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Fossil = direct or indirect evidence of ancient life preserved in rocks

Fossil = direct or indirect evidence of ancient life preserved in rocks. gastroliths. http://www.fossilmall.com/Fossil_Archive/Trace_Softbody_Fossils/Climactichnites/dfd100d-large.gif. http://www.gc.maricopa.edu/earthsci/imagearchive/coprolite.jpg. How does a dead organism become a fossil?.

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Fossil = direct or indirect evidence of ancient life preserved in rocks

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  1. Fossil = direct or indirect evidence of ancient life preserved in rocks gastroliths http://www.fossilmall.com/Fossil_Archive/Trace_Softbody_Fossils/Climactichnites/dfd100d-large.gif http://www.gc.maricopa.edu/earthsci/imagearchive/coprolite.jpg

  2. How does a dead organism become a fossil? • Most organisms that lived in the past left no record of their existence. • To become preserved as a fossil, an organism usually: • Has hard parts. • Is buried by sediment. • Escapes physical, chemical, and biological destruction after burial. • BAD = burrowing (bioturbation), dissolution, metamorphism, or erosion • ….A bias towards benthic (bottom dwelling marine life with hard parts)! 

  3. How does a dead organism become a fossil? Modes of Preservation: 1. original preservation (unaltered remains) http://paleo.cortland.edu/tutorial/Taphonomy&Pres/Taph%26Pres%20Images/horseshoe.GIF http://upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Misc_pollen.jpg/290px-Misc_pollen.jpg http://www.ambermine.com/images/page1/18m.jpg

  4. Modes of Preservation: 2. altered remains (structurally or chemically altered) Direct Fossil EvidencePermineralization Direct Fossil EvidenceReplacement http://paleo.cortland.edu/tutorial/Taphonomy&Pres/preservation.htm http://www.gc.maricopa.edu/earthsci/imagearchive/cephalopod.jpg

  5. Modes of Preservation: 2. altered remains (structurally or chemically altered) Direct Fossil EvidenceCarbonization http://paleo.cortland.edu/tutorial/Taphonomy&Pres/preservation.htm

  6. Modes of Preservation: 2. altered remains (structurally or chemically altered) Direct Fossil Evidencecast and molds Direct Fossil Evidencemolds (internal mold shown here – outer shell gone but internal septa visible) Direct Fossil Evidencemolds (external mold shown here) http://www.getyourwebsitehere.com/fossils/images/fos_0011a.jpg http://www.clas.ufl.edu/users/pciesiel/gly3603c/external.jpg

  7. What do we use the fossil record for? 1. Understand the evolutionary history of life http://www.ruf.rice.edu/~leeman/GeoTimeSpiral.gif

  8. What do we use the fossil record for? • 2. Determining relative ages of the rocks that contain them (biostratigraphy) • and correlating rock units of the same age. • Index fossils - especially good fossils for this purpose • wide geographic range (swam or floated) • evolved rapidly • easily identified

  9. http://pubs.usgs.gov/gip/geotime/fossils.gif

  10. What do we use the fossil record for? 3. Interpreting past environments http://www.geology.ohio-state.edu/~vonfrese/gs100/lect29/xfig29_02.jpg http://oceanworld.tamu.edu/students/coral/images/coral_reef_1.jpg http://www.wsgs.uwyo.edu/Coal/coal_brochure/images/fig1_swamp.jpg

  11. How are fossils classified? Based on morphology (shape) and inferred phylogenic (family tree) relationships http://www.anselm.edu/homepage/jpitocch/genbios/25-07-HierarchicalClass-L.jpg

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