NATURE OF SCIENCE. Professor Andrea Garrison Biology 3A

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1 NATURE OF SCIENCE Professor Andrea Garrison Biology 3A

2 Nature Science Process of asking questions 2

3 Nature Science Process of asking questions Questions that involve logical reasoning 3

4 Nature Science Process of asking questions Questions that involve logical reasoning 2 types logical reasoning 4

5 Nature Science Process of asking questions Questions that involve logical reasoning 2 types logical reasoning Deductive reasoning 5

6 Nature Science Process of asking questions Questions that involve logical reasoning 2 types logical reasoning Deductive reasoning Inductive reasoning 6

7 Nature Science Deductive reasoning Applies general principal to specific cases 7

8 Nature Science Deductive reasoning Applies general principal to specific cases Used to test validity of scientific idea If principle does not work in specific situation, it isn t a valid principle 8

9 Nature Science Deductive reasoning Applies general principal to specific cases Used to test validity of scientific idea If principle does not work in specific situation, it isn t a valid principle Much of our everyday life is run by deductive reasoning (applying the principles we ve learned to new situations) 9

10 Nature Science Inductive reasoning Determines general principles from examination of specific cases 10

11 Nature Science Inductive reasoning Determines general principles from examination of specific cases General principles explain how & why phenomena occur 11

12 Nature Science Inductive reasoning Determines general principles from examination of specific cases General principles explain how & why phenomena occur General principles can be applied later to other situations (used deductively) 12

13 Many possible explanations for how/why phenomena occur How do we know which is correct? 13

14 Many possible explanations for how/why phenomena occur How do we know which is correct? Use Scientific Method 14

15 Scientific Method Observation Question Hypothesis Design experiment Prediction Run experiment Analysis Accept/reject hypothesis 15

16 Scientific Method Observation about phenomenon you find interesting 16

17 Scientific Method Observation about phenomenon you find interesting Question (eg, why does it happen that way?) 17

18 Scientific Method Observation about phenomenon you find interesting Question (eg, why does it happen that way?) Develop hypothesis (possible answer to question) 18

19 Scientific Method Hypothesis must be valid 19

20 Scientific Method Hypothesis must be valid Cause and effect (scientifically reasonable) 20

21 Scientific Method Hypothesis must be valid Cause and effect (scientifically reasonable) Only one variable 21

22 Scientific Method Hypothesis must be valid Cause and effect (scientifically reasonable) Only one variable Be testable 22

23 Scientific Method Hypothesis must be valid Cause and effect (scientifically reasonable) Only one variable Be testable Not anthropomorphic Not imply human emotions to non-human entity 23

24 Scientific Method Hypothesis must be valid Cause and effect (scientifically reasonable) Only one variable Be testable Not anthropomorphic Not imply human emotions to non-human entity Not teleological Not imply purpose 24

25 Scientific Method Design experiment to test hypothesis 25

26 Scientific Method Design experiment to test hypothesis Make prediction as to outcome of experiment If I (explain expt), then (predict outcome) 26

27 Scientific Method Design experiment to test hypothesis Make prediction as to outcome of experiment If I (explain expt), then (predict outcome) Run experiment and record results 27

28 Scientific Method Design experiment to test hypothesis Make prediction as to outcome of experiment If I (explain expt), then (predict outcome) Run experiment and record results Analyze results 28

29 Scientific Method Design experiment to test hypothesis Make prediction as to outcome of experiment If I (explain expt), then (predict outcome) Run experiment and record results Analyze results Provisionally accept hypothesis if prediction correct OR- reject hypothesis if prediction incorrect 29

30 Scientific Method If prediction is wrong and hypothesis is rejected, if can be modified based on new information and then tested again 30

31 Scientific Method Everyday Use Pearson Education, Inc. 31

32 Scientific Method For More In-depth Scientific Use Allows researchers to: answer questions about topics they don t already know so much about crystallize their thoughts make additional observations review scientific literature devise method to formally test their ideas and collect measureable data 32

33 Observations Inductive reasoning Hypothesis Deductive reasoning Predictions Experiments Purpose: The scientific method is a method of inquiry. Protocol: 1. Make detailed observations about a phenomenon of interest. 2. Ask question (my modification to slide) Use inductive reasoning to create a testable hypothesis that provides a working explanation of the observations. Use deductive reasoning to make predictions about what you would observe if the hypothesis were applied to a novel situation. Design and conduct a controlled experiment (or new observational study) to test the predictions of the hypothesis. Interpreting the Results: Compare the results of the experiment or new observations with those predicted by the hypothesis. Figure 1-14 p14

34 Scientific Method Use of Control Control is necessary to know we are testing what we think we are testing A control represents null hypothesis; what we would see in the absence of experimental manipulation (no variable) In control group, everything is exactly the same, except for experimental variable Any difference in results between experimental and control groups attributed to experimental variable 34

35 Scientific Method Use of Replicates Replicates are necessary to show reproducibility The result is always consistent; not just a fluke Show how much variation there is in results when different individuals are used Allows use of an average to minimize errors 35

36 Experimental Research: Controls and Replicates Question: Will giving the plant fertilizer induce it to flower? Add fertilizer Friend added fertilizer You did not add fertilizer Experiment: Establish six replicates of an experimental and control treatment Experimental Treatment Add fertilizer Control Treatment No fertilizer Possible Result 1: Neither experimental nor control plants flower. Possible Result 2: Plants in the experimental group flower, but plants in the control group do not. Experimentals Controls Experimentals Controls Conclusion: Fertilizer alone does not cause the plants to flower. Conclusion: The application of fertilizer induces flowering in this type of plant.

37 Scientific Method Acceptance of hypothesis is provisional Hypothesis not immediately accepted as fact Scientists must be open to new evidence which might disprove hypothesis (even one expt that doesn t support the hypothesis requires modification of hypothesis 37

38 Scientific Method Acceptance of hypothesis is provisional Hypothesis not immediately accepted as fact Scientists must be open to new evidence which might disprove hypothesis Spontaneous generation Mice recipe 38

39 Scientific Method Acceptance of hypothesis is provisional Hypothesis not immediately accepted as fact Scientists must be open to new evidence which might disprove hypothesis Spontaneous generation Mice recipe Flies 39

40 Scientific Method Acceptance of hypothesis is provisional Hypothesis not immediately accepted as fact Scientists must be open to new evidence which might disprove hypothesis Spontaneous generation Mice recipe Flies Red wine and cardiovascular disease 40

41 Scientific Method Theory Hypothesis which has never been proven wrong Great amount of evidence 41

42 Scientific Method Theory Hypothesis which has never been proven wrong Great amount of evidence Can be used to predict natural phenomena 42

43 Scientific Method Theory Hypothesis which has never been proven wrong Great amount of evidence Can be used to predict natural phenomena Science (including Biology) based on theories Hypotheses which are consistent with observations and never proven wrong 43

44 Scientific Method Use of Model Organisms Often used by researchers Easy to work with in labs or find in nature Short life cycle Fast development Small Findings applied to other living organisms Deductive testing will show if info is applicable 44

45 What criteria qualify as scientific? 45

46 What criteria qualify as scientific? Must be observable Must be able to be tested Must be falsifiable 46

47 What criteria qualify as scientific? Must be observable Must be able to be tested Must be falsifiable Ideas that are not observable or testable Beliefs Not necessarily wrong Not science 47

48 Mechanism vs. Vitalism Mechanism Science Holds to philosophy that universe governed by set of natural laws that explain all events 48

49 Mechanism vs. Vitalism Mechanism Science Holds to philosophy that universe governed by set of natural laws that explain all events Vitalism Religion Holds to philosophy that universe governed by supernatural power(s) that guide behavior of natural phenomena, gave rise to life, etc. 49

50 Mechanism vs. Vitalism Mechanism and vitalism not mutually exclusive 50

51 Mechanism vs. Vitalism Mechanism and vitalism not mutually exclusive Basic science does not incorporate vitalistic ideas (even though they may be CORRECT) Not testable 51