Fossilization ppt

Fossilization ppt

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  Fossilization Submitted to: Dr.Shafaq Fatima Submitted by: Sarwat Ishaq Class: BS IV (Maj/ Zoology: Roll #: 339 LCWU
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  Definition  preserved remainsor traces of animals, plants, and other organisms from the remote past. A Pectinatites amm onite, mould of a bivalve shell http://www.discoveringfossils.co.uk/kimmeridge_ fossisl.htm
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  Fossil record  Thetotality of fossils  their placement in fossiliferous, Rock formations  sedimentary layers (strata)  fossil record  important functions of the science of paleontology  vary in size  A fossil normally preserves only a portion of the deceased organism  bones and teeth of vertebrates,  the chitinous or calcareous exoskeletons of invertebrates.
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  Trace fossils (orichnofossils)  The type of fossil which consist of the marks left behind by the organism while it was alive Chirotherium footprints in a Triassicsandstone. http://en.wikipedia.org/wiki/Trace_fossil
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  Chemo fossils orbiomarkers Past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals; these are known as chemo fossils or biomarkers
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  Fossilization There are twomajor types of fossils 1. Body fossils 2. Trace fossils
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  Taphonomy • The processof fossilization is called taphonomy 1. First, there is the death of the organism 2. There are certain processes that can happen to the organism before it is buried. • processes can include body decay 3. different categories of fossils
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  What are somefactors that can affect fossilization 1. Body construction 2. Environment 3. Predators
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  How is fossilizationdependent upon the environment  The environment plays a crucial role  The best scenario  Area with high rate of sediment deposition  The environment can also affect where the fossil is found  Drier environments, lead to erosion
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  How do fossilsform 1. Original soft part of organism 2. Original hard part of organism 3. Altered hard part of organism 4. Traces of organism
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  Original soft partof organism  organisms are fossilized but under exceptionally favorable conditions  Even soft part of organisms  Org. preserved in a medium that protect them from bacterial decay
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  Examples i. Ice ii. Amber iii.Volcanic ash iv. Oil Saturated soil
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  i. Ice  Thebest known example of fossil preserved in ice  wooly Mammoth of Siberia and Alaska.  huge elephant like animals died due to glaciation about 23,000 years ago  The first such find was reported in 1779  The ice preservation is so perfect
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  Frozen Mammoth in ICE http://www.trat.com/Pages /FossilPreservation.html
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  ii. Amber  Amberis a natural tree resin  that had hardened through various chemical changes  Sometimes this sap surrounds an insect, preserve it with perfect details & look like stone  The formation of Amber  Amber may trap foreign objects, which are called inclusions
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  a. An antinside the amber b. wood resin, source of amber http://en.wikipedia.org/wiki/Amber
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  AMBER WITH SMALL SNAKEINCLUSION https://www.pinterest.com/pin/164592561354978254/
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  iii. Volcanic Ash In AD 79 an eruption of Mount Vesuvius  Volcanic ash and pumice rained down on the town for about 18 hours  many roofs collapsed under the weight  followed by explosive superheated pyroclastic clouds of toxic gas and debris  and remained hidden for over 1600 years.
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   In 1748,Pompeii was rediscovered  not only its houses, but (eventually) some of its citizens  only fragmentary skeletal remains  Suffocated by volcanic gasses and covered in ash and debris  their bodies eventually decayed inside the hardening matter.  This air space essentially formed a mold  ash that had surrounded the person retained an imprint of the body
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   air pocketsfilled with plaster  The resulting "plaster mummies”  capture the human tragedy of Pompeii http://jasonstravels.com/2012/09/17/t raveling-to-pompeii-with-the- denver-museum-of-nature-and- science/
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  Dog from Pompeii http://jasonstravels.com/2012/09/17/traveling- to-pompeii-with-the-denver-museum-of- nature-and-science/
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  Pompeii city http://www.mummytombs.com/pompeii/background.htm
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  Original hard Partof organisms  Most of the animals have some hard parts i. Calcite (CaCO3 )is the most abundant original skeletal material found in fossils ii. Aragonite (CaCO3) is preserved in the shells of some corals and molluscs iii. Tricalcium Phosphate (Ca3(PO4)2) is a chemically resistant mineral found unaltered in vertebrate bones, some arthropods and brachiopods iv. Opal (SiO2H2O) is amorphous hydrated silica preserved in latter geologic time in some Protozoans and sponges v. Chitin is an organic compound that is resistant to bacterial action and is not readily altered
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  Tricalcium Phosphate (Ca3(PO4)2) http://www.thefossilforum.com/index.php?/ga llery/image/17509-crocodilian-osteoderms/
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  CALCITE (CACO3 ) http://www.tripadvisor.com/LocationPhotoDirectLink-g191249d585694- i22926045-Dinosaur_Isle-Sandown_Isle_of_Wight_England.html
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  3- Altered HardPart o The original hard structure of many organisms o The preservation of altered hard part of organisms can be classified as: i. Carbonization or Distillations ii. Permineralization or petrification iii. Replacement
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  Carbonization or Distillations oThe type of fossil in which only the carbon remains in the specimen o volatile elements in organic matter distill away, o thin carbon film as the only fossil record o especially carbon copies of leaves, the flesh of fish o organisms become trapped and squeezed, then form compression
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  o fossils ofleaves and insects are often formed by compression o The organic matter may be altered during decay and rock formation o distillation of volatile compounds and the polymerization o The thin, dark, film is made of stable, polymerized carbon molecules o impression
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  Cone & Needle Compression Leaf& Seed Compression Fish Compression http://petrifiedwoodmuseum.org/carbonization. htm
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  Permineralization or petrification •Permineralization is a process of fossilization in which mineral deposits from internal casts of organisms • Permineralization is a process of fossilization that occurs when an organism is buried • empty spaces filled with mineral-rich groundwater • Minerals precipitate from the groundwater • occupying the empty spaces • This process can occur in very small spaces • For permineralization organism must become covered by sediment • The permineralization process is very slow • water seeps through the sediment that covers an organism; • petrification may result in incredibly detailed preservation
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  •petrified fossils containprimarily silica •undergone silicification •When sulfur is involved, the process is called pyritization •Pyritization happens most commonly to marine organisms
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  Permineralization or petrification http://www.wisegeek.org/what-is- permineralization.htm
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  Replacement  Replacement takesplace when water dissolves the original hard parts and replaces them with mineral matter  Bone, shells and wood are often well preserved in this manner  The most common replacement minerals are i. calcite ii. silica iii. pyrite iv. hematite v. Aragonite
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   This occurswhen skeletal material is replaced, molecule by molecule, by some new alien material  process occurs gradually (1) Silicification - where calcium carbonate is replaced by silica, and (2) Pyritization - where pyrite replaces calcium carbonate  Minerals can replace bone, shell, wood, and even soft body parts  due to the action of water and decay  The replacement of soft Replacement occur when minerals precipitate out of solution due
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  Silicified (replaced with silica) http://en.wikipedia.org/wiki/Fossil#Wood
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  Trace of Organisms •Mold •Cast •Tracks& Trails •Burrows •Gastroliths
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  Mold & Cast Skeletonsare frequently found completely dissolved  Formation of CAST  cast is a positive image I. natural mold II. external mold III. internal mold
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  Animals with shellsor hard exoskeletons buried in sediments are often acted upon by acid-rich ground water which may dissolve away shells or other organic structures.
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  Cast & Mold http://www.mpm.edu/content/colle ctions/learn/reef/diagenesis.html
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  How mold &cast form? http://www.guokr.com/post/477970/
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  Gastroliths Modern birds useswallow stones  muscular stomach  gastrolithes
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  Tracks & trails particular form of trace fossil  range from the worm trails to dinosaur  even the footprints of Stone Age people  great variety of invertebrate’s tracks Reptile’s tracks http://www.t-rat.com/Pages/ FossilPreservation.html
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  Burrows o evidence ofbottom-living creatures o labyrinth of hollow tunnels o filled by silt & preserved o labyrinth of hollow tunnels o rarely show much detail http://www.t-rat.com/Pages /FossilPreservation.html
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  Conclusion  fossil recorddoes not represent all of the living things  The reason  Some organisms may have decayed  Organisms that live on land or have soft body parts  fossils provide a piece of Earth's history
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  References Cleal C.J. &Thomas, B.A. (2009). Introduction to Plant Fossils. United Kingdom: Cambridge University Press. Grimaldi, D. & Engel, M.S., (2005). Evolution of the Insects. New York: Cambridge University Press. Meyer, H.W., (2003). The Fossils of Florissant. Washington: Smithsonian Books. Thompson, I. (1982). National Audubon Society Field Guide to Fossils. New York: Alfred A. Knopf. Schopf, J.M. (1975). Modes of Fossil Preservation. Review of Palaeobotany and Palynology, vol 20: pp. 27-53.