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Evolution L-318 > Lecture 17 > Flashcards

Lecture 17 Flashcards

1
Q

Uniquely Human Features

A
  • large brains
  • bipedal walking
  • verbal symbolic speech
  • music
  • domestication of wolves and other animals
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2
Q

Human Features Shared With Chimps

A
  • self awareness
  • use of tools
  • making tools
  • making weapons for hunting
  • warfare
  • complex social structures
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3
Q

Ape–>Human size/proportion

A
  • hips changed first, then foot then rib cage and skull
  • variety of different things changing under variety of selective pressures at different times
  • didn’t evolve because of our smarts, those came later
  • upright walking came when we started to move away from forests, forests retreating and much of the ground is being replaced by dryer land ecosystems
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4
Q

A. afarensis

A
  • foragmen magnum that’s now in the base of the skull like ours because of how they walked (upright now)
  • shows a lot of changes in anatomy
  • pelvis and links to legs changes so they can walk upright (pelvis has to support vertical being)
  • number of vertebrae changes as well as number of ribs
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5
Q

Human vs. Ape Hip Girdle

A
  • apes is longer and sticks out backward to support their locomotion
  • humans is smaller and oriented so the human can walk upright
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6
Q

Chimps vs. Humans

A
  • femur is a straight line from hip articulation down to inside of kneecap
  • human femur goes from inside hip articulation down to outside of kneecap (so it crosses over)
  • chimps birth canal is smaller than humans because we have bigger brains to fit through
  • human butt helps you stand upright-gives you stability; gut is upright and has to be supported by the pelvis so the butt helps with holding all this vertically
  • humans developed to be able to run for a long
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7
Q

Humans vs. Gorillas

A
  • humans are the only primate with a chin

- humans teeth shaped in a parabola while gorillas shaped in a larger U

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8
Q

Mosaic Evolution

A

-in bits that aren’t at the same time/place

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9
Q

Piltdown Man

A
  • made skull with human and ancient orangutan jaw

- fooled lots of people into thinking this was the most likely ancestor

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10
Q

First Skull of A. africanus

A
  • has endo cast of brain
  • child skull
  • fairly large brain
  • teeth like ours
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11
Q

H. ergaster (1)

A

-when this was discovered so are stone tools in the same strata

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12
Q

H. erectus (1)

A
  • individuals leave Africa and survive for a very long time
  • last one died around 20,000 years ago in East Asia
  • split with Neanderthals around 500,000 years ago (sister species)
  • Neanderthals took care of each other and injuries had a culture
  • at least two hybridization events that take place with these two ancient humans
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13
Q

How many kinds humans living on earth at one time?

A
  • 5
  • Denisovians (only known via genome sequence from 43 kyr finger bone found in Denisova cave-Russia)
  • H. neanderthalensis (genome also sequenced by Paabo lab)
  • H. floriensis (possibly dwarfed H. erectus or older hominid-no DNA available) “Hobbits”
  • H. erectus (slight chance that they survived this late in S. Asia)
  • H. sapiens (rapidly leaving Africa at this time and meeting up with other hominids)
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14
Q

What makes a human a human?

A
  • speech

- gene required for human speech is FOXP2

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15
Q

Weirdest Discovery Ever Made

A
  • H. floresiensis
  • called hobbits, didn’t ever get much bigger than a couple feet
  • is it an australopithecine?
  • a lot of species developed miniature variations of many that’s what this little guy is
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16
Q

Body Size on Islands

A

-big animals get smaller and small animals get bigger

17
Q

Ardipithecus ramidus

A
  • now our oldest well known ancestor
  • likely split of humans and chimps 6-7 million years ago
  • ape like skull
  • brain ape sized
  • teeth intermediate between ape and human
  • walked upright-hip
  • could climb well-foot still hand like
18
Q

H. hablils

A
  • many features still similar to Australopithecus
  • dates about 1-1.8 mya
  • somewhat larger brain than Australopithecus
  • small in stature
  • post cranial skeleton not well known
19
Q

H. ergaster (2)

A
  • early Homo
  • post cranial skeleton much more like ours, larger skull than earlier hominids
  • probable maker of first stone tools, 2.5 mya, and probable ancestor of H. erectus
20
Q

H. erectus (lots of info)

A
  • appeared 1.8-1.7 mya
  • closely related descendant of H. ergaster, but migrated from Africa into Eurasia as early as 1.8 mya-first hominid to adapt to cold conditions
  • by about 700 kya gave rise to H. heidelbergensis, the ancestor to H. neanderthalensis and H. sapiens
  • remarkably stable in morphology and apparently behavior for about 1 mya, although brain size increased
  • brain size 800-900 cc earlier members and 1100 cc in latest
  • pronounced supraorbital torus and prognathism
  • dentition human, postcranium similar to humans, similar in size
  • first human nose
  • moderately arched basicranium-some ability to speak?
  • stone tools limited and conservative use of fire (China)
  • processed meat, likely hunter
  • persisted in Asia to somewhere between 100 kya 20 kya
21
Q

Tools Australopithecus

A
  • no trace oldest ca 2.5 million years oldowan tradition possible copper associated with H. habilis
  • by ca 1.5 million years have much more sophisticated acheulean industry
22
Q

H. neanderthalensis

A
  • middle East, western Asia, Europe-an ice age phenomenon (with a bad name in pop culture)
  • brains size larger than ours (1200 to over 2000 cc)
  • powerful skeletons-injuries like modern extreme athletes
  • mid facial prognathism, an adaptation to serve cold
  • very large supraorbital torus
  • peculiar wear on incisors-behavioral indication
  • brain asymmetry as in H. sapiens
  • some interbreeding with humans indicated by genomic studies
  • appear in Europe 130,000 years ago
  • became extinct within a few thousand years from time of entry of H. sapiens into Europe
23
Q

Some indications of culture in Neanderthals

A
  • buried dead

- no art of personal adornment as in modern humans, made clothing, spears and sophisticated stone tools

24
Q

Homo Sapiens

A
  • Europeans and Asians-a bizarre evolutionary history revealed by genome sequencing of us, Neanderthals, and Denisovans
  • H. sapiens expanding out of Africa and into Europe asia and southern asia and pacific
  • meet and mate with neanderthals in europe
25
Q

Interbreeding

A
  • all out of africa
  • H.s. and Denisovans-in south Asia
  • also traced in western pacific
  • H.s. and H.n. intermingling occurred just out of Africa
26
Q

Genome Sequencing of Extinct Humans

A
  • methods developed by Svante Paabo in Germany
  • DNA isolated from bones in caves or other cool dry sites.
  • DNA survives up to 100,000 years
  • Fragments sequenced and aligned and compared to modern human genome
  • they have nearly complete genomes of Neanderthals and Denisovans (from a single finger from Denisova Cave)
27
Q

Modern Humans-Record of Hybridization

A
  • Africans-no Denisovan and no Neanderthal genes–highest diversity of modern humans
  • Europeans and north Asians-4-6% neanderthal genes in their DNA, but not Denisovan
  • Australian and New Guinea people–a few percent Denisovan genes in their DNA, as well as some Neanderthal genes
  • molecular clock says Denisovans 1 myr diverged from us
28
Q

FOP2 Gene

A
  • required for human speech
  • differs in two bases from all apes
  • these two bases are shared between modern humans and neanderthals
29
Q

An enhancer of the FZD9 gene in neocortex growth

A
  • human version increases neocortex growth when expressed in mouse embryos
  • the enhancer from chimp does not
30
Q

Unexpected Discoveries Still Happen

A
  • H. floresiensis complete skull and skeleton of recent, tiny and primitive looking hominid
  • possible explanations: Australopithecus, island miniaturized H. erectus, pathological H. sapiens
  • DNA not preserved in hot wet environment
  • hope for more fossils

Evolution L-318 (28 decks)

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