Spontaneous Generation

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A soiled shirt and some grain: these are the ingredients needed to make mice spontaneously appear. At least, that's what some people used to think…

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Spontaneous Generation

  1. 1. TEACHER MATERIALS SPONTANEOUS GENERATION Purpose At one point in history, spontaneous generation was a reasonable explanation for the emergence of life due to the evidence (or lack of it) for how life developed. This activity will help remind students that our understanding of why something occurred sometimes changes over time based on new evidence and new discoveries. Process How did life begin? For centuries, many people believed in an idea called spontaneous generation, the idea that life could “spontaneously” appear from nothing. Why did many people believe this explanation for the origin of life? Post the three examples of spontaneous generation that appear on the following pages. Ask students to think about the quotations, and then use the worksheet to respond to the four questions about them. BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY
  2. 2. TEACHER MATERIALS SPONTANEOUS GENERATION(ANSWER KEY) BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY Directions: Think about the three examples of spontaneous generation and respond to the following four questions. 1. Why did the scientists who studied these cases think that life had “spontaneously” appeared? Sample answer: Life was not present at the start of the experiment in a closed environment with nonliving matter. Within the highly religious belief system at the time, it was generally accepted that something could appear from nothing through divine intervention. 2. Why did these scientists think their conclusions were based on sound scientific methods? Sample answer: The results were predictable and repeatable with no visible cause for life that they could observe. 3. What was wrong with the scientific methods they used? Sample answer: Seventeenth-century scientists had no understanding of microbiology and accepted that life could come from nothing. 4. What do they think the scientific explanation for the appearance of life in each of these cases was? Sample answer: Mice seek out wheat as food. Mice seek out cheese as food. Mold spores present in the air settle on the bread and grow mold. Flies lay eggs in meat to produce maggots. Discuss the students’ responses to the three claims. Based on what they now know, ask each student to choose one of the four claims and use the Claim Testing Worksheet to more thoroughly evaluate that claim. Talk through how they tested the claims as a class. Let them know that in the second half of the course they will be doing a lot of research on their own and should have their claim testing skills down pat.
  3. 3. TEACHER MATERIALS 1. “If a soiled shirt is placed in the opening of a vessel containing grains of wheat, the reaction of the leaven in the shirt with fumes from the wheat will, after approximately twenty-one days, transform the wheat into mice.” Source of Louis Pasteur’s description of an experiment of Jan Baptista van Helmont.: An Address delivered by Louis Pasteur at the “Sorbonne Scientific Soirée” on April 7, 1864. Accessed 29 June 2014. http://faculty.humanities.uci.edu/bjbecker/NatureandArtifice/week7f.html. SPONTANEOUS GENERATION BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY
  4. 4. TEACHER MATERIALS 2. “Pieces of cheese and bread wrapped in rags and left in a dark corner…produce mice… because after several weeks, there were mice in the rags.” Source: “Spontaneous Generation. Dictionary.com. Encyclopedia Britannica, Inc. Accessed: 29 June, 2014. http://dictionary.reference.com/browse/spontaneous generation. SPONTANEOUS GENERATION BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY
  5. 5. TEACHER MATERIALS 3. “Mold seems to grow spontaneously on bread, maggots appear as if by magic in old meat, and every spring new plants sprout and grow….” Source: Robert Hazen, Genesis (Washington, DC: Joseph Henry Press, 2005) 83. SPONTANEOUS GENERATION BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY
  6. 6. STUDENT MATERIALS SPONTANEOUS GENERATION Purpose This activity will help remind you that our understanding of why something occurred sometimes changes over time based on new evidence and new discoveries. At one point in history, spontaneous generation was a reasonable explanation for the emergence of life due to the evidence (or lack thereof) for how life developed. Process How did life begin? For centuries many people believed in an idea called spontaneous generation, the idea that life could “spontaneously” appear from nothing. Why did many people believe this explanation for the origin of life? Read the following statements: “If a soiled shirt is placed in the opening of a vessel containing grains of wheat, the reaction of the leaven in the shirt with fumes from the wheat will, after approximately twenty-one days, transform the wheat into mice.” Source of Louis Pasteur’s description of an experiment of Jan Baptista van Helmont.: An Address delivered by Louis Pasteur at the “Sorbonne Scientific Soirée” on April 7, 1864. Accessed 29 June 2014. http://faculty.humanities.uci.edu/bjbecker/NatureandArtifice/week7f.html. “Pieces of cheese and bread wrapped in rags and left in a dark corner…produce mice… because after several weeks, there were mice in the rags.” Source: “Spontaneous Generation. Dictionary.com. Encyclopedia Britannica, Inc. Accessed 29 June 2014. http://dictionary.reference.com/browse/spontaneous generation. “Mold seems to grow spontaneously on bread, maggots appear as if by magic in old meat, and every spring new plants sprout and grow….” Source: Robert Hazen, Genesis (Washington, DC: Joseph Henry Press, 2005) 83. Use the worksheet on the following page to answer the four questions about the examples of spontaneous generation. Be prepared to discuss your answers with the class. Based on what you now know, choose one of the three claims and use the Claim Testing Worksheet to more thoroughly evaluate that claim. Be prepared to talk about how you tested your claim. In the second half of the course you will be doing a lot of research on your own and you should have your claim testing skills down. BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY
  7. 7. Name: Date: STUDENT MATERIALS SPONTANEOUS GENERATION(ANSWER KEY) BIG HISTORY PROJECT / LESSON 5.1 ACTIVITY Directions: Think about the three examples of spontaneous generation and respond to the following four questions. 1. Why did the scientists who studied these cases think that life had “spontaneously” appeared? 2. Why did these scientists think their conclusions were based on sound scientific methods? 3. What was wrong with the scientific methods they used? 4. What do they think the scientific explanation for the appearance of life in each of these cases was?
  8. 8. Name: Date: STUDENT MATERIALS CLAIM TESTING Directions: Decide if the claim passes each claim tester and provide evidence for your decisions. Claim Test Test Passed? (Yes, No, Don’t Know or Needs More Information) Why did you decide the claim passed (or did not pass) the claim tester? What evidence did you use to decide? Where did you get your evidence? Intuition • Does your gut reaction tell you the claim is reliable? • Do you feel that the claim is true? Authority • Does the person stating the claim have experience in the field? • Has the person making the claim made trustworthy claims in the past? Logic • Does the claim make sense to you and follow a clear line of reasoning? Evidence • Do you have facts that others can “see” that support the claim? BIG HISTORY PROJECT / WORKSHEET The claim you are testing:

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