02 Scientific Method

1. Environment & Ecology 02 Scientific Method

2. The nature of science Science: A systematic process for learning about the world and testing our understanding of it The accumulated body of knowledge that results from a dynamic process of observation, testing, and discovery Science is essential: To sort fact from fiction Develop solutions to the problems we face

3. Vaccines cause autism Fact or Fiction?

4. Global Warming Fact or Fiction?

5. Scientists test ideas Two Primary Approaches to Science Hypothesis-driven or experimental science. Discovery or observational science.

6. Hypothesis-Driven Studies

7. Discovery/Observational Studies

8. Applications of science Restoration of forest ecosystems altered by human suppression of fire Policy decisions and management practices Technology Energy-efficient methanol-powered fuel cell car from DaimlerChrysler

9. The scientific method A technique for testing ideas • Observations • Question • Formulate Hypothesis • Conduct Experiment • Analyze Results • Conclusions • Discussion

10. Testing predictions Experiment: an activity that tests the validity of a hypothesis Variables: conditions that can be manipulated and/or measured Independent variable: a condition that is manipulated Dependent variable: a variable that is affected by the manipulation of the independent variable Controlled experiment: one in which all variables are controlled Control: the unmanipulated point of comparison Treatment: the manipulated point of comparison Data: information that is generally quantitative (numerical)

11. Experiments test the validity of a hypothesis Manipulative experiments yield the strongest evidence Provides the strongest type of evidence Reveal causal relationships: changes in independent variables cause changes in dependent variables But many things can’t be manipulated: long-term or large-scale questions (i.e., global climate change) Natural experiments show real-world complexity Only feasible approach for ecosystem or planet-scale Results are not so neat and clean, so answers aren’t simply black and white

12. Scientific Method: Example Observations Many habitats are fragmented. Corridors are being constructed between patches. Do they really work?

13. Scientific Method: Example Corridors facilitate movement of butterflies between isolated habitat patches Hypothesis Common buckeye Variegated fritillary

14. Prediction Butterflies will move into connected habitat patches more frequently than into unconnected habitat patches Experiment and/or data collection

15. Experiment results

16. Ben Franklin & the Gulf Stream Observation: Question: 1786 Hypothesis: Test hypothesis: Analyze Results: Draw Conclusion: 1996

17. Paine’s study on Pisaster and blue mussels What effect does starfish removal have on community structure? mussels (Mytilus) Pisaster barnacles chiton limpet

18. Paine’s study on Pisaster and blue mussels Keystone Species

19. Coral Reef Benthic Habitat Point and Area Assessments Kaneohe Bay, HI • Large sample size • Random sampling

20. Do sponges affect mangrove root growth? Mangrove Study

21. Mangrove Study Select a large sample size Randomly divide the sample into 2 groups Treat the groups equally in all ways but one Observe or make measurements Compare results

22. Inquiry • What is the difference between a hypothesis, theory and law? • Can a theory ever be proven? • In the mangrove study, what is the dependant variable? • State Ben Franklin’s hypothesis. • In Paine’s study on Pisaster, what role did blue mussels play?

23. QUESTION: Review Which is the correct order of the scientific method? Observation, question, hypothesis, testing, results Hypothesis, observation, testing, question, results Observation, question, testing, results, hypothesis Question, observation, hypothesis, testing, results

24. QUESTION: Interpreting Graphs and Data What happens if test results reject a hypothesis? The scientist formulates a new hypothesis. It shows the test failed. The scientist should be fired. The scientist used faulty data .