Outline 22: Hominid Fossil RecordHuman ancestors A.=AustralopithicusAssumed direct lineage to modern humansBabcock textbook Lots of names but pattern is clear that Homo evolved from an australopithecine over 2 m.y. ago.Collecting hominid fossils in East AfricaUsing Stratigraphy and Radiometric Dating of volcanic ash beds to date hominid fossilsA Hominid Jawbones from EthiopiaSahelanthropus tchadensis, 6.5 MY oldSahelanthropus tchadensis, 6.5 MY oldGorilla – female on left, male on right; note the sexual dimorphismOrrorin tugenensis – the sum total of specimensArdipithecus ramidus, 2009Australopithecus anamensisThe Australopithecines • Ardipithecus: oldest definite bipedal ancestor, over 4 M.Y. old • Australopithecus: the gracile australopithecines • Paranthropus: the robust australopithecinesFossil Species • Ardipithecus ramidus: 4.4 MY, teeth, jaws and bone fragments suggest it is a hominid, not a pongid. • Australopithecus afarensis: 3.8-3.0 MY based on good fossils. Clearly a bipedal animal based on bones and fossil footprints.Bipedal Footprints of Australopithecus in Lithified Volcanic Ash 4 MY old from Tanzania. Found by Mary Leakey.Australopithecus couple making footprints in volcanic ashJawbones of Australopithecus afarensisFossil remains of “Lucy”, the most complete specimen of Australopithecus afarensis.An adult skull, A. afarensis. The spinal cord opening is underneath the skull.Pelvis of Australopithecus afarensisReconstruction of Australopithecus afarensisFace-to-face with A. afarensisA troop of A. afarensis feeding on tubers in the forest.A. afarensis family unit crossing the savannah.Fossil Species • Australopithecus africanus: 2.8-2.5 MY • Robust australopithecines: Paranthropus aethiopicus: 2.6-2.2 MY P. robustus: 2.0-1.2 MY P. boisei: 2.6-1.0 MYThe Taung Child, A. africanusSkull of Paranthropus boiseiParanthropus aethiopicusParanthropus aethiopicusJustus Erus found the fossil Kenyanthropus platyops, 3.5 MY old from KenyaKenyanthropus rudolfensis or Homo rudolfensis?Fossil Species • Homo habilis: 2.5-1.6 MY • H. erectus: 1.8 MY- 25,000 yrs? Java man Peking man • H. sapiens: archaic vs. modernSkull of Homo habilisH. rudolfensis, H. habilis, and P. boisei. Hominids in East Africa around 2 MY ago.Phylogeny 2000Homo erectus from Indonesia, Java ManSkull of Homo erectus from China Peking ManSkeleton of Homo erectus, Turkana Boy from KenyaH. erectus skull of Turkana BoyThe face of Homo erectusHomo erectus using fire to sharpen spearsHomo sapiens? • Archaic H. sapiens or unique species? H. antecessor: 800,000 years old H. heidelbergensis: 500,000 years old H. neandertalensis: 200,000-32,000 years old • Currently all thought to be unique species.Homo antecessor from Spain, 800,000 years oldHomo heidelbergensis, 500,000 years BPNeanderthal skull, SpainFleshing out a Neanderthal skullNeanderthal skeleton, GermanyShanidar Cave, Iraq: Neanderthal burial, 50,000 yrs. BPShanidar Cave, Iraq: Neanderthal burial, 50,000 yrs. BPDid Neanderthals have naked skin like we do? What would the Theory of Neoteny say?Reconstruction of Neanderthal child from Gibraltar, Spain, 30,000 years B.P.http://www.bbc.co.uk/news/science-environment-19960748 How scientists recreated Neanderthal manhttp://news.bbc.co.uk/2/hi/science/nature/8660940.stm 1%-4% DNA 500 ky 30 ky 2010: Genetic studies of Neanderthal bones indicates that between 1-4% of modern human DNA is from Neandertals. Suggests interbreeding around 60,000 years ago.Fig. 1 Samples and sites from which DNA was retrieved. R E Green et al. Science 2010;328:710-722 2010: Genetic studies of Neanderthal bones indicates that between 1-4% of modern human DNA is from Neandertals. Suggests interbreeding around 60,000 years ago.Homo sapiens • modern H. sapiens: first appearances East Africa: 195,000 years ago Middle East: 90,000 years ago Australia: 50,000 years ago Europe: 32,000 years ago Americas: 20,000 years agoHomo sapiens, Israel, 90,000 yrs BP FYI: Abraham lived only 4,000 yrs BPCro-Magnon man from France, Homo sapiens, 28,000 years oldHomo floresiensis, a hobbit-size human from Flores Island, Indonesia, 18,000 BP Modern humanHomo sapiens (Cro-Magnon people) drew the cave art in France and Spain about 17,000 years ago.Lascaux, France, cave artLife in the late Stone Age, which ended at different times on different continents.The invention of farming, plus domestication of animals, started civilization.Evolution of Modern Humans Two Theories: • Out of Africa: all modern humans descended from a single population. Racial differences have very recent origins. • Multiregional Theory: modern humans evolved from local populations of H. erectus at several places in the Old World. Accounts for the racial differences in modern humans.How far back in time did the modern races diverge from a common ancestor?DNA studies show the common ancestor of all humans lived in Africa about 170,000 years ago Tree Diagram of Genetic SimilarityAnother tree diagram of genetic similarity; nearest neighbor