Earth's Early History

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Across
  1. 6. extinct primitive toothed bird of the Jurassic period having a long feathered tail and hollow bones
  2. 10. When molten rock from inside Earth moves through cracks in the rock layers. This molten rock will sometimes reach and break through the surface.
  3. 11. the part of geologic time 570-245 million years ago ; invertebrates, fishes, amphibians, reptiles, ferns, and cone-bearing trees were dominant
  4. 13. When rocks are broken down into smaller pieces.
  5. 14. When sediment stops moving and collects in a new area.
  6. 16. era that began about 66 million years ago, known as the "Age of Mammals"
  7. 20. boundary where two plates slide past one another
  8. 21. The permanent disappearance of a species from Earth
  9. 22. a small, rocky object that orbits the Sun
Down
  1. 1. The geologic principle that states that in horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it.
  2. 2. explosion, or burst of evolutionary origins when most of the major body plans of animals appeared in a relatively brief time in geologic history; recorded in the fossil record about 545 to 525 million years ago.
  3. 3. oldest and longest era : unicellular organisms originated
  4. 4. middle life (245-144 million years ago); rise of mammals and dinosaurs; the rise of birds; extinction of dinosaurs, rise of flowering plants
  5. 5. When small pieces of rock (sediment) are moved around by wind and/or water.
  6. 7. drift the gradual movement of the continents across the earth's surface through geological time.
  7. 8. Plate tectonic boundary where lithospheric plates are moving apart.
  8. 9. when living material is replaced with mineral substances in the remains of an organism
  9. 12. Era or period that began when the oldest easily identifiable fossils first appeared (544 million years ago to present)
  10. 15. Rock that forms when sediment from erosion is compressed together.
  11. 17. A supercontinent containing all of Earth's land that existed about 225 million years ago.
  12. 18. Evidence of past life that have been preserved in rocks.
  13. 19. A plate boundary where two plates move toward each other.
  14. 23. a fossil known to have lived in a particular geologic age that can be used to date the rock layer in which it is found