EOSC 326 : EOSC 326 Module C.docx
8 Dec 2012
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Lesson 10: fossil preservation and modes of life 12/8/2012 9:40:00 am. Describe why organisms have different potential for preservation. Compare and contrast body and tract fossils. Compare and contrast the different methods of fossil preservation. Define and identify an external mold, a cast and an internal mold. List and define the different modes of life that have been exploited by marine organisms over time. 2 main types of fossils: trace fossils impression made on substrate which record past activities of organisms. Trails, tracks, burrows, excrement: body fossils preserve a record of actual organism or some part of it. Hard parts of organism are preserved bones, shell. More rarely, soft parts are preserved skin, muscles, tendons, and organs. Chemical reaction that water transforms the organic material of plant/animal into thin film of carbon. Nitrogen, hydrogen and oxygen are driven off as gases, leaving a carbon outline of original organism.
