P a g e | 1Table of ContentsNature of a fossil 2Paleocene 3Eocene & Oligocene 4Miocene 5Hominins 5Table on early hominins 6Earliest Homo 10Homo erectus 11Homo heidelbergensis 12Neandertals 13Origin of Homo sapiens 14Study guide questions 14Study guide answers 16P a g e | 2Nature of a fossil- Fossil—evidence of preexisting specieso Can be tooth, feather, bone, imprinto If conditions are favorable, minerals replace substances in the bone, fill in porous spaces, and convert it into rock.o Bone consists of organic and inorganic material; organic starts to decay after death.- Forces of destructiono Physical, chemical, biological forceso For fossilization to occur there must be protection from these forceso Sources of bias in the fossil record that produce non-random representation: Size of species—larger species more likely to fossilize Where fossilization occurs—best in a cave or near water Whether the fossil is exposed and discoveredo Paleontologists don’t just dig randomly—they search where underlying sediment is already exposed by natural forces- Geological time scaleo Important to understand ancestral recordo Pre-cambrian—Paleozoic—Mesozoic—Cenozoic (present) Epochs of Cenozoic (know names and dates)- Paleocene—65-56 mya- Eocene—56-33 mya- Oligocene-33-23 mya- Miocene—23-5 mya- Pliocene—5-1.8 mya- Pliestocene—1.8 mya-10,000 ya- Holocene—10,000 ya-present- Plate tectonicso Influences migratory routes, climate, and ecology- Cenozoic erao North America and Europe were connected by Greenland during Paleocene and Eocene—this explains similar species from these periods in both Europe and the Americaso Africa was an island continent before 19 mya. Then, Africa contacted SW Asia—this explains migration of apes throughout the old world.- Problem: how did lemurs colonize Madagascar?o It was an island before the emergence of primateso Theory: they crossed the Mozambique channel on floating masses of vegetation- Problem: how did monkeys colonize South America?o It was an island continent before the emergence of primates and the isthmus of panama connected north and south America less than 5 myao Theory: ancestor of new world monkeys crossed either the Caribbean sea (they island hopped) or the Atlantic on floating masses of vegetation- Categories of dating techniqueso Relative dating Organizing items in terms of rank sequence StratigraphyP a g e | 3- Sequencing of sedimentary rock—dating fossils based on their position in the layers of sediment- Principle of superposition says that older fossils will be deeper in the ground.- Problem: sedimentation is not constant Biostratigraphy- Dating of fossils based on association with fossils of another species- If we know that one fossil is 60 million years old, then a fossil on top of it must be <60 million years old. - Index fossils (index species)—fossil species of known age which isused to estimate the age of another species Fluorine analysis- Finding the relative age of a fossil based on fluorine concentration (from fluorinated water) - If two organisms died at the same time in the same environment then they should have the same amount of fluorine.  Charles Dawson and Piltdown specimen- Fluorine test was applied to Piltdown- Less fluorine than contemporaneous (younger) fossils- Mandible had different fluorine content than cranium - Declared a hoaxo Chronometric dating Based on principle of radioactive decay—radioactive isotope releases energy as a half-life.  Potassium-argon dating- Radioactive potassium decays into stable argon- Half-life is 1.25 billion years- Uses volcanic rock—date rock underneath and on top of a fossil to determine fossil’s age Argon-argon dating- Same procedure, less material Carbon-14 dating- We (and animals) eat plants which have C14 and C12- Half-life of C14 is 5,730 years- Determine ratio of C14/C12 - Only for relatively recent specimens- Paleoceneo Fossil primates found primarily in North America and Europe o Not all anthropologists believe that these are primateso Differences between plesiadapiforms (primitive primates) and modern primates Longer snout Eyes not at front of skull No post-orbital bar Smaller brain Specialized dentition Claws, not nails Non-prehensile hands and feeto Anatomies that suggest that Paleocene species may be primatesP a g e | 4 Anatomy of molars—grinding, more suggestive of primate than insectivore Middle ear- Eoceneo Primates look more moderno Anatomies Eyes face forward Post-orbital bar Short snout Prehensile hands and feet Nails Larger cranial capacityo Where fossils of Eocene primates are found Principally in north America and Europe (remember connection of North America and Europe by Greenland—may explain similarity of these) Later in Asia and North Africa—end of Eocene o Environmental context of Eocene primates Tropical and subtropical forestso Taxonomy and phylogeny  Two lineages: adapids and omomyids  Adapids may be ancestral to lemurs and lorises Omomyids may be ancestral to tarsiers and antrhopoidso Inferences about Eocene primates Some were diurnal, others were nocturnalo Locomotion Quadrupedality and leapingo Diet Insectivory, frugivory-folivoryo Absence of tooth comb - Oligocene o Where fossils are found in Oligocene Fayum, Egypt—33-35 mya Environment: tropical foresto 2 lineages Propliopithecines and parapithecineso Propliopithecines Dental formula: 2,1,2,3/2,1,2,3 Same dental formula as modern catarrhines Has 5 molar cusps, but not Y-5 pattern May be ancestor; divergence has not yet occurred o Parapithecines Dental formula: 2,1,3,3/2,1,3,3 Same dental formula as modern platyrrhines  May be ancestor- Inferences about Oligocene antrhopoidso Locomotion Aegyptopithecus—slow quadrupedal climber Apidium—quadrupedal runner and leaper—more slenderP a g e | 5o Body size and diet  2-4 pounds for Apidium 13-18 pounds for Aegyptopithecus Diet: frugivory—rounded cusps for crushingo Oligocene antrhopoids were diurnalo Social organization Aegyptopithecus shows sexual dimorphism in canines which implies polygyny- Mioceneo First hominoids/homininso Geographical distribution In early Miocene, Africa was an island separated from Europe and Asia bythe Tethys sea. About 19 mya, the Arabian plate formed a migratory corridor from Africa to Europe and Asia.o African taxa 23-14