4/11 Lecture - Hominoid Adaptations

Question 1

4 Early Hominoid Adaptations* (HRTL)

Answer 1

1st Set of Core Adaptations

1 ) Habitual Bipedal }

2) Reduced Canines }
3) Thick Enamel }
4) Large Molars }

Sahelanthropus, Orrorin, and Ardipithecus

Question 2

Australopithecus Adaptations*

Answer 2

2nd Set of Core Adaptations

1) Tool use }
2) Megedonty (Super large teeth) }

Australopithecus. Kenyanthropus , Paranthropus

Question 3

Australopithecus Afarensis

Answer 3

Lucy

= Had a Valgus knee = she normally moved by walking upright

Question 4

Australopithecus Africanus

Answer 4

Primitive ape-like cranium
Bipedal like modern human

Key Concept : BIPEDALISM is the FIRST MAJOR adaptive shift
NOT large brain size

Question 5

DIkika:

Answer 5

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

Question 6

Lomekwi:

Answer 6

3.3 MYA - Stone Tools found in Kenya

                   1) Found in Context
                  2) Simplest possible tools manufacturable

Tools: Big, Crude, Unknown whom used them

Question 7

Ethiopia: Olduvai gorge

Answer 7

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

Question 8

Oldowan “Pebble Chopper” + Flakes (Manufactureing process)

Answer 8

Easy to make
BUT more complex & planned the Lomekwian Tools

Evidence of Systematic Butchery

Found With *Australopithecus garhi

Question 9

Australopithecus garhi

Answer 9

The Typical Australopithecine

Question 10

Early Stone Tools*

Answer 10

) Used for butchering animals
) Used for hunting and gathering/scavenging
TOOL USE BEFORE BIG BRAINS

Question 11

Increase in leg length =

Answer 11

more efficient Bipedalism

Question 12

7 - 2.5 MYA Brain size

Answer 12

Not much increase

Question 13

Australopithecus Cheek Teeth:

Answer 13

Molars suggest New Diet from :

           1) Thick Enamel
          2) large molars

Question 14

Hypothesis For Evolution of Bipedalism:

Answer 14

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

Question 15

derived characteristics distinguish modern humans from other living hominoids:

Answer 15

bipedal locomotion, 
larger brain, 
slower development, 
several features of dental morphology, - small cheek teeth
and cultural adaptation

Question 16

Sahelanthropus tchadensis

Answer 16

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

Question 17

Orrorin tugenensis

Answer 17

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

Question 18

Ardipithecus

Answer 18

The genus Ardipithecus includes two species,

                   -  Ar. kadabba and Ar. ramidus, 

both from the Middle Awash region of Ethiopia.

Question 19

Ar. ramidus,

Answer 19

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

Question 20

The Adaptive Advantages of Bipedalism : huh

Answer 20

1) harvesting of fruit from small trees efficiently
2) Upright posture = cooling
3) Hands-free

Question 21

General Australopithecus

Answer 21

“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

Question 22

General Paranthropus

Answer 22

“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,

Question 23

General Kenyanthropus

Answer 23

“Kenyan man”

East Africa between 3.5 Ma and 3.2 Ma.

flattened face and small teeth.

Question 24

General Homo

Answer 24

larger brains,
smaller teeth,
developed more slowly than contemporary hominin species