Hominid Fossil Record Geology 230: Fossils and Evolution Human ancestors A.=Australopithicus Collecting Hominid fossils in East Africa Using Stratigraphy and Radiometric Dating to date hominid fossils A Hominid Jawbone in Ethiopia Hominid Record, 2002 Sahelanthropus tchadensis, 6.5 MY old Sahelanthropus tchadensis, 6.5 MY old Gorilla – female on left, male on right; note the sexual dimorphism Orrorin tugenensis – the sum total of specimens Ardipithecus ramidus, 2009 Ardipithecus ramidus, 2009 Hand Foot Ardipithecus ramidus Digitally Reconstructed Skull from Broken Pieces using Computed Tomography Australopithecus anamensis The Australopithecines • Ardipithecus: oldest definite bipedal ancestor, over 4 M.Y. old • Australopithecus: the gracile australopithecines • Paranthropus: the robust australopithecines Fossil 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 ash Jawbones of Australopithecus afarensis Fossil remains of “Lucy”, the most complete specimen of Australopithecus afarensis. An adult skull, A. afarensis Pelvis of Australopithecus afarensis Reconstruction of Australopithecus afarensis Face-to-face with A. afarensis A 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 MY The Taung Child, A. africanus Skull of Paranthropus boisei Paranthropus aethiopicus Paranthropus aethiopicus Justus Erus found the fossil Kenyanthropus platyops, 3.5 MY old from Kenya Kenyanthropus 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. modern Skull of Homo habilis H. rudolfensis, H. habilis, and P. boisei. Hominids in East Africa around 2 MY ago. * Phylogeny 2000 * * * Poorly known * * * Phylogeny * 2007 * * * * Poorly known * * Prothero, 2007 2010 Skull of Homo erectus from China Skeleton of Homo erectus, Nariokotome boy from Kenya H. erectus skull of Nariokotome boy The face of Homo erectus Homo erectus from Indonesia, Java Man Homo erectus using fire to sharpen spears Homo 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 Homo antecessor from Spain, 800,000 years old Homo heidelbergensis, 500,000 years BP Neanderthal skull, Spain Fleshing out a Neanderthal skull Neanderthal burial, 50,000 yrs. BP Neanderthal skeleton, Germany Homo neadertalensis leading a nomadic existence Neandertals were big-game hunters. Neandertal night life around the fire. A more modern view of Neandertals with naked skin like ours? Reconstruction of Neanderthal child from Gibraltar, Spain, 30,000 years B.P. Homo sapiens • modern H. sapiens 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 ago Homo sapiens, Israel, 90,000 yrs BP FYI: Abraham lived only 4,000 yrs BP Cro-Magnon man from France, 30,000 years old Homo floresiensis, a hobbit-size human from Flores Island, Indonesia, 18,000 BP Modern human Homo sapiens (Cro-Magnon people) drew the cave art in France and Spain about 17,000 years ago. Lascaux, France, cave art Life 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. Multiregional vs Hypothesis Out of Africa Hypothesis Tree DNA studies Diagram show the of Genetic Similarity common ancestor of all humans lived in Africa about 170,000 yrs ago How far back in time did the modern “races” diverge from a common ancestor? Maybe 50-100 Ka.