Fossils
Objectives <ul><li>Classify  the processes that lead to fossil formation </li></ul><ul><li>Understand  key concepts in the...
Fossilization <ul><li>Frequency? </li></ul><ul><ul><ul><li>Rare Event </li></ul></ul></ul><ul><li>How? </li></ul><ul><ul><...
Key concepts of Fossils <ul><li>Fossils represent the remains of once-living organisms </li></ul><ul><li>Most fossils are ...
Four types of fossils
Petrified Fossils <ul><li>The tissues of organism are slowly replaced by minerals </li></ul><ul><li>Organism turns into st...
Mold <ul><li>Organism is completely dissolved, but leaves a space in rock </li></ul>
Cast <ul><li>Mold can fill later with minerals and harden into shape of organism </li></ul>
Preserved Remains <ul><li>Organism trapped in preservative </li></ul><ul><ul><li>Amber </li></ul></ul><ul><ul><li>Ice </li...
Relative Dating <ul><li>Layers of sediment are laid down in order </li></ul><ul><ul><li>Oldest layers are on the bottom </...
Radioactive Dating <ul><li>When organism dies it stops consuming radioactive material </li></ul><ul><li>All radioactive ch...
Mass Extinction <ul><li>Times in fossil evidence when many things stop appearing in one layer </li></ul><ul><li>Event has ...
Gradualism <ul><li>Organisms change slowly over time </li></ul><ul><ul><li>Fossil evidence shows long periods of time with...
Punctuated Equilibria <ul><li>Organisms change rapidly in a short period of time </li></ul><ul><ul><li>Some change gives a...
Describing a million <ul><li>Close your eyes and when I say, “go” mentally time one minute </li></ul><ul><li>Raise your ha...
Fossilization <ul><li>Frequency? </li></ul><ul><ul><ul><li>Rare Event </li></ul></ul></ul><ul><li>How? </li></ul><ul><ul><...
Key concepts of Fossils <ul><li>Fossils represent the remains of once-living organisms </li></ul><ul><li>Most fossils are ...
Four types of fossils <ul><li>Petrified Fossils </li></ul><ul><ul><li>The tissues of organism are slowly replaced by miner...
Homework Describe how fossils form
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Fossils

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Fossils

  1. 1. Fossils
  2. 2. Objectives <ul><li>Classify the processes that lead to fossil formation </li></ul><ul><li>Understand key concepts in the study and use of fossils </li></ul><ul><li>Describe the importance of index fossils </li></ul>
  3. 3. Fossilization <ul><li>Frequency? </li></ul><ul><ul><ul><li>Rare Event </li></ul></ul></ul><ul><li>How? </li></ul><ul><ul><ul><li>Organism dies and becomes buried in sediments </li></ul></ul></ul>
  4. 4. Key concepts of Fossils <ul><li>Fossils represent the remains of once-living organisms </li></ul><ul><li>Most fossils are the remains of extinct organisms </li></ul><ul><li>The same fossils found in different rock layers indicate they are the same age </li></ul>
  5. 5. Four types of fossils
  6. 6. Petrified Fossils <ul><li>The tissues of organism are slowly replaced by minerals </li></ul><ul><li>Organism turns into stone </li></ul>
  7. 7. Mold <ul><li>Organism is completely dissolved, but leaves a space in rock </li></ul>
  8. 8. Cast <ul><li>Mold can fill later with minerals and harden into shape of organism </li></ul>
  9. 9. Preserved Remains <ul><li>Organism trapped in preservative </li></ul><ul><ul><li>Amber </li></ul></ul><ul><ul><li>Ice </li></ul></ul>
  10. 10. Relative Dating <ul><li>Layers of sediment are laid down in order </li></ul><ul><ul><li>Oldest layers are on the bottom </li></ul></ul><ul><ul><li>Layers must remain undisturbed </li></ul></ul><ul><ul><ul><li>Therefore fossils in deeper layers must be older than fossils in top layers </li></ul></ul></ul>156
  11. 11. Radioactive Dating <ul><li>When organism dies it stops consuming radioactive material </li></ul><ul><li>All radioactive chemicals decay at a specific rate </li></ul><ul><ul><li>Half-life = amount of time for half of the material to decay </li></ul></ul><ul><li>The amount of decay within fossil will determine its age </li></ul>158
  12. 12. Mass Extinction <ul><li>Times in fossil evidence when many things stop appearing in one layer </li></ul><ul><li>Event has occurred multiple times in Earth’s history </li></ul><ul><li>Called a mass extinction event </li></ul><ul><li>Why? </li></ul><ul><ul><li>Climate change </li></ul></ul><ul><ul><li>Asteroid impact </li></ul></ul>162
  13. 13. Gradualism <ul><li>Organisms change slowly over time </li></ul><ul><ul><li>Fossil evidence shows long periods of time with no change </li></ul></ul><ul><ul><li>Often changes occur rapidly within a fossil layer </li></ul></ul><ul><li>Incomplete fossil records </li></ul>163
  14. 14. Punctuated Equilibria <ul><li>Organisms change rapidly in a short period of time </li></ul><ul><ul><li>Some change gives a huge advantage and that organism replaces others </li></ul></ul><ul><li>Long periods of no change, “Stability” in fossil record </li></ul>163
  15. 15. Describing a million <ul><li>Close your eyes and when I say, “go” mentally time one minute </li></ul><ul><li>Raise your hand and open your eyes when you think one minute has passed </li></ul><ul><li>Sit quietly until everyone has raised their hand (ready) </li></ul><ul><li>Was it easy or hard to count one minute? </li></ul><ul><li>Is it easy or hard to think about how much time is let till the end of the school year? </li></ul><ul><li>Is it easy to picture how big a million is? </li></ul>
  16. 16. Fossilization <ul><li>Frequency? </li></ul><ul><ul><ul><li>Rare Event </li></ul></ul></ul><ul><li>How? </li></ul><ul><ul><ul><li>Organism dies and becomes buried in sediments </li></ul></ul></ul>
  17. 17. Key concepts of Fossils <ul><li>Fossils represent the remains of once-living organisms </li></ul><ul><li>Most fossils are the remains of extinct organisms </li></ul><ul><li>The same fossils found in different rock layers indicate they are the same age </li></ul>
  18. 18. Four types of fossils <ul><li>Petrified Fossils </li></ul><ul><ul><li>The tissues of organism are slowly replaced by minerals </li></ul></ul><ul><ul><li>Organism turns into stone </li></ul></ul><ul><li>Molds </li></ul><ul><ul><ul><ul><ul><li>Organism is completely dissolved, but leaves a space in rock </li></ul></ul></ul></ul></ul><ul><li>Casts </li></ul><ul><ul><li>Mold can fill later with minerals and harden into shape of organism </li></ul></ul><ul><li>Preserved Remains </li></ul><ul><ul><ul><li>Organism trapped in preservative </li></ul></ul></ul><ul><ul><ul><ul><li>Amber </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Ice </li></ul></ul></ul></ul>
  19. 19. Homework Describe how fossils form

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