HE - evolution of modern humans

Regional evolution
Replacement
Admixture
(or potentially all happened at the same time)

Stone

1992
Continuous anatomic sequence in Asian and Australian hominin fossils might suggest linear evolution of Homo erectus to Homo sapiens

Structure of living human variation - allelic diversity decreases with distance from Africa (founder effect), suggests replacement process
Gene flow - modern humans and non-modern humans interbreeding
Geographical pattern - was first appearance of modern humans in Africa?

Allelic diversity higher in Africa - suggests location of human origin
Gene flow between different human populations - suggests interbreeding

Middle east
East Africa and South Africa
Morocco
Ranging from 300 - 82 kyr
Supports earliest Homo sapien being in Africa

Different populations potentially existing at same time
Coexistence of Nesher Ramla Homo (archaic hominin) and Homo longi (modern human)
Homo longi might be a sister group of Homo sapiens

Late emergence of globular brain with prolonged maturation
Potential behavioural implications
No globular maturation in early Homo sapiens
Slowly became more globular

Increased no. of neural connections in brain
Helped to create new behavioural innovations

Body proportions and effective dissipation of heat produced to allow for continuous running
Allowed for persistent hunting? - wait until prey is overexhausted

Cumulative culture
Stone tool technology - flakes, mini handaxes, hafting techniques (artefact attached to handle), elongated picks
Non-lithic material culture - personal ornaments, abstract drawings, engravings

Sophisticated technology
Stone tool technology - prismatic blades, geometric microliths (small stone tool)
Non-lithic material culture - bone flutes, cave paintings, carved figurines

Co-occurrence of brain changes

Origins
Expansion 130 - 100 kyr
Dispersals 70 - 50 kyr
Structuring 45 - 25 kyr
Holocene filter 15 - 0 kyr

o Complex archaeological and fossil record 300-130ka in Africa suggests prolonged phase of repeated expansions and contractions
o Origin of modern human lineage around 200ka
o Evolution of distinct, universal morphological traits of H. sapiens
o Change from archaic to modern morphology in one African lineage
o Don’t know the date of the last African ‘archaic’ or the spatial framework of the disappearance of this population

Africa, Western Asia
Environment:
Shift from hyper-glacial to warm conditions allowed for dispersal
Expansion of forests
Period of important behavioural innovations:
First evidence of personal ornaments
Non functional-use of pigments
Carefully chosen plants for bedding
Burials with objects

Africa, Eurasia
End of mega-draught
Multiple groups in Africa (regional differentiation) as a consequence of deteriorating climatic conditions
From this population: ancestors of African populations and of modern humans out of Africa in contact with Neanderthals and other hominins like Denisovans
Eurasian dispersal

- Very poorly represented fossil record of H. sapiens during this period

Eurasia, Australia
Last Glacial Maximum (global): refugia (move to refuges - icy/cold so move to better habitats), major tech innovations (oldest pot in China)
First lithic industry accepted as reflecting modern humans
Northern latitudes covered by glaciers and become depopulated
Tropical deserts become hyper arid - reduces land availability and shifts animal distributions
Extremes of cold and aridity led to refugia
Intergroup diversity increases

Worldwide
Last deglaciation (rising sea level as a result of melting glaciers in Northern Hemisphere): expansion of hunter-gatherers out of refugia across vast spaces created by abrupt climate change, peopling of Americas, agriculture removed unpredictability of hunter-gatherer lifestyles
Forests expanded in Africa

Forest animal produce (eg. bee keeping)
Fishing and shell-fishing
Key plant produce
Levels of storage

Ealy dispersal at 130 kyr?
Main out-of-Africa event 70 - 60 kyr
Early human dispersal within Americas

Hominin remains in China (teeth), Sumatra, Australia - 80 - 65 kyr
Unsuccessful dispersal with replacement by Neanderthals in the Levant (eastern Mediterranean shores) and Europe - modern humans travelled through and couldn't survive OR replace by Neanderthals?
Don't know why this expansion wasn't successful

First wave: into Southeast Asia and Australia via a southern route
Second wave: into Eurasia via a northern route

Ancestral native Americans diverged from Siberians and East asians ~23 kyr
Mass extinction of North America's megafauna (very large mammals)- more likely climate change than overkill by humans
Modern humans arrived from Africa

African populations

Ethiopia

Allelic diversity highest in African populations
Earliest modern human fossil found in Ethiopia

Limited number of African fossils before and after out-of-Africa dispersals
Ergo, difficult to contrast behaviour of first Eurasian humans and African ancestors / relatives

Sum of unique biological and cultural variation within our species

Climate change

Adverse periods
Resource depletion
Nutritional deficits
Increased habitat fragmentation