Hominin Origins

Question 1

In humans, males are on average ____% larger than females.

Answer 1

Males are on average 15% larger than females.

Question 2

What social structure do people naturally have?

Answer 2

Polygynous

Question 3

Describe Piltdown man.

Answer 3

It was a hoax, in 1950s exposed

“Eoanthropus dawsonii

Found in Sussex gravel pit

Ape-like jaw

Lots of people thought the big brain came first and they would still have a primitive jaw so it fit the preconceptions of the time and that’s why people believed it.

Question 4

What was the habitat like during the time of the early hominins?

Answer 4

1) Pliocene habitats were dry
2) East Africa Rift Vally forms rain shadow (with rain shadow you lose a lot of rainforest and get expansion of savannah)

Question 5

What is a supraorbital torus?

Answer 5

Brow ridge

Question 6

Describe Sahelanthropus tchadensis

Answer 6

1) Chad
2) 6-7mya
3) about 62kg
4) Robust supraorbital torus
5) Short subnasal region
3) Vertical upper face
4) Similar sized brain to Pan
6) forward position of foramen magnum (bipedal)
7) Smaller canines with apical wear indication occlusion. (Small canines like us)

Question 7

Describe Ardipithecus Kadabba

Answer 7

1) Ethiopia hominin
2) 2.8-5.2mya
3) Finger bones were curved so was at least partially arboreal but was also bipedal on the ground

Could be bipedally arboreal but the toe bones are usually curved if bipedal in trees

Question 8

Describe teeth of Ardipithecus kadabba.

Answer 8

1) Taller canine than in later taxa –> instead of occlusion it will go past and hone against pre-molar
2) Diastema (it has one for the lower canine to go)

Question 9

Describe postcrania of Adripithecus

Answer 9

1) Long arms (high intermembral index) so it was probably spending lots of time in trees
2) No knuckle walking features
3) Divergent hallux
4) Short, wide ilium (only seen in people amongst extant apes)

This indicates bipedal pelvis might have evolved before big toes was in line in others

Question 10

Describe Australopithecus anamensis.

Answer 10

1) 3.9-4.1 mya, Kenya
2) 47-55kg
3) Open habitats)

Question 11

List the primitive dental features of Australopithecus anamensis.

Answer 11

1) Large, stout canines
2) Thick mandible (people have narrow mandibles)
3) Parallel tooth rows (whereas in people it’s wider at the back than at the front)

Question 12

List the derived dental features of Australopithecus anamensis

Answer 12

1) Broader molars

2) Thicker enamel (unlike gorillas and chimps but like us)

Question 13

Explain how the postcrania of Au. anamensis is similar to the postcrania of humans

Answer 13

The condyles are large where the femur joins the tibia, which you see in people.

If you’re a biped the surface of the joint has to be wider to take the extra weight!

Question 14

Describe Praeanthropus afarensis.

Answer 14

A.K.A Australopithecus afarensis

1) 3.6-2.8mya, Ethiopia and Tanzania
2) Lots of specimens
3) Prognathic (due to front dentition large compared to people)
4) Large incisors (Unlike people)
5) EQ = 2.5 (Pan is 2.0)
6) Long forelimbs
7) Short stature
8) Pronounced sexual dimorphism (polygynous)
9) Some have distema and some don’t (so it is in the process of changing)
10) Curved phalanges (still spending time in trees)
11) Scapula tilted slightly posteriorly due to arms being held above head a lot
12) Short and wide ilium (bipedal)
13) knee is valgus (bipedal)

Question 15

What is Lucy’s fossil code?

Answer 15

AL 288-1

Praeanthropus afarensis

Indicates bipedalism before brain expansion

Question 16

Describe the bipedal features of Lucy.

Answer 16

1) Valgus knee
2) Lumbar curve (puts pelvis directly below centre of gravity
3) Short, curved pelvis

Question 17

Describe the arboreal features of Lucy

Answer 17

1) Cone shaped torso (unlike humans in which it is more barrel shaped)
2) Broad, muscled shoulders
3) Curved phalanges

Question 18

How did Lucy die?

Answer 18

Fracture pattern suggests fall

Question 19

What do the Laetoli footprints reveal about Lucy’s kind?

Answer 19

1) Bipedal
2) Footprints in volcanis ash 3.66mya

Two hominins walked together and one was larger than the other. No knuckle marks so it wasn’t using it’s forelimbs to walk. Also showed hallux was in line with other toes.

Footprints also show they had an arched foot (hominin trait)

Question 20

Describe Australopithecus garhi.

Answer 20

1) 2.5 mya, Ethiopia
2) Very large molars, no diastema
3) Prognathic
4) Long, ape-like arms
5) Femur lengthened so intermembral index is similar to humans
6) Tools and evidence of large animal butchery

Question 21

Describe Taung child.

Answer 21

1) Australopithecus africanus
2) Found in Africa,
3) 2.3mya
4) Foramen magnum forwardly places
5) No browridge (like us)
6) High forehead
7) No projecting canine
8) Parts of brain expanded

Question 22

Why was there scepticism surrounding the Taung child?

Answer 22

1) Jaw of human and brain of ape is unlike piltdown
2) Would mean Africa was the home of hominins
3) It’s a child (adult could look different)

Question 23

Describe the cranium of Australopithecus africanus

Answer 23

1) Braincase more domed than Pr. afarensis
2) Brain 430-480cm3
3) EQ= 2.7
4) Face deeper and less projecting

Question 24

What does the reduction in incisors and canines and large molars in Au. africanus reflect?

Answer 24

Reflects shift away from slicing towards crushing and grinding

They also had thicker enamel

Question 25

What is Mrs Ples?

Answer 25

STS 5

Adult Au. africanus

1) 2.5mya
2) Showed Taung child was not an ‘ape’
3) Oldest hominin individual in the fossil record (short incisor from heavy wear)

Question 26

What is the EQ of Pr. afarensis?

Answer 26

2.5 (larger than a chimp with 2.0)