Unit 3Fossil Record, Neanderthals, Modern Humans, New World Expansion, Paleo-Indian Cultures, Domestication, and Development of Complex CivilizationsPrimate Evolution●Pliocene (5-1.8 mya) ○Hominids and Hominins ●Pleistocene (1.8mya-10kya) ○Modern humans emerge ●Holocene (10kya-present) ○Modern times NOT ON TESTPaleoanthropology●Goals – identify, determine relationships, gain insight on behavior ●Hominids vs Hominins ○Hominid – family Hominidae ○Hominins – subfamily Homininae !More closely related to humans than Hominids ●“The Big 3” – the three major differences between humans and nonhuman primates ○Culture and material culture ○Brain size ○Obligate bipedality – primary means of getting around ○Big 3 did NOT occur simultaneously !Became more complicated with timeSkeletal Adaptations for Bipedality“Bipedal locomotion is extraordinary in that, with each step, the body teeters on the brink of catastrophe” ●Skull ○Foramen magnum – hole in bottom of skull in which spinal cord comes through (centrally located) ●Spinal Curvature ○Absorbs shock ○Stabilizes ○Positions muscles ○Keeps body and torso balanced ●Pelvis Shape (ilium/ilia) ○Ilium – flattened, winged area ○More anterior and posterior position (bowl shaped)Skeletal Adaptations for Bipedality cont’d●Femur ○Bicondylar Angle !The medial angle of the femur when its in proper anatomical position ○Neck length !Helps create angle !longer neck length in bipeds ●Feet ○Opposable big toe ○An arch inside the bottom of foot – more muscles for stability ●Limb ratios ○Modern humans – legs longer than arms ○Apes – longer arms than legsHypotheses for Bipedality●Freeing the hands ○Can carry food or offspring ○Stand upright and pick things ○“Man the Hunter” ○“Woman the Gatherer” ○“Provisioning” ●Better view of open country ○Able to see predators approaching ●Energy Efficiency ○Bipedalism is more energy efficient when walking long distancesPaleoanthropology•East Africa •Geology: African Great Rift Valley where the tectonic plates run through. Volcanoes and earthquakes impact its stratigraphy. A lot of the fossils have been found at sites of erosion. •Dating: Because of the volcanic activity, they’ve been able to obtain radiometric dates. We tend to have smaller and more precise date ranges. •South Africa •Geology: There’s a lot of subterranean limestone formation. A lot of fossils are found through limestone quarrying. It’s difficult to place the fossils into context. Because of how limestone is beneath the ground, there’s a lot o subterranean caverns. If there’s a small opening in the ground, it can let rain water through, creating a larger cavern below than over the ground for debris and animals. Breccia is unique to South African sites. It’s a matrix of sand, pebbles, dirt, and debris. Mixed with limestone dust, it creates a hard substance without damaging them. It helps with preservation even from dynamites, but it’s hard to remove the fossils encased within them. •Dating: There’s been limited use of radiometric methods. They have to rely on relative dating methods like biostratigraphy.Terms•Postorbital constriction (POC): a narrowing of an area behind the eye orbits •Supraorbital torus (SOT or brow ridge): an enlarged area of bone above the eye orbits •Prognathism: an anterior projection of the maxilla •Orthognathism: a flattened or vertical maxilla •Sagittal crest: a ridge of bone along the sagittal suture that runs front to back on the center on top of the skull •Nuchal crest: a roughened ridge of bone in the back of the skull usually toward the base, where the neck muscles attach •Gracile: a specimen that’s relatively small and smooth •Robust: a specimen that’s large and has roughened muscle-attachment sites •Lumper: someone who emphasizes similarities and lumps fossils into fewer species •Splitter: someone who emphasizes variation and separates fossils into more species •Spoiler: a fossil or site that challenges the current understanding of the fossil recordMiocene Fossils•Sahelanthropus tchadensis •Found in Central not East nor South Africa •6–7 mya → a last common ancestor between apes and humans •Primitive cranium representation (i.e., ape-like; e.g., a small brain and crest, POC, a large and robust SOT) •Possibly bipedal → a last common ancestor between apes and humansMiocene/Pliocene Fossils•Ardipithecus radius (“Ardi”) •Skeletal representation •Mix of ancestral and derived traits •Cranium: small-brained, relatively prognathic, gracile sagittal crest and superior skull, moderate SOT •Post-cranium: not flat and rectangular like chimps but not round like ours •Not quad- nor bipedal: long forearms, no ridge for knuckle walking •Interpretation: a type of bipedalism based on the rounded pelvis and how the femur would’ve attached to it but also retained opposable toe and elongated arms. Last common ancestor or offshoot.Pliocene Fossils•Kenyanthropus platyops •Nearly complete cranium representation •First spoiler species: date + derived traits = better candidate for human ancestor than Australopithecus •Date overlaps with Australopithecus •More derived morphology than Australopithecus•Australopithecus •A. afarensis •Geography: three counties and ten sites throughout East Africa •Cranial traits: small brain, skull shape (posterior sloping and flattened forehead), POC, small to moderate SOT, robust nuchal crest, some lack sagittal crest but is small, prognathic, parallel molars •Post-cranial traits: short (3–4 ft.) in height, no opposable big toe, obligate bipedalism, round pelvis (loose manifestation of bipedalism), nearly complete femur (bicondular angle and long neck), wrist ridge found in modern knuckle walkers, long arms relative to their legs (limb proportion of knuckle walkers) •Lucy (AL-288-1): 40% skeletal representation; 3.2 mya obligate bipedalism •Selam (DIK 1/1): 60% skeletal representation; 3.3 mya oldest juvenile •Laetoli: an East African site 3.6 mya with multiple sets of footprints in softened and cooled volcanic ash → obligate bipedal evidence; no opposable toes and longitudinal arch•A. africanus •Endocast: the solid impression of the inside of a skull, preserving structural details of the brain in size and shape •Taung: a bipedal