Humans Flashcards
1
Q
What are the key features of the modern human skull
A
Humans have smaller face (than Neanderthal) and relative orthagnathic, face underneath skull with vertical forehead and globular skull – tall skull to length of skull
No contiuous SO torus
Have mental eminence
2
Q
When was the human most recent ancestor
A
Many hominin fossils date from 400-200kya so will be contemporaneous with sapiens ancestor but none show distinctive features of sapiens
3
Q
When was there a shift in human technology
A
Major dichotomy between Middle Palaeolithic (Mousterian Mode 3 lithics,
Neanderthal) and Upper Palaeolithic (Mode 4/5 lithics, modern humans) behaviour
4
Q
What are the key features of the multiregional model
A
1 – time-depth : ~ 2 million years of an evolutionary trend towards sapiens
2 – parallelisms : similar selective pressures (throughout the 2 million years) in different regions of the world, leading to single evolutionary trend
3 – gene flow : besides the parallelisms, 2 million years of isolation would lead to speciation, so gene flow (at rate and frequency x) throughout the whole world would be necessary to maintain all regional populations as part of a single evolving species
4 – chronological synchrony : since gene flow has to have taken place to maintain the species’
genetic unity, it must have also acted as a homogenising force ; therefore, the changes
observed in one region of the world should be soon observed in all regions.
5 – regionality precedes humanity …
5
Q
What is the mtDNA that showed multiregionalism is wrong
A
First mtDNA study of human variation showed
that:
All modern humans are genetically closely related to each other
The last common ancestor of all humans lived recently
That the root of the modern human genetic tree is in Africa
Cann et al. (1987) Nature
6
Q
How do “CONTINUITY TRAITS” and difference in selective pressures refute multiregionalism
Use other mammals to refute multiregionalism
A
“continuity traits”: unique features shared by recent East
Asians and Chinese H erectus, and recent Australians
and Javanese H erectus
Different regional impact of climate change: regional
hominin populations under different selective pressures
Of the ~30 regional characteristic Asiatic traits, only 10 actually occurred in the stated regions
this type of multiregional evolution has never been observed in mammals apart from maybe the Javanese rhino
7
Q
How does sapiens morphology refute multiregionalism
A
All modern humans are morphologically more closely related to each other than to any non‐modern hominin population, independently of which part of the world
8
Q
How did Gagneux et al. (1999) disprove multiregionalism
A
The ancestral African population was extremely small:
FST = µ 2Ne ‐ ancestral effective population of 15,000‐10,000 people
genetic bottleneck
9
Q
What is chronological synchrony
A
gene flow maintaining the species’ genetic unity, thus acting as a homogenising force spreading the changes that emerge in one region to the rest of the world
10
Q
What showed that different hominins chronologically NOT synchronous, refuting multiregionalism
A
• Modern human fossils from Skhul and Qafzeh, Isral
• Discovered in the 1930s
• Several individuals
• Modern human anatomy, but very robust and Middle
Palaeolithic tools
• Originally thought of as “transitional” Neanderthal‐modern
• Re‐dated in the 1980s and 1990s: shown to pre‐date some of
the Neanderthals (Amud, Kebara) in the Middle East
11
Q
When were the earliest modern humans
A
Earliest modern humans in Africa, 200,000+ years ago
12
Q
Why do the Denisovans help refute multiregionalism
A
Neanderthals/Denisovans and modern humans are sister clades, with a common ancestor in the Middle Pleistocene
The earliest record of modern human morphology and complex behaviours is in Africa, much earlier than anywhere else in the world
13
Q
What are the key rebuttals to multiregionalism
A
Neanderthal & Denisovan DNA
different hominins chronologically NOT synchronous
Shared H. sapiens morphology and small ancestral population size
absence of “CONTINUITY TRAITS” and difference in selective pressures
mtDNA
14
Q
Give Fossil ancestral “candidates” in Africa for most recent human ancestor
Give the ages in kya
A
Morocco: Jebel Irhoud ~315
South Africa:
Florisbad ~280
naledi ~260
East Africa:
Kabwe (Zambia) ~300
Eliye Springs (Kenya) ~360
Ndutu (Tanzania) >400
15
Q
What has changed in the evolutionary geography of Homo sapiens
A
- Time
• ~300,000/200,000 years ago to the present - Space
• from Africa to worldwide - Demography
• from 10,000‐30,000 people to > 7,000,000,000
16
Q
Describe the theory of African multiregionalism for human origins
A
Requires extremely large estimates of ancestral effective population size as it
incorporates ancestral lineages across sub‐groups
- Limited pan‐African population structure
- Inconsistent with range of estimates of Ne (9,000‐30,000)
• If Ne reflects ~10% of census size, the maximum estimate (32,500) =1.4
individuals/100 km2
lowest recorded: Dobe !Kung ~6.6 x 100 km2; Hadza ~30 x 100 km2 - no HG communities are as sparse as necessary DEMOGRAPHICALLY UNLIKELY INCONSISTENT WITH HOMININ DIVERSITY IN AFRICA 400‐200 Ka
17
Q
What are the features of the single origin range expansion with local extinctions model of human diversity
A
• Genetic variation should decline with distance from one source African population [1] • Most genetic lineages should originate from a single ancestral African population (despite incomplete lineage sorting which would lead to some basal lineages elsewhere) [1] • Predicts large expansion within Africa prior to out of Africa Consistent with range of estimates of Ne (9,000‐30,000) and KhoeSan as the most divergent human population with largest Ne [2‐5] DEMOGRAPHICALLY LIKELY
18
Q
What are the features of the single origin range expansion with regional persistence model of human diversity
A
• Clinal patterns of genetic diversity and coalescence from a single African source [1]
• Complex phylogeography, with deep coalescent events in regions outside the
source (reflecting gene flow)
• Consistent with recent findings that ~10%
divergent ancestry in W Africa [2,3] and the
deeply divergent Y‐chromosome lineage in
W Africa (tMRCA ~250,000 yrs; 4]
DEMOGRAPHICALLY LIKELY, BUT NEEDS MORE
DATA
19
Q
What are the features of the archaic hominin admixture in Africa model of human diversity
A
• Predicts “archaic” African hominin
admixture into living populations [1] – not
yet identified, but there are genomic
outlying regions in Africa [2,3] with very old
coalescent ages (~1 Ma in pygmies – 3)
suggesting deep population structure
Consistent with the age of H naledi, for example
But poor fit between demographic
models and interpretation of
“introgressed” segments
NEEDS MORE DATA
20
Q
- What is the Mode 3 hypothesis? What is the recent genetic evidence for it?
A
Humans and neanderthals doing similar technology unless it happened before split Neanderthal mtDNA closer to modern humans than Denisovans – dispersal of humans out of Africa 300-400kya and mixed with neanderthals and gave them Y chromosomes (both male and female admixture) making them closer to us than we are to DEN
Further mixing 200kya during a green sahara event – recurrent mixing of western Eurasians and modern humans
21
Q
Where does the idea of African multiregionalism stem from
A
the presence of regional geographic variation in the African archaeological record by 300kya, the morphological diversity of the African fossil record between 300 and 100kya, and the presence of modern, derived morphological features in divergent regions of Africa
Together, these findings inspired the hypothesis that populations across Africa were all connected to each other. This model states that migration across the continent is more parsimonious than independent convergence of anatomical features and archaeological innovations
22
Q
Explain the Single Origin Range Expansion with Local Extinctions
A
Many near modern human populations exist in Africa since 200kya
Modern humans originated from a single population in Africa (south or east) that expanded and outcompeted other groups of near modern humans, or expands into regions left empty by these other groups going extinct due to external factors.
23
Q
How does the Single Origin Range Expansion with Regional Persistence differ from the Single Origin Range Expansion with Local Extinctions model
A
Again gives importance to a single population in a specific area of Africa, but allows for gene flow between this group and other near modern human groups
24
Q
Explain African multiregional theory
A
Modern humans originate from a pan-African population
25
Describe Archaic Hominin Admixture in Africa model of human origins
Modern humans evolved in parallel with other hominin species (eg naledi) and there is gene flow between species
26
When are the earliest modern human fossils from
from Ethiopia, 200 – 160 Kya –
derived universal traits of
Homo sapiens, but very
different from each other
27
How big was the ancestral human population
~ 10,000‐15,000 people
28
Is the Kabwe fossil modern human
No
Very different to modern humans – synchronicity (300kya) – closer to mid-Pleistocene hominins
Tall, pronounced SO torus, bregmatic eminence, enormous face
29
Is the Florisbad fossil modern human
Very similar to modern humans but not got full package of traits
275kya
30
When is naledi from
250kya - v primitive hominin
31
What is one of the first modern human skulls
from Monokibish, 200kya
chin
high globular skull
32
What is the importance of Skhull
Modern features
Already out of Africa
125-100kya
33
Describe the quantification of human's globular head
• A quantitative measure of the globular modern human head
• Genetic association of values of this “index of endocranial
shape” amongst Neanderthal introgressed genomic fragments in the genomes of 4468 Europeans
• Key SNPs correlations associated with reduced globularity
• Correlated SNPs: affect neural expression of 2 genes linked to neurogenesis and myelination
Gunz (2018)
34
What actually is a human, from a palaeontological perspective? Which features are autapomorphies? (6)
Large brained hominin
Tall and narrow
globular cranium
reduced cranial superstructures
small faced under vault
mental eminence
35
Which human populations are likely to have been the earliest to diverge
Khoisan groups in southern Africa:
The most genetically differentiated living
human population, followed by the Hadza (TZ) and the Pygmies (Mbuti, Efe, etc)
36
What is the paradox of the modern human LHS
Relatively higher energy budget and reproductive output than apes (“fast”)
Long juvenile period and lifespan (“slow”)
Homo sapiens evolved a unique life‐history amongst all hominins, probably driven by hypothalamic output from the brain - indicated by Retzius Periodicity
37
What is a way to assess regulation of LHS pace
Retzius Periodicity (RP): number of days between the deposition of successive long‐period growth lines in teeth (striae of Retzius in tooth enamel)
histological manifestation of a neuroendocrine biorhythm (Havers‐Halberg oscillation)
closely related to body mass and BMR, role in regulating pace of life‐history in mammals
38
How does the LHS of other Homo vs sapiens differ, considering energetics, ecology, and behaviour?
other Homo: large size, encephalised, fast growth
• Energetically very demanding – diet shift, carnivory
• Ecologically effective – early independence, predator risk minimisation
• Socially and behaviourally challenging – likely increase role of social cohesion, provisioning, innovative
solutions (cooking?)
Homo sapiens: large size, encephalised, slow growth
* Energetically efficient – budgeted development through longer ontogeny
* Ecologically challenging – longer dependence on mother, big risk of predation
• Socially and behaviourally very demanding – provisioning of mothers with dependent children, social
cohesion and belonging, major pressure on technological solutions, increased dependence on learning
social norms and skills, increased importance of social memory
39
Where are Mode 3 and 4 technologies found
Mode 4: Only seen in parts of Eurasia
NOT in Australia
Mode 3: seen in Neanderthals and first modern humans in Africa
40
What happens between 300-400 Ka?
Environmental change extreme aridity
Turnover in fauna – perhaps because of humans becoming a mega-predator
– middle stone age
41
What is modern human behaviour
All living humans have ‘modern behaviour’
‐ Complex cognition symbolism, abstraction
‐ Complex behaviour, altruism, cooperation, teaching, etc.
‐ Complex societies, kinship/non‐kinship
networks, shared heritage, norms
‐ Cumulative culture
42
Why do advanced stone tools suggest increased cognition
- Production of a core implies pre-preparation so that when struck a particularly shaped flake will come away – level of abstraction (also seen in N)
43
What is the importance of ochre
Symbolism – neanderthals liked shells of particular colours – also in human s
Ochre processing workshop in Qafzeh, Israel, 93kya
Found a lump of ochre with pestle still inside it
Ochre also used as mastek fro hafting artefacts onto handles – may be practical not symbolic
But pervasive presence of red ochre particularly (not seen in N) suggests they were choosing a particular colour scheme
44
How do early human ornaments compare to those of Neanderthals
N has only 1 case of necklace
Many cases in humans from 100kya onwards – why?? – form of singalling personal and group identity (cf football t-shirt – display of support; married woman with ring etc)
45
How long ago can art be seen
Blombos, South Africa
Middle Stone Age layers
~70,000 yrs
– deep intentional zigzag engraving – aesthetic or communication – major change in symbolism
Lion-man (40kya) -> clear display of abstraction/ imagination
46
Give examples of the emergence of more complex behaviour in the Middle Stone Age
Pinnacle Point, South Africa, 164kya: evidence for early use of marine resources (shellfish) and production of microliths (Marean et al. 2007)
Ethiopia, 160 kyr: evidence
of mortuary behaviour. White et al (2003)
Qafzeh 11 burial, Israel,
120 kry: complex
burial/grave goods
Increased distance travelled for raw material before 300kya – trade?
Grass bedding at back of cave – 200kya
Different ways to make necklaces look by changing string
47
What is the importance of the Herto child
160kya – polished skull from being passed around
had associated antlers
also Adult at Herto – cut marks - defleshed
48
Why is modern human technology different
Humans are characterized by changing culturally very quickly
| Stone tools lasted 1.5My – cf. technology now
49
Humans are characterized by changing culturally very quickly. Can we see this in the record
South Africa HP culture (Howiesons Poort, mid stone age tradition, see Jacobs 2008 paper) lasted only 5ky – came, succeed, then disappeared
50
What is the importance of cumulative culture
social networks increase efficiency of knowledge transfer – investment in friendship from early childhood – these friendships are more important predictors of shared knowledge than family ties – peer group is important aspect for cumulative culture
Multi-level sociality increases rate of social evolution – high mobility between camps – lots of knowledge transfer despite low population density
Our slow LHS requires specific social structures for interdependence on other people and communities – evolution of modern behaviour evolved so will not suddenly appear as a package in the record
(Migliano et al. 2017)
51
Give the dates for the following transition events in sapiens' history
```
The Holocene Filter
Structuring
Dispersals
Expansion
Origins
```
```
The Holocene Filter (15 – 0 Ka)
Structuring (45 – 25 Ka)
Dispersals (70 – 50 Ka)
Expansion (130 – 100 Ka)
Origins (240 – 200 Ka)
```
52
When did Expansion occur in human history
What were the associated climatic events
130-100kya
```
135‐128 Ka: climatic shift from hyper‐glacial to very
warm conditions (Green Sahara)
• 128‐72 Ka: long and complex interglacial, MIS5
```
53
What are the associated modern human fossils found during sapiens' expansion
Modern human fossils bsaically found across Africa & the Levant (from Israel to Sudan to South Africa):
Singa, Sudan (133 Ka)
Mumba, TZ (130‐109 Ka)
Aduma, Ethiopia (105‐79 Ka)
Klasies River Mouth, South Africa (115‐60 Ka)
Skhul & Qafzeh, Israel (130‐90 Ka)
54
What were the Skhul fossils originally interpreted as
modern human‐Neanderthal hybrids, more recent than Neanderthals in the Levant
1987: Dated to 80‐130,000 yrs (ESR, TL), older than the Levantine Neanderthals
55
What was the first key sapiens dispersal OoA
130-80kya
130‐80 Ka: modern humans in the Levant (Skhul & Qafzeh) but reached as far as Australia
=> Archaeological evidence: Fuyan cave – teeth of modern humans 80kya;
Madjedbebe Rockshelter in Australia - stone tool technology from middle stone age of Africa
70‐50 Ka: Neanderthals in the Levant
(Kebara, Shanidar, Amud, Dederiyah)
56
Why do genetics suggest the sapiens dispersal OoA 130kya was only small (2)
Neanderthal born in last 100ky has modern human genes in genome from population who dispersed before most modern Eurasians – grew up Neanderthal – if humans assimilated into Neanderthals that suggests it was not a major movement out of Africa
Genetic tree of humans very skewed – most people come from an explosion of diversity that occurred very recently – very few people can trace their ancestry back to the root of the tree (all in africa – hunter gatherers – Khcesan from southern Africa, and Sandawe)
57
Are all click languages related?
No
– not closely related – very distant in fact – relics from time of hunter gatherers in Africa before the expansion of farmers and pastoralists – early modern humans used clicks?
Hunter gatherers would have encountered archaic hominins and these would have been assimilated into human community
58
When do most people share a LCA from
What was this period marked by, population-wise?
80-70kya
marked by population contractions and regionalization within Africa, so we do not know where this ancestral population lived
59
When was the main sapiens dispersal OoA
When did this dispersal reach Australia
Was there any admixture
70-50kya
by 50kya
The dispersal involved admixture with both DEN and N in Eurasia, and possibly with archaic human populations in West Africa.
this is mostly from mtDNA research as there are v few fossils
60
How do tools reveal the expansion and contraction of sapiens in Africa
tech in one area differs from the others – ochre and shell beads in Morocco and south Africa BUT then in south Africa we see the Stillbay (shift in tech) while in North africa we see Aterian tanged points – regionalization 100-70kya
61
When was there a megadrought in East Africa in last 150kya
East Africa had a megadrought between 135-75kya – asynchronous with higher latitudes
62
When were the key splits since Neanderthal, Denisovan and ancient modern human LCA
1. Split of AMH x NEA/DEN lineages 603 Ka [496‐797 Ka]
2. Split of NEA x DEN lineages 426 Ka [333‐539 Ka]
3. Split of AMH x XAf lineages 528 Ka [230‐700 Ka]
4. AMH LCA
XAf introgression:
3.8% Khoisan; 3.9% Mbuti; 5.8% W Africa
63
Where and when did the ancestors of today’s living people that have fragments of Neanderthal DNA meet those Neanderthals?
Must happen before humans left Africa bc all non-africans have it – occurred right at point of leaving – exchange happened as they disperse into middle east before they separated into different populations
64
What is the multiple dispersals model
what is the evidence (4)
```
Northern Dispersal :
55‐45,000 yrs
and
Southern Dispersal :
70‐50,000 yrs
```
Evidence:
The morphology of Australian aborigines – today and in the past (Multiregional Model,
etc.)
• The archaeology of Sahul,
as well as of much of
Southeast Asia (not part of the typical ‘Upper
Palaeolithic)
```
• The (potential) persistence
of ancestral phenotypes in
South Asia, Southeast Asia
and Australia (for example
dark skin)
```
• Modern humans in Southeast Asia and Australia before than Europe
65
What is the evidence against the multiple dispersals model
the mtDNA data does not back this up – more likely to be a single very rapid dispersal – coastal route had too many barriers to be sustainable
Different studies show different numbers of dispersals about Australian aboriginals
66
What is a key difference between Australo-Papuan genes cf. Eurasia populations
* Denisovan‐like genes found today in Australo‐Papuan populations
* The % of Denisovan genes among Australo‐Papuans (4‐8%) is much greater than the % of Neanderthal genes among Eurasians in general (1.5‐2%)
* Admixture took place before the founding of Australia and New Guinea, 60-50kya
67
Give the key aspects of 70-50kya
period to which the vast majority of living humans can trace their ancestry
• Period of regionalisation in Africa
• Main ‘out of Africa’ dispersals
• Unresolved source of ‘out of Africa’ populations
• Unresolved number and routes of dispersal
68
By 45kya, where are sapiens living
How had this changed 5ky later
```
By 45 Kyr, modern humans are in:
Western Asia
Eastern Europe
Southeast Asia
Australia
```
By 40 Kyr, they are also found in:
Western Europe
China
India & Sri Lanka (from the archaeology)
69
Around 40kya What were key events happening to different populations (4)
• Shared ancestral Neanderthal admixture
subjected to population‐specific drift
• Population‐specific admixture with Denisovans
and related groups
• Localised selection during climatically variable
MIS3
Transition from Middle to Later Stone Age in Africa
70
What did SE Asia look like 45kya
sea levels were low so SE Asia was not land with lots of islands but actually one exposed land continent (Sundaland) and Australia and Tasmania and Papua New Guinea formed another landmass (Sahul) – they were separate with an ocean
71
What kind of culture has been discovered 45-25kya in Russia?
huts 35000 years old in Russia, burials of kids covered with bones and beads – period of cultural richness with instruments and figurines (found from Russia to spain)
Genomes well preserved bc cold environment
The genomes from early Upper Palaeolithic people from Ust’Ishim (~45 Kyr) and Kostenki (~36 Kyr), western Russia, shows the structuring of the early Eurasian modern populations
Subsequent Neanderthal admixture events
Population extinctions
72
What kind of culture has been discovered 45-25kya in Eastern Europe?
Romania: 35kya, strange phenotype – genome descended from human Neanderthal hybrid – hybridization had occurred only 4-6 generations before this individual’s death – further encounters at edges of human expansion
Look at Hublin 2015 paper on Western colonization
Bulgaria – 45kya – teeth and mtDNA – all early modern humans – mtDNA shows Eurasians related to people across the world
73
How similar are human genomes in China to the rest of the world
* The 40,000 yr old Tianyuan fossil’s genome is part of the modern human clade, with an estimated last common ancestor in Africa 150,000‐200,000 years ago
* Similarly to other Eurasians, it has 1.5‐2 % Neanderthal genes
* The % of Neanderthal genes is no greater than in present Han Chinese
• It has NO Denisovan genes
Did they just not meet DEN or was the meeting anatagonistic?
74
What happened with technology 45-25kya
Middle stone age tech is abandoned and increasing use of microliths
Icnreasinf use of bone and egg shell
Used as measure of CULTURAL diversity
While in western Africa, middle stone age tech used until 10kya – populations with a deeper ancestry survived until very very recently
Hofmeyr fossil – SA – 36kya – only fossil of its age – closest relatives are European not other south africans
Sterkfontein – limpet size – size responds directly to predation – LSA predation increases significantly thanks to improved to tech
MSA -> LSA in kenya – maps transition from shells to ostrich egg to make decoration to make identical beads with notation - enhanced group identity
75
When do the oldest needles date to
Why is this important
• oldest ~45‐40 Ka, Siberia & China – possibly
independently
• Western Europe: during the Solutrean (~20kya)
Make the difference between hanging clothes on yourself and sewing them up – big thermoregulatory difference – enhances survivorship
76
What happened 25-15kya
The Last Glacial Maximum (LGM)
| Population contractions and extinctions 25,000 – 15,000 years ago
77
What allowed mass expansion after 15kya
After drop in temperature after the Younger Dryas Cooling, temperature has existed at a relatively stable level – post glacial improvement led to mass expansion
‘Post‐glacial’ improved environmental conditions and increased competition
15,000 – 8,000 years ago
78
What are some key questions about the first human occupation of America
* 3 migrations or many
* Ice‐free corridors or coastal routes
* Palaeoindian ancestry or population replacement
* Megafauna overkill or climatic catastrophes
* One linguistic mega‐family (Amerind) or many
79
What can we tell about the location of origin populations from Native American genomes?
Some have a small part of Australasian ancestry
Relate to Paleolithic Siberian populations and east Asian too
Palimpsest
80
Who first occupied the Arctic
first inhabited by PaleoEskimos who populated from Siberia to Greenland but these are not ancestors of modern Inuit, who descend from the Thule who replaced PaleoEskimos in last 1kya
81
What happened to the climate in the Late Pleistocene and Early Holocene
What did this lead to
• Climatic instabilitiy followed by peak: hotter
than present, high lake levels
• localised resource pressure
….. plant and animal domestication …
82
When did plant and animal domestication occur
Plant and animal domestication developed in at least 6 parts of the world independently between 12,000 and 4,000 years ago.
83
What is one possible answer to the question “why were plants and animals domesticated only in the last 12,000 years?”
Maybe because it was only at this point did population density reach high enough where you can trade high quality food of a hunter for low quality food of a farmer’s carb rich diet
Richerson (2001) argues however, that agriculture was impossible before the Holocene – levels of CO2 in Holocene and water levels made agriculture possible
84
When was the earliest agriculture and bread making
• Tel Abu Hureyra (13‐9 Ka BP):
earliest agriculture in the world
• Shubayqa 1, Jordan(14.5 Ka BP)
– earliest bread‐making
• Raqefet Cave, Israel (13 Ka BP) –
oldest beer
85
what about the question “what came first, farming or sedentism?”
Natufians – last hunter gatherers in Western Asia – lots of groups around then who were becoming more and more sedentary – Natufians never became sedentary but did exploit cereals using stone tools like sickles
86
What special type of farmer took place in East Africa during the last Green Sahara event
East African ‘Aqualithic’ –
semi‐sedentism amongst fisher foragers
during the last Green Sahara
semi sedatism – foraging – water ways connecting west African lakes to the Atlantic – harpoons from bones and ivory – semi sedentary without domesticating plants or animals
87
How does agriculture affect number of surviving offspring
What does this mean
Phylogenetically controlled (Sellen & Mace)
10% dependence upon agriculture leads to 0.2
extra offspring per female
According to subsistence strategy agriculturists only have slightly more babies than hunter-gatherers (6.6 and 5.4 respectively)
BUT
Infant mortality is very different – for current HG it is 43.7% - critically issue related to foraging – give farmers the advantage
Current exponential growth characterizes humans in the last 10ky thanks to farming
88
How did the agricultural revolution affect health
Sedentary – live near your own waste and stagnant water and increased population density (pathology) and worse diet (malnutrition)
Can be seen in the drop in stature in the Neolithic due to malnourishment BUT this didn’t last
89
Discuss lactose tolerance
Cow domestication – cultural and bio evolution happening together – only 1/3 of world are lactose tolerant – dairy farmers of Europe at this time
Pastoralism took over northern Africa in a big way
90
How do cows differ in Europe vs Africa
First cows crossed the Levant and are related to European cows but many cows are the humped cows from India – African cows are a hybrid of the 2 – more resistant to some flies,
underscores expansion of pastoralism
Africans have 3 different mutations (cf 1 in Europeans) for lactose tolerance
91
Is lactose tolerance the same for all who have it
What does this suggest
No
• Europeans: mutation in LCT gene (T‐13910)
• Africans: (at least) 3 other different mutations, on
highly differentiated, geographically restricted
haplotype backgrounds
independent convergent evolution of lactose
tolerance under strong selective pressure for adult
milk consumption
92
Discuss the genetic patterns in Australasia
Deep ancient population – some have become pygmies and some have developed very dark skin for example
Massive expansion in last 3ky bringing pigs etc from Taiwan – mixed with Papuans and spread downwards so most peoples of different islands here look very similar
Went into the pacific and also west to colonise Madagascar
93
Summarise the evolutionary relationship between farming and linguistic diversity today.
Farmers were the biggest demographic input into Europe in the last 10ky
BUT this was superseded during the Bronze Age via a population from Russia (Yamnaya) – complete replacement of Neolithic genome in the Bronze age – these brought Y. pestis – first plagues – layered history
Expansion of Bantu speaking farmers replace entire population of sub-Saharan Africa (basically) – this process of homogenization also occurred across the world both via genetics (population replacement) and culture (others picking up the language)
94
What was found from studying Y pestis' genome
oldest direct evidence of Yersinia pestis identified by ancient DNA in human teeth from Asia and Europe dating from 2,800 to 5,000 years ago.
plague infection was endemic in the human populations of Eurasia at least 3,000 years before any historical recordings of pandemics.
95
How does the linguistic pattern in Africa reflect its diversity
Among the 50 linguistically most diverse countries in the world (of a total of 218 countries), 29 are African
96
How long did people have dark skin in Europe
Hunters of Europe still had dark skin 7kya – then come the farmers
97
What happened when HGs met farmers in South America
maku (hunter gatherers – symbiotic relationship with Tukano) and tukano (farming community
o Tukano are a caste society and now have a caste called ‘Maku’
o Assimilation – Tukano will take Maku women as wives
o Selknam
Fully nomadic
Tall strong and robust – similar to arctic
Search for gold led to their genocide
98
Give examples of what happened when farmers met HGs in East Asia
o Yayoi
Related to prehistoric population
2kya – rice farmers from korea invaded and took over islands
Now Yayoi only exist in the remote islands to the north of Japan
Survivorship only possible through isolating themselves
Look very different to traditional idea of Japanese people
Tattooing of mouths
99
Give examples of what happened when farmers met HGs in Australia
o Never any farming
o Aboriginals remained hunter gatherers until recent past
o But have suffered from economic expansion of farmers/ western colonisers
o Absolute impact – extinction of cultures and languages
100
Give an overview of the demography of language
347 (or approximately 5%) of
the world's languages have at least one million speakers and account for 94% of the
world's population.
The remaining 95% of
languages are spoken by only 6% of the world's people
101
What was the 5th transition H sapiens underwent
The Holocene Filter
The 5th transition: 15,000‐present
Change in global diversity, expansion of post‐glacial foragers and Holocene food producers
102
What is the Holocene Filter
the mechanisms by which human diversity throughout the world decreased as a
consequence of the differential expansion of a few populations since 15,000 years ago
‘population factories’
103
Give examples of the human palimpsest that has appeared since the Holocene filter
contrast between large agricultural societies and neighbouring HG societies that look very different
eg Japan, Borneo and Philippines
104
Explain the importance of extinction in biodiversity
* Extinction plays as important a role in the structure of biodiversity as speciation
* The probability of extinction is not related to phylogenetic proximity
• Extinction is a key link between micro‐evolutionary process and macro‐evolutionary
pattern
105
How do pygmy populations come about?
Pygmies: males with mean height of <150cm, happened independently – happened with previous hominins – has always been an adaptive option –
different body proportions due to different mutations:
eg Congo have mutation in IGFR so no adolescent growth spurt,
while those in Philippines are shorter due to a change in timing of reproduction, reproducing early due to early adult mortality
106
What are the earliest undisputed remains of modern H sapiens
Ages?
```
Omo I (200ka)
Herto (169ka)
```
both have tall skull vault and a chin
107
How does Marta place the origin of Homo sapiens
used phylogenetic modelling to reconstruct vLCA
While Florisbad shares the most phenotypic affinities with the computed vLCAs, some of the LMP fossils present a different phenotypic profile which supports the recognition of several African hominin populations and lineages
support the view that H. sapiens’ origin may be the result from the coalescence of South and, possibly, East-African source populations. In this scenario, the North-African hominins may represent a population which introgressed into Neandertals during the LMP
108
What environmental changes would have led to diversity in early sapiens
current evidence suggests a dynamic biogeographic period driven by pronounced shifts in aridity and temperature, during which drift and selection would have acted to create diversity at population and potentially species levels
109
Why does Marta attribute extinction of lineages eg naledi to
harsh climatic conditions of Marine Isotope Stage 6, which may have triggered local extinction events, and to competition with expanding groups of H. sapiens during the early phases of MIS5
110
What does Marta suggest Irhoud specimens represent
represent local descendants of a population that dispersed OoA during a Green Sahara event ~340kya and introgressed into the European Neanderthal lineage
111
What does Lahr's 2019 study suggest about the geographical origins of sapiens
350-200kya: phenotypic diversification forming local morphs of pre-sapiens
200-100kya: fragmentation and expansion leading to anatomically modern humans
Not all regional variants would have contributed equally - expansion with introgressions, extinctions and founder effects
112
To what extent was the Neolithic demographic transition a life history trade-off
Page et al. (2016) conducted blood composition tests in 345 Agta and found that viral and helminthic infections as well as child mortality rates were significantly increased with sedentarization. Nonetheless, both age-controlled fertility and overall reproductive success were positively affected by sedentarization and participation in cultivation
suggest that the spread of agriculture involved a life history quality–quantity trade-off whereby mothers traded offspring survival for increased fertility, achieving greater reproductive success despite deteriorating health
Phylogenetically controlled (Sellen & Mace, 1997)
10% dependence upon agriculture leads to 0.2
extra offspring per female
According to subsistence strategy agriculturists only have slightly more babies than hunter-gatherers (6.6 and 5.4 respectively)
BUT
Infant mortality is very different – for current HG it is 43.7% - critically issue related to foraging – give farmers the advantage
113
Give local genetic adaptations that help humans globally
Lactose persistence
Diet
Endemic pathogens
High altitude
114
When did lactose persistence emerge
Europe: 9kya
E Africa: 5kya
this is convergence - absent in early Neolithic Europeans
115
How have some humans adapted to high altitudes
selection in genes involved in hypoxia-inducible factor pathway
Tibet: strongest selection signal at EPAS1 (transcription factor in HIF pathway)
May have originated from Denisovan introgression
116
How have certain human genes been affected by diet
What are the implications on modern populations
Samoan adaptation to fast-feast lifestyle
mutations in CREBRF where Samoan variant decreases energy use and increases adipose storage
>80% of Samoans are overweight or obese
117
Which migration event most influenced the genomic of Africa?
movement of Bantu-language-speaking populations from their homeland in the highlands of Nigeria and Cameroon into much of sub-Saharan Africa in the past 4 kyr
118
Which extant populations reflect the deepest split between human populations
click-language-speaking San populations of southern Africa (160-110kya)
interestingly, other click-language populations eg Hadza display limited genomic affinity with these San populations
119
Give 3 key genetic signals indicating African origins of sapiens
1) lower levels of diversity and 2) higher levels of linkage disequilibrium in non-African populations
3) all non-Africans have 2% Neanderthal ancestry (50-65kya)
120
Give a very brief overview of the OoA event
all contemporary non-African peoples branched off from the same ancestral population that left Africa, possibly with minor genetic contributions from an earlier modern human migration wave into Oceania
immediately separated into 2 waves one founding Australasia and New Guinea and the other contributed to the ancestry of present-day mainland Eurasians
121
How does the amount of Neanderthal DNA differ between populations
What does this reflect (3)
East Asian people have about 20% more Neanderthal sequences com-pared to European people,
may reflect the effects of natural selection, the occurrence of further admixture events in the ancestors of present-day East Asians after the population split from Europeans or the dilution of Neanderthal ancestry in Europeans owing to admixture with populations that did not contain considerable levels of Neanderthal sequences.
122
Give an example of an individual who suggests Neanderthal introgression was complex
SNP genotyping in an early mod-ern human from Romania who lived about 40 kyr ago provided further evidence that introgression occurred at several times and locations in Eurasia
(Nielsen, 2017)
123
How early were anatomically modern humans in Europe
43kya
124
What were the 3 colonisation events of Europe
first Europeans 43kya
genetic turnover with Last Glacial Maximum
When LGM passed and Neolithic culture emerged in Fertile Crescent.
Neolithic farmers from Anatolia colonised Europe and had reached Iberian peninsula by 7kya - this was mass migration of farmers NOT just cultural spread
Yamnaya herders from the Caspian steppe migrated to central Europe ~4.5kya
(Nielsen, 2017)
125
What does genetic diversity look like in Europe today
decreasing diversity with increasingly northern latitude
after multiple waves of migration, gene flow became limited by geography and culture
126
How was Asia colonised
2 waves
One wave included the ancestors of Australians and the Papuan people and the other included other ancestors of East Asians, with admixing between the two
(Nielsen, 2017)
127
Describe the first wave of colonisation in Asia
5kya - expansion of Yamnaya herders
2.5-3.5kya - Yamnaya were replaced by Sintashta people from Urals and Europe
(Nielsen, 2017)
128
What does genomic data suggest about the peopling of Sahul
47.5-55kya:
1 extensive migration followed by a divergence of the Papuan and Aboriginal Australian ancestral population and further genetic diversification in the Aboriginal Australian population
(Nielsen, 2017)
129
Is there evidence for Oceanian individuals migrating into Americas before Europeans
yes
human remains from Brazil that date to around AD1650, and therefore pre-date the recorded trade of Polynesian slaves to South America, shows that the individuals are closely related to contemporary Polynesians.
GWAS of Easter Island inhabitants suggests early contact between Polynesians and Native Americans hundreds of years before Europeans reached the islands (Nielsen, 2017)
Chilean chicken aDNA suggests introduction of chickens pre-Columbus from Polynesia (Storey, 2007)
130
What is the earliest well-characterized archaeological assemblage in the Americas?
emergence of the Clovis complex (around 12.6–13 kyr ago)
131
When did a biologically viable corridor from Beringia (now northeastern Siberia and northwestern North America) to the southern parts of the Americas.
What is the importance of this
from 12.6kya
makes it an unlikely early route for the southward migration of pre-Clovis and Clovis groups
a movement towards the south along the west coast of North America that occurred more than 14 kyr ago may have been possible
132
Who are Native Americans descended from
On the basis of cranial morphology and lithic analysis, it has been proposed that early Americans were not direct ancestors of con-temporary Native Americans, but instead were related to Australo-Melanesians, Polynesians, the Ainu people of Japan or Europeans who were later replaced or assimilated by ancestors of Native Americans from Siberia
BUT
- genome from 12.6kya in Montana is directly ancestral to Native Americans
- Kennewick Man's genome suggests the same
(Nielsen, 2017)
133
What is one of the most obvious adaptations that sapiens' genetics has undergone since OoA
adapting to changes in UV exposure
Populations that live near the equator have dark skin to protect against skin damage and the photolysis of folate by ultraviolet radiation
at higher latitudes, lighter skin is thought to be an advantage that enables more efficient vitamin D production (affecting genes eg MATP)
134
Give benefits of human introgression with other hominis
adaptive EPAS1 haplotype in Tibetans seems to be introgressed from Denisovans
selection on the major histocompatibility complex genes and the gene MC1R is probably facilitated by introgression from Neanderthals
135
How high might Neanderthal introgression have been
Why does it appear lower than this
What is an implication of this
as high as 10%
substantial amounts of Neanderthal DNA was purged by selection
high inbreeding in Neanderthals
Neanderthals may not have become extinct because they lacked suitable ecological adaptations or through competition or warfare with humans. Instead, they may simply have been absorbed into the human species.
(Nielsen, 2017)
136
What is the trend in face shape from Middle Pleistocene to modern day
a temporal trend for brow ridge reduction is apparent from the late Middle Pleistocene (pre–80 Ka BP) to Late Pleistocene (post–80 Ka BP)samples and continuing to the recent human samples (increasing feminisation with time)
significant reduction in androgen-mediated craniofacial masculinity between the MSA/MP and LSA/UP, coincident with genetically and archeologically visible increases in human population size and density and with a markedly increased rate of cultural evolution
137
What have the selection processes been to reduce human face masculinity
educed aggressiveness and enhanced social tolerance may have had direct reproductive benefits in the later part of the MSA and MP
more tolerant males may simply have enjoyed a greater number of cooperative exchanges with others, which would have served to improve foraging return rates (through cooperative foraging and through shared innovations in subsistence technology) and reduce the risk of foraging shortfalls (through food sharing)
may also be a honest signal - increased social skills and paternal care
138
What are the key phases of human diversification
(i) origins of the species,240–200 ka;
(ii) at the time of the first major expansions, 130–100 ka;
(iii) during a period of dispersals, 70–50 ka;
(iv) across a phase of local/regional structuring of diversity, 45–25 ka;
(v) during a phase of significant extinction of hunter–gatherer diversity and expansion of particular groups, such as farmers and later societies (the Holocene Filter), 15–0 ka
139
Why is it believed East Africa is the origin of Homo sapiens
Why is South Africa less likely
consistent with some genetic studies, and supported by models of the role of refugial networks during climatic instability
SA is suggested by some genetic studies but these are strongly influenced by the current distribution of the few surviving African hunter–gatherer populations
140
What location acted as a refugia during MIS 6
What happened after tis
Give study
lakes in Eastern Africa acted as oases during the increased aridity of MIS 6/ ~200kya
hominins were restricted to lake margins
climatic amelioration 130kya, leading to population expansion
Basell (2008)
141
When was the expansions phase of human diversification
Give fossil evidence
Is there genomic evidence
130–100 ka, MIS 5
climatic amelioration allowed expansion across Africa as seen by the following fossils in:
Sudan (133kya)
South Africa (115kya)
and into the Levant:
Skhul and Qafzeh (~100kya)
even reached China:
modern human teeth dated to ~80 ka in China
Genomic evidence - Altai Neanderthal
142
Which extant HG societies can trace their lineage back to the pan-African expansion in MIS5
Khoe San
143
Give examples of increased cultural complexity during expansions stage of human diversification
Give an example of regionalized culture in the MSA (300-30kya)
Qafzeh was intentionally buried (ochre at scene - ritualistic or pragmatic?)
SB flake-based technology includes finely shaped, bifacially worked, lanceolate points that were prob-ably parts of spearheads (2), whereas the blade-rich HP is associated with backed (blunted) tools
see also geometric markings on stone from >70kya
144
What genomic evidence suggests humans made it to Eurasia ~30kya before the true dispersal
What does this evidence imply about this dispersal
Altai Neanderthal - genomic signs of admixture with a modern human population that dispersed into Eurasia before the ancestors of living non-African peoples sampled to date
the Altai Neanderthal is the only case so far in which the children from a human-Neanderthal sexual encounter were brought up as Neanderthals, suggesting that, by that stage, the populations of early MIS5 Eurasian modern humans were small and outcompeted
145
What had happened to sapiens' populations by the second half of MIS-5
(Dispersals, 70–50 ka, MIS 4–3)
(i) African populations were structured into different groups
(ii) that one of these groups (‘X’) underwent sequential waves of expansion that led first to the establishment of descendant populations within Africa, creating the north–south cline of matrilineal relatedness in this group;
(iii) that one of the descendant groups expanded out-of-Africa (‘X-ooA’), came into contact with Neanderthals, and assimilated some Neanderthal individuals into the group;
(iv) that this population with Neanderthal admixture
REMEMBER INCREASED CULTURAL COMPLEXITY FROM 70kya
146
When was the structuring phase of human diversification
What happened here generally
Structuring of existing variation, 45–25 ka, MIS 3–2
shaping of non-African diversity when local patterns of extinction/survivorship magnified the differences acquired during the process of population dispersals of the preceding phase and created the basal inter-population structure among non-Africans, magnifying the differences acquired during the process of population splitting in the dispersal phase
this structuring was intensified by admixtures with other hominins eg Neanderthal and Denisovans, which selection on the introgressed genes
147
When was the LGM
What happened globally
26.5–19 ka
Northern latitudes were partly covered by glaciers or developed polar desert conditions and became depopulated; the tropical desert and semi-desert belts became hyper arid, further reducing land availability and shifting animal distributions; in between extremes of cold and aridity, populations contracted into refugia
led to changes in genes and tech (eg first recorded manufacture of pottery in China)
148
What was the last phase of human diversification
What was the first thing to happen in this period
The Holocene Filter, 15–0 ka, MIS 2–1
onset of African humid period 15kya and the expansion of some hunter–gatherer–fishers from localized refugia across vast spaces newly created by abrupt climate change and forest expansion
149
Describe how different populations in Africa changed 15kya during beginning of Holocene filter
In Eurasia?
an extensive hunting–fishing population and/or trading network spread from the northern Kenyan lakes to the Nile, across the Sahel and into the greening Sahara
Eurasia: HGs expanded north, which had previously been covered in permafrost, eventually leading to the peopling of the Americas
150
Which area was unique during the early Holocene filter (15kya)
Southeast Asia is a unique case, since the Late Pleistocene/Early Holocene is not period of niche expansion but reduction associated with the flooding of the Sunda landmass and Sahul
(although archaeological, fossil, linguistic and genetic evidence suggests that Aboriginal Australian and Papuan populations already had differentiated trajectories)
151
What allowed the rapid expansion of farmers
What slowed down the expansion?
removed unpredictability of HG lifestyle and increased fertility (even at cost of health)
farmers' need for protein - obtained by trading with hunter–gatherers at the edge of forests, mountains and lakes
this may have led to decreased linguistic diversity (eg Mbuti who now only speak Bantu like the neighbours they trade with; although Hadza have maintained their languages)
152
What do the transitions in sapiens evolution result from
interaction between (i) the addition of variation during population collapse and rapid expansion and (ii) the loss of variation due to localized population extinction and/or their partial assimilation into expanding groups.
153
What is an adaptive radiation
a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches.
Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits.
