ANT 102 1st Edition Lecture 16Outline of Last Lecture I. Primate brain sizeII. Language and communicationIII. Seyfarth and Cheney: VervetsIV. Social learningOutline of Current LectureI. FossilsII. preservation Current LectureFossils: organic components are gradually replaced by minerals precipitating through sediments to become rock (petrification)Favors hard tissues (bone, shell, teeth, woody stems, etc.)Preservation depends on surrounding sediments and other environmental circumstancesSite formation and discovery:1. Depositional environment2. Stable environment3. Erosional environmentCommon context for preservation:Good: rapid burialfine grained sedimentstill water environmentsThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.cavesBad:weathering (sunlight)consumption and trampling by animalsAcidic soil Volcanoes, etc.Extreme preservation:Very cold: Oetzi (Iceman)Very dry: mummies Very wet (anaerobic): bog bodies Taphonomy: study of the processes that act upon organic remains from the time of death until they recover (also used for crime scene investigation!) 1. Death2. Burial3. Lithification/ fossilization4. Re-exposureThrough all these processes, few bones become fossilsContext is important!Where and in what circumstances are things found?Excavation is destructionDating techniques: Relative: gives age of an object or feature in relation to something else (older/younger)Lithostratigraphy uses the correlation of rock units to estimate the relative age ofrocksLaw of Superposition: older geologic strata will be below newer ones, cross cutting strata will always be newerBiostratigraphy uses the principle of faunal successionPaleomagnetism: earth’s magnetic pole has changed through geologic timeChonometric: gives the age of an object or feature on a specified time scale (date range)Radiocarbon: applicable to bone, wood, charred seeds, etc. (400-40,000 years ago)Potassium-Argo: Half-life: 1.25 billion yrsApplied to volcanic sedimentsConsiderations to keep in mind for dating:Error rangesContaminationAssociation between the material being dated and the artifacts or remains**dating techniques are useless without good context!Highlights of evolutionary Earth is 4.55 billion years oldProkaryotes are the first forms of life (bacteria)Archaea (3.8 billion years ago)Eukaryotes: nucleus shows up (1.3 billion years ago)Protists: single-cell eukaryote that is not a plant, animal or fungus (1.8 billion years ago)Plants (1 billion years ago)Fungi (1 billion years ago)Animalia (570 million years