Bio lesson1 introduction


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Bio lesson1 introduction

  1. 1. Lesson 1March 6, 2012
  2. 2.  Ffdg
  3. 3.  Organism  A living thing. Observation  Gathering information in a careful, orderly way. Data  Information gathered from observations. Inference  A conclusion based on experience or evidence. Hypothesis  A proposed explanation for observations.
  4. 4.  DESIGNING AN EXPERIMENT Asking a question Forming a hypothesis Doing a controlled experiment Recording and analyzing results Drawing a conclusion
  5. 5.  An EXPERIMENT…  Can make a discovery.  Can test a hypothesis.  Can prove a known fact.
  6. 6.  Example: how do organisms come into being?  In the past, observations showed that some living things just appeared.  Mice appeared in grain.  Maggots appeared on meat.
  7. 7.  People thought that the mice came from the grain, and the maggots came from the meat.  This idea was called spontaneous generation. Do you think spontaneous generation is correct?
  8. 8.  A doctor named Redi had a different idea. He observed that maggots appeared on meat a few days after flies were around it. His hypothesis was that flies made the maggots.
  9. 9.  A hypothesis is a possible explanation based on observations and evidence. All experiments begin with a hypothesis.
  10. 10.  Remember: an experiment tests a hypothesis. Redi wanted to test his hypothesis. He had to figure out which variable to change.  A variable is any part of the experiment that can change. For example: equipment, material, temperature, light, time.  An experiment should only change 1 variable at a time.  The variable that the scientist changes is called the manipulated variable.  The variables that change as a result of the manipulated are called the responding variables.
  11. 11.  Here is Redi’s controlled experiment. What are the controlled variables? What are the manipulated variables? What are the responding variables?
  12. 12.  Controlled variables: jars, type of meat, location, temperature, time. Manipulated variables: closing the jars Responding variable: maggots
  13. 13.  Redi observed that maggots appeared on the meat in the open jars. No maggots appeared on the meat in the closed jars. He recorded his findings by writing them down for future scientists.
  14. 14.  The conclusion uses evidence from the experiment to state if the hypothesis was supported or refuted.  Supported = hypothesis was correct.  Refuted = hypothesis was incorrect.  Was Redi’s hypothesis supported or refuted?  What was his conclusion?
  15. 15.  Redi’s hypothesis was SUPPORTED. His conclusion: flies produce maggots.  Spontaneous generation is incorrect.  New organisms come from existing organisms. This is called biogenesis.
  16. 16. What is a theory?
  17. 17.  If a hypothesis is supported by many different experiments, it can become a theory. A theory is a well-tested explanation that brings many observations together.  Theories let scientists make better predictions about new situations. Sometimes more than one theory is needed to explain something. For example…
  18. 18.  …kangaroos and koalas!Oy mate. G’day Why are they only in Australia?
  19. 19.  The answer can be explained by 2 theories:  Evolution (more later in this class)  Plate tectonics (more later in Physics)
  20. 20.  Plate Tectonics Millions of years ago, Australia, Antarctica and South America were all joined in one continent. This continent broke apart, and Australia became a continent by itself. Evolution Organisms change over time to survive. Since Australia was so far away from other continents, the animals in Australia changed in unique ways