Human Evolution

Question 1

What is the overarching term for humans+ apes?

Answer 1

Homininds

Question 2

Describe adaptations

Answer 2

Helps it to surviva and reproduce in the specific enviroment

Question 3

Describe Tribe

Answer 3

name given to a relatively new level of classification between subfamily and genus.

Question 4

Descrribe hominidae

Answer 4

chimpanzee, gorilla, oragn-utans

Question 5

Describe homininae

Answer 5

chimpanzee, gorilla, humans

Question 6

Describe homini

Answer 6

Humans

Question 7

Compare hominid( family) and hominin (tribe)

Answer 7

Hominid( family) modern and extinct great apes ; humans, orangutan, chimpanzee, gorillas

Hominin (tribe) consists human specie, modern , extinct our immediate human ancestors.

Genus homo
australo pitheceus
Paranthropus
ardipithecus

Question 8

What are the primate characteristics

Answer 8

not one characteristic which can be used to seperate primates from all other mammals.

Common features-> grasping fingers + toes and overlapping vision

Question 9

Describe phylogenetic Trees

Answer 9

What is the purpose? To represent the relationships between groups of organisms, derived from a common ancestors.

Tree diagram is based off differences and simililarities ( physical / genetic characterisitics)

The distance of the node on phylogenetic trees indicate the degree of relationship

Question 10

What are the limitations of phylogenetic Trees

Answer 10

Not 100% accurately represent the revolutionary history of specific group of organisms

May not be valid as only use one set

Question 11

What are the evolutionary trends within primates

Answer 11

Primates more than any other order of mammal, show a gradual change in characteristics

Question 12

What is Family: Hominidae

Answer 12

1. A larger more complex brain than other primates -> increased cognitive abilities
2. Five cusps in the molar teeth of the lower jaw
3. Arms that can freely rotate at the shoulder
   4.Wide and shallow chest cavity
4. An appendix
5. No external Tail
6. Being active during the day

Question 13

Analyse the trends of mobiity of digits

Answer 13

Mobility-> Increased mobility and ability to move digits independently

Opposability-> First digit opposable + increased length result in increased effectivenness of oppoabiliity

Claws/ Nails-> primitive primates retain clas on some digits, higher order primates have nails on all digits.

Precision Grip-> one of the marks of human beings, not unique to humans

Power grip-> thumb and fingers apply force against object

Question 14

Describe the features of relative size of cerebral cortex

Answer 14

Cerebral cortex shape has made the largest degree of development.

Frontal lobe-> greatest enlargement in surface area.

Large brain= larger cranium
Humans have more complex brains thus it being larger causes adaptations of bigger craniums.

-> this results in frontal skull being vertical removing the prominent brow ridge possesed by apes.

-> shortening of snout and removal of brow ridge, gives humans a flat face ( bones of nose still protrude).

Brain size can be measured by measuring volume in cranium ( cranial capacity)

Question 15

What is an endocast and the trend specifically to austropithecines

Answer 15

-> impressions of the inside of the skull made from rock or other solid material.

-> Endocast of austro pithecines indicate beings were more human like then ape like and foreman magnum were more forward in comparison to Apes and more rounded at the back]

-> increase in cranial capacity and number of convulations and frontal lobe enlarged.

-> because brain case expand= flatter face= forehead more exposed because of expanding frontal lobe.

Question 16

What are limitations of Endocast

Answer 16

sometimes only fragments of skulls are found, thus unreliable

Question 17

Features of dentition and prognathism trends

Answer 17

Human dentition is very distinctive
Humans has parabola shape whilst Apes are v ( rectangular shaped)

Dental Garden-> shape of the tooth row, evolved into different shape.

Diastema-> gap in between row of teeth, gap between canines in primates

Early Humans=> lower jaw and face like an apre in comparison to modern day humans ( teeth are large, distinct gap between canines and incisors, rows of teeth parallel)

Homo habilis-> Smaller molars and premolars narrower canine still prominent.

Homo Erectus-> smaller molars and decrease in robustness of teeth

Humans have 10% smaller teeth in comparison to humans.

Question 18

Sight and Smell trends

Answer 18

Eyes-> Increasing efficiency in vision, eyes gradually move forward ( give stereo scope vision)

Eye socket-> Eyes gradually become enclosed in a protective boney sockey

Visual area of brain-> increasing proportion of the cerebrum devoted to vision

Smell-> Sense of smell reuced with gradual reduction in length of the snout

Question 19

What are the adaptations for erect posture

Answer 19

Forms of locomotion
1. Brachiating ( branch swinging)
2. Quadrupedalism
3. Bipedalism

Human= relatively hairless ( thin layer of hair in comparison to early humans)

Structure of lower body and upper body allows for bipedal ways of walking-> humans.

Erect posture+ striding gait allows for normal walking and standing.

Bipedal locomotion= walking on two legs with body upright

Striding gait= way of walking in which hip and knee are fully extended.

Question 20

Describe climate change and evolution

Answer 20

3 million years in Africa-> main driving force in the evolution of the humans.

Concept of cooler and drier and more variable conditions lead to a reduction in tropical rainforest= more open woodland and savanna grass land.

Question 21

Advantages of Bipedalism

Answer 21

1. Free hand to use tools
2. Free hand to carry items
3. Upright stance allows for greater height-> can see further.
4. Upright stance means less of your body is exposed to direct sunlight
5. Upright stance increases exposure to cool breeze.
6. Increase of efficiency when moving

Question 22

Definition of Adaptations

Answer 22

any characteristics that help an organism survive and reproduce in its natural enviroment.

Question 23

Position foreman magnum

Answer 23

Humans=> centrally placed underneath skull

Apes=> posterior position

Foreman magnum gradually moved forward in centre of base of skull= allows skull to balance on top of vertebral column.

Apes=> large neck muscle to hold skull in place.

Question 24

Jaw/ Prognathism

Answer 24

Apes-> protruding jaw (prognathism)

Humans=> facial profile much flatter, size and protrusion of jaw has gradually reduced during evolution.

-> allows skull to balance on top of spine= as weight is at front of foreman magnum= equal weight behind and infront.

Question 25

Curvature of the Spinal Column

Answer 25

Apes=> C- shaped spine ( single curvature) and have small lumbar vertebrae.

centre of balance is not in line with feet and skull doesn’t balance on top of spine.

Humans=> Double curvature ( S-shaped)

Lumbar curve improves balance in upright position, enables skull to balance on top of neck.

cervical curve in neck brings vertebrae column right under centre gravity of skull

lower spine being larger, more wedge shaped from fron to back= help support

Question 26

Pelvis

Answer 26

Apes=> Long and narrow pelvis -> pelvis is tilted forward

Humans=> Short and broader pelvis-> pelvis is no long tilted forward. -> provides wider base for support-> supports weight of upper body

Bowl- shaped-> support- internal, abdominal organs-> for female supports developing foetus and allow passage for birth.

Broad hipbones provide space for attachment of large buttock muscle= more stability for upright position. Large glutes muscles also help improves stride when walking.

Pelvis not being tilted forward ( Humans) bring centre of balance over feet.

Question 27

Femurs and Carrying angle

Answer 27

Humans=> hip-sockets are wider apart due to the broadness of the pelvis thus femus tend to converge inwards= carrying angle

This ensure distribution of weight is at the central axis of the body-> increasing the stability of the body. Head of Femus is larger thus can fit inside the hip socket= increased stability

The arrangement of the carrying angle allows for increased stability when walking as it enables the body to be rotate about the lower leg and foot, each foot step allows in a straight line.

Question 28

Chimpanzee Sway

Answer 28

Humans=> weight transmissions tend to fall through outside of femur

Apes=> weight transmissions tend to fall through inside of femur

Question 29

Knee

Answer 29

Human=> because of carrying angle= weight of body transmitted down outside of femur to the knee instead of inside

knee=> two part hinge joint, hinge is either side with ligament in middle.

Humans=> lateral condyle( outer knee) larger and stronger than inner knee ( medial codyle)-> outer knee carries more weight since weight is mainly transmitted to the outer knee.

Apes=> larger and stronger inner knee over outer knee because all the weight is transmitted to the inner knee.

Ligaments=> prevents gravity trying to bend backwards-> now a joint that requires no energy to support body in standing position

Question 30

Foot

Answer 30

-> most distinctive adaptation for bipedal locomotion

Human feet has lost grasping ability ( prehensitility) and gained specialty in locomotion.

Big toe in humans are not opposable yet is large and alligned with other digits-> provides thrust when taking off and improves stride.

Large heel bone-> 1. helps bare weight of body above 2. acts as shock absorber

APES=>have opposable big toe and not in line with other digits-> smaller heel bone

Question 31

Different foot arches.

Answer 31

longitudanal arch-> carries weight from front to the back of the foot-> transfer energy from heel to toe to walk

vertical arch-> carries weight from side to side helps shock absorb as foot comes down.

Humans have both arches whilst Apes only have longitudanal

The feet bares weight and is the main structure for propulsion

Question 32

Arms vs Legs and centre of gravity

Answer 32

Apes have longer arms then legs (L=1/3h)
Humans have longer legs then arms ( L = 1/2h)
long legs= increase length of stride when walking and lowers the centre of gravity of the body

lowers the centre of gravitty of the body= increased stability

Apes with longer arms over legs= increased centre of gravity= decreased stability on two legs

Question 33

Muscle tone

Answer 33

partial contraction of skeletal msucles, needed for upright stance.

Sustain muscle tone is more evident in the muslces that support the body at a upright stance ( spine, ligaments, hip, knee, ankle, abdominal muscles).

Question 34

Swinging of the arms

Answer 34

When walking, our trunk rotates about the pelvis. Forward swinging negates this natural tendency as the left leg is extended.

swinging arms tends to keep the shoulders at the right angles to the direction of travel= reducing amount of energy expanded.