History of Life
Chapter 14
http://paleobiology.si.edu/geotime/main/htmlversion/archean3.html
http://www.mhhe.com/biosci/genbio/raven6b/graphics/raven06b/other/ch04.pdf
http://www.livescience.com/13363-7-theories-origin-life.html
http://www.ecology.com/2011/09/10/earths-beginnings-origins-life/
http://www.extremescience.com/earth.htm
1. Describe what early earth looked like before any plants or animals inhabited earth.
2. What evidence is there to support your answer for question #1?
3. What critical ingredients (things) were missing to support any kind of life?
4. If you have more than one ingredient for the above question, when did each critical ingredient appear? What evidence do you have to support this?
5. When did the first life form appear, whether on land or in the ocean? I am looking for how many million/billion of years ago.
6. You have postulated how the first the first life forms were created. Write your theory here.
7. What problems might you have to support your theory?
8. What proof do you have to support your theory?
9. List at least 4 published theories how life, in any form, was created. Give a brief description of each theory.
10. How do we know the age of rocks?
11. How old is earth estimated to be?
12. How do we know the age of living matter? In other words, how do we calculate the age of organisms that once were alive?
13. What is a radioactive isotope?
14. Explain how we use radioactive isotopes to calculate the age of a woolly mammoth.
15. Does radioactive dating with isotopes of thorium and uranium provide an estimate of the beginning, middle, or end of the period of Earth’s formation? Support your answer.
16. If 1.0 grams of radioactive isotope had a half-life of 1 billion years, how much of it would be left after each of the following intervals of time:
a. 1 billion years
b. 2 billion years
c. 3 billion years
d. 6 billion years
17. Some radioactive isotopes that are used in medicine have half-lives of a few years. Would these isotopes also be useful in dating rocks? Why or why not?
18. Using your book or other resource-not another student-describe Alexander Oparin and John Haldane’s hypothesis on how the first organic compounds formed. Later Miller-Urey tested this hypothesis.
19. What problem do you see with this hypothesis?
20. From the first organic molecules to cells, which do scientists think came first—RNA or DNA?
21. Support your choice.
22. Describe three major scientific inferences about the first living cells on Earth.
23. Explain the difference between chemosynthesis and photosynthesis.
24. Place in order from oldest to newest
a. Photosynthetic prokaryotes
b. Photosynthetic eukaryotes
c. Chemosynthetic prokaryotes
d. Aerobic eukaryotes
e. Heterotrophic prokaryotes
25. What evidence supports the hypothesis that mitochondria were once free-living prokaryotic cells?
26. Using your book or other resource-not another student-define
a. Biogenesis
b. Spontaneous generation
c. Vital force
27. Describe Redi’s experiment.
28. What was he trying to disprove? Was he successful?
29. Give one problem with Redi’s idea. Support your thought.
30. Give one positive conclusion regarding Redi’s experiment. Support your thought.
31. Describe Spallanzani’s experiment.
32. Why did Spallanzani boil the broth in his experiment?
33. What was he trying to disprove? Was he successful?
34. Give one problem with Spallanzani’s idea. Support your thought.
35. Give one positive conclusion regarding Spallanzani’s experiment. Support your thought.
36. Describe Pastur’s experiment.
37. How did Pasteur’s experiment differ from Spallanzani’s experiment?
38. Both Spallanzani and Pasteur used a technique widely used today. What is this technique?
39. What would have happened if Pasteur had tipped one of his flasks so that the broth in the flask had come into contact with the curve of the neck?
40. If spontaneous generation does not occur and the principle of biogenesis is true, what scientific question remains?