Ch. 17 Primate Evolution

Question 1

define primate

Answer 1

a member of an order of mammals that includes the lemurs, lorises, tarsiers, monkeys, apes and humans

Question 2

define binomial system

Answer 2

the system of naming organisms using generic (genus) and specific (species) names to describe a species

Question 3

define hierarchy

Answer 3

: a series of groups that move from broad general categories to narrow specific ones

Question 4

what are the movement of going down the hierarchal pyramid

Answer 4

Kingdom (Plant/Animal) > Phyla (Phylum) > Classes > Order

Question 5

what were the early classifications of priamtes

Answer 5

o Prosimians (primitive primates) and anthropoids (monkeys, humans and apes)

Question 6

what are the suborders of primates

Answer 6

o Strepsirrhini (non tarsier prosimians) and Haplorrhini (tarriers, monkeys, apes and humans)

Question 7

what do most primate characteristics due to

Answer 7

arboreal lifestyle

Question 8

what are the 8 common characteristics of primates

Answer 8

brain 
eyes
smell
teeth
body 
limbs
hand feet
reproduction

Question 9

What are the four areas of evolution of the digits

Answer 9

Mobility and opposability
tactile pads
nails
arrangement of hand

Question 10

what does the fact that limbs are not specialed result in

Answer 10

diversity in use

Question 11

what was the mobility trend of digits

Answer 11

increasing mobility ability to move digits independently of one another

Question 12

what is prehensility important for primates

Answer 12

gripping trees

Question 13

what is the most developed digit

Answer 13

• thumb and big toe

Question 14

what does opposability mean and what does it depend on

Answer 14

o Opposable= ability to use thumb to touch the tips of each other digit on the hand
o Degree of opposability depends on relative length of first digits compared with other four

Question 15

why did humans loose opposability of big toe

Answer 15

o All species bar humans= opposable big toe

♣ Lost opposability when human foot became a weight-bearing rather than grasping appendage

Question 16

what does humans having longest thumb result in

Answer 16

o Humans= longest thumb of primates= contribute to ability to manipulate objects with our hands

Question 17

explain tactile pads in evolution

Answer 17

• Ends of digits= sense receptors so that digits can grip and manipulate objects
• Nails and tactile pads on under surface= evolved together
  o Pads developed small ridges to increase grip b/w ends of digit and object
  ♣ = friction ridges, finger prints= pattern varies b/w individuals and species

Question 18

why did claws evolve into nails

Answer 18

• Claws limit grasping= prevent opposable surfaces from coming together
  o Nails evolved from claws that became flattened
  o Evolutionary less advanced primates still possess claws

Question 19

explain had arrangement of humans

Answer 19

• Human hand compared to other primates= short and broad, with short straight fingers and long strong thumb

Question 20

wha does the arrangement of the human hand allow

Answer 20

• This arrangement= great degree of freedom for thumb and can readily oppose other digits= allowing precision grip= one of the hallmarks of being human, though not unique to humans
• What is unique amount of contact b/w index and thumb
  o Enables effective handling of small or delicate objects
  o Precision grip also seen in old world monkeys (requires truly opposable thumb)
  ♣ These monkey= 2nd only to humans in manipulation abilities

Question 21

What are the 4 areas of evolution for dentition

Answer 21

number of teeth
structure
diastema
cusps

Question 22

what is the evolution of number of teeth

Answer 22

decrease- o Probs related to gradual reduction in size of face and jaw that has occurred in primates

Question 23

explain dental comb

Answer 23

• Lemurs and lorises= unusual specialisation of incisor teeth= lower front incisors= slanted forward with crowns= narrow + closely spaced to form dental comb
  o Used for grooming fur, only rarely for feeding/fighting

Question 24

what is the trend in cusps

Answer 24

3 > 4 > 5

Question 25

explain the olfactory/occiptial shift

Answer 25

- Arboreal life= emphasis on vision (with decreasing reliance on sense of smell, olfaction) - = Shift in sensory orientation

Question 26

what was the shift in vision accompanied by

Answer 26

- accompanied by overall change in shape of skull compared with other mammals o I.e. decrease smell= reduced snout > allows for more forward facing eyes > better stereoscopic vision

Question 27

how is observable behaviour linked to shift of vision

Answer 27

o E.g. lemurs= use their snout and teeth for what apes use eyes and hands for (investigating an object, grooming, communicating)

Question 28

difference between mammals and primates in eye sockets

Answer 28

- Most mammals have eye socket that face sideways, but primates developed eye sockets that face forward

Question 29

what does forward facing eyes allow

Answer 29

o Enables fields of vision of each eye to overlap= distances judged accurately o = important adaption for a tree living animals

Question 30

how do primates compensate for narrow vision

Answer 30

a highly mobile head and neck

Question 31

explain eye socket and protection

Answer 31

- As eyes become more forward= bony eye socket developed to give protection o Gradual change in eye socket clearly visible in fossil primate skulls o As position of eye socket changed for eyes to face forward, bone gradually closed in side and rear of socket

Question 32

what are the four areas of evolution for vision

Answer 32

shift eyes eye socket visual area of brain

Question 33

explain increase in area of vision in brain

Answer 33

- Increasing importance of vision= region of brain concerned with interpretation of visual information increased in size o While that concerned with olfaction decreased - Unlike smell or hearing, reliance on vision to move about, locate and manipulate food generates large amount of complex sensory information that has to be processed and stored

Question 34

what are the three areas of evolution of the cereal cortex

Answer 34

size convolutions cerebral cortex (higher order)

Question 35

what are the five areas of evolution and gestation and parental care

Answer 35

single offspring placental mammals length of gestation sexual maturity

Question 36

what does increase length in development and delayed sexual maturity result in

Answer 36

- Enables ideas and techniques to be passed on from one generation to the next - Delay in maturation + sexual maturity = reduce # of offspring female has in lifetime o // each offspring important, + time and effort invested in care and survival o Investment in prolonged parental care evolved because increases survival chances of offspring and provides a long period during which the young can learn from older members of the group