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evolution > Human Evolution, Eugenics > Flashcards

Human Evolution, Eugenics Flashcards

w9

1
Q

Gibbon
Human
Chimpanzee
Gorilla
Orangutan

all have a lot in common

A
  • much more upright posture
  • big brains
  • mobile ankle
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2
Q

diffs & similarities between human and gorilla skeletons

A
  • gorillas chunkier / larger than humans
    -> big pelvis
  • but v similar!
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3
Q

humans & apes more similar than old world monkeys & humans.

A

looked at Albumin, DNA & haemoglobin…

ape-human diff much smaller than old world monkey-human diff

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4
Q

humans are closest related to chimpanzees, only splitting ~ 5 mya.

however, if you look at skull of human, chimp, orangutan & macaque, chimp skull looks more similar to other apes than humans.

what is this eg. of?

A
  • neoteny
  • in human skull:
    -> taller skull
    -> less ridged brow
    -> shorter face
  • ^what we see in fetal chimps!
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5
Q

hominin

A
  • tribe that inc humans & extinct v recent ancestors
  • in hominin, striking feature is bipedalism:
    -> apes: quadrupedal (walk on 4 legs)
    -> humans: bipedal (walk on 2 legs)
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6
Q

1st fossil showing bipedalism

A
  • Lucy - found in Ethiopia
  • fossil of female ape from 3.5 mya
  • called Australopithecus afarensis
  • adaptations in Lucy’s hip, leg & foot allowed a fully bipedal means of movement (proven by reconstruction model of Lucy)
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7
Q

when did bipedalism first evolve?

A
  • at least 3.5 mya
  • in Laetoli, Tanzania - impression fossil
    -> evidence of australopithecines walking on 2 legs in imprints left in muddy river bank
  • walking on 2 legs meant hands were free to move -> this might be crucial innovation in evolution of our sp
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8
Q

what is selective adv of bipedalism?

A

walking on 2 legs meant hands were free to move -> this might be crucial innovation in evolution of our sp

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9
Q

knuckle-walking

A
  • what we see in our close relatives in great apes is predominant form of locomotion is knuckle walking
  • a re-evolved form of quadrapedalism -> allows animal to walk on all 4s while retaining features in shoulders & forearms to be good at climbing (chimps & gorillas)
  • energetically v costly for chimps -> 75% more energy per unit mass than normal quadrupedalism
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10
Q

why did hominins stand up?

A

we don’t know…

  • habitats in Africa became more open in last 3 million years (changes in climate)
  • 2.6 mya - simple stone tool use & evidence of carnivory (hands free)
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11
Q

how did hominins hunt?

A
  • NOT through use of projectile weapons (relatively new)
  • bipedalism = not fast but economical…
  • most mammals cannot sustain a gallop -> cannot pant when galloping
  • humans can sustain running for hours
  • humans can outrun horse over long distances especially when hot (eg. in Africa)
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12
Q

benefits of bipedalism

A
  • less solar radiation -> only hits top of our head
  • more upright => being hit by more air/wind so get cooling effect
  • provides calories through capacity it gives us to hunt
  • frees up hands
  • allows brain to ↑ in size, this in turn allows for tool use, culture, language, art, smart-phones…
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13
Q

sweating in humans

A
  • lack fur & have v high densities of sweat-glands all over our bodies
  • this means we’re less likely to overheat
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14
Q

how humans are adapted to be good at running

A
  • anatomy = great for running
  • long legs, large gluteus maximus, long tendons
  • springy, bounding gait
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15
Q

adaptations to be good at running gives human ancestors the abiity to be good at hunting, giving us v high energy food resource

A
  • reward to cost is high -> cost of running only 40% more than walking
  • 15km chase only requires 1100 kcal (doesn’t require lots of meat)
  • when ppl study San Bushmen in Kalahari, their success rates in these hunts is v high (~50% success rate of persistant hunting)
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16
Q

race is an old concept

A
  • Homer - refers to Ethiopians; literally ‘burnt face’
  • skin colour referred to less often than religion, language & geographical origins
17
Q

Carl Linnaeus 1707-1778

A

invented binomial naming system for organisms in Systemae Naturae

Linnaeus’ human taxonomy:

  • Europeanus: white; blue eyes; gentle, acute, inventive; governed by laws
  • Americanus: red; black, straight, thick hair; stubborn, zealous; regulated by customs
  • Asiaticus: yellow; stiff; black hair, dark eyes; haughty, greedy; ruled by opinions
  • Africanus: black; frizzled hair; silky skin, flat nose; females without shame; crafty, lazy; governed by caprice
18
Q

humans originated in Africa

A

lot more genetic diversity in Africa than rest of world

19
Q

Multilocus analysis of race - 53 populations

A
  • looked at 360 loci in genome
  • looked at ~1056 individs from 53 diff pops
  • ^gives rough idea of how much variation there is across the genome
  • then divide genetic variation into 5 groups -> these groups map onto geographic areas
  • shows lots of evidence of genetic mixture between pops BUT is geographical signature in pops of humans

MAIN BITS:

  • within-pop differences account for ~94% of genetic variation
  • 6 main genetic clusters, 5 of which correspond to major geographic regions
  • differences among major groups constitute only 3 to 5%
20
Q

2020: Genomic analysis of race - 54 populations

A
  • sequenced 929 genomes
  • each pops harbour unique variants, but none is fixed between regions
  • substantial gene flow between populations
21
Q

traits under strong selection can vary between human population

A
  • Tibetan Sherpas
    -> evidence of selection on genes associated with metabolism (to deal with high altitude)
    -> Andean pops too
  • Greenland inuit
    -> adaptations to high fat diet (seafood diet)

BUT

  • observations of genetic diffs are limited to specific adaptations to extreme env
  • no evidence for diffs among ethnic groups in general-purpose adaptations eg. athleticism or IQ
22
Q

race and biology

A
  • alleles associated with both light & dark pigmentation predate Homo sapiens by 100,000s of years
  • more variation in pigmentation within Africa than in rest of world
  • most genetic variation occurs within pops
23
Q

race is a social construct

A
  • racial groups are “constructed” from historical, political, & economic contexts
  • racial groups do not correspond well to inherited, biological variations
24
Q

eugenics

= good breeding

A

“study of the agencies under social control, that improve / impair racial qualities of future gens either physically or mentally”

-Francis Galton

25
Q

Key idea: The concept of ‘improving’ / controlling a pop via selection is ancient

A
26
Q

Francis Galton

A
  • looked into fingerprints -> established they were unique to individs
  • geography and meterography -> made first weather wap
  • coined term ‘eugenics’ -> encouraged reproduction among those with desirable traits & discouraging it among those deemed “undesirable”
  • came up with phrase “nature vs nurture” -> & introduced twin studies into this field
27
Q

when were we closest to having a eugenics policy in the UK?

A
  • 1910: Churchilll proposed sterilisation of ‘feeble minded’
  • 1912, proposed using “Röntgen Rays” (X-rays) to sterilize men & women
  • 1912: included sterilization in drafts of 1913 Mental Deficiencies Act -> removed at final reading

evolution (8 decks)

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