Chapter 17

Question 1

Primate characteristics?

Answer 1

• non specialised body/limbs
• pentadactyl
• nails instead of claws
• first digit (opposability)
• poor sense of smell
• large and complex brain
• rhythmical sexual cycle

Question 2

Evolutionary trends within primates: digits

Answer 2

Grasping = prehensile
Opposable = thumb touching all digits
As we go up the evolutionary scale = increased mobility, ability to move digits independently, opposability of thumb/increased length and nails instead of claws

Question 3

Evolutionary trends within primates: dentition

Answer 3

Diastema = lower gap for large lower canine
As we go up the evolutionary scale = reduction in the number of teeth (36->32), 4 cusped molars->5, monkeys/apes have large projecting canines with diastema
Humans - 2:1:2:3, both upper and lower
From old world monkeys -> loosing 2 pre molars

Question 4

Evolutionary trends within primates: Sense of smell

Answer 4

Olfaction = sense of smell
As we go up the evolutionary scale = reduction in olfaction/snout length (flatter face), reduced prognathic (stick out) jaw
Our reliance on it has decreased

Question 5

Evolutionary trends within primates: vision

Answer 5

Degree overlap increases from Lemur (90) -> human (120)
As we go up the evolutionary scale = increasingly forward facing eyes (stereoscopic vision), efficiency of eyes, protection of eyes and increased visual area within brain

Question 6

Evolutionary trends within primates: brain

Answer 6

As we go up the evolutionary scale = increased size, convolutions (making us more advanced, increased SA), cerebral cortex. Brain become larger and more complex from lemur -> human.

Occipital lobe is devoted to vision.

Question 7

Evolutionary trends within primates: gestation and development

Answer 7

As we go up the evolutionary scale = increased length of time offspring are dependent on parents
Gestation, weaning, infantile period, juvenile period and life span all increase from Lemur -> human.
Increases learning -> spending more time with someone who’s more educated.

Question 8

Arboreal?

Answer 8

Tree-like movement

Question 9

Primate?

Answer 9

A member of an order of animals that include:

Lemurs, lorises, tarsiers, monkeys, apes and humans

Question 10

Why did humans loose ability in their big toe?

Answer 10

Later became a weight bearing rather than a grasping appendage
Bipedalism

Question 11

Why did claws go to nails?

Answer 11

Limitations of grasping

Can’t manipulate objects

Question 12

What do forward facing eyes allow? (Stereoscopic vision)

Answer 12

Allowing distance to be judged accurately (e.g. when jumping from tree -> tree)