Human Evolution Session 26

Question 1

What does the hominid line of descent begin with ?

Answer 1

• Australopithecines

Question 2

Originally, What were the two ways australopithecines were classified as?

Answer 2

• Gracile which meant having a more slender body
• Robust which meant having strong upper bodies and massive jaws

Question 3

What are gracile and robust australopithecines now classed as ?

Answer 3

• Gracile : genus Australopithecus
• Robust : genus Paranthropus

Question 4

What was the first hominin to be discovered ?

Answer 4

• Australopithecus africanus , dated 2.9 MYA

Question 5

What is Mosaic evolution ?

Answer 5

• IT is when the different body parts change at different rates and different times

Question 6

What are some things that allows fossils to be assigned to the genus homo ?

Answer 6

• If the brain size is 600 cc or greater
• the jaw and teeth resemble those of humans
• Tool use is evident
• Not a straight lineage : still missing links
• Importance of migrations , replacement

Question 7

What was the earliest Homo and when was it dated ?

Answer 7

• Homo Habilis , between 2.0 and 1.9 MYA

Question 8

When did Homo eretus started to migrate out of Africa?

Answer 8

• 1.7 MYA

Question 9

When did the Homo Erectus expand into Asia?

Answer 9

• 0.8 MYA

Question 10

What is the replacement model ?

Answer 10

• It is the model that states that modern humans evolved from earlier Homo species only in Africa and then migrated to Asia and Europe , where they replaced the early homo species

Question 11

What is the meaning of founder effect ?

Answer 11

• it is a special case of genetic drift , occurring when a small group in a population splinters off from the original population and forms a new colony

Question 12

What are the oldest fossils to be designated Homo sapiens and did they enter Asia, Europe and Africa ?

Answer 12

• it was the Cro-Magnons around 100,000 years ago.