“Know Thyself” Carolus Linnaeus. Human Origins: A Confluence of Research Paleontology Paleontology Anthropology Anthropology Archaeology Archaeology Genetics

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  • Know Thyself Carolus Linnaeus
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  • Human Origins: A Confluence of Research Paleontology Paleontology Anthropology Anthropology Archaeology Archaeology Genetics Genetics Paleoclimatology Paleoclimatology
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  • Conflict, Racism and Uncertainty Human origins commonly at center of the Evolution vs. Creation debate Human origins commonly at center of the Evolution vs. Creation debate Evolution and human origins are investigated scientifically hypotheses are proposed and tested Evolution and human origins are investigated scientifically hypotheses are proposed and tested Creationism/Creation Science/Intelligent Design, etc. are faith, not science Creationism/Creation Science/Intelligent Design, etc. are faith, not science Topic is full of uncertainty Topic is full of uncertainty A) Very young discipline A) Very young discipline B) Relatively sparse fossil record B) Relatively sparse fossil record
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  • A Family Dynasty the Leakeys: Louis, Richard, Mary and Richard Jr. Mary Leakey - A lifetime of contributions including: Many first discoveries of skulls, etc. First hominid footprints
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  • A Patchy Fossil Record Upland habitat erosion vs. deposition Upland habitat erosion vs. deposition Fossils are not abundant Fossils are not abundant Most important sites are in Tanzania, Kenya, Ethiopia (East African Rift System) and Egypt Most important sites are in Tanzania, Kenya, Ethiopia (East African Rift System) and Egypt Teeth predominate Teeth predominate Jaw and skull fragments Jaw and skull fragments Taphonomic changes make taxonomy difficult Taphonomic changes make taxonomy difficult Rare post-cranial skeleton Rare post-cranial skeleton Few complete or nearly complete skeletons Few complete or nearly complete skeletons Footprints Footprints
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  • The Cradle of Humanity The East African Rift System Earthquakes and formation of rift as Africa splits Sinking of rift floor promoted accumulation of sediments Early hominids preserved in these sediments Recent erosion cuts through sediments to reveal fossils
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  • Famous locations of hominid fossils Olduvai Gorge Hadar Laetoli
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  • Arboreal Ancestors? Characteristics of tree dwellers Characteristics of tree dwellers Flexibility and agility Flexibility and agility Parallax vision eyes in front of head Parallax vision eyes in front of head Vision predominates over sense of smell Vision predominates over sense of smell Enlarged brain to handle visual data Enlarged brain to handle visual data Secondary adaptations to bipedality (from tree swingers) Secondary adaptations to bipedality (from tree swingers)
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  • Of Apes and Man Divergence in Early Cenozoic Oligocene? Divergence in Early Cenozoic Oligocene? Apes and Hominids Apes and Hominids More gap than record More gap than record Too early to establish evolutionary relationships among species Too early to establish evolutionary relationships among species Discovery of each new species changes picture Discovery of each new species changes picture So, what is a hominid? So, what is a hominid?
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  • Characteristics of Hominids (a.k.a. hominins) Arched palate Arched palate U shaped jaw U shaped jaw Uniform dentition (no diastema) Uniform dentition (no diastema) Enlarged skull and brain case Enlarged skull and brain case Opposable thumb Opposable thumb Bipedal Bipedal Paralax vision Paralax vision
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  • Australopithecus afarensis Lucy Circa 3.8 Ma Pliocene to Pleistocene (?) Female Four feet tall Less than 100 lbs. Tool user, but not maker Coexisted with A. robustus Upright posture and bipedality arise before enlargement of braincase
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  • Australopithecus afarensis
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  • Footprints at Laetoli, Tanzania (3.6 Ma) probable A. afarensis
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  • Australopithecus afarensis and Homo habilus
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  • One Version of the Time Line
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  • General Picture of Hominid Evolution Probable common ancestor of humans and chimps circa 5.5 Ma Probable common ancestor of humans and chimps circa 5.5 Ma Pliocene saw several hominid species coexising Pliocene saw several hominid species coexising Several lineages became extinct Several lineages became extinct Which one was our ancestor? Which one was our ancestor?
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  • Kenyanthropus platyops an early ancestor to rival A. afarensis? Mid-Pliocene (circa 3.5 Ma) Some similarities to Homo (Kenyanthropus) rudolfensis Coeval with A. afarensis More modern appearances millions of years earlier than previously thought Possibly incorrect taphonomic distortion?
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  • General Picture of Hominid Evolution Genus Homo arises circa 2.0 Ma (H. habilus) - Pleistocene H. habilus a tool maker and user, fire, built shelters, social structure H. sapiens arises circa 500,000 to 300,000 ybp (Late Pleistocene) Modern Humans arise about 100,000 ybp
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  • The Hominid Time Line Accurate dating of fossils is critical Accurate dating of fossils is critical Direct evolutionary relationships are still unclear Direct evolutionary relationships are still unclear New fossil discoveries prompt revisions all the time New fossil discoveries prompt revisions all the time The burning questions: Who are we? What is our heritage? Where do we fit in the grand scheme of things? The burning questions: Who are we? What is our heritage? Where do we fit in the grand scheme of things?

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