Geologic Time Scale

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Across
  1. 2. True or False: Humans and dinosaurs never lived at the same time.
  2. 4. The end of the Paleozoic is marked by the largest mass _______ in Earth's history, known as the great dying.
  3. 5. "Paleo" means ________.
  4. 6. The first life on earth was made of _______ cell.
  5. 8. True or False: You can find Human and wooly mammoth fossils in the same rock layers as a T-rex.
  6. 9. The Cenozoic is known as the age of ____________.
  7. 11. Life during the precambrian can be generally described as ___________.
  8. 12. "Meso" means ________.
  9. 13. During the Precambrian, the ______ life appears on Earth.
  10. 16. Earth's history is condensed and outlined into the ______________ time scale.
  11. 18. This era began directly after the Mesozoic, 65 mya.
  12. 21. Evidence of past life usually preserved in sedimentary rocks.
  13. 22. The Mesozoic era is known as the age of ___________.
Down
  1. 1. The first era of geologic time.
  2. 3. "Ceno" means ________.
  3. 5. 75% of all species, including the all the dinosaurs, went extinct when an ____________ hit the Earth.
  4. 7. Earth formed 4.6 ___________ years ago.
  5. 8. The Paleozoic is known as the age of __________.
  6. 9. The ___________ era began directly after the paleozoic, 251 mya.
  7. 10. The Paleozoic is best described as having an explosion of _________.
  8. 14. The large iconic reptiles that are alive during the Mesozoic are known as the ______________.
  9. 15. This era began directly after the Precambrian 541 mya.
  10. 17. Scientists have created the geologic time scale using evidence from Fossils and _________.
  11. 19. Early on in the precambrian, the atmosphere did not contain this element. It was added to the atmosphere 2.4 bya when some organisms began utilizing photosynthesis.
  12. 20. The Cenozoic is noted as having large climate shifts, with long periods of time where it is very cold known as an ____________.