4/11 Lecture - Hominoid Adaptations Flashcards
4 Early Hominoid Adaptations* (HRTL)
1st Set of Core Adaptations
1 ) Habitual Bipedal }
2) Reduced Canines }
3) Thick Enamel }
4) Large Molars }
Sahelanthropus, Orrorin, and Ardipithecus
Australopithecus Adaptations*
2nd Set of Core Adaptations
1) Tool use }
2) Megedonty (Super large teeth) }
Australopithecus. Kenyanthropus , Paranthropus
Australopithecus Afarensis
Lucy
= Had a Valgus knee = she normally moved by walking upright
Australopithecus Africanus
Primitive ape-like cranium
Bipedal like modern human
Key Concept : BIPEDALISM is the FIRST MAJOR adaptive shift
NOT large brain size
DIkika:
3.5 MYA - bones found with cut marks
(act of butchering animals WITH TOOLS)
Plenty of tool like stones lying on surface
However, knowledge of whom used them is unknown
Lomekwi:
3.3 MYA - Stone Tools found in Kenya
1) Found in Context
2) Simplest possible tools manufacturable
Tools: Big, Crude, Unknown whom used them
Ethiopia: Olduvai gorge
2.5 MYA - New stone tools were found
Oldowan Tool Industry : 3 Different Names
1) Mode 1
2) Early Stone Age
3) Lower Paleolithic
Used the “Pebble Chopper”
Found With *Australopithecus garhi
Oldowan “Pebble Chopper” + Flakes (Manufactureing process)
Easy to make
BUT more complex & planned the Lomekwian Tools
Evidence of Systematic Butchery
Found With *Australopithecus garhi
Australopithecus garhi
The Typical Australopithecine
Early Stone Tools*
) Used for butchering animals
) Used for hunting and gathering/scavenging
TOOL USE BEFORE BIG BRAINS
Increase in leg length =
more efficient Bipedalism
7 - 2.5 MYA Brain size
Not much increase
Australopithecus Cheek Teeth:
Molars suggest New Diet from :
1) Thick Enamel
2) large molars
Hypothesis For Evolution of Bipedalism:
Greater Efficiency
Greater Endurance
Eff. - Knucklewalking is less efficient for traveling but more efficient for retaining suspensory traits
Eff.2 - bipedalism is the Opposite
Persistence hunting: known for use in Humans - running for slow speeds for a long period of time over long distances
derived characteristics distinguish modern humans from other living hominoids:
bipedal locomotion, larger brain, slower development, several features of dental morphology, - small cheek teeth and cultural adaptation
Sahelanthropus tchadensis
the earliest known hominin
foramen magnum: located in the back of the skull in most quadrupedal primates. However, in Sahelanthropus the foramen magnum is located under the skull, as it is in modern humans
Orrorin tugenensis
second early fossil with similarities to humans
smaller molars/thicker enamel
The morphology of the femur (thighbone) is between those of Miocene apes and later bipedal hominins
- which SUGGESTS that these creatures were BIPEDAL
Ardipithecus
The genus Ardipithecus includes two species,
- Ar. kadabba and Ar. ramidus,
both from the Middle Awash region of Ethiopia.
Ar. ramidus,
1) Ar. ramidus resembles Sahelanthropus and Orrorin
2) Ar. ramidus has a distinctive dental traits: thicker molar enamel, canine reduction, and no honing by the premolars.
3) Evidence Ar. ramidus walked upright/ Bipedalism
The Adaptive Advantages of Bipedalism : huh
1) harvesting of fruit from small trees efficiently
2) Upright posture = cooling
3) Hands-free
General Australopithecus
“southern ape”
thick enamel/ megadonty;
larger brains than chimps;
developed rapidly like modern apes,
- sexual maturity at 8 years old.
subnasal prognathism;
*Diastema - space between incisors and canines
Lordosis - spine must have an “S” shape
General Paranthropus
“parallel to man”
Extreme Megadonty
enormous chewing muscles
entire skull has been reorganized to support the massive chewing apparatus.
pronounced sagittal crest -> enlarges the surface area of bone available for attaching the temporalis muscle,
General Kenyanthropus
“Kenyan man”
East Africa between 3.5 Ma and 3.2 Ma.
flattened face and small teeth.
General Homo
larger brains,
smaller teeth,
developed more slowly than contemporary hominin species
