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FOSSILS

FOSSILS. I. What is a fossil?. A fossil is any evidence of past life preserved by natural processes. II. There are many different types of fossils. 1. Fossilized footprints, casts and imprints. Example 1: Human-like footprints.

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FOSSILS

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  1. FOSSILS

  2. I. What is a fossil? • A fossil is any evidence of past life preserved by natural processes.

  3. II. There are many different types of fossils

  4. 1. Fossilized footprints, casts and imprints

  5. Example 1: Human-like footprints • Footprints of human ancestors in Laetoli, Africa. The footprints were formed 3.5 million years ago when at least two individuals walked over wet volcanic ash. The wet ash hardened like cement and was then covered by more ash.

  6. The footprints also show that the individuals had perfect, two-footed strides. They reveal that one hominid was larger than the other. And because the footprints fall next to each other, they indicate that the two hominids were walking side-by-side and close enough to each other to be touching.

  7. Example 2: • Fossilized worm from the early Cambrian period - around 500 million years ago.

  8. 2. Mineralized hard tissue • When hard tissues such as bone, wood or shells are covered by sediments, the tissue is partially or totally replaced by minerals over time(like petrified wood).

  9. No longer made of pure bone, this skull consists at least partially of minerals (rock). Very old specimens consist entirely of rock. Example 1: • Cave Bear fossil from the Pleistocene period (1.8 MYA - 10,000 YA) The Cave Bear stood over 9 feet tall on its hind legs.

  10. Example 2: Megalodon tooth At up to 100 feet in length the Megalodon is believed to be the largest predator to ever exist.

  11. Example 3:Fossilized T-Rex skeleton found in 66 million year old Hell Creek deposits in Montana

  12. 3. Fossils preserved in amber or ice

  13. Example 1: • A praying Mantis fossilized in Amber

  14. There are 300 insect specimens in this large fossilized amber sample.

  15. Example 2:Otzi the iceman found frozen in the Italian Alps in 1991 is over 5,000 years old!

  16. Example 3: “La Doncella” is the Inca girl who was almost perfectly preserved in ice on top of a volcano after being sacrificed 500 years ago.

  17. III. Fossil formation is an extremely rare event • We see evidence for only a small percentage of the life that existed in the past. • http://www.bbc.co.uk/sn/prehistoric_life/dinosaurs/burying_bodies/

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