Characteristics of Primates- Digits (17)

Question 1

Define Primates

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

What are the areas of primate characteristics that are identifiable in all primates

Answer 3

Body, Limbs, Hands/Feet, Eyes, Sense of Smell, Teeth, Brain, Reproduction

Question 4

Primate Characteristics: Limbs

Answer 4

Generally unspecialised, diversity in use

Question 5

Primate Characeristics: Hands and Feet

Answer 5

• Pentadactyl
• Nails instead of claws
• Prehensility (+ friction ridges)
• Opposable first digit

Question 6

Primate Characteristics: Body

Answer 6

Not specialised for a particular environment

Question 7

Primate Characeristics: Eyes

Answer 7

• Forward facing for stereoscopic vision

- Most able to distinguish colour

Question 8

Primate Characeristics: Sense of smell

Answer 8

• very poor

Question 9

Primate Characteristics: Teeth

Answer 9

Four incisors in both upper and lower jaw

Question 10

Primate Characeristics: Brain

Answer 10

• Large and complex

- cerebrum size increase as primates become more highly evolved

Question 11

Primate Characeristics: Reproduction

Answer 11

• Not restricted to a breeding season
• Rhythmical sexual cycle
• Usually only one offspring at a time
• Long period of parental care for offspring

Question 12

Why are digits thought to be highly mobile (linking their ability to prehensility)

Answer 12

• related to arboreal ancestors

- essential for climbing and wrapping digits around trees

Question 13

What was the evolutionary trend of digits

Answer 13

• = toward increasing ability to move digits independently of one another

Question 14

Define opposable

Answer 14

ability to use thumb to touch the tips of each other digit on the hand

Question 15

What does degree of opposability depend on

Answer 15

♣ Degree of opposability depends on relative length of first digits compared with other four

Question 16

What is the difference between the first digit of humans and other primates

Answer 16

♣ All species bar humans= opposable big toe

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

Question 17

What does the fact that humans have the longest thumb of all primates contribute to

Answer 17

Contribute to ability to manipulate objects with our hands

Question 18

Evoluntionary trends of claws and why

Answer 18

o Nails evolved from claws that became flattened

Because Claws: limit grasping= prevent opposable surfaces from coming together

Question 19

What is the development of ends of digits

Answer 19

• Developed sense receptors so that digits can grip and manipulate objects

Question 20

have nails and tactile pads developed together

Answer 20

Nails and tactile pads on under surface= evolved together

Question 21

What are tactile pads

Answer 21

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 22

Explain the arrangement of the human hand

Answer 22

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

Question 23

What has the arrangement of the human hand enabled

Answer 23

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

• unique amount of contact b/w index and thumb= enables effective handling of small and delicate objects

Question 24

Besides humans, where else is the precision grip

Answer 24

old world monkeys

Question 25

What are the general areas of development of hand and digits

Answer 25

1. Independence and Opposability
2. Nails instead of claws
3. Tactile Pads
4. Arrangement of hand