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3.6 human evolution Flashcards

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1
Q

brow ridge

A

a defined area of bone around the eyes. in apes it is thick and prominent to protect the eyes from the powerful forces involved in chewing and biting. it is less prominent in humans as we have less muscles

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2
Q

prognathism

A

the lower part of the face which projects forwards in apes. as humans evolved, the angle of the face decreased, becoming flatter due to smaller canines and a larger brain

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3
Q

diastema

A

the space between teeth for canine teeth to fit into so other teeth are able to come together. the diastema is quite large in apes. in humans, we have a chin which allows for speech. the cause for a diastema is changed

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4
Q

canines

A

apes have large canine teeth which are pointed teeth used to hunt, they are useful in tearing rough plants and meat. they are also weapons and used for aggressive display

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5
Q

sagittal crest

A

a pronounced bone ridge that runs lengthwise along the midline of the top of the skull/ it is where strong jaw muscles are attached to. humans do not have a sagittal crest as we do not have as much jaw muscles, we evolved to eat softer foods and cooked meat

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6
Q

premolars/molars

A

large flat teeth which crush and shear food when chewing. larger in apes than humans

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7
Q

cranium

A

a part of the skull that encloses the brain and protects it from injury. humans have a much larger cranium

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8
Q

foramen magnum

A

a large hole in the base of the skull where the spinal cord and arteries enter the skull. in apes, it is located at the back of the skull which connects to the spine at an angle. this helps with balance and aligns it with their centre of gravity. in humans, it is in the centre of the skull, which allows the head to rest upright. it ensures the centre of gravity is directly above the spine for better balance which is favourable for bipedalism

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9
Q

mandible

A

larger in apes due to having larger and more muscle attachments for strong chewing

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10
Q

nuchal crest

A

an extension of the skull where neck muscles are attached. which position, move and stabilise the head and cervical vertebrae. it is smaller in humans as our heads are kept upright. the ape head tends to droop down more as it is at an angle (due to foramen magnum) which requires a lot more muscles

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11
Q

zygomatic arch

A

an arch in the cheekbone where muscles used for chewing pass through. these muscles are attached to the mandible and skull. the arch is wide and thick. it is bigger in apes as humans have less muscles

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12
Q

ribs in apes

A

small and cone shaped, which allows for a wide range of shoulder and arm movement which is good for their tree top environment. it fits their gut as well

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13
Q

ribs in humans

A

larger and barrel shaped to protect and suspend organs. this minimises the effect of gravity which may cause the organs to fall and get crushed. the rib shape allows for free swinging arms at the sides and assists with balance as well

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14
Q

spine in apes

A

a c-shaped spine requires many muscles. the shape helps to distribute weight more evenly on the 4 limbs from quadrapedalism. it supports the abdomen and organs, absorbing impact.

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15
Q

spine in humans

A

the s-shape spine helps us stand upright by ensuring our COG is aligned, which increases balance. it absorbs the impact of bipedalism

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16
Q

pelvis in apes

A

longer, narrower, flatter, this allows for gluteal muscles to attach differently to assist quadrapedalism and distribute weight better

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17
Q

pelvis in humans

A

broader and shorter curves to support organs in the abdomen when standing upright. its bowl-like shape helps balance torso weight. achieves smooth gait through muscle attachments which helps balanced forward walking

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18
Q

valgus angle in ape femur

A

the femur is 90 degrees to the pelvis as an aligned COG is not very important for quadrupedal movement

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19
Q

valgus angle in human femur

A

the femur is less than 90 degrees to the pelvis, this aligns the feet closer to the midline of the body, hence COG. the knees will go slightly inwards

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20
Q

femur length and head in apes

A

apes have shorter femur bones which are less robust than humans. they do not be buttressed as weight is distributed on 4 limbs

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21
Q

femur length and head in humans

A

long femur bones to increase weight transfer through hip joints and increase stability. the head and knee is more robust and buttressed to support the legs holding all body weight

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22
Q

human vs apes brain size

A

humans have an increased brain size, the body size ratio is high.

humans have increased brain capacity as bipedalism allowed for more energy in development

the human brain has a higher surface area due to it being complexly folded

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23
Q

differences in frontal lobe size of humans and apes

A

humans have a larger frontal lobe which is linked to abstract thought, logic, imagination, artistic ability and complex language. this had a big role in cultural evolution

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24
Q

differences in cerebellum size in humans and apes

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A

humans have a larger cerebellum for balance and co-ordination. this is important for bipedalism

25
differences in wernicke's and broca's area in humans and apes
humans have a larger wernicke area which correlates to receiving and understanding language. we also have a larger broca's area for a better co-ordination of muscle movements and speech. wernicke's area leaves an indentation in the skull, it can be seen to increase over time
26
biological evolution
the transfer of genetic material from parent to offspring through sequences of bases in their DNA. slow + limited by natural selection. occurs in all species. impacted by mutations and random chance changes
27
cultural evolution
the non-genetic transmission of information to another individual that is not necessarily related. occurs in only some species, it is purposeful and an instantaneous transmission of information that occurs in one's lifetime. it is built on information from past generations.
28
how did tools help humans
- let us be the predator and not prey. it helped us hunt, thus increasing survival - allowed us to control our environment like never before - sharp tools let us to exploit new niches. we could butcher meat and bring it to a base - could make clothing and shelter from bone-made tools
29
tool
a modified or made hand-held object used to carry out a particular function. it was one way humans were distinguished from animals. humans were the only species to use tools that left an archaeological record
30
impact of tools and survival
tools minimised the effect of biological evolution / natural selection
31
oldowan tool
the oldest tool a cobble rock that had some flakes knocked off to create a sharp edge. took around 5 blows. used for digging, hammering, grinding and chopping flakes were used for cutting and skinning animals
32
who created the acheulean tool
homo erectus
33
who created the oldowan tool
homo habilis
34
acheulean tool
the second tool made larger, more symmetrical, tear shaped flakes were either knocked off one side or both sides of the rock as well as a long running sharp edge or a sharp edge that was only at the top - giving it different purposes more technique was required to make it, around 65 blows the tool was long lasting
35
mousterian tool
the third tool produced it was more finely crafted rather than just a cobble rock with some blows. complex worked edges which required more effort and skill to produce
36
who produced the mousterian tool
homo neanderthalensis (neanderthals)
37
upper palaeolithic tools
the fourth and last tool there were 3 different shapes, ovoid, triangular, rectangular produced through levallois method - chipping a rock until its core which was very sharp the tool edges were as sharp as modern day metal tools used for carving, butchering, digging for plants, making holes in hides they were specialised and could have handles attached to it (shown through indentations) required a lot of skill and effort.
38
who created the upper palaeolithic tools
homo sapiens
39
what species discovered fire
homo erectus - fire could've been used by other species but there is evidence that homo erectus was the first species to be able to control it around 800k years ago
40
benefits of fire
- warmth at night - light extends time, they could make tools at night - safety from predators - focus for social interactions (sitting around the fire) - explore new niches - used to harden and sharpen tools - cooking
41
evidence of fire
charred bones and stones
42
impact of fire and diet
cooking food let us to make the most out of our meals. we had a more protein and nutrients rich diet, letting us grow and become smarter. leading us to evolve, create better tools, and better hunters. we spent less energy digesting food positive feedback loop
43
impact of fire and our jaw
cooking food made it softer, we needed less jaw muscles thus we have a smaller nuchal crest, zygomatic arch, and no sagittal crest as well as less defined brow ridge. energy was diverted to brain
44
impact of fire and social interactions
we could sit around the fire, leading to more social interactions and cultural evolution. we could teach each other to make things as well as talk. there was more social organisation and communication (larger brocas and wernickes) it made us live together
45
fire and base
where the fire was acted as a base. we could bring back food to the group and base through communication and live as one. fire led us to develop bases
46
order of australopithecines species
ramidus, afarensis, africanus, paranthropus boisei
47
order of the homo species
habilis, ergaster, erectus, heidelbergensis, neanderthals, sapiens
48
impact of clothing
we lost body hair due to hot african environment made from animal hide let us explore new niches increased our survival spent less energy keeping us warm, which could've been diverted to brain growth social wealth/identity impacted by tool culture: knitting hunting and camouflage better
49
impact of shelters
proof: collection of fires, indentations, matter in a particular order led to increased social connections, groups, storage and served as a home base we could make more tools and store them protection needed planning and co-ordination to occur so demonstrates some brain development was made through using caves, wood or other resources
50
disadvantage of shelter
diseases more easily spread vulnerable as we were stuck in one place could only really utilise resources around the base
51
impact of hunting
we went from being scavengers to predators larger brain = better tools = hunted larger animals = got more protein = brain increased... required communication with each other and mobility
52
impact of agriculture
we could use animals for their wool, hide, milk, meat etc... they were also companionship gathered plant seeds to produce barley, wheat and plants we didn't have to travel as far to gather resources, we were less nomadic diet changes led to specific tools being produced
53
disadvantages/limitations of agriculture
animals would be inbred as the farm would be small (leading to fixed alleles and low genetic diversity) we could only really eat what we grew food poisoning
54
impact of speech
started off with basic gestures and sounds with special meanings, such as calls and grunts. this is shown in primates more complex language = better co-ordination = better tool making = better hunting in groups = better diet = larger brain the development of speech is due to broca and wernickes area social hierarchy, alliances, talking to each other, teaching teaching is paramount of cultural evolution
55
ardipithecus ramidus
the oldest species arboreal, tree dwelling, hand grasping toe very short possibly bipedal but more adjusted to tree life. shown by its torso small brain, meaning it ate lots of vegetation and had little protein no sexual dismorphism, male and females had similar teeth big canines = aggressive display omnivores = ate small animals such as insects. shown by teeth and prognathism
56
australopithecus afarensis
2nd oldest species likely to be the first bipedal ancestor lived in a forest and semi-savana it lasted extremely long, meaning it had good adaptions and/or little competition children grew up early, less parental guidance and socialisation. this meant the environment was safe, there was abundant resources and increased reproduction high survival as it was well adapted for ground and tree life
57
australopithecus afarensis body
small canine teeth = less aggressive bipedal, regularly upright. shown through slightly different changes in everything. ex. foramen magnum slightly more centred had ape and human characteristics. the face was more ape-like whilst the body was more human-like, showing the effects of its diet and bipedalism it was GRACILE - meaning not robust
58
australopithecus afarensis cultural evolution
no articulated speech, thus small wernickes and brocas area hung out in groups, bones were found together did not use tools, it had a small brain possibly scavenged for small animals

Biology (6 decks)

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