Prelim 2 Flashcards

Lectures 10-18

1
Q

What are the costs of bigger body size?

A

Need more food

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2
Q

What are the 3 benefits of bigger body size?

A
  1. Need food less often
  2. Better at intra-species competition for resources and less vulnerable to predators
  3. Locomotion - once moving, can run/walk long distances
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3
Q

Benefits of larger brains/CBS

A
  1. Social intelligence
  2. Technological intelligence
  3. Control of fire
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4
Q

Costs of larger brains/increased CBS

A
  1. Premature/helpless infants
  2. Lots of energy needed
  3. Tradeoff - smaller guts & higher quality diets needed
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5
Q

Expensive Tissue Hypothesis

A

Theory that increased brain size is afforded through decreased gut size - acc. Wrangham, this is possible due to cooking

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6
Q

Impact of helpless infants

A

Women need constant help and must carry infant

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7
Q

Morphological differences between H. erectus & sapiens

A

Below head - basically the same
H. erectus has smaller brain and more prognathic

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8
Q

Radiation

A

Rapid expansion of many new, related species (due to natural selection)

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9
Q

Phylogenetic Species Concept

A

Use physical traits and “clusters” of similar traits to group species together

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10
Q

Miocene

A

23-5.3 MYA, more cooling, radiation of ape species - human evo. from apes begins at end of this

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11
Q

Sources of variation within species

A

Age, sex, geography

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12
Q

Derived characteristics

A

Characteristics that deviate from past ancestors

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13
Q

How can we date human evolution?

A
  1. Fossils - different strata of Earth
  2. Molecular clock - DNA comparison (e.g. between humans and chimps)
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14
Q

Adaptive shifts in hominid evolution

A
  1. Locomotion
  2. Diet & dentition
  3. Brain size increase
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15
Q

Obstacles to bipedalism

A
  1. Loss of balance/stability
  2. Difficulty of pulling leg up
  3. Less speed initially
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16
Q

Indications of bipedalism in fossils (5)

A

Foot - parallel big toe, 2 arches
Leg - upper femur angle
Pelvis - bowl-shaped & outward flare
Spine - double curve (vertebrae)
Skull - Foramen Magnum at bottom center

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17
Q

Ardipithecus ramidus time + place

A

4.4 MYA, Ethiopia

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18
Q

Ardipithecus ramidus morphology + behavior

A

Small, bipedal climbers with changing dentition

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19
Q

Australopithecus afarensis morphology + behavior

A

“Bipedal apes”
Small, long armed, flared pelvis, no grasping big toe (likely poor climbers)

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20
Q

Australopithecus afarensis time + place

A

4-3 MYA, Ethiopia

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21
Q

First adaptive shift

A

Bipedalism

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22
Q

Second adaptive shift

A

Diet + dentition

23
Q

Gracile species

A

Huge back teeth
Australopithecus africanus and A. sediba
Tiny, bipedal small-brained apes with giant molars
3-1.9 MYA

24
Q

Robust species

A

REALLY huge back teeth
Paranthropus aethiopicus, boisei, robustus
Huge chewing muscles, sagittal crest and bigger brains
Died out(?)
2.5-1.8 MYA

25
Q

Theories of bipedal advantage

A
  1. Reach fruit above head
  2. Scan for predators/resources
  3. Free hands (for infants, food, tools)
  4. More efficient locomotion (maybe not)
  5. Heat stress in savanna
26
Q

Early hominid diets

A

Hard foods - USOs, nuts
More flexibility in savanna - survive dry season and scattered resources

27
Q

Types of diet data

A
  1. Chemical - isotopes & proportions of elements
  2. Archaeological - tool marks on bones, teeth fossils
  3. Ethological - examine chimp use of tools (can dig for USOs)
28
Q

Homo habilis morphology + behavior

A
  1. Big brain to body ratio
  2. First to fully benefit from bipedalism (Bigger bodies, longer legs, no divergent big toe)
  3. Loss of Sagittal crest, but big molars
  4. Extensive tool use (“handyman”)
29
Q

H. naledi

A

Super recent discovery - possible offshoot of paranthropus, b/c brains are way too small
Throws everything into question

30
Q

Last great adaptive shift

A

H. erectus: new range, ecology, genus

31
Q

H. erectus range

A

Africa –> Eurasia, Indonesia

32
Q

H. erectus morphology

A

Postcranium, essentially modern
Less prognathic and bigger-skulled than H. habilis

33
Q

Societal implications of helpless infants

A

Mothers need much more help and must constantly attend infants, plus need more energy/food

34
Q

Acheulean tools

A

Second tool industry
Hand axes, cleavers
Made by intentionally shaping multiple sides of a rock

35
Q

Oldowan tools

A

First tool industry
Stones with flakes taken off

36
Q

Archaic H. sapiens characteristics

A
  1. Habitual use of fire
  2. Better tools
  3. Big game hunting
37
Q

What ecological changes led to the emergence of hominins?

A

Global drying and reduction of rainforests –> hominins move to savanna

38
Q

Pleistocene

A

2.5-.01 MYA
“Ice Age” aka many glaciers, up to 70-80% of surface
Sea levels fell & land bridges

39
Q

When did habitual fire use begin?

A

Direct evidence - 400,000 YA
Hearths (repeat burning) and concentrated, burnt artifacts prove

40
Q

Early archaic H. sapiens

A

400,000 - 125,000 YA
Brain size into modern range
Reduced posterior dentition but big anterior teeth
Massive brow ridge

41
Q

Levallois tools

A

Third tool industry - early H. sapiens
Made out of super sharp stone flakes
Sometimes lashed to a shaft to create 7ft spears

42
Q

What are the implications of big game hunting?

A

Additional intelligence to cooperate, plan, preserve meat

43
Q

What are the results of range expansion?

A

Flexibility and generalism

44
Q

When did bipedalism begin? Which species is associated with this?

A

~4 MYA, A. ramidus

45
Q

When did dentition begin to change? Which species is associated with this?

A

~2.5-1 MYA, Paranthropus genus and A. africanus/sediba

46
Q

When did brains and bodies grow bigger? Which species is associated with this?

A

~2 MYA, H. habilis/erectus

47
Q

Recent Replacement

A

Splitters
H. erectus travels, dies out in other continents
H. sapiens evolves in Africa and expands to other continents, maybe pushing out old erectus species

48
Q

Multi-Regional Evolution

A

Lumpers
H. erectus leaves Africa, evolves into H. sapiens separately
Gene flow ensures no speciation

49
Q

Neanderthal time + place

A

400,000 - 30,000 YA in Europe and Middle East

50
Q

Neanderthal morphology + behavior

A

Sloping forehead, big nose, no chin, occipital bun at back of skull
Short, stocky, thick bones
No evidence of diff. brain function

51
Q

The Neanderthal Question

A

Are Neanderthals
1. a different species from us which developed from H. erectus (RR)?
2. a subspecies, but still Homo sapiens (MRE)

52
Q

Flores hominins time + place

A

700,000 - 13,000 YA
Indonesia

53
Q

Flores hominins morphology + behavior

A

Super tiny, simple tool use, no gene flow with other populations

54
Q

How did humans reach the Americas?

A

Land bridge during Pleistocene (low sea levels) between Russia and Alaska, then walking/rafting to Patagonia