Geologic Time and Earth’s 
           Biological History
             Designed to meet South Carolina 
               Department of Education 
             2005 Science Academic Standards
                Table of Contents
  What is the Geologic Time Scale? (slide 4) Standard 8-2.4  
    `Epochs, Eons, Eras, and Periods (slide 4)
     How was the time scale and it‟s divisions created? (slide 5)
     A complete Geologic Time Scale with references to S.C. (slides 6-7)
  Principles of the Geologic Time Scale (slide 8)
     Principles of Superposition, Horizontality and Original lateral continuity
     Principle of biologic succession (slide 9)
     Charles Lyell, the Principle of cross-cutting relations & Inclusion principle (slide 10)
     Charles Darwin
  Relative Age Dating using unconformities (slide 10) Standard 8-2.6
  Relative Age dating using cross-cutting relations and index fossils (slide 11)
  Absolute Age dating (slide 13)
     Isotopes and radiometric dating
     Carbon dating (slide 14)
  How old is old? (slide 16)
  Breakdown of geologic time periods 
  Are we now living in the Anthropocene Era? (slide 17)
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        Table of Contents, cont. (2 of 2)
           The Earth through time (slide 19) Standard 8-2.5
                Ordovician and Silurian
                Devonian, Mississippian, Pennsylvanian (slide 21)
                Permian and Triassic (slide 22)
                Jurassic and Cretaceous (slide 23)
                Triassic and Quaternary (slide 24)
          Adaptation (slide 25) Standard 8-2.1
           Punctuated events through time (slide 26) Standard 8-2.3
                Comet impact
                Climate shift
                Volcanism
          Extinction (slide 29) Standard 8-2.7
           The study of fossils and fossil types (slide 30) Standard 8-2.2
           South Carolina Standards (slide 32)
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                       What is the Geologic Time Scale?
  Standard 8-2.4: Recognize the relationship among the units—era, epoch, and period—into which the geologic time scale is 
  divided.
  What does the time scale represent?
   The geologic time scale divides up the history of the earth based on life-forms that
  have existed during specific times since the creation of the planet. These divisions are
  called geochronologic units (geo: rock, chronology: time).
   Most of these life-forms are found as fossils, which are the remains or traces of an
  organism from the geologic past that has been preserved in sediment or rock. Without
  fossils, scientists may not have concluded that the earth has a history that long precedes
  mankind.
   The Geologic Time Scale is divided by the following divisions:
  Eons:  Longest subdivision;  based on the abundance of certain fossils
        Eras:  Next to longest subdivision; marked by major changes in the fossil record
               Periods:  Based on types of life existing at the time
                       Epochs: Shortest subdivision;  marked by differences in life forms and can 
                      vary from continent to continent.
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