Biological Evolution

Question 1

What is bipedalism?

Answer 1

Evolution of species that leads to Homo sapiens being adapted to more easily fit the environment, as well as development of the brain, becoming larger and smarter

Question 2

Facultative bipedalism

Answer 2

an organism, like a chimpanzee, will only walk on 2 legs when it needs to carry something of reach for something, like a branch. Only sometimes on 2 legs

Question 3

Habitual Bipedalism

Answer 3

used by humans and kangaroos, walking on 2 legs all the time, having the ability to carry something in their hands constantly if needed

Question 4

arboreal meaning

Answer 4

living in trees

Question 5

Bipedalism spine change

Answer 5

spine became S-shaped rather than C-shaped. This brings the bodys mass over the feet, more balanced and better distribution of mass. Shock absorber

Question 6

Bipedalism Valgus angle

Answer 6

Chimps: No vulgus angle, legs go straight down below pelvis to support 4 limbs
Humans: Vulgus angle increases, allowing the knee and leg to be more efficient for walking, means we are not swaying from side to side

Question 7

Bipedalism Pelvis change

Answer 7

Chimp: long, flat, narrow
Human: broader, bowl shape, helps to more legs in a straighter line

Question 8

Bipedalism foot

Answer 8

foot becomes arched and forward facing big toe

Question 9

Bipedalism Shoulders change

Answer 9

dropped so they are slightly lower than the top of the rib cage

Question 10

Bipedalism Rib Cage

Answer 10

Chimp: round and hangs low to support organs
Human: flatter and rounded. Organs stack up rather than fall forward in chimps

Question 11

Bipedalism Foramen magnum

Answer 11

chimp: near the back of the head so the chimp can move their head around while on 4 limbs
Human: more central in the skull so the head it upright, not tilted forward, means the head is more centered with spine

Question 12

Reasons for skull change

Answer 12

main change of the skull is due to bipedalism and a change in diet, softer foods

Question 13

Nuchal crest

Answer 13

neck muscle attachment point
became small because standing on 2 legs means we dont need to hold our heads up forward facing

Question 14

Saggital crest

Answer 14

ridge on top of skull
smaller size, slowly disappeared in humans

Question 15

brow ridge

Answer 15

bone above eyes
smaller

Question 16

Jaw

Answer 16

smaller

Question 17

teeth

Answer 17

became small due to diet, diastema slowly disappeared

Question 18

zygomatic arch

Answer 18

arch on side of face above the muscles supporting chewing
smaller size over time

Question 19

Why do these changes occur to the skull?

Answer 19

foramen magnum becomes more centred due to standing on 2 feet
changes to skull occur because of a change in diet, softer food means less chewing required, so less muscles needed therefore smaller skull to support these smaller muscles. more energy used elsewhere instead of making large muscles

Question 20

Endocranial meaning

Answer 20

inside skull, brain

Question 21

Broca’s area

Answer 21

controls language expression, in the frontal lobe

Question 22

Wernicke’s area

Answer 22

control language reception, left temporal lobe

Question 23

frontal lobe/cerebrum

Answer 23

region in the cerebral cortex that has specialized areas for movement, abstract thinking, planning, memory, and judgement

Question 24

Cerebellum

Answer 24

large structure in the brain that controls balance and skills

Question 25

Cerebrum change

Answer 25

greater expansion

Question 26

cerebellum change

Answer 26

greater expansion

Question 27

Brocas area

Answer 27

more organised to form sentences from sounds

Question 28

Wernickes areas

Answer 28

more able to interpret sounds to be meaningful

Question 29

Power grip

Answer 29

gripping with as much hand surface as possible in contact with the object, all finger bent at the same angle and thumb as support

Question 30

precision grip

Answer 30

involves opposing the tip of the thumb to the tips of other fingers, allowing fine control of small objects

Question 31

Why is bipedalism beneficial? (5 reasons)

Answer 31

Being taller, able to see further
hands, able to carry and do things
less exposure to the sun, minimising exposure to radiation heat
outrun distance, long-distance walkers and runners, didn’t make us faster but gave us the energy to use 2 legs rather then 4
larger brain, brain development to become more creative and thoughtful