Origin of Life
Study Questions
1. What was the theory of spontaneous generation?
2. What observations were explained by the theory of spontaneous generation?
3. How did Redi’s experiment disprove the spontaneous generation of flies?
4. Describe Pasteur’s experiments and his results.
5. What did Pasteur conclude from his experiments?
6. What caused people to think there was a “vital force” in air that produced life?
7. Why didn’t Spallanzani’s experiments disprove the “vital force” hypothesis?
8. How does biogenesis differ from abiogenesis?
9. What part of Spallanzani’s experiments is still used to kill bacteria although it is now called pasteurization?
10. Why did Pasteur’s experiments disprove the “vital force” hypothesis when Spallanzani’s did not?
11. What is the theory of biogenesis?
12. Briefly describe the formation of a planet.
13. How did Earth’s atmosphere form?
14. How did the composition of the early atmosphere contribute to the development of life?
15. Why did the first life form in oceans?
16. What are the oldest fossils?
17. Why are radioactive isotopes useful for dating materials?
18. What is half-life?
19. Why is it usefull to know the half-life of an isotope?
20. Use 14C to explain the use of radioactive isotopes for dating?
21. What are the limitations of 14C dating?
22. What four things are required for life to form?
23. What is a fossil?
24. What was Oparin’s Hypothesis?
25. How has Oparin’s hypothesis been tested?
26. How do coacervates resemble living cells?
27. How do microspheres resemble living cells?
28. Briefly describe the experiments of Miller and Urey?
29. Explain the role of the gases CH4, H2, and NH3 and the role of the electric spark in the Miller-Urey apparatus?
30. Organic molecules will not form in the Miller-Urey apparatus if oxygen is present. Why is this not a serious problem for scientists who study the origin of life?
31. What role did RNA play in the development of early life?
32. What recent discoveries support a more active role for RNA?
33. How have computers aided in our understanding of how life may have begun?
34. What is endosymbiosis?
35. Explain the endosymbiont hypothesis of eukaryotic evolution.
36. Why do biologists believe the first organisms were anaerobic heterotrophic prokaryotes?
37. What survival advantage would an autotrophic prokaryote have?
38. How might aerobic respiration have protected early cells from damage?
39. What evidence supports the hypothesis that mitochondria were once free living prokaryotes?
40. What evidence supports the hypothesis that chloroplasts were once free living organisms?
41. Explain how early eukaryotes could have developed.
42. What was the source of oxygen in Earth’s early atmosphere?
43. Why did the theory of biogenesis pose a dilemma regarding the origin of life?
44. What modern organisms are thought to be most like the first life-forms on Earth?
45. What environmental factors probably favored the evolutions of autotrophs?
46. How might the bonding of oxygen gas serve evolving organisms?
47. How did the formation of the ozone layer permit organisms to colonize land?
48. What energy sources do the chemosynthetic autotrophs have?
49. Why have many scientists begun to focus on RNA chemistry in the search for the origins of life?
50. What process did the first autotrophs use to make energy?
51. What genetic phenomena led Margulis to become interested in the endosymbiont hypothesis?