10 30 2015 ANTH 1001 UNIT 3 Part 1 Taphonomy Fossil Formation Taphonomy Fossil o The study of what happens to organisms after they die o Preserved remains or traces of remains include footprints or imprints conditions have to be just right for fossil formation Remains can be leatherized frozen desiccated dried out mummified preserved in some substance or petrification Petrification o A process whereby organic materials in the bone are replaced by inorganic materials from the surrounding matrix o Literally turned to stone Primate Evolution Questions on test o Matching o When do we see first primates o when do we see 1st anthropoids dates are not something to memorize but it is important to learn these EPOCH s in order Paleocene 65 55mya o Plesiadapiforms China They ve been found in North America Europe and Found over 70 species NOT primates Small bodied Small brained Long narrow snout No post orbital bar Eyes are more laterally facing Large spiky teeth Claws instead of nails Dexterous and arboreal Quadrupeds Possible ancestor to primates based off of arboreal and dexterous Origins of primate lineage are murky Eocene 55 37mya o We have the 1st true primates o Over 200 different species of definite primates o Euprimates general term for first primates Adapids Omomyids Small bodied More encephalized Completely enclosed forward facing eye orbits Opposable toes Opposable hands Oligocene 37 22 5 o Anthropoids Adapids are said to be streps Like lemur like in terms of morphology Omoyids are said to be tarsier like haplor Like referring to as monkey like we start to see fossils similar to monkeys Genuses Apidium Aegyptopithecus Api Small bodied arboreal Apidium has NWM dental formula found in Egypt aegypt larger bodied longer snout OWM dental formula also found in Egypt Miocene 22 5 5mya o Explosion of diversification in the primate lineage o Golden Age of Hominoids Brachiation other ape characteristics ape like o African form Afropithecus Small bodied Beginning of crest in skull Reduced anterior projection reduced snout Large teeth o European form Dryopithecus Dental characteristics similar to apes OWM Really great brachiators narrow tooth rows Throughout France and Spain larger bodied o Asian forms Sivapithecus So similar to modern orangutans not a direct ancestor but probably a relative Gigantopithecus Primarily known for h u g e teeth Estimates based on tooth jaw size for this is that it could ve been 10ft tall and weigh 1200lbs Found in southeast Asia Pliocene 5 1 8mya o Hominids and Hominins Pleistocene 1 8mya 10kya o Modern Humans Emerge Holocene 10kya present o Modern Times Paleoanthropology Goals o Identify o Relationship o Behavior Hominids vs Hominins o Hominid generic name for Hominide Related to humans but now sure how closely related Between ape and human More ape like o Hominin subfamily hominine or group hominine More human like the Big 3 o culture tool use ritual behavior art community language o brain size endocast brain enlargement brain expansion o bipedality Bipedality skeletal system was not made for anything bipedalism o Big 3 did NOT occur simultaneously o Bipedal locomotion is extraordinary in that with each step the body teeters on the brink of catastrophe o Skull Foramen magnum The hole in the bottom of the skull o Skeletal Adaptations for Bipeality Spinal curvature S shaped spine Pelvis shape ilium ilia Bipeds more front to back bowl shaped square like Quadrupeds rectangular like back to front Femur Bicondylar angle Angle created from a vertical axis Places support closer to your center of The bigger the angle the longer the neck gravity Neck length Bipeds Larger angle Quadrupeds Smaller angle almost straight up and down Feet Limb ratios Bipeds Smaller arms longer legs No opposable big toe more stable platform Quadrupeds Opposable big toe o Hypotheses for Bipedality Freeing the hands man the hunter woman the gatherer provisioning tied into the pair bonded social unit better view of open country energy efficiency fewer calories burn less energy East Africa o Geology Made it a geologically active area in terms of volcanic eruptions earthquakes etc making fossil formation good Lots of erosion Fossils come to light when erosion happens Preservation is generally pretty good o Dating Use radiometric dating Radio potassium South Africa o Geology o Breccia Lots of limestone multiple subterranean caves Very hard substance Debris fossils bones and other minerals matrix that is encasing fossils o Dating Methods best used Primary dating method is biostratigaphy Not quite as precise as East Africa Rely on relative dating methods Terms Post orbital constriction POC o May show up as part of a questions OR the term itself could be a question o Post behind o Orbits eye orbits o Constriction an area that has become narrowed o A narrowing behind the eye orbits Supra orbital torus SOT o Supra above o Orbital eye obribts o Thickened area of bone above the eye orbit o Humans do NOT have one Prognathism orthognathism o Prognathism Anterior projection of the maxilla o Orthognathism Humans have orthognathism Flatness more vertical orientation of the maxilla Sagittal crest o Sharp ridge of bone on the top of the skull going front to back o Aka bony Mohawk o Some species have a very pronounced one some will have a wimpy one some humans don t have one at all o Muscle attachment spot jaw muscles o Sharp ridge of bone in the back of the skull towards the base Nuchal crest going left to right o Neck muscles attach here Gracile robust o General terms to categorize terms features o Gracile referring to the smaller end on the range of variation Very small sagittal crest small undeveloped nuchal crest o Robust large and well developed Pronounced big POC Later Fossil Record Lumpers and Splitters o Lumper paleoanthropologist who wants to combine the fossils into fewer species Tend to think in terms of similarities o Splittesr paleoanthropologist who separates into more o meaning it is spoiling our current understanding of the fossil species Spoiler record Miocene Fossils Sahelanthropus tchadensis o Sahel region in Africa o Anthropus mainlike o Tchadensis found in country of chad in central Africa o Central Africa Important because most fossils were in East or South Africa o 6 7mya earliest fossil in contention for being in our lineage dated by biostratigraphy o primitive cranium not well represented in fossil record about size of chimpanzee not very big small brained POC BIG SOT Partial big