FOSSILS

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FOSSILS

• Should I stay or
• should I go??

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Rapid burial
Petrification
Death
Uplift
Erosion exposure
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DECAY

• Because of decay, animals with hard parts are
  more likely to become fossils in rock

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Mineral Replacement

• Mineral replacement usually happens underwater.
• Also called petrification

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Sticky Stuff

• Hardened sap (amber) (sticky stuff) can preserve
  insects and other small animals

? See the frog?
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Put it in the Dryer???

• Drying out quickly (mummification) reduces decay.
  Bacteria need moisture or they die too.

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Keeping meat in the freezer

• Freezing preserves some of the best specimens.
  Just like at home

Frozen Mammoth
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This is the pits..

• Tar pits were good for preserving many mammals.
  (i.e. Saber Tooth tigers)

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Check out the evidence

• Tracks, burrows and droppings are good trace
  fossils. That means they left evidence that they
  existed.

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Which are which???

• Are each of these actual body fossils or trace
  fossils?

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Answers

• A. body fossil,
• B. trace fossil,
• C. body fossil,
• D. body fossil (both the fossil animal in the egg
  and the egg itself),
• E. trace fossil,
• F. trace fossil,
• G. body fossil.

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A Series of Unfortunate(?) Events

• Changes in environment are obvious when marine
  fossils are found on mountains or in land locked
  areas.

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Check it out
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Putting things in order
Superposition
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Whos on FirstWhats on Second?

• Superposition indicates that certain life forms
  came before others (fish amphibians reptiles
  etc.)

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Look in the INDEX!!!

• Index fossils help find the age of rocks w/o
  radiometric dating (kind of expensive)

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What makes a good INDEX fossil?

• Easily identifiable ?
• Wide spread over Earth
• Short amount of time between first appearance and
  last appearance in the geologic column
• Easily preserved