Chapter 8 - The History of Life on Earth

1234567891011121314151617181920
Across
  1. 3. The supercontinent whos name means "all Earth".
  2. 5. Organisms that first used photosynthesis to create oxygen on Earth.
  3. 7. The calendar scientists use to outline the history of life on Earth.
  4. 8. Era during which the first birds appeared.
  5. 11. The process of dating fossils based on the half life of unstable particles in the fossil.
  6. 14. Organisms that do not need oxygen to survive.
  7. 16. Era during which the first land-dwelling organisms appeared.
  8. 17. The scientist who proposed the idea of a supercontinent named Pangaea.
  9. 19. The time it takes for half of the unstable particles in a sample to decay.
Down
  1. 1. The era also known as Early Earth.
  2. 2. The process of dating fossils based on where they appear in layers of rock.
  3. 4. Cells that lack a nucleus.
  4. 6. Scientists who use fossils to reconstruct what happened in the past.
  5. 9. Cells that contain a central nucleus and a complicated internal structure.
  6. 10. Huge pieces of the Earth's crust on which the continents and oceans reside.
  7. 12. Large blocks of time on the Geologic Time Scale that are characterized by the type of animal that dominated the Earth
  8. 13. The era during which large mammals evolved.
  9. 15. A gas that absorbs ultraviolet light from the sun.
  10. 18. When a plant or animal species dies out completely.
  11. 20. Traces or imprints of living things, such as animals, plants, bacteria, or fungi, that are preserved in rock.