An electric field E u = 200,000 i n N/C causes the point

Physical Anthropology 3/21/16 Fossils and Their Place in Time and Nature­ Chapter 8 continued Taphonomy Most fossils are found in sedimentary rocks­ because of either constant flooding or other sources bring sediment onto the fossil Problems w/ the Fossil Records ● Decomposition and Predation ● Geological distortion/deformation ● Weathering Limitations of the Fossil Record ● Low likelihood of anything becoming a fossil ● Bias towards hard parts ○ Cartilage and soft tissue not likely to fossilize ● Missing pieces ○ Causing not to have all the pieces for each fossil ○ Causing to mix up fossils ● Time bias ● No idea what animals actually look like ● Environments pressure different ○ Wet environments pressure better ○ Acidic soils (tropics) will eat the fossils away The Fossil Record and the Timing and Tempo of Evolution ● Provides evidence for evolution and its process ● It is incomplete so their is some disagreement of time and tempo ● Two Models of it ○ Gradualism vs. Punctuated Equilibrium ■ Gradualism­ change is a slow process ■ Punctuated Equilibrium­slow stasis than a rapid change ○ Both will happen, case by case basis of which is appropriate Bringing Fossils to Life ● What did they look like ● Exclusive: Building the Face of a Newly Found Ancestor ○ https://www.youtube.com/watchv=eatqu7hWw5g Time in Perspective ● Hard to comprehend ● Eon­4 total, half a billion years or more ● Era­ 10 defined, several hundred million years ● Period­22 defined, 10s to 1 hundred millions years ● Epoch­34 defined Physical Anthropology 3/21/16 Geological Time: EArth History ● 200 mya ○ pangean ● Late Jurassic (about 150 mya ● Cretaceous (about 70 mya) ● Present Day Stratigraphic Correlation ● Krakatau, Indonesia ● 1883 ● Massive Volcano, deposit ash 3,700 miles away ○ Creates a layer, a new strata ○ Can no date that layer ○ Chemical Dating ● Fluorine Dating ● Krapina Neanderthal Fossils ● Dragutin Gorjanovic­Karmberger ○ First guy to use fluorine levels to date fossils items ○ The longer the fossil is in the soil the more fluorine it will absorb ○ Is a localized technique because fluorine levels are different based on the area Biostratigraphic (Faunal) DAting ● Index fossils ○ Fossil pig molars Physical Anthropology 3/21/16 ○ Irish Elk ■ Extinction 10.600 BPY ● Have to be widespread ● Evolve fairly quickly Cultural Dating ● Deals with human artifacts ● Its relatively recent ● Ceramics ● Stone tools ○ Oldowan INdustry ○ 2.6­1.7 mya ○ Don’t change for a long time Relative and Absolute Dating ● Previous methods were Relative Dendrochronology ● A.E. Douglas 1920s ● Dating by the growth cycle of trees Carbon Dating ● Half lifes ● Works for fossils up to about 60,000 years ● For older fossils use elements that are more unstable Early Hominin Origins and Evolution: The Roots of Humanity­ Chapter 10 ● Olduvai gorge, in East Africa. ○ Questions addressed in this chapter: ■ What is a hominin ■ Why did hominins evolve ■ What was the evolutionary fate of the first hominins ○ Hominid = all the great apes ○ Hominins = the humans ancestry tree ● What is a Hominin ○ What is different about humans ■ Upright walking ■ Nonhoning chewing ● The teeth do not get sharpened by each other ○ Apes do have honing chewing ■ Material culture Physical Anthropology 3/21/16 ■ Speech ■ Hunting and cooperation ■ Domestication of plants and animals ○ Foramen Magnum ■ Humans have it directly underneath the skull ■ Gorillas have it in the back of the head ○ Spine ■ S curve in the human spine ● Allows for the human head to sit straight over the body ■ Gorilla mostly straight ○ Pelvis ■ Humans Hips are on the side ■ Gorillas Hips are on the back of the body ○ Femur ■ Human has an angle, body condylar angle ■ Gorillas straight ○ Feet ■ Humans, an arch ■ Gorillas, flat, an opposable thumb ○ Teeth ■ Canines ● Humans have smaller canines ■ Apes ○ Honing (wearing at the back) versus apical (wearing at the point) wear ○ Shearing versus grinding ○ male ­male aggression ○ Have thinner enamel ■ Allows for the teeth to remain sharp ● Why Did Hominins evolve ○ Bipedal ■ 4­7million ○ Tool Use ■ 2.6 million ○ Canines size ○ Brain size ○ Hunting Hypothesis ■ Charles Darwin ● Hominins evolved in Africa ● Hunting meat= tool use = large brain ● Tool use = small canine ● Tool use = free hands ● Free hands = bipedalism Physical Anthropology 3/21/16 ○ The times don’t add up ■ Patchy Forest Hypothesis ● Peter Rodman and Henry McHenry ● African Savanna ● Two legs energetically more efficient than four ○ Problem is the earliest hominins come from straight up forests ■ Provisioning Hypothesis (Dinner Date) ● Owen Lovejoy ○ Apes have a long interbirth interval ■ About 7 years ○ Humans have a shorter interbirth interval ■ About 2 years ○ If you get more food have more infant ○ Suite of anatomies and behaviors co­evolve ■ Food provisioning ■ Bipedalism ■ Pair bonding ● Reduced canine size ■ Cooperation ■ Predicts reduced sexual dimorphism but that is not the case ● Who were the first Hominins ○ Fall in the time period 4­7million years ago ○ Genre ■ Not in agreement that these two are actually hominins ■ Sahelanthropus tchadensis ● Chad, Central Africa ● 6­7 million years old ○ Forest near lake ● M. Brunet ● Not in east africa but out in the middle of africa ● Discovered in 2001 ● Anatomies ○ Small Brain(350cc) ■ Low end for a chip ○ Bipedal Foramen magnum is pointing down ○ Nonhoning chewing ■ Smallish canines ■ Massive brow ridge ● Flat face ■ Orrorin tugenensis ● Tugen Hills, Kenya, Africa Physical Anthropology 3/21/16 ● 6million years old ○ Forest ● M.Pickford and B. Senut ● Anatomies ○ Bipedal ■ Based on femur ■ Obturator externus groove, on the femur proves that there's a muscle important for bipedalism ■ Tree climber ● Based on hand bones ■ Partially honing canines ○ Next Genus Ardipithecus and the Middle Awash Valley ■ Almost everyone agrees they were hominins ○ Ardipithecus kadabba ■ Middle Awash Valley, Ethiopia, Africa ■ 5.2­5.8 million years old ● Forest ■ T. White and Y Haile­Selassie ■ Anatomies: ■ Bipedal ● Found a toe bone ● It proved that they can push off with there foot just like humans do ● Perihoning complex ○ The honing canines are decreasing ○ It is transitional ○ Ardipithecus ramidus ■ Middle Awash Valley, Ethiopia, Africa ■ 4.416 million years old ○ Forest ■ International team led by T. White and Y. Haile­Selassie ■ Anatomies: ● Bipedal ○ Based on pelvis, femur, and foot ○ Climbing based on hand and foot ■ She would not be able to walk on her knuckles ○ Nonhoning canines The Earliest Hominins Evolve Physical Anthropology 3/21/16 Pre­Australopithecine Australopithecine Teeth Wear on tip of canine, nonhoning but with modified honing Bones Vestiges of apelike Loss of Traits arboreal traits Brain Small Slight increase ● Australopithecus ○ Australopithecus anamensis ■ Kenya and Ethiopia, Africa ■ 4 million years old ● Woodland ■ M. Leakey and T. White ■ Anatomies ● Bipedal ○ Based on Shin bone ■ Was well adapted to upright walking but spent time tree climbing ● Nonhoning canines ○ Australopithecus afarensis ■ Lucy ■ Dikika, Ethiopia (Infant) ■ Korsi ■ 3­3.6 million years ago ● Woodland and grassland ■ D. Johanson and others ■ Anatomies ● Small brain ● Nonhoning canines ○ Large molars and premolars ■ Eats different diet ■ Grasses, tubers, nuts, etc... ● Bipedal ○ Short and stout pelvis ○ Femur bends in ● No language (hyoid bone) ○ Important for speech production ■ Animals bones w/cut marks ● Meat, but no tools ○ Australopithecus afarensis Physical Anthropology 3/21/16 ■ Footprints ■ Fingers are bent in the middle, not completely like a gorilla, but not straight like ours ○ Australopithecus (Kenyanthropus) platyops ■ Burtele foot (3.4 Ma) ■ Kenya, Africa ■ 3.5million years old ● Woodland ■ M.Leakey ■ Anatomies ● Flat face ● Small molar teeth ○ Can be placed into 3 different groups ■ Robust Australopithecus ■ South African Australopithecus ■ Australopithecus garhi ○ Australopithecus garhi ■ Ethiopia, Africa ■ 2.5 million years old ● Woodland ■ T. White and Y. Haile­Selassie ■ Anatomies ● Large teeth (premolars and molars) ● Long legs ● Stone tools ○ Oldowan stone tools (2.6 million years) ○ Australopithecus first stone­tool make; not homo