CEE 1030 1nd Edition Lecture 24: FossilsOutline of Last Lecture I. Weather and climateII. Ice AgeIII. Paleoclimatologya. Instrumental recordsb. Historical informationc. Proxy dataIV. Causes of climate changea. Natural causesV. Human causesOutline of Current Lecture I. Fossil recorda. Process of fossilizationb. Preservation potentialc. Enemies of preservationII. ReviewIII. Modes of preservationIV. Preservation of ecosystemsCurrent LectureI. Fossil recorda. Remains or traces of once living organismsb. Environmental info on habitats in which organisms lived and/or diedc. Ecological info on coexistence and/or interactions of speciesd. Process of fossilizationi. Deathii. Burial: survive decay and mechanical destruction long enough so some part is buried in sedimentiii. Diagenesis: once buried, remains must survive long enough to be found as paleontology (many potential fossils are destroyed or altered during lithification/metamorphism)e. Preservation potentiali. Hard parts vs. soft parts: soft tissue less likely to be preserved than hard partsThese 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.ii. Number of parts: organism with more parts is more likely to fall apartiii. Population abundance: species that was abundant in life is more likely to be preservediv. Depositional environment: organism that dies in a place where it is immediately covered by sediment is more likely to be fossilized than an organism that dies in an area of net erosionf. Enemies of preservationi. Destructive scavengingii. Transport of organism by wind or wateriii. Slow or delayed deposition of sedimentiv. Bioturbation: organisms burrowing through sedimentv. Dissolution: hard parts such as bones, teeth, and shells can dissolve from certain pH or chemical factorsvi. Diagenesis: physical and chemical changes during lithification of sedimentvii. Exposure: to be studied, a fossil must be found, so the rock must be exposed through erosion, uplift, drillingg. Compression fossilsi. Organism is physically compressed by overlying sedimentsii. Carbonaceous film preserves outline and surface featuresiii. Reduced to 2D, often distortedh. Impression fossilsi. Carbon film in compression fossils is lost, only imprint of organism in sedimentii. Preservation of morphological detail associated with sediment grain size (fine grains have better preservation)i. Molds and castsi. Organism is covered with sediment, leaving an impressionii. Hard part dissolved away leaving an empty space, then mold is filled with sediments or mineralsiii. Produces replica of organism (cast)j. Other types of fossilsi. Resin fossil: mode of fossilization made from hardened sapII. Reviewa. Fossilized bone has pore spaces filled with pyrite but some of the original bone remains. This is permineralization.b. Petrified wood is an example of the fossilization process known as replacement.III. Modes of preservationa. Body fossil: preserved remnants of organismb. Ichnofossil: tracks, burrows, or other indications without having the organism itselfi. Trackway: continuous series of tracks or footprints left by a single organismii. Coprolites: fossilized excrement that can be used to determine the diet and internal organs of extinct organismsiii. Burrows: where an animal burrows, the burrow is flooded and filled with sediment, which provides information on behaviorIV. Preservation of ecosystemsa. Taphonomy: the study of all processes occurring after the death of an organism until its discovery as a fossilb. What proportion of the ecosystem’s species is preserved?c. The preservation of communitiesi. Autochthanous: organisms preserved in their original living positionii. Allochthonous: fossils preserving organisms that were transported prior to depositiond. Live-dead study: a census of organisms living in an