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BI143: Fundamentals of Life Science

BI143: Fundamentals of Life Science. THE PROCESS of SCIENCE CHAPTER 1. SCIENCE:. The Body of Knowledge Accumulated Using the SCIENTIFIC METHOD. The Scientific Method. Observations : Plants grow better in sunny areas. Question : Do plants need sunlight to grow?

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BI143: Fundamentals of Life Science

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  1. BI143: Fundamentals of Life Science THE PROCESS of SCIENCE CHAPTER 1

  2. SCIENCE: The Body of Knowledge Accumulated Using the SCIENTIFIC METHOD

  3. The Scientific Method • Observations: Plants grow better in sunny areas. • Question: Do plants need sunlight to grow? • Hypothesis: Plants need sunlight to grow. • Prediction: If plants need sunlight to grow, then plants not in sunlight will die.

  4. The Scientific Method cont. • Controlled Experiment: • Control Group: Plants in sunlight • Experimental Group: Plants without sunlight • Independent Variable: Exposure to sunlight • Dependent Variable: Growth of plants • Data/Results: Plants with no sunlight die. • Conclusion: Hypothesis is correct. • Theory: ???

  5. There is a difference between a theory and a hypothesis • A hypothesisis a proposed explanation for a set of observations • A theory is supported by a large and usually growing body of evidence

  6. The History of a THEORY: SPONTANEOUS GENERATION ARISTOTLE’S THEORY 4th Century B.C.

  7. REDI’S EXPERIMENT • 1668 • Tries to disprove Spontaneous Generation of small organisms (flies) • Meat Sealed in jar: Produces no maggots • Meat in Unsealed jar: Produces maggots • Conclusion: Flies are needed to produce flies • Problem with the experiment???

  8. SPALLANZANI’S EXPERIMENT • 1767 • Tries to disprove Spontaneous Generation of Microorganisms • Sterilizes broth by boiling it for 1 hour • Broth in sealed flask produces no microorganisms • Broth in open flask produces microorganisms • Problems with the experiment???

  9. PASTEUR’S EXPERIMENT • 1860 • Similar to Spallanzani’s experiment, but uses a swan-neck flask instead of a sealed flask (let’s “LIFE FORCE” from air into both flasks • Flask with swan-neck produces no microorganisms • Material from the bend in the swan-neck flask produces microorganisms

  10. Mistakes Can Lead to Discovery • Fleming discovers Penicillin (1929) • Fleming was investigating the bacterium, staphylococci • Fleming returned to his laboratory after a vacation and noticed that one culture was contaminated with a fungus • The part of the culture near the fungus was killed • Fleming identified the mold as being from the Penicillium genus • The substance (first antibiotic) that was produced by the mold was named penicillin

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