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FOSSILS :

FOSSILS : . How do we know that there was life millions of years ago?? BY: BRIANNA SHIELDS. DO NOW. 1. What do you call remains or evidence of past life? 2. What large group of organisms currently do not exist, because they became extinct during the ice age?

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FOSSILS :

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  1. FOSSILS: How do we know that there was life millions of years ago?? BY: BRIANNA SHIELDS

  2. DO NOW • 1. What do you call remains or evidence of past life? • 2. What large group of organisms currently do not exist, because they became extinct during the ice age? • 3. The theory of ------------- is the scientific theory that explains how humans, and all living organisms can to be on planet Earth.

  3. GOAL • To define fossil and to determine which types of fossils are older based on layering

  4. Fossils The remains or evidence of living things, traces of past life What are fossils?

  5. Good Fossil Conditions 1. Objects should be hard: Bone, teeth, shell, wood (Soft things like flesh, fur and petals don’t make good fossils) What are fossils?

  6. Good Fossil Conditions 2. Remains need to be there long enough sometimes the remains get destroyed before a fossil can form What are fossils?

  7. Good Fossil Conditions 3. Quick burial- air will rot remains keeps air from rotting remains, and animals from ruining them What are fossils?

  8. Fossils can be ruined by: 1. Volcanic Activity What are fossils?

  9. Fossils can be ruined by: 2. Bacterial Rotting What are fossils?

  10. Fossils can be ruined by: 3. Crushing by other animals What are fossils?

  11. Fossils can be ruined by: 4. Remains eaten What are fossils?

  12. Fossils can be ruined by: 5. Weathering & Wave Action (broken down by nature) What are fossils?

  13. Fossil Video Questions • In what type of rock do fossils typically form? • How do remains become fossilized?

  14. Fossil Formation BBC Making Fossils Website A. In sedimentary rock B. Marine animal dies, settles to ocean bottom C. Remains cover by sediment (body decays) D. Hard parts protected from air E. Sediment layers continue to build and compress F. Erosion uncovers fossil How do fossils form?

  15. Molds Remains cover with sediment, soft part rots leaving a hollow space Types of Fossils

  16. Casts Formed when the mold gets filled in with hard sediment Types of Fossils

  17. Prints Footprints harden in soft mud Can tell us how it walked, how big, body shape, skin appearance Types of Fossils

  18. Changed Hard Parts Actual remains preserved & hardened with minerals Types of Fossils

  19. Actual Remains Actual parts of plant or animal is preserved, no rotting Ex: Freezing, drying, amber, tar Types of Fossils

  20. Frozen entire whooly mammoths Extremely dried out mummies Insects in hardened tree sap Hot tar pits that have hardened: La Brea, California

  21. Relative Dating of Fossils Younger rocks (top layer) are found on top of older rocks (bottom layer) “LAW OF SUPERPOSITION” Ex: Diagram A Finding the Age of Fossils

  22. Index Fossils Fossils that lived during a short period of time Can help in aging rock Ex: Diagram E Which are index fossils? Which fossils are not as helpful for aging? Finding the Age of Fossils

  23. Absolute Dating of Fossils Use radioactive elements whose length of break down is known C-14 and U-238 Geiger Counter Finding the Age of Fossils

  24. Fossil Age Rule A fossil is the same age as the rock that it’s found in Finding the Age of Fossils

  25. What have fossils told us? Life has existed on Earth for nearly 3 billion years Life on Earth: According to Fossils

  26. What have fossils told us? Life forms have changed (evolved) Life on Earth: According to Fossils

  27. What have fossils told us? Simple life began in water, evolved, became terrestrial Life on Earth: According to Fossils

  28. What have fossils told us? Some organisms have become extinct Trilobite, Woolly Mammoth, Dinosaurs Life on Earth: According to Fossils

  29. What have fossils told us? Some life forms have hardly changed Ex: Cockroaches, snails, snakes Life on Earth: According to Fossils

  30. Fossil Websites • BBC- Burying Bodies • BBC- Making Fossils

  31. Explain why many animals/plants don’t become fossils? Many remains are crushed, ruined, eroded, rotted, eaten or burned before they become fossils Assessment

  32. What types of objects make the best fossils? Hard parts- teeth, shells, bones, wood Assessment

  33. Describe where most fossils are formed and how they actually form. Many fossils form in sedimentary rock that used to be covered by oceans. When organism dies, gets buried by sediment in ocean, soft parts rot, hard parts preserved by sediment Assessment

  34. Tell about the difference between a mold and a cast Mold is hollow space left in sediment when animal rots, cast is when mold gets filled back in with other sediment Assessment

  35. Explain how changed hart parts fossils are formed When actual body parts fill with minerals changing them to a harder substance Assessment

  36. Compare techniques used for dating fossils Law of superposition (relative dating), index fossils, absolute dating Assessment

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