ORIGIN OF HOMININS

Question 1

Why is the chimpanzee fossil record limited?

Answer 1

It is limited because they live in forests where decomposition is rapid and it is rare to fossilize

Question 2

Describe Ardipithecus ramidus.

Answer 2

• 4.4 Ma
• Small brain (character = brain; character state = small)
• Large canines
• Flat face
• Foramen magnum central = bipedal motion
• opposable toes
• long arms to swing from trees because they are arboreal

Question 3

Describe Sahelanthropus tchadensis

Answer 3

• Named after “Chad” in Africa
• 6-7 Ma
• Skull
• Small brain
• Large brow ridge
• Foramen magnum central (hole in skull) – suggests bipedalism
• Hominina? Usually yes, due to bipedalism, but still debated

Question 4

Is australopithecus gracile or robust?

Answer 4

Gracile; paranthropus is robust

Question 5

How are australopithecus afarensis believed to have died?

Answer 5

Evidence of impact found on fossils suggests they had commonly fallen off trees to their death.

Question 6

Which structure allowed for Paranthropus boisei to produce a large biting force?

Answer 6

Saggital crest: attachment site for muscles that control the jaw, allowing for a larger biting force

Question 7

What size was the brain of the Homo habilis?

Answer 7

Medium; they also made simple tools

Question 8

How are Homo erectus similar to modern day humans?

Answer 8

They could control fire to cook food, used sophisticated tools, and had a large brain

Question 9

Which lineage was the first hominin to move out of Africa?

Answer 9

Homo erectus, to some parts of Eurasia

Question 10

Which lineage was the first to have tattoos and cave paintings? What evidence is there for this?

Answer 10

Homo neanderthalensis because tools were found that seemed to perform that purpose; skin with tattoos was not found, as it does not fossilize.

Question 11

What came first, Homo sapiens evolving into their modern forms, or moving out of Africa?

Answer 11

They evolved first, and interacted with other species before moving out of Africa

Question 12

Why is genetic diversity greatest in Africa?

Answer 12

This is because Homo sapiens evolved their and interbred with other species, allowing for greater diversity.

Question 13

What are the pros and cons of bipedalism?

Answer 13

PROS: - thermoregulation, as lower sun exposure on 2 legs than 4
- foraging, as two limbs were freed to make tools and hunt
- migration, as bipedalism allowed for greater conservation of energy when travelling long distances
CONS: - bowl-shaped pelvis for balance on 2 legs developed but limited size of newborns