12.2

Question 1

Hominidae characteristics

Answer 1

More complex brain than other primates
No tail
Appendix
Diurnal
Freely rotating arms
Five cusps

Question 2

4 main changes

Answer 2

Relative size of the cerebral cortex
Mobility of the digits
Locomotion
Proganisthism and dentition

Question 3

How does brain development help?

Answer 3

Move about, locate food and social skills
Enabled tool making
Mutual cleaning and grooming, fighting for dominance
Larger brain

Question 4

Changes in cerebral cortex

Answer 4

Increase in size- especially cortex
Large brains relative to body size
Strong convultion patterns

Question 5

Mobility of digits

Answer 5

Unspecialised limbs
Pentadactyl= five digits
Highly mobile
Precision grip and power grip
grasping toe lost, to become weight bearing

Question 6

Locomotion

Answer 6

Change from quadrupedalism to bipedalism

Question 7

Position of foramen magnum

Answer 7

Gradually moved forward, to become more central- allows skull to balance (hence why apes had large neck muscles)

Question 8

Jaw changes

Answer 8

Apes have protruding jaw, humans are flatter
-Due to smaller and less teeth over time.

Question 9

Pelvis

Answer 9

Pelvis in humans is shorter, broader and more bowl shaped than apes
Bowl shape supports stability, and foetus development

Question 10

Carrying angle

Answer 10

Position of pelvis results in hip joint being directly under trunk, allows weight to be transferred
Femurs also converge inwards, allows weight to be distributed evenly when walking

Question 11

The knee

Answer 11

Outer hinge is larger and stronger
COG in front of knees
-Results in a force trying to bend knee backwards- resisted by ligaments= NATURAL RESISTANCE THAT REQUIRES NO ENERGY

Question 12

The foot

Answer 12

Lost grasping ability to become a highly specialised moving organ- weight bearing

Metartarsals form 2 arches:
-Longitudinal (front to back)
-Tranverse arch (side to side)

Question 13

COG

Answer 13

Longer legs= lowering centre of gravity
Humans is at pelvis, apes at chest level
Lower cog support bipedal movement

Question 14

Muscle Tone

Answer 14

Partial contraction of skeletal muscles
-Spine, hip, knee, ankle and abdominals
-Muscles in back of neck partially cntract to avoid head slumping

Question 15

Striding gait

Answer 15

Walking upright when the hip and knee are fully straightened is referred to as the striding gait

Question 16

Bipedalism advantages (6 of them)

Answer 16

1. More efficient
2. Leaves the hands free to use tools
3. Hands free to carry items
4. Upright stance ahieves greater height= see further
5. Less body to sunlight
6. Increas exposure to breeze= cooling mechanisms

Question 18

Dental formula in primates

Answer 18

Primitive= 3:1:4:3, three incisors, one canine, four premolars and three molars on each side= 44 teeth total

Question 19

Dental arcade changes

Answer 19

Dental arcade changed from U shaped to more parabolic

Question 20

Proganithism and Brow ridges

Answer 20

Apes and easrly hominids= Prognathism and distinct brow ridge
-Tooth size decreased- flatter face, devlopment of chin and nose