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ARCH 131 (HUMAN ORIGIN) FINAL EXAM NOTES SIMON FRASER UNIVERSITY.
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ARCH 131 (HUMAN ORIGIN) FINAL EXAM NOTES SIMON FRASER UNIVERSITY.
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ARCH 131 (HUMAN ORIGIN)FINAL EXAM NOTES SIMON FRASER
UNIVERSITY.
,Unit 6 CONTINUATION
Paranthropus (Australopithecus?) aesthetics
• Aka “Black Skull”
o Stained kind of black by some kind of mineral
o 2.5 million yr old
o Flaring cheek bone (make face kind of flat), large molars, sagittal crest
▪ Bone that make up mouth super thick/strong
• Highly developed chewing apparatus
Masticatory Apparatus
- Temporalis muscle (underneath cheek to skull) & Masseter muscle (cheekbone area)
o Two muscle provide bite power
o Bite force: Human – 150psi / Gorilla – 1300psi (example)
▪ Gorilla need strong so the Temporalis muscle goes up to skull edge
(human ends at centre area of skull)
• Sagittal crest is an anchor at the top
- Seeing this development with specialized chewing
o Seeing little from africanus; aethiopicus = more dramatic
▪ Like gorilla description
- Aethiopicus direct linage to Paranthropus species; robustus & boisei
bosei
- East Africa (also afarensis)
- 2.3 to 1.3 mil yrs ago
- Zinj (some skull) discovered in 1959
o Important in human origin research
o Indicated the place Liki (liki tiki I think) was the place to look for early
hominal ancestors
o Spurred on discovery of other fossils
- About same size than afarensis and africanus
o Still small hominin
o 120cm F / 140cm M
- Prominent canine pillars (not as prom as chimpanzee but more than africanus
- Brain size = 500-550 cubic cm
o Increase in cephalization (brain size to body size)
- Massive jaw, robust
o Further increase in canine, but small like ours
o Further increase in molar (bigger than aethiopicus)
- Nickname “Nutcracker Man”
o Powerful jaws/cracking nuts
robustus
- Slight more recent 2-2.1 mil yrs ago
- Similar size, little difference with bosei and small bodied hominins
, - Prominent canine pillars, remains of sagittal crest, flaring cheek bone, big molars, big
bony structure in mouth
o Increase in chewing apparatus
- 530 cubic cm for brain
- Brain not just larger, but components of brain that related to abstract thinking increase
- Sig. change like bosei; increase in chewing apparatus
o Big molars, small front teeth, huge robust mandible, big flaring cheekbone,
sagittal crest
robustus and bosei (also aethiopicus)
- Both increase in chewing apparatus (most sig.)
- Megadontia = “huge teeth”
o Massive molars, front teeth small
- Designed to chew hard/poor quality plant food
o Roots, tubers, inner bark, gorilla food, fibre
- Haven’t found any descendent fossils
o Seen to be extinct around 1 mil ago
▪ Dead end of branch
▪ Starting from africanus
o Specialized species, did well for a few mil years but died due to change
▪ Eg. Drier environ. (was major climate change)
▪ Classic examples (bosei robusto)
o Evolutionary branch highly specialized in diet
- Specialized species, classic ex.
▪ Very specialized food resource, environments, climate
▪ Hard to adapt when circumstance change
▪ Can go extinct
- Generalists/generalized species: not particularly adapted to any environ. Resource
▪ Kind of wide range of environments (sort of like us)
▪ Always under lil selective stress
▪ Can go extinct but tend to do better since not super attached to one
thing
Unit 7: Emergence of the Genus Homo
Possible origins of our genus Homo?
- Many see afarensis as our homo lineage
o Not 100 but most likely, since no better candidate
o Others too specialized
- Two earliest we see “guess” see in our tree
o habilis and rudolfensis
▪ for moment we see as two separate species
Homo habilis
, - 2.8-1.5 mil yr ago
o Almost as old as recent afarensis fossils
- Most in East Africa (maybe some in South Africa)
- Aka “Handy Man”
- best candidate for stone tool maker
o but have some potential for older stone tool makers
o Tools got some cut marks (left on bone to butcher animal to eat)
o Not everyone agree
▪ Some species using stone tools as early as 3.4 mya
• Predate homo fossils
• Maybe afarensis
• Both bosei and robustus (little later than this) also use stone
tools
o Found a few in South Africa
- Holotype or “Type Fossils”
o people fnd new fossil, they analyze/study, decide that it is something new
(new species genus)
o Become “holotype” for that species
▪ Reference for that species
o Some broken fossil
▪ Considered early homo species
▪ No nice complete homo habilis
- Still small bodied
- Dk sexual dimorphism (can’t tell F from M)
o Early hominins easier, from teeth
- 130cm
- Brain size (increase)
- Reduction in molars
- Intermembral Index: body proportion
o Arm length/leg length * 100
o Over 100 = arm longer than leg
o Less = arm shorter than leg
- Lower Intermembral index
o Potential in our lineage
- KNM
o Cranial capacity 510 cc (cubic cm)
o Not super big
- “Twiggy” skull
o 590 cc
- Found some up to 700 cc
- Avg brain size bigger than early hominins
- Mandibles
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