Human Evolution and Computer Modelling

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Human Evolution and Computer Modelling

• Adam Newton
• School of Archaeology, Classics and Egyptology
• University of Liverpool
• anewton_at_liv.ac.uk

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• Setting the scene to human evolution
• The Oldowan world
• Computer Modelling
• Modelling Human Evolution

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Human Evolution

• Setting the Scene

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Setting the scene

• African Plio-Pleistocene hominins
• Boundary of Pliocene and Pleistocene geological
  epochs, 2.5-1.5 million years ago (ma)
• Hominins us and our (extinct) relatives
• Share a common ancestor not shared with any other
  animal

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The common ancestor

• 5 to 8 ma humans and chimpanzees shared a common
  ancestor
• Probably lived somewhere in Africa
• Common ancestor probably ape-like
• Still a quadruped (walked on all fours)
• Not necessarily like a chimp
• Evidence for bipedal apes starts to appear

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The Australopithecines
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Australopithecus afarensis

• Ethiopia to Tanzania, 3.9 2.9 ma
• Chimp-sized brain
• Upright posture
• Generalised diet fruit, seeds, nuts, meat?
• Mostly wooded habitat

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A.africanus

• Southern Africa
• 3.5-2.0 ma
• Generalised diet fruit, seeds, nut, meat?
• Wooded environment
• Biped, but with tree-climbing adaptations

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Bipedal Apes
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The Oldowan World
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Why Oldowan?

• Name given to the earliest manufactured stone
  tool industries.
• Named after Olduvai Gorge, Tanzania
• Plio-pleistocene

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Why study the Oldowan World?

• Earliest manufactured stone tools
• Brain enlargement beyond that of modern Great
  Apes
• Two distinct types of hominin
• Early Homo
• Robust australopithecines
• Expansion of hominins out of Africa
• First modern human body

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The Oldowan hominins

• Robust australopithecines
• Early Homo

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The Robusts

• A. aethiopicus
• 2.6 ma
• E. Africa
• A. boisei
• 2.2-1.3 ma
• E. Africa
• A. robustus
• 2-1 ma
• S. Africa

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Big jaws, teeth and chewing muscles
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Overview of the Robusts

• Widespread
• Long lived (lt2.5-1.0 ma)
• Similar body to australopithecines
• Relatively open environments
• Massive jaws and molars
• Tough diet seeds, nuts, roots, tubers, etc.

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Early Homo

• H. habilis
• 2.3-1.6 ma
• S. E. Africa
• H. rudolfensis
• 2.4-1.8 ma
• E. Africa

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Homo habilis

• Lived 2.3? 1.6 ma
• Widespread
• Compared to australopithecines
• 50 Larger brains
• Smaller teeth and jaws
• Very similar below the neck
• Found in association with stone tools
• Increased meat-eating?

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The story so far

• Increased brain size
• 650-750cc against 400500cc
• Simple stone tool-making
• Used for hunting or scavenging animals?
• Still not especially human
• Quite small and without modern human body
  proportions

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The Oldowan

• Earliest manufactured stone tools
• Olduvai Gorge, Tanzania
• Kada Gona, Ethiopia, 2.6 ma
• Densest clusters in Africa 2.0-1.5 ma

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Oldowan assemblage
chopper
Hammerstone
scraper
polyhedron
discoid
Flake scraper
flakes
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How Oldowan tools were made
Hard-hammer percussion
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What were they used for?

• Breaking open bones for bone marrow.
• Flakes are useful for cutting hide, meat and
  tendons.

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Homo erectus
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Overview of H. erectus

• Appeared 1.9 ma
• Larger brains (900cc against 650cc)
• Similar body to modern humans
• Fully terrestrial lifestyle
• More open habitats
• More sophisticated tools
• Increased hunting and/or scavenging?
• Soon left Africa

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The Oldowan environment

• Environmental change
• African climate cooler and more variable
• Africa became less vegetated
• Less forests
• More woodland and grasslands
• Vegetation shifts led to migrations

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In the beginning
8 ma
Present day
Desert and shrubland
Savannah and woodland
Rainforest
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Later climate change
After 3 ma climate cools and becomes more variable
Before 3 ma climate was relatively warm and stable
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Hominin habitats

• Australopithecus (non-Robusts)
• Relatively closed wooded habitats
• A. boisei (Robust)
• Relatively open and wet
• A. robustus (Robust)
• Relatively open but more arid than for A. boisei
• Homo
• Wider range of habitats

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Robusts
Homo
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Computer modelling
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What is meant by a Model?

• All models are simpler versions of the real
  thing
• Child making a model aeroplane
• Scientist trying to model the global climate
  change
• Modelling on a computer is similar to, say
  building a model aeroplane, but is more abstract
  and usually mathematical
• "creating an analogue to a real object"

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Steps to modelling

• Decide what you want to model
• Evaluate what the important features of the
  system are
• Build a conceptual model
• Convert conceptual model into a computer model
• Run the model
• Go back and refine your model

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Modelling Paradigms

• Procedural modelling
• Process specified in advance of its being
  undertaken
• Algorithm with ordered steps carried out in a
  specified sequence, e.g.
• Calculate this value
• Loop over this
• Print the value for this
• The process of the system is not modelled
• Examples are Fortan or C

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• Declarative modelling
• A set of facts that are true about the model
• The order of the facts is irrelevant
• The conceptual model will match the
  implementation of the model
• Good for
• Supports development of models with strong
  qualitative elements and emergent processes
• Where the forces for change are well understood
  but their consequences not
• The forces for change are the objects of analysis

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Benefits to modelling

• Allow us to understand something more complex and
  draw attention to how the whole thing works.
• Simply making a model allows us to appreciate
  what is involved in the thing that is being
  modelled.

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• Forces us to declare our assumptions
• If the model is reasonable
• It will give outcomes
• It will allow us to ask "what if" questions
• It may provide us with predictions

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SIMILE

• Visual modelling software
• Declarative modelling
• Earth, environmental and life sciences
• Developed by Simulistics

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Predator-Prey Models

• PROGRAM predator_prey_simulation
• IMPLICIT NONE INTEGER, PARAMETER
  MAX_TIME_STEPS 20 ! Maximum number of time
  steps
• INTEGER prey_num 800 ! Prey population
• INTEGER predator_num 300 ! Predator
  population
• INTEGER prey_new ! Temporary holder for new
  population of predators
• INTEGER predator_new ! Temporary holder for
  new population of predators
• INTEGER time_step 0 ! Current time step
• WRITE (, ) 'Time step 0 predators ',
  predator_num, ' prey ', prey_num
• DO
• time_step time_step 1
• prey_new NINT(1.0955prey_num -
  .0005prey_numpredator_num)
• predator_new NINT(.9155predator_num
  .0001prey_numpredator_num)
• prey_num prey_new
• predator_num predator_new
• WRITE (, ) 'Time step ', time_step, '
  predators ', predator_num, ' prey ',
  prey_num
• ! Simulation runs until one species extinct or
  MAX_TIME_STEPS steps

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Modelling Human Evolution

• Investigating the Oldowan World

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Interesting questions

• If Homo was more of a dietary generalist to what
  extent was this aided by technology?
• To what extent were the Robusts really dietary
  specialists?
• What was the payoff for the long distance
  transport of tools and raw materials for early
  Homo?

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To make a model.

• For any hominin species I would want information
  on
• Yearly/daily home ranges
• Diet/subsistence strategies
• Environment
• Technologies
• Would need some sort of virtual environment
• SIMILE is able to link up to GIS

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Where the evidence would come from

• Palaeontological record
• Archaeological evidence
• Ethnographic studies
• Primates
• Modern hunter-gatherer societies

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And finally

• Models allow us to observe behavioural processes
  as they unfold
• The results can be tested against the
  archaeological record
• Models cannot prove anything but they can show us
  what could have happened to explain what we find
  in the archaeological record

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The End

• Thank you for coming
• Enjoy the wine and snacks
• www.simulistics.com