Fossils

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Fossils

• EQ How can I determine the relative age of
  fossils in sedimentary rocks?   
• SPI 0807.5.5

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What are fossils?

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

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What is sedimentary rock?

• Sedimentary rock is formed by sediment that is
  deposited over time, which eventually harden into
  solid layers of rock.

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• Sometimes when organisms die, they are quickly
  covered by sediment.
• When the sediment hardens and becomes rock, the
  hard parts of the animal are preserved, creating
  fossils.

How are fossils formed?
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What can be fossilized?
Insects
Animals
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Plants
Dinosaurs
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• Scientists can determine the age of the fossil by
  looking at.
• Absolute Dating
• Atoms

2. Relative Dating Layers of rock
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Relative Dating

• The bottom layers of rock are usually the oldest,
  and the top layers are usually the youngest.
• Scientists can use the order of rock layers to
  determine the relative age of objects within the
  layers.

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• Fossils in the bottom layers are usually older
  than fossils in the top layers.

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Which layer is the oldest? Youngest?
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Which layer is the oldest? Youngest?
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Which layer formed first? Last?
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MOST fossils are found in sedimentary rock, but
there are some exceptions

• Some insects have been found perfectly preserved
  in amber.

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Some animals have been found perfectly preserved
in ice
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La Brea Tar Pit

• What is the La Brea Tar Pit?

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Draw this picture in your notebook
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On your picture

1. A fish fossil was found in the oldest rock layer.
   Draw the fish fossil in the oldest layer.
2. An animal skull was found in the youngest layer.
   Draw an animal skull in the youngest layer.

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To leave class
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Which fossil layer is the oldest?

1. 1
2. 2
3. 3
4. 4

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• A scientist would use the relative dating method
  to
• reconstruct past climates.
• determine the causes of extinction.
• measure the age of fossils in years.
• determine whether one rock layer is older than
  another rock layer.

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Which organisms are likely to be the same
relative age?

1. A and E
2. B and D
3. C and D
4. A and F

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Which fossil is the oldest?

1. 1
2. 2
3. 3
4. 4

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• Fossils are preserved most often in which of the
  following substances?
• Ice
• Sedimentary rock
• Asphalt
• Amber

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Which of the following rock layers in the diagram
have the same relative age?

1. 1 and 6
2. 3 and 7
3. 2 and 9
4. 5 and 10