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Human Evolution. Naked Apes. Phylogeny of Primates. Primates Large brain:body ratio Forward-directed eyes Flexible hands Arms that can fully rotate Anthropoids diurnal primates Homonoids lack tail Divided into lesser apes and great apes (size) Homonids all humans.
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Human Evolution Naked Apes
Phylogeny of Primates • Primates • Large brain:body ratio • Forward-directed eyes • Flexible hands • Arms that can fully rotate • Anthropoids • diurnal primates • Homonoids • lack tail • Divided into lesser apes and great apes (size) • Homonids • all humans
What derived traits make humans unique? Structural Differences • Hairlessness • Skeletal structure • Skull • Larger Brain Case • Less protruding mandible • Position of foramen magnum • Pelvis: Wider & shorter • Spine: Lumbar curve
What derived traits make humans unique? Cognitive Differences • Ability to perform complex reasoning and exceptional ability to learn • Linked to longer childhoods • Communicate using complex language • Lower position of voice box enables speech
Hominid Clade • The clade ending in humans, includes many smaller branches that represent many of our direct ancestors. • However, there is still much debate over the exact organization of this clade. • There is incomplete information about many species, so determining the most parsimonious arrangement of derived traits can be tricky
Hominid Clade Some derived traits used to classify different hominids
Hominid Phylogeny Ardipithecusramadusis the oldest known bipedal species; it dates back 4.6 mya (formerly thought to be “missing link”)
A. afarensis (“Lucy”) vs H. Sapien Lived between 3.9 and 3.0 mya Australopithecines gave rise to Homo genus 2.5 mya Biggest difference between Australopithecines and Homo genus is the size of the brain case and brow ridge and the shape of jaw and teeth
H. heidelbergenesis • Existed 500 000 years ago • Also called archaic H. sapiens • Traits are intermediate between erectus and sapiens (skull roundness, tooth size, brow ridge, slope of forehead and chin)
H. Neaderthalensis(neadertal) vsH. Sapiens H. neanderthalensisand H. sapiens coexisted as recently as 130 000 years ago and may be a sub species of modern humans H. heidelbergenesisis MRCA for H. sapiens and H. neaderthalensis
Out of Africa • The oldest H. sapiens fossils have been found in Ethiopia. This, in combination with recent DNA evidence, suggests that humans evolved out of Africa. • Suggested time frame for migration • Left Africa ~100 000 years ago • Australia and Asia ~50 000 years ago • Europe 40 000 years ago • N.A. 20 000 years ago • S.A. 12 000 years ago
Video Clip • National geographic with Spencer Wells: The Journey of Man – A Genetic Odyssey • Part 1 – 4:53 Introduction to project • Part 2 – 9:55 Explain how ‘markers’ are used to determine path of human migration