1.List the fossils in order from the

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2/26/13

• 1.List the fossils in order from the
• oldest to the youngest.
• Explain why you know that is the
• correct order.

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Today I will investigate fossils in sedimentary
rock layers to gather evidence of changing life
forms.
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What is a fossil?

• The trace or remains of an organism that lived
  long ago most commonly preserved in sedimentary
  rock.

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How are fossils preserved?

• Petrification is a process in which minerals
  replace an organisms tissues. One form of
  petrification is called permineralizations.
  Permineralization is a process in which the pore
  space in an organisms hard tissue is filled with
  minerals. Replacement is a process in which
  minerals completely replace the tissues of an
  organism.

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Petrified Wood
This piece of petrified wood was fossilized
through replacement.
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Types of Fossils

• Trace fossils-
• imprints filled with sediments and preserved
  with rocks.

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Mold and Cast fossils
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Index fossils
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Geologic Time Scale
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Fossil Exit Quiz
1. Fossils found in the bottom layers of
sediment are probably older than fossils found
in top layers because a. the bottom layers are
older than the top layers. b. the bottom layers
are younger than the top layers. c. all of the
layers are the same age. d. the bottom layers
have folded over the top layers
2. Any naturally preserved evidence of animal
activity is called a(n) a. trace fossil. c.
index fossil. b. cast. d. mold.
3. A mark or cavity made in a sedimentary
surface by a shell or other body is a(n) a.
index fossil. c. mold. b. cast. d.
coprolite.
4. An ideal sequence of rock layers containing
all of the known fossil and rock formations on
Earth is called the a. geographic column. c.
geologic column. b. relative column. d.
geologic sequence.