Study Guide: A Brief History of Life

  1. Put the geological time periods from smallest to largest: eras, eons, periods.

  2. List the eons in order from oldest to youngest.

  3. What three eras are in the Precambrian Eon, in order?

  4. As far as we know, how old is the Earth?

  5. As far as we know, when did life begin on Earth?

  6. How do we date rocks?

  7. What was the atmosphere like in the Precambrian Eon?

  8. What was life like in the Precambrian Eon?

  9. What the main determinant of the Precambrian Eon? What defines the boundary between the Precambrian and the Phanerozoic?

  10. What event started the Hadean Eon?

  11. What events happened during the Hadean Eon?

  12. What marks the transition from the Hadean Eon to the Archaean Eon?

  13. What marks the transition from the Archaean Eon to the Proterozoic Eon?

  14. What is the first chemical evidence we have of life on Earth?

  15. What is the first physical evidence we have of life on Earth?

  16. Why was the oxygenation of ocean and the atmosphere so important for life on Earth?

  17. How is it theorized that aerobic respiration came to be in eukaryotic organisms?

  18. What marks the transition from the Precambrian Eon to the Phanerozoic Eon?

  19. What eon did the moon form?

  20. What eon did liquid water form on Earth?

  21. What eon did the Earth formation complete?

  22. What eon did the first oceans appear?

  23. What eon did the Earth experience heavy bombardment from large asteroids?

  24. What eon did the origin of life appear?

  25. What eon did photosynthetic cells appear?

  26. What eon did the first evidence of oxygenic photosynthesis appear?

  27. What eon did first cyanobacteria appear?

  28. What eon did the first eukaryotic organisms appear?

  29. What eon did the lichen-like organism appear?

  30. What eon do we have the first evidence of sexual structures? What type of organism?

  31. What eon did the oceans become completely oxygenated?

  32. What eon did the first animals appear? What were they?

  33. What major life forms first appeared during the Cambrian Explosion?

  34. Why is the Cambrian Explosion so important?

  35. Why did Darwin struggle to explain the events of the Cambrian Explosion with his theory of natural selection?

  36. What is the theory of punctuated equilibrium? (and who came up with it)?

  37. What are three possible causes of the Cambrian Explosion?

  38. Know the fossil evidence for the Cambrian Explosion. What type of fossils existed in the following sites and what are their relative temporal relationships: Doushantuo, Ediacara Hills, and the Burgess Shale.

  39. What is the largest extinction event (other than current times) in the history of Earth?

  40. What percentage of marine species went extinct in the Permian-Triassic extinction? Terrestrial species?

  41. What are the possible causes of the Permian-Triassic extinction?

  42. Why did the Permian-Triassic extinction cause a greater decline in marine species, compared with terrestrial species?

  43. What happened in the Mesozoic Era?

  44. What happened during the Cretaceous-Paleogene extinction? What is the culprit? What evidence supports this?

  45. From an animal perspective, the Cenozoic Era is known as the Age of the ____.

  46. What type of plants came to dominate during the Cenozoic?

  47. Insect pollination is a mutualistic relationship that blossomed during which era? (You get it…blossomed!!!)