Human Evolution

Question 1

What are the main evolutionary themes of the Homininae?

Answer 1

Locomotion, Diet, and Brain

Question 2

How did Hominoids methods of locomotion change, in response, to a shift from an arboreal to a terrestrial lifestyle?

Answer 2

Shift from brachiation to increased bipedality

A bowl-shaped pevis to support the torso

Question 3

How did Hominoids diet change, in response, to a shift from an arboreal to a terrestrial lifestyle?

Answer 3

Now a fibrous diet resulting in a shift from thin to thick enamel, with reduced canines and reduced prognathism

Question 4

How did Hominoids brain change, in response, to a shift from an arboreal to a terrestrial lifestyle?

Answer 4

Increased cranial capacity due to the complexity of the fluctuating climate

Slowly increased until the pleistocene ~1mya

Question 5

Why are we so interested in studying Chimpanzees?

Answer 5

Closest living relatives (~99% DNA) and can be used as a comparison of evolution.

Question 6

What are some traits of the Australopithecus afarensis hominin? When are they dated to?

Answer 6

3.8-3.0mya eg. Lucy

Obvious sexual dimorphism in dentition

Thick enamel on teeth

Brain capacity of 400-450cc

Longer forelimbs relative to hindlimbs

Question 7

What are some traits of the Paranthropus boisei hominin? When are they dated to?

Answer 7

2.6-1.2mya

Endocranial capacity ~500cc

Massive cheek teeth relative to incisors

Saggital crest and large muscle attachment on mandible

Question 8

What are some traits of the Homo Habilis hominin? When are they dated to?

Answer 8

2.8-1.5mya
Brain capacity of 700cc

Reduced facial size

Smaller teeth with thinner enamel

Discovered in association with Oldowan stone tools

Question 9

What are some traits of the Homo ergaster hominin? When are they dated to?

Answer 9

1.8-0.5mya
Brain capacity of 850-1000cc

First wave of migration out of Africa

Very tall

Fully committed terrestrial biped

Longer development periods (later molar eruption)

Question 10

What are some traits of the Homo erectus hominin? When are they dated to?

Answer 10

1.6-0.2mya

Brain capacity of 840-1000cc

Controlled fire and used oldowan tools

Question 11

What are some traits of the Homo Heidelbergensis hominin? When are they dated to?

Answer 11

800-200kya

Brain capacity of 1200-1300cc

Second wave of migration out of Africa

Manufactured Acheulian tools

Hunted and controlled fire

Question 12

What are some traits of the Homo Neanderthalensis hominin? When are they dated to?

Answer 12

400-35kya

Brain capacity of 1200-1600cc

Occipital bun

Question 13

What are some traits of the Homo Sapien hominin? When are they dated to?

Answer 13

300kya

Brain capacity of 1250-1400cc

Third wave of migration out of Africa

Present chin

Question 14

What is the significance of the Australopithecus ‘Lucy’?

Answer 14

Was an early bipedal hominin

Represented the postural adaptation for feeding that came about due to the shift from forest to savannah environment

Broad and narrow pelvis and inward slanting femur

Question 15

What is the significance of the Australopithecus ‘Taung Child’?

Answer 15

Displayed the early shift from prognathism to orthognathism

Displayed shift in teeth size to be more in proportion and more similar to modern humans

Question 16

What is the significance of the Homo Ergaster ‘Nariokotome Boy’?

Answer 16

It is one of the most complete skeletons of H. ergaster

Displayed;
Relatively large brain of 850cc

Tall, 190cm

Fully committed to terrestrial life;
Long legs, narrow hips, narrow shoulders, barrel-shaped chest, and short arms

Reflected longer development periods through later eruption of molars

Question 17

What is the main significance of the hominin, Homo Ergaster?

Answer 17

First to display a slowing of history through longer juvenile periods

They ate meat, a rich food source

1st major dispersal of hominins out of Africa

Question 18

What is the obstetrical dilemma?

Answer 18

Through increased bipedality, the bowl-shaped pelvis that developed restricted the size of the birth canal.

But brain size was rapidly increasing

As a result, increase in maternal pelvis with longer superior pubic radius and an increase in the neonatal cranium (softening of pubic symphyses)