lecture 4- evolution of humans 1

Question 1

what is the superfamily for primates and when did it exist?

Answer 1

Eurachonta, 80mya

Question 2

what two groups did Eurochonta diverge into?when?

Answer 2

• simians
• prosimians
• 50ma

Question 3

what are the differences in characteristics between prosimians and simians?

Answer 3

-promisians are nocturnal, simians are diurnal
-prosimians have binocular vision, simians have overlapping fields of vision
-promisioans are primarily aboreal
prosimians have grasping fingers and toes, simians (in majority) have opposable thumbs
-simians are far more social

Question 4

Give simian and prosimians examples

Answer 4

Prosimians: lemurs
Simians: humans, gorillas etc

Question 5

What are the direct ancestors of monkeys and hominids?

Answer 5

The first simians

Question 6

what two species underwent different adaptive radiations 40ma from a common ancestor?

Answer 6

the new world monkeys and the old world monkeys

Question 7

where are the new world and old world monkeys found?

Answer 7

• new world in south America

- old world in africa and asia

Question 8

what two species does the superfamily hominoidea break into?

Answer 8

• hylobatidea (lesser apes)

- hominidae (greater apes)

Question 9

What are the characteristics of greater apes?

Answer 9

Large brain relative to body size,flexible behaviour, no tail, high social behaviour

Question 10

What are the similarities between humans and chimps?

Answer 10

96% of DNA is shared, and 99% of this is coding dna

Question 11

If the genes aren’t that different between humans and chimps, why are we so different?

Answer 11

The phenotypes (gene expression) are different

Question 12

What’s the difference between shared and derived characteristics?

Answer 12

Shared characteristics are found in organisms across clandestine (eg. Legs) whereas a derived characteristic is on specific to a certain Clade (eg. Feathers on birds )

Question 13

What are the derived characteristics of humans?

Answer 13

Bipedalism, large brains capable of language,symbolic though and complicated too use, reduced jawbone, jaw muscles and digestive tract, flat faces

Question 14

What is the difference in skull between humans and chimps?

Answer 14

Humans have an INFERIROY attached skull, chimps have a POSTERIORLY attached skull

Question 15

What is the difference in spine shape between humans and chimps?

Answer 15

Chimps have a curved spine whereas humans have an s shaped ones

Question 16

What is the difference in foremen magnum position between humans and chimps?

Answer 16

In chimps it’s located relatively far back in the skull, in humans it’s located underneath

Question 17

What is the difference in pelvis shape between humans and chimps?

Answer 17

Long and narrow in chimps, bowl shaped in humans

Question 18

What is the difference in femur angle between humans and chimps?

Answer 18

Points outward in chimps, inward in humans

Question 19

How is bipedalism thought to have evolved?

Answer 19

When India and Eurasia collided (approx 10 ma) there was a drastic change in habitats. The environment went from being tree dominated to Savannah dominated, and natural selection acted on hominins leaving those best adapted to walking on the ground remaining.

Question 20

How did hominin bipedalism evolve?

Answer 20

In a non linear fashion, with many different evolutionary stages demonstrating the ability

Question 21

When is the approx start of hominin permanent bipedalism? Why?

Answer 21

1.9 million years ago, as they lived in arid environments and two legged motion required less energy than four legs

Question 22

When did humans start using tools? What was the evidence?

Answer 22

2.5 ma. Marks on animal bones found in Ethiopia

Question 23

What hominins were found with the first tools? What did this imply?

Answer 23

Australopithecus ghani, suggesting evolution of tool use occurred before the evolution of large brains