal
- occipital
Give the brain sizes of Australopithecus, early Homo, H. Erectus and pan
450 600 900 320 -sapien is 1200cc
What are the attributes of the unman brain
- huge proportionate to its body mass
- complex
- highly convoluted cortex-more surface area comp vol
- highly interconnected
- grey matter (100 billion neurons)
- white matter (10-15 trillion axons)
- lateralization and specialization
- left Sid elf cerebellum controls right side of the body
- specialized higher function also lateralized
- language, music, geometry, math
Name the parts of the brain responsible for language (4)
- Wernicke’s area: cognitive, meaning
- Broca’s area: vocal cords, physical aspect
- somatosensory cortex: sensory information
- motor cortex: moving and manipulation
What is produced as a result of human experiences and learning
Axons
How do we know early Homo had foresight
The flake and hammer production
-lomekwi, Kenya 3.3Ma
Uses for tools
- meat-marrow exploitation
- hunting or scavenging