HUMAN EVOLUTION Flashcards

1
Q

HUMANS IN ANIMAL KINGDOM

A
  • mammalia and into the genus Homo.
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2
Q

SIMILARITIES BETWEEN APES AND HUMANS

A
  • opposable thumbs that allow for power grip
  • two hands with five fingers (toes too)
  • no tail
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3
Q

DIFFERENCES BETWEEN APES AND HUMANS

A

H - bipedal, A - quadrupedal
H - large, developed brain, A - small less dev brain
H - narrow flat face, A - wider sloping face

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4
Q

EVIDENCE OF COMMON ANCESTORS

A
  • fossil evidence
  • genetic evidence
  • cultural evidence
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5
Q

WHAT DOES FOSSIL EVIDENCE LOOK AT

A

looks at:

  • bipedalism
  • dentition
  • palate shape
  • brain size
  • cranial and brow ridges
  • prognathism
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6
Q

PALEONTOLOGY

A

study of fossils

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7
Q

BIPEDALISM

A
  • walking upright on two feet

- foramen magnum in the middle of the skull enables bipedalism, as opposed to it being at the back of the skull

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8
Q

ADVANTAGES OF BIPEDALISM

A
  • upright bodies expose less surface area to the sun - less overheating
  • hands are free to use tools and hunt
  • adaptable - can occupy wider variety of habitats
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9
Q

PALATE SHAPE

A
  • was previously narrow and rectangular, later became more u-shaped and then became wider and more curved in humans
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10
Q

CRANIAL AND BROW RIDGES

A
  • apes have prominent c&b ridges for attachment of chewing muscles
  • decreased in size over time and completely reduced in humans
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11
Q

DENTITION

A
  • teeth size decreased with evolution
  • apes have prominent canines, but human canines are the same size as other teeth
  • tooth enamel thickened over time
  • diastema disappeared over time
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12
Q

DIASTEMA

A

the large gap between the incisors and canines

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13
Q

PROGNATHISM

A
  • when the jaw protrudes and there is no chin (in apes)
  • apes have sloping face bc of this
  • teeth smaller over time = reduced prognathism
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14
Q

BRAIN SIZE

A
  • cranium size inc in most fossils over time = brain capacity inc as well
  • ape cranium is small and elongated, less dev brain
  • humans have rounded skull = bigger cranium and larger dev brain
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15
Q

MORE COMPLEX HUMAN BRAIN HELPED WITH

A
  • well developed hand-eye coordination
  • the capacity for language
  • the use of fire
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16
Q

GENETIC EVIDENCE

A
  • very rare to extract DNA from a fossil
    organisms contain:
  • chromosomal DNA
  • mitochondrial DNA
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17
Q

COMPARING mtDNA

A
  • by comparing mtDNA of living hominids, scientists can determine when the evolutionary paths of humans and apes separated
  • many diffs = sep occured earlier
  • more time for mutations to occur = more variation
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18
Q

CULTURAL EVIDENCE: TOOLS

A

the production and use of tools (and other cultural practices like fire making and art) are suggested as further evidence of common ancestors for living hominids

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19
Q

TYPES OF TOOLS

A
  • made of stone, sometimes bone and wood
  • some sharp stones, others carved blades
  • provide access to wider variety of foods
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20
Q

THREE MAIN TOOL CULTURES

A
  • oldowan
  • acheulian
  • mousterian
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21
Q

MAIN HOMINID GENERA WITHIN THE HOMINID GROUP

A
  • ardipithecus
  • australopithecus
  • homo
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22
Q

ARDIPITHECUS

A
  • 5,8 - 4,4 mya

- transition between apes and australopithecus

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23
Q

CHARACTERISTICS OF ARDIPITHECUS

A
  • probably bipedal
  • long arms for climbing trees
  • small brain capacity
  • sloped face
24
Q

AUSTRALOPITHECUS

A
  • first bipedal primates

- lived between 4,5 and 1,4 mya

25
Q

CHARACTERISTICS OF AUSTRALOPITHECUS

A
  • bipedalism and upright walking
  • large brow ridges
  • u-shaped palate
  • protruding jaw, no chin
26
Q

FIVE WELL KNOWN AUSTRALOPITHECINES

A
  • Taung child
  • Mrs Ples
  • Lucy
  • Little Foot
  • Australopithecus sediba
27
Q

TAUNG CHILD

A
  • found by Raymond Dart
  • was of a 3-4 yr old child
  • small brain, human-like teeth, bipedal
28
Q

MRS PLES

A
  • Robert Broom

- possibly bipedal, no protruding canines

29
Q

LITTLE FOOT

A
  • Ron Clarke

- bipedal, short arms, similar hands to humans

30
Q

CHARACTERISTICS OF HOMO

A
  • bipedalism
  • flat face
  • wide, curved palate
  • larger brain
  • no brow ridges
31
Q

HOMO HABILLIS

A
  • smaller body and larger brain than Australopithecus

- fossil found in Tanzania

32
Q

HOMO ERECTUS

A
  • closer to modern humans than Australopithecus

- large bodies, thick skulls and large teeth

33
Q

HOMO TIMELINE

A
  • habillis
  • erectus
  • neanderthalensis
  • sapiens
34
Q

HOMO SAPIENS

A
  • direct ancestors of modern humans
  • developed better skills and more advanced technology
  • had a large brain capacity
  • used tools and wore clothing made of various materials
35
Q

OUT OF AFRICA HYPOTHESIS

A
  • states that all human life originated from Africa and Homo sapiens migrated from Africa 50000 mya
  • resulted in more Hs replacing He around the world
36
Q

EVIDENCE OF AFRICAN ORIGINS

A
  • genetic links (chro, mit, Y-chro DNA)

- fossils and artifacts of hominins (Africa has largest numbers)

37
Q

THE USE OF GENETIC LINKS (OOA) mtDNA

A
  • mtDNA of diff pops are compared to determine the extent of genetic variation in a pop
  • more variation = more mutations
  • high variation in Africa = Africans are the oldest humans
38
Q

STRUCTURAL CHANGES IN HUMANS IN TERMS OF BIPEDALISM

A
  • the moving forward of the foramen magnum
  • the vertabral column in humans is S-shaped for flexibility & shock absorption
  • longer arms, shorter legs
  • stronger knee-joints
  • arched foot, instead of flat
39
Q

CHROMOSOMAL DNA DEF

A

occurs in the nuclei of all cells and contains all the genetic information

40
Q

COMPARISON OF CHROMOSOMAL DNA

A

determine how closely related they are, more similarities more closely related

41
Q

cultural changes that distinguishes modern humans from primates

A
  • development of speech and language (improved comm and social interaction) (helped with hunting and defence)
  • tools
42
Q

Oldewan tool culture

A
  • oldest tools found, found in Tanzania
  • 2,6 to 1,5 mya
  • choppers, flakes, scrapers
  • rock, stone
43
Q

Acheulian tool culture

A
  • more advanced, found in France
  • 1,5 mya to 250 000 ya
  • hand-axes, picks, cleavers
  • stone, wood, bone
44
Q

Moustertian tool culture

A
  • found in France
  • 250 000 to 50 000 ya
  • flakes, scrapers, points
  • hand axes w carefully shaped blades
45
Q

what did refined tools help with

A
  • gave access to better food, clothing and shelter

- more comf and complex lifestyles

46
Q

microliths

A

smaller blades that formed part of arrowheads and fishhooks

47
Q

fossils found in Great Rift Valley

A

h-h and h-e in Kenya

ardi and austra in Ethiopia

48
Q

the Cradle of Humankind

A

the richest source of hominin fossils in the world, 40km North of Jhb

49
Q

importance of CoH

A
  • produced over one third of the world’s hominin fossils

- scientists have concluded that humans originated in Africa

50
Q

why is it important to know the dates of fossils

A
  • to compare diff fossils and observe evolutionary trends

- determine the order in which different life forms appeared on Earth

51
Q

radiometric dating

A
  • based on radioactivity, if the age of the rock of the fossil is known, it is assumed that the fossils are the same age
  • if fossils are older than 50 000 years
52
Q

relative dating

A
  • based on the fact that deeper layers of sed rock are older than shallow years
  • therefore deeper layers = older fossil
  • not very accurate
53
Q

alternatives to evolution

A

creationism
literalism
intelligent design

54
Q

reproductive isolation

A

occurs by means of various isolating mechanisms which prevent pops from exchanging genes

55
Q

mechanisms of reproductive isolation

A

behavioral patterns, physiological processes that prevent diff species from crossbreeding an producing viable offspring
eg.) prezygotic and postzygotic

56
Q

prezygotic division

A

occur before fertilization and prevent mating and/or fert from taking place

57
Q

postzygotic division

A

after fert and cause abnormal zygote development so that no viable / fertile offspring can be produced