Human Origins

• Constant state of flux - small number of fossils
• Emotional subject - its us!
• Currently unsure how many species between us and early humans
• Not linear progression - branching

Lemurs, monkeys, apes, humans (~240 species)

Ancestors - small insectivores (sister groups either tree shrews/flying lemurs)

• Grasping hands and feet - arboreal lifestyle (trees)
• Large brain
• Forward facing eyes - depth (swinging in trees)
• Omnivorous diet

Subgroups:

• Lemurs
• Tarisers
• Anthropoids - opposable thumbs (manipluate objects)
  • New world monkeys
  • Old world monkeys
  • Hominoids - lack of tail

Distinguished by lack of tail - confusion about earliest homonids due to no full skeletons being found (no evidences of tails/no tails)

Around 20-15mya in Africa (Kenya, Tanzania, Ethiopia)

• Gibbons
• Orangutans (Bornean and Sumatran)
• Gorillas (Western and Eastern)
• Chimps (Chimpanzee and Bonobo)
• Humans

Specis more closely related to humans than chimps

• Big brain - 1,350cm in humans (X3 bigger)
• Bipedal - walk on 2 legs (no ability of grasping in feet)

Cooling of climate = savannah replaced forests -> bipedalism selection pressure

Easrliest hominids (debated always):

• Sahelanthropus - 7-6mya
• Orrorin - 6 mya

• Ardipithecus
  • 4.4.mya
  • 1.2m
  • 300-400cm brain
  • Upright posture, grasping hands and feet
  • Direct or parallel evolution?
• Austalopithecus
  • 4-2.5mya
  • 1.2-1.4m
  • 400-500cm brain
  • Full bipedal (footprints!)
  • Lucy and lucy's baby
• 

Paranthropus

• ~2.5mya
• 1.3-1.5m
• 550cm brain
• Strong, heavy bones
• Big teeth
• EXTINCT LINEAGE - ~1mya

• Debate - big brian generally accepted (+ flat face, weak jaws, small teeth)

Homo habilis

• 2.5mya
• 600-700cm brain
• Evidence of tools
• Later forms H.ergaster 900cm+ brain

Homo erectus

• ~2mya
• 1000-1200cm brain
• First to migrate out of Africa to Europe/Asia 1.5mya
• 

Homo neanderthalensis

• Europe 350,000-200,000ya
• Heavy, muscular
• 1500-1600 brain
• Descendents of H.erectus
• EXCTINCT LINEAGE - 30,000mya - not our ancestor!

Homo sapiens

• Probably populated Out of Africa model - 2 waves of migration
  • Descended from H.erectus in Africa
• Also multiregional model - 1 wave of migration
• Left Africa 100,000-50,000ya
• Replaced H.erectus in Asia (maybe coexisted)
• Coexisted and replaced H.neanderthalensis in Europe - genetic evidence of interbreeeding

• Found in cave on island of Foresis, Indonesia
• 1m height
• 400cm brain
• Fire/tools evidence
• Island dwarfism? - evolve smaller due to less resources
• Youngest remains 12,000ya - coexisting w/ H.sapiens
• Alternatively, microcephalous (dwarfism) H.sapiens  = same species

• ~1500 bones = multiple people
• Mix of primitive and less primitive traits
• Age?!?!?!?!?!

• Metabollicaly expensive - 18% budget
• Forces premature birth - kill mother otherwise
• = surely beneficial
• Increase survival from practical skills?
• Increase survival from social skills?
• Traits passed on culturally = memes