5. Human evolution II

Question 1

what are the hypotheses for the origins of modern humans

Answer 1

out of africa model
multiregional model
assimilation model
leaky replacement model

Question 2

define the out of africa model

Answer 2

anatomically modern humans evolved in Africa first then left africa to colonise new continents

Question 3

what did the anatomically modern humans do once out of africa

what does this mean in terms of the global population

Answer 3

replace h. erectus in regions out of africa

should be more closely related

Question 4

define the multi-regional model

Answer 4

homo erectus left africa first, colonised new continents, then evolved into anatomically modern humans outside of africa

Question 5

if the multi regional model is correct, what does this mean in terms of the global population

Answer 5

more distantly related

Question 6

according to the multi-regional model, why do we see similarities between modern humans?

Answer 6

this is the product of occasional interbreeding between neighbouring populations

Question 7

describe mitochondrial evidence for the two hypotheses

Answer 7

• mitochondrial dan suggests a dated time of 200,000 y/a
• suggests there was a single woman which mitochondrial dan originated from, known as ‘mitochondrial eve’, she then left africa
• does not support either hypothesis

Question 8

describe how evidence of neanderthals supports the out of africa model

Answer 8

mitochondrial dna shows sharp differences between anatomically modern humans and neanderthals, this shows distinct evolutionary lines
-suggests AMHs replaced neanderthals

Question 9

what is the assimilation model

Answer 9

• ancestor left africa but rather than becoming extinct there was interbreeding with neanderthals
• predicted neanderthals contributed to 10% of living peoples genome

Question 10

why do majority of humans have neanderthal DNA

Answer 10

due to interbreeding between Early modern humans and Neanderthals

Question 11

when did denisovan and neanderthal populations split

Answer 11

200KA

Question 12

what is the leaky replacement model

Answer 12

neanderthals went east and interbred with Denisovans- these form the basis of modern day melanesians

Question 13

what is the evidence for leaky replacement

Answer 13

2018- found a skeleton in a cave, mother was neanderthal and father was denisovan

Question 14

what is the argument against the interbreeding theory

Answer 14

suggests that if neanderthals and modern humans shared a common ancestor, the similarities could be due to this rather than interbreeding

Question 15

what are some of the theories for how speech evolved

Answer 15

• started with manual gestures, moved to vocalise ideas if hands were busy
• a part of the brain evolved to facilitate speech

Question 16

what is Kebara 2

Answer 16

a neanderthal male skeleton, use of the hybrid bone suggests this man has the capacity for speech

Question 17

what did early agriculture look like

Answer 17

cultivating grains such as wheat and barley

livestock was domesticated about 9ka

Question 18

what was lamarcks theory for evolution

Answer 18

it was wrong:
- he described it as the heritability of acquired characteristics, eg the giraffe stretches its neck to reach fruit on trees, passes on a long neck to offspring