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Human evolution Flashcards

1
Q

Quote on the relevance of human evolution

A

Dobzhensky- “nothing makes sense except in the light of evolution”

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2
Q

Outline the evolutionary context of human traits

A
  • Humans have traits only because of their evolutionary history
  • e.g. hand shape closest to gorilla as closest relative - shared traits reflect ancestry
  • combination of traits that are shared with all mammals (e.g. hair, breastfeeding, love birth), but some that come/go
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3
Q

Outline the role of behaviour in evolutionary process, outline a specific example/study

A
  • has an impact on reproductive success- acts as interface between phenotype and selection
  • for example, the development of walking behaviour led to reproduction

Kaplan and Hill (1985):
- good hunters are selected (3 vs 2 children)
- note- may jus be expressed due to separate factor that leads to reproduction

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4
Q

Outline the role of extinction in human evolution

A
  • Humans are unique (like all species)
  • uniqueness is shaped by extinction
  • evolution is a continuous process- - gaps between species (evolutionary distance) are arbitrary- not real/historical- created by extinction in-between rather than evolutionary divergence
  • gap is about adaptation (not time)
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5
Q

Outline evolutionary theory (process)

A

Conditions:
- inheritance
- reproduction
- variation
- competition

Mechanism is natural selection

Consequences:
- adaptation- how well suited an organism is to its environments (selection makes better fit)
- evolutionary change

Note- can have adaptation without evolution as evolution described change over time- if nothing changes, will keep selecting same thing

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6
Q

Outline the nature/characteristics of evolution

A
  • evolution as adaptation and history, including the role of chance (e.g. dinosaurs asteroid)
  • neither random (like mutations), or deterministic (like natural selection)- but the interaction of the two
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7
Q

Outine the historical context/development of Darwinism

A
  • 18th century- enlightenment, natural history and science
  • rise of evolutionary ideas (Lamark)
  • 1859 – Origin of species
  • Late 19th century – acceptance of evolution (Man’s place in nature)
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8
Q

Outline the shift in perspective caused by darwinism

A
  • Materialist explanations (mechanistic rather than progress based)
  • Human uniqueness challenged
  • Functional explanation of humanity
  • Origins research
  • Political, religious and social implications
  • The Darwinian revolution – complete
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9
Q

Outline the nature of the Darwinian approach

A
  • reconstructing human evolution based on comparison of living apes and people
  • evolution as progressive nit adaptive
  • typological thinking
  • Race was a primary conceptual framework- social darwinism
    (Late 19th century)
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10
Q

Outline the beginnings of the hominid fossil record

A
  • early 20th century
  • pre-genetics- questions about patterns (from brains, teeth and feet) and progress- origins placed in Asia and Europe
  • problem of time- didn’t know how to measure time in deep past
  • question of what makes human shaped way of thinking
  • Neanderthals- Germany, 1858
  • Homo erectus- Java, 1891
  • Piltdown Man- England, 1912
  • Australopithecus- South Africa, 1924
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11
Q

Outline the modern synthesis

A
  • Ernst Mayr
  • neo-darwinismm
  • population based thinking (as opposed to typological/progressive thinking)
  • biological processes and mechanisms (not just history)
  • inhibitions to speciation among hominids (culture)
  • pruning the evolutionary tree- Australopithecus Africanus, homo Erectus, Homo sapiens
  • relation between genetic mutation and selection
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12
Q

Outline the explosion of the fossil record

A
  • last 50 years- from fieldwork in Africa
  • developed ides a that not ladder of evolution (to linear- bush not ladder)
  • number of hominid taxa increased- near 30 species (as compared to 10 in 1950), and 7 genera (as compared to around 3 in 1950)
  • hominin diversity- patterns of adaptation
  • problem of phylogeny
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13
Q

Hominin diversity timeline

A
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14
Q

Outline the chronological revolution

A
  • carbon dating in 1950s- means could date how old things are
  • chronometric dating techniques
  • K/Ar, Ar/Ar, OSL, U-series, C14
  • scale of evolutionary change- happens day to day
  • micro and macroevolution (micro means not just about anatomy)
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15
Q

Chronology/time periods diagram

A
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16
Q

Outline the most recent framework shift in human evolution

A

1960-2017:
- shift from phylogeny and history based anatomy, to behaviour and adaptation, based on multiple lines of evidence
- emphasis on role of ecology
- Research focused changed from evolutionary history to behaviour and ecology- how and why, not who and when
- New scientific methods gave access to entirely new domains of information (diet, energetics, growth, behaviour, genomes, proteins)
- evidence including bipedalism, meat-eating, tools, and megadonty

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17
Q

Outline the genetic revolution

A

1970-2017:
* Evolutionary history is found in genetic similarities and differences
* Genes provide a mostly true record of phylogeny
* Insights into diversity and demography
* Genomics has transformed human evolutionary studies

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18
Q

Why does more being discovered make modelling evolution harder, and what does this give rise to

A
  • scale of the data (large amounts)
  • diversity of data (genes, behavioural ecology)
  • complexity of the pattern (not linear- complex pattern of speciation, extinction, and dispersion)
  • more than just looking for the missing link

Gives rise toe the importance of the interdisciplinary approach

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19
Q

Outline an example of the interdisciplinary nature of human evolutionary studies

A

Life history:
- Causes and conditions- evolutionary history- comparative and palaeobiological evidence for the evolution of human life history- using comparative evolutionary biology and paleoanthropology
- consequences and mechanisms- contemporary human evolution- the context, ecology and mechanisms of human life history variation- using behavioural sciences and evolutionary genetics
- leads to evolution of derived human life history schedule (including life history and ecological and behavioural correlates)

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20
Q

Outline the geological time scale for human evolution

A
  • key periods- cenzoic (last 65 million years)- miocene (23 mya), pilocene (5.2mya), Pleistocene (1.64 mya)
  • in Phanerozoic eon, cenzoic era, late tertiary (pliocene) and quaternary (holocene and Pleistocene)periods
  • holocene etc are epochs
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21
Q

Cenozoic explanation and diagram

A
  • contains the evolution and diversification of mammals
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22
Q

Outline the scale of evolutionary time

A
  • generations rather than years
  • problems in estimating generation times, as males live shorter
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23
Q

Human evolution in the context of evolution of life- diagram and explanation

A
  • Cambrian explosion- some plants/fungi- different to any life today- begin to see life diversity
  • if clock, would be 20 seconds before midnight- humans in the context of the evolution of life are trivial
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24
Q

Humans in comapartiev perspective to bacteria /archaea diagram

A
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25
Q

Outline the place of humans/hominids in linenean systematics

A
  • hierarchical nested classification
  • tree structure
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26
Q

Primate evolution summary

A
  • Origin of primates – early mammalian radiations (60)
  • Strepsirrhines and haplorrhines (50) – Lemurs and loris distribution
  • Origin of anthropoids – the monkey grade (45+)
  • Old and New World monkeys – dispersals, isolation and plate tectonics (30+)
  • Apes and Old World monkeys (25) –Great apes and hominins (20)
  • note- old world monkeys more rennet than apes- example of evolution as diversification not progression
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27
Q

briefly outline what the question of when we became human depends on

A
  1. The scale of primate evolution
  2. The key features – what makes a human?
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28
Q

List key features (question of what makes a human)

A
  • bipedalism
  • dependent upon technology
  • language
  • culture
  • consciousness/self awareness
  • meta-cognitive function- ToM
  • longer life history (extension of the pre-adult)
  • larger brains
  • longevity
  • hair
  • small K9s
  • cooperation/socialisations
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29
Q

Outline molecular perspectives now hen we became human

A
  • divergence from chimpanzees- the last common ancestor
  • Humans are apes, great apes, African apes
  • Sister clade of chimpanzee
  • Genetically very similar
  • “Recent” common ancestor
  • diverge from chimpanzee- 8-5mya
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30
Q

Outline the earliest fossil hominins

A
  • 7.5-4 myr
  • Sahelanthropus tchadensis (7)
  • Ororrin tugenensis (6)
  • Ardipithecus spp (4/5/6)
  • question of what makes these human- bipedalism/social behaviour
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31
Q

Outline early Homins as African apes

A
  • hominins are African apes
  • differences in geographical distribution
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32
Q

Outline australopithecine diversity

A
  • relatively small brains
  • human like teeth
  • earlist- anamnesis (around 4mya), latest Boisei (korund 2mya)
  • extinct- ‘bipedal’ but no sturdy gate
  • diet specialisations
  • not similar brain size (and therefore life history/social behaviour)- limited evidence for other human traits
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33
Q

Outline the 2 phasesof hominin evolution

A
  • homo is separate pattern
  • form radiation
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34
Q

Outline the early evolution of Homo

A
  • around 1.6 mya
  • smaller brain homo- more human- longer body form, specialised bipedalism (2 mya)
  • earliest- Habilis, latest- Erectus
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35
Q

Outline the 2 million year horizon of when we became human

A

*Human body shape
*Stone tools
*Larger brain size
*Meat eating/hunting
*Slower growth
*Wider distribution
- obligatory and habiturary tool use

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36
Q

7-0.5 mya human evolution timeline

A
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37
Q

Outline the evolution of homo sapients

A
  • earliest 200,000 years ag
  • first modern huamns- specifically in Africa (African lineage)
  • anatomic evidence from skills
  • Neanderthals in Eurasia
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37
Q

Outline genetic evidence for human diversity

A
  • prado-Martinez et al (2013)- human diversity is limited
  • most human diversity is African (African populations more diverse)
  • use of MtDNA
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38
Q

Cumulative process off becoming a modern human diagram

A
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39
Q

Outline accumulation of traits as an explanation for when we became human

A
  • evidence for novelty in phenotypes and behaviour
  • changes in traits- ressources are transitions- environnent changed- point at which food use etc changed
  • changes in traits/behaviour reflect changes in ecology- way in which organism interacts with environment
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40
Q

Outline the ecological process of becoming human

A

resource use transitions- e.g. technological dependent foraging, social group maintenance, to cumulative culture and cooperative foraging

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41
Q

Outline climate change as part of evolutionary context

A
  • Hominin evolution occurs against the backgdrop of major climatic change (as well as being driven by competition)
  • Colder and direr across time
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42
Q

Summarise the basic mechanisms of becoming human

A

Locomotion —> Forgaing —> growth —> technology —> brains —> culture

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43
Q

Outline the ecological basis of evolution

A
  • Ecology and environment is likely to be the primary ‘causal agent’ in evolutionary explanations
  • The “ecological theatre and the evolutionary play” (Hutchinson, 1965)
  • ‘Evolutionary ecology’ because evolution is driven by natural selection
  • Evolutionary ecology = how the environment shapes the survival and fitness of the organism, and hence evolution
  • adaptation solves environmental prelims- survival element- has to be just good enough to reproduce
44
Q

Outline elements of the ecological environment

A
45
Q

Briefly outline the ecological process of becoming human

A
46
Q

The early hominins diagram (list bipedalism evidence sources)

A
47
Q

Outline teh anatomy of bipedalism

A
  • farma magnum- hole where spinal cord attaches- on back in humans (by occipital love)- in chimpanzees, hunched over
  • longer legs relative relative to shorter arms
48
Q

Outline evidence for bipedalism in Australopithecus anamensis

A
  • Kanapoi, Kenya
  • 4.2 – 3.8 mya
  • Proximal and distal tibia
  • ankle more flat than in chimpanzees
  • proximal and distal tibia- proximal wide flat and robust (angled in chimpanzee)
49
Q

Outline evidence for bipedalism in Australopithecus afarensis

A
  • Hadar, Ethiopia
  • 3.9 – 2.9 mya
50
Q

Outline evidence for bipedalism in Sahelanthropus tchadensis

A
  • Chad, Central Africal
  • 7.2 – 6.8 mya
  • Position of foramen magnum
    is forward, and more horizontal than a chimpanzee (more humanlike than chimpanzee like)
    (fragments from ~6 individuals)
51
Q

Outline evidence for bipedalism in Ororrin tugenensis

A
  • Baringo, Kenya
  • 6.2 – 5.7 mya
  • Femoral anatomy
  • small femoral head
  • long, flat femoral neck
  • lesser trochanter points towads middle of the body
52
Q

Outline evidence for bipedalism in Ardipithecus ramidus

A
  • Middle Awash, Ethiopia
  • 4.4Ma
  • Pelvic shape is more chimpanzee like
  • Problem of arboreal adaptations elsewhere in skeleton
  • long arms
  • big toe sprayed outwards
    (material from 30 individuals)
53
Q

Outline footprint evidence for bipedalism

A

Laetoli footprints:
* Tanzania
* 3.7 mya
* 27 meters, 70 footprints
* Attributed to A. afarensis
- heel first, big ties aligned with rest of good

54
Q

Summarise the evidence for the development of bipedalism

A
  • Clear evidence for more upright stance and bipedal gait aby 4 Ma, but still question as to whether it’s ‘human like’
  • upper limbs still more adapted for trees- suggests both bipedal and in trees
55
Q

Outline first evidence for human bipedalism

A

Homo ergaster:
* Nariokotome, West Turkana Kenya
* 1.6Ma
* Homo ergaster (1.9 mya)
* Not fully adult
* Modern human body proportions
- just as bipedal as we are- moved out of Africa to south east asia- moving across landscapes- indicates successful

56
Q

List problems that bipedalism solves

A
  • carrying offspring while following the large game herds of the savannah on long seasonal migrations
  • Seeing over the grass may have helped to spot predators or locate carcasses at a distance
  • Holding tools and weapons was probably a consequence of bipedalism, rather than a cause
  • Carrying food away from a kill site or growing site to a position of safety
  • Efficient Locomotion:
    Bipedalism provides an energy efficient method that favors low speed, long distance movement- walking
  • Thermoregulation- smaller surface area presented to the sun at midday (60% less), greater air flow across the body when it is lifted higher off the ground assists cooling
57
Q

What locomotion is bipedalism a form of

A

specialised form of locomotion related to terrestriality

58
Q

Outline explanations of why bipedalism evolved

A
  • indirect- tool-making, thermoregulation
  • direct- energetic advantages
59
Q

models of bipedalism development (list/explain diagram)

A
60
Q

Outline ranging behaviour

A
  • refers to where living and foraging occur
  • home range-n area habitually exploited- overlapping- ecological model
  • territory- area defended, non overlapping, behavioural
  • locomotion and locomotor strategy- refers to movement across the landscape, part of daily energetics
  • more time moving mean less time eating
61
Q

Outline the link between bipedalism nd ranging behaviour

A
  • bipedalism is a solution to ranting behaviour
  • time budgets (Dunbar, 1992)
  • Bipedalism is energetically efficient in terrestrial contexts at low speeds
  • As trees become further apart, more time spent travelling on the ground,
    feeding in trees (mixed locomotion)
  • As environments become more open (savanna), plant resources are poorer, more patchy and dispersed
  • Home range sizes are likely to get larger
  • More travel time, higher locomotion costs
  • Selection for locomotor efficiency

Ultimately, Bipedalism is an adaptive solution to longer ranging distances

62
Q

Outline consequences of bipedalism

A
  • Calloused feet
  • Thermoregulation
  • Hands for carrying, tool use
  • Problems in infant carrying
  • Backache
  • Basis for further evolutionary change in locomotion
63
Q

Outline the short from Australopithecine bipedalism to Homo

A
  • Longer ranging
  • Running
  • Endurance running
  • Thermoregulatory efficiency
  • shift to Homo erectus is a major change in hominin locomotion
64
Q

outline the link between home range and adaptation

A
  • How individuals and populations move across a landscape is a fundamental aspect of all ecology and behaviour
  • Ranging behaviour is central to all foraging (subsistence) activities
  • Day and home range size are tightly linked to energy budgets (costs,
    benefits, optimal foraging)
  • Changes in foraging (movement) and diet (food quality) are at the basis of human evolution
  • means Day and home ranges are sensitive indicators in evolutionary and behavioural ecology
65
Q

Outline variation in home range with ecology

A
  • home rang increases with latitude, % emit in diet
  • decreases with dependence on farming and aquatic resources, and with effective temperature
66
Q

outline the link between climate and environments/ecology (bipedalism)

A
  • more C4 when warmer- environments more sparse- more space- meaning bipedalism more energy efficient
  • chimpanzees pelvis is less energy efficient- have to lift up leg muscles (quadrapedalism also energy inefficient)
67
Q

Outline how climate is studied

A
  • Oxygen isotopes from foraminifera
  • unlimited fossil record
  • respond to chemical changes/water acidity in shells
  • more O16 when cold, more O18 when hot
68
Q

outline the link between geography phylogeny, and evolution

A
  • Geography reflects the evolutionary history of species
  • barriers- distinction between species are reflected geographically
  • Phylogeny reflects evolutionary history
  • e.g. Baboon evolution (Papionini, < 6 Ma)- refleces significance of dispersals
69
Q

World zones based on evolutionary history diagram

A
  • Olsen et al, 2001
  • species in areas tend to share same private phylogenetic relationships- long term patterns reflected
70
Q

Outline the Wallace line

A
  • divides the Indo-Malay biome from the Australasian
  • Reflects long term isolation
  • Marsupial and placental mammals
71
Q

List reasons why geography matters in evolution

A

1) day –> home –> species range
2) species ranges –> species divergence
3) Distance links to genetic/phenotypic distance
4) dispersals as mechanism for diversity
5) Barroers and isolation

72
Q

outline the development of species ranges (geography and evolution)

A
  • individuals and groups have day ranges, which become home ranges- this leads to population range
  • populations overlap ranges and therefore interact with eachotehr, and therefore share genes
  • this leads to the development of species ranges, from overlapping population ranges
73
Q

Outline the move from species ranges to species divergence

A

ALLOPATRY:
- species have ranges
- these can be divided though- e.g. by a river
- this separates rnges- may cause on population to evolve into something else (speciation)
- genetic difference increased- means can sometimes correlate with distance- makes spatial distribution fundamental to speculation, which is a binding block of macro evolution

74
Q

Outline the relationship between distance and genetic/phenotypci distance

A
  • Betti et al (2009)- distance from sub saharan Africa causes genetic and phenotypic variance
  • Diniz-Filho et al (2013)- relationship between pairwise Fst and geographic distance
75
Q

Outline dispersals as a mechanism for diversity

A
  • Xi Sun et al (2023)- Lion and tiger genetic differences reflect recent dispersals
  • Patterns repeated across many species
  • Applies to humans as well]- genetics reflect dispersals- primary mechanism by which geography shapes evolution
  • dispersal increases chance of isolations and provides novel selection pressures
  • promotes adaptive differences
76
Q

Outline barroers and isolation as geographical influences on evolution

A
  • Vicariance – evolutionary differentiation without dispersal
  • habitat fragmentation
  • accidental- splits up
  • e.g. split between platyrrhine (New world) and Catarrhine (Old world)
77
Q

Outline evolution as a geographical prrocess

A
  • geography influences the ecological conditions for innovation, speciation, diversity, adaptation, dispersals and extinction
  • populations are local distributions- changes occur in small population to cause morphologically different phenotypes
  • when successful they spread
  • this breaks geographical boundary- e.g. monkeys from trees to open environments
  • this is dispersal
  • then contract as environments change- many isolated distributions- gradually becomes extinct
78
Q

Outline worldwide patterns of species diversity

A

Davies et al, 2011:
* Species diversity varies with latitude
* Speciation is more frequent in the tropics
- temperate- lower- as amount of energy/stability in environments- means don’t need to spread as far- causes greater diversity in the tropics
- means that often evolve in tropics, and disperse into temperate

79
Q

Outline the evolutionary geography of hominid origins (initial)

A
  • African endemism
  • 8-4mya (earliest hominins)
  • Hominin origins are part of the evolutionary geography of apes in Africa
  • early from east Africa
80
Q

Outline how changes in evolutionary patterns can be calculated from geography

A
  • molecular clocks- non functioning alleles unaffected by natural selection can only be affected by random mutation
  • if know rate of mutation, can use genes as clock- count differences
  • gives dates in evolutionary trees
  • can therefore match in when languages diversify and when found first hominid to be
81
Q

Summarise the geographical/species diversity of the Plio-Pleistocene hominins

A
  • australopithecines- includes generalised and robust
  • then early homo- rudolfensis and Habilis
  • new design- H.ergaster
82
Q

Outline generalised australopithecines (geography and evolution)

A
  • Eastern and southern Africa
  • 4.2 – 2.0 Myr
  • Small-brained (400 – 500 cc)
  • Prognathic
  • Some trend towards megadont- molar death as coarser, drier diet
  • Mixed post-crania, but bipedal- mixed locomotor
  • e.g. A. anamensis, A. afarensis
83
Q

Outline robust australopithecines (geography and evolution)

A
  • Paranthropus genus
  • Eastern and southern Africa
  • 2.6 – 1.0 Myr
  • Small-brained (400 – 550 cc)
  • Less prognathic (mostly)
  • Major trend towards megadontic specialisations
  • Very worn thick-enamelled teeth
  • e.g. P. robustus, P. boisei
84
Q

Outline the early Homo species (geography and evolution)

A

*Early Homo – 2.5 – 1.6 Myr
*East Africa; South Africa (?)- tropics- brings novelty
*Facial and dental reduction
*Increased brain size (~600+ cc)
Encephalization quotient
*Loss/absence of cranial robusticity
- e.g. H. rudolfensis, H. habilis

85
Q

Outline a diversifying Homo from the earliest Homo

A
  • Homo ‘ergaster’/ African H. erectus
    *Eastern Africa, but disperses across Africa and
    into Eurasia
    *1.9? – 0.9? Myr
    *Increased brain size (800 – 1000 cc)
    *More human facial proportions
    *Human post-cranial proportions and structure *Brow ridges
    *Increased body size
    *Associated with tools
86
Q

hominin phylogeny/dispersals diagram

A
87
Q

geographic map of early hominids relationships and phylogeny

A
  • patterns reflect dispersals and vicariance
88
Q

Early hominin phylogeny as dispersals diagram

A

Foley (1999)

89
Q

Outline the adaptive radiation of early hominins

A
  • Evolution as adaptive radiation and cladogenesis (like Galapagos finches)
  • single ancestral unit diversifies into different niches (e.g. Dawrwin- finches beaks)- necessary for successful evolution
  • Hominin evolution as a series of adaptive radiations
  • Adaptive radiations reflect common ancestry followed by divergence
  • Adaptive radiations have an adaptive basis
  • e.g. bipedalism caused adaptive radiation as can adapt to drier environments, Homo from resource, carnivore/technology allow larger geographic range- new conditions that can survive in Africa
  • mean human evolution no longer ladder like- series of adaptive dispersals

(UP UNTILL 2 MYA)

90
Q

Outline evolution and geography link since 2 mya

A
  • until 2mya, entirely African evolutionary history
  • later hominin evolution is predominantly and African but includes Eurasia
  • novelty in African tropics- driving force in dispersal
91
Q

Outline Homo geographical outliers

A

Homo floresiensis (‘the hobbit’):
* ~50Ka
* ~1m tall
* 350 cc cranial capacity
* Contemporary with
modern humans and neanderthals
* Island dwarfism

Homo naledi:
- South Africa
- 250 – 350 Ka
- example of isolation non island-based (only in one cave on continent)

92
Q

Outline the dispersal of modern humans out of Africa

A
  • Modern humans evolved in Africa and dispersed beyond from 100 Ka
  • Single of multiple dispersals?
93
Q

Outline climatic and biogeographic context of dispersals

A
  • O16/18 ratio
  • Dispersals are at least partly a response to changing climates and sea levels
94
Q

summarise the geography of human evolution

A

*Early hominin evolution is entirely African
*The pattern of early hominin evolution is an adaptive radiation
*Out of Africa dispersals is a repeated process

95
Q

Ecology to evolution timeline

A
96
Q

What is a key geographical characteristic of Africa

A

size- triple Europe, USA, or china (30.4km^2x10^6)

97
Q

Summary- human evolution process

A
  • 10 to 5 mill years- African apes (hominins 1 element)
  • main lineage established 4 mill
  • Hominin origins are related to the evolution of African apes as they adapt to the cooling and drying environments of the Later Miocene and Pliocene (7 – 4 Ma), form of bipedalism is basal hominin adaptation
  • 4-2 mill- pilo-pleistocene- adaptive radiation- bipedalism provided new niche opportunities- dispersal geographical and adapation- cause morphological differences that suggest adapting to different environments (e.g. megadonty)
  • 2.7 mill large brain sizes
  • 1.9- grade shirt from australopithecines to more humanlike forms- change in body size/shape- (homo Erectus)- disperses out of Africa to Eurasia- continue over million years
  • homo in pleistocene- one of repeated expansions/contarctuons in ration too hanging climates
  • half a million- trend in Africa towards modern humans (face/tooth/behaviour/cranium), 2nd is evolution of eurasian hominin- neadrethals- separate-(main adaptive trend of hominins is distinct to evolution of homo), part of repeated dispersals OoA
98
Q

human evolution events/species table

A
99
Q

summary- patterns underlying human evolution

A
  • Evolutionary change reflects responses to ecology and changes in resource distribution
  • Diversification and geographical dispersals are a driver of evolution
  • Dispersals and speciation are responses to climatic and environmental change
  • BUT role of behaviour- agency influence- selection operates on behaviour that is independent of environmental change
100
Q

Outline basis/examples of behaviour as a factor in evolution

A
  • question whether changes cause/effect of evolution
  • e.g. beaver dam creation places selective pressure on dentition
  • behaviour affects phenotype- extended phenotype includes behavioural elements as well as morphology (e.g. birds nest)
  • some isolated examples (e.g. bipedalism)- leads to new behaviours, or accumulated phenotypic differences may lead ti behavioural changes
  • behaviour often first- puts phenotype under new selective pressure (e.g. pelvis shape)
101
Q

Outline evidence/basis of behavioural innovation in human evolutionary history in primates

A
  • chimpanzees- influence of male controlled boundaries and terrain use; cultural variation present- community basis of behaviour
  • if behaviour present in chimpanzees and humans, can imagine was present in arbitrary last common ancestor (e.g. hunting/male residents/female dispersal)
102
Q

Outline inferred behaviours of the last common ancestor of humans and chimpanzees/bonobos

A
  • Tool use
  • Tool making
  • Hunting
  • Male residence and female dispersal
  • Multi male, multi female groups
  • Inter-group aggression
  • Cultural variatio
    Note- bonobos different social behaviour/structure- more egalitarian
103
Q

Outline potential novel behaviours of hominin species (up to neanderthals/humans)

A
  • earliest hominids- ardipithecus ramidus- habitat/ranging and social behaviour
  • australopithecines- stone tools (Lomekwian, 3.3Ma- Kenya); technology (heavy object with sharp edges provided carcass access and increased time budget- time essential when foraging)
  • paranthropines- adapting to open environments- use of underground storage organs
  • Homo- oldowan technology- core reduction and flake removals (Kenya, 2.3ma)- requires skills to preserve core suggesting cognitive shift- move from occasional/cultral use to being essential for survival- no hominin species can survive without technology after 2.3ma
  • Homo resets and heidelbergensis- pointed tools- goal oriented object- later spears to access resources from distance; fire and cooking (South Africa wonderwek cave- 1ma)- allowed reduction in digestive costs (lower when cooked + ground)
  • neanderthals and modern humans- see next card
104
Q

Outline novel behaviours in neanderthals/humans

A
  • shift from simple flaking –> handaxes –> prepared cores –> prismatic blades
  • shift to prepared cores may suggest major cognitive shift, and be associated with more wide ranging changes (brain expansion, life history parameters etc), as cores suggest hierarchically nested actions towards goal (have to imagine shape before hitting), also shared ancestral trait
  • intermittent symbolic behaviour in humans and neanderthals e.g. use of Ochre in neanderthal/eurasian lineage and use of ritual behaviour with dead and ochre in African modern human lineage before 100ka
  • pervasive signallng as human trait after 100ka (e.g. burials), including complex ochre use and bead engravings in African lineage, and Burials in eurasian
  • suggests symbolic use of material culture must have been present in latest common ancestor of neanderthals and modern humans, but became pervasive in modern humans after 100Ka
105
Q

Outline the nature of novel behaviours possibly unique to modern humans

A
  • differences between humans and extinct hominins vary- e.g. major with australopithecines, opens of degree with neanderthals, and variable with others
  • differences between modern humans- early modern humans (around 200ka)- where different- ‘modern’ term creates false boundary
  • differences may be in cimilative cultire/process of adaptation, in ecological differences/use of aquatic resources, in technology, and in language (language not rpesent in earliest homos as needs extra area of expansion in stone to control diaphragm- seen in enanderthals)
  • suggests becoming human behaviourally is gradual and that behaviour and biology deeply integrated
106
Q

more detail on role of language in becoming human

A
  • thoracic expansion and human structure of the supralyrngeal tract- absent in early H.erectus at 1.6Ma
  • present in H. Heidelbergensis and H. neanderthalensis after 0.5Ma- shared ancestral trait present in the last common ancestor of modern human and neanderthals (~0.5Ma)
  • rate of breathing also different in ancestral/human conditions, then changes to supralaryngeal tract
107
Q

Outline the broad nature of human behavioural evolution

A
  • cumulative in nature- e.g. bipedalism to resource speciflisation, to running, rot life history schedule, too tool, fire and aquatic resources
  • mostly spanning 4-7ma, but bipedalism before
  • role of increasing brain size
108
Q
A

b1 (8 decks)

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