Becoming Human

Question 0

Where is the fossil evidence found of the first hominins?

Answer 0

Great Rift Valley, East Africe

Question 1

The first Hominins: Difference in the skull

Answer 1

• brain size, cranial proportions, reduction in bony crest

- facial size decrease

Question 2

The first Hominins: Sahelanthropus tchadensis (aka chad)

Answer 2

• 5.2- 7 mya
• earliest pre-australopithecine
• brain size 350 cc
• massive browridge
• bipedal
• lived very near time of ape-human divergence
• lived in a forest near a lake

Question 3

The first hominins: Orrorin tugenesis

Answer 3

• 6 mya
• lake Turkana, Kenya
• bipedal
• curved fingers
• apelike canines & premolars
• spent time in trees
• lived in forest

Question 4

The first hominins: Ardipithecus kadabba

Answer 4

• 5.2-5.8 mya
• teeth intermediate between ape & human
• middle Awash Valley, Ethiopia

Question 5

The first hominins: Ardipthecus ramidus (aka “Ardi)

Answer 5

• 4.4 mya
• Awash River Valley, Ethiopia
• lived in a forest
• hominin chewing complex, small canines
• tooth enamel intermediate
• opposable big toe
• part-time biped, part time quadruped

Question 6

Ardi’s story

Answer 6

• female adult
• weighed 110 lbs
• 4 feet tall
• 300-350 cc brain size
• projecting face
• nonspecialized teeth (omnivore diet)
• primate arms & hands, legs & feet (did not knuckle walk)
  * Long toes, divergent big toes
• Hominin pelvis (walked bipedally on ground

-“the breakthrough of the year”

Question 7

Australopithecus & kin

Answer 7

• 4.2- 1.0 mya
• “southern ape” (raymond Dart, 1920s)
• small bodied (30-45 kg)
• small brained (340-500 cc)
• moderately prognathic faces
• several species
• robust australopithecines had massive jaws and molars, strong chewing

Question 8

Australopithecus anamensis

Answer 8

• 4.2- 3.9 mya
• most primitive australopithecine
• earliest incontrovertible evidence of bipedality in postcranial skeleton
• woodland enviroment

Question 9

Australopithecus afarensis

Answer 9

• 3.9- 2.9 mya
• Awash valley, Ethiopia (Don Johansen, 1974)
• brain size 350-500 cc
• prognathic face
• funnel-shaped thorax
• arms longer relative to leg length
• arms not used for walking
• some level of arboreality
• biped with aboreal characteristics
• retreated to trees to escape predators, forage and sleep
• lived in woodlands
• likely lived in polygynous groups
• extreme sexual dimorphism

Question 10

Lucy (Australopithecus Afarensis)

Answer 10

• both humanlike and apelike features
• 1 metre tall
• brain size of adult chimpanzee
• most complete fossil hominin skeleton

Question 11

Dikka Baby (Australopithecus afarensis)

Answer 11

• 3.3 mya
• Awash Valley
• small brain
• apelike upper body
• biped lower body
• probably no speech

Question 12

Australopithecus bahrelghazali

Answer 12

• 3.5-3.0 mya
• found in chad
• known from one single fossil, a mandible with 7 teeth
• proves that hominins lived in areas other than easten Africa

Question 13

Kenyanthopus platyops

Answer 13

• 3.5 mya
• “the flat-faced hominin from kenya”
• flat faced
• small molars
• woodland habitat
• lived at same time as A. afarensis

Question 14

Australopithecus garhi

Answer 14

• 2.5 mya
• small brain
• prognathic face
• large canines
• sagittal crest
• found in same beds as early stone tools
• ancestral to Homo?
• may have made & used stone tools
• oldawan tool complex
• earliest tool culture
• primitive tools
• used for butchering & other functions

Question 15

Australopithecus africanus “Taung child”

Answer 15

“Taung child”

• type specimen
• found in Tuang limestone quarry near Johannesburg, 1924
• fossilized impression of interior of skull (endocast) revealed general appearance and size of brain
• apelike
• 2.3 years old

Question 16

What is a type specimen

Answer 16

the anatomical reference specimen, the species definition

Question 17

Australopithecus africanus

Answer 17

• 3.5- 2.4 mya
• short, broad iliac blade (pelvis)
• spine, leg, feet adapted to habitual bipedality
• 24- 40 kg
• lived in woodland enviroment
• may have evolved from A. afarensis that migrated south
• brain size 450- 550 cc
• no cranial crests
• less prognathic face
• flexed cranial base
• generalized teeth
• gracile

Question 18

The robust Australopithecines (paranthropines)

Answer 18

• an evolutionary dead end?
• extreme specialization
• shared cranial features, sagittal crest, flared zygomatics (cheeks), smaller front teeth, large molars

Question 19

Paranthropus aethiopicus

Answer 19

• 2.7- 2.5 mya
• “the black skull”
• Lake Turkana
• large sagittal crest
• flaring cheekbones
• prognathic face

Question 20

Paranthropus boisei

Answer 20

• 2.3- 1.2 mya
• brain size 500 cc
• body size 34-50 kg
• strong chewing adaptations
• shape of nasal bones & brow-ridges like that of P. aethiopicus

Question 21

Paranthropus Robustus

Answer 21

• 2.0- 1.5 mya
• Kromdraai, Swartkrans, Drimolen
• brain size 500-550 cc
• body size 30-40 kg
• animal protein in diet- termites?

Question 22

Australopithecus sediba

Answer 22

• 2- 1.5 mya
• Malapa Cave, South Africa
• brain size 420 cc
• Small face, jaws, teeth
• pelvis like Homo
• long arms like australopithecines

Question 23

Earliest evidence of stone tool use is an association of?

Answer 23

A. garhi and butchered animal remains 2.5 mya

Question 24

Hand and thumb anatomy show what?

Answer 24

A capability for making stone tools.

Question 25

Paranthropines are probably too specialized to be ancestral to Homo. An ancestor should:

Answer 25

- exist early enough to give rise to later groups - not be more derived than those later groups - have characteristics that look as if they could give rise to later groups

Question 26

Evolution & Extinction of Australopithecines

Answer 26

- early evolutionary trend was to cranial robusticity & strong chewing musculature - robust australopithecines (paranthropines) perhaps unable to adapt to changing vegetation & became extinct - the lineage that led to Homo was perhaps more adaptable & survived