02 Scientific Method Environment & Ecology

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

Vaccines cause autism Fact or Fiction?

Global Warming Fact or Fiction?

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

Hypothesis-Driven Studies

Discovery/Observational Studies

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

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

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)

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

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

Example Scientific Method: Example Corridors facilitate movement of butterflies between isolated habitat patches Common buckeyeVariegated fritillary Hypothesis

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

Experiment results

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

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

Keystone Species Paine’s study on Pisaster and blue mussels

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

Mangrove Study Do sponges affect mangrove root growth?

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 Mangrove Study

Inquiry 1.What is the difference between a hypothesis, theory and law? 2.Can a theory ever be proven? 3.In the mangrove study, what is the dependant variable? 4.State Ben Franklin’s hypothesis. 5.In Paine’s study on Pisaster, what role did blue mussels play?

QUESTION: Review Which is the correct order of the scientific method? a)Observation, question, hypothesis, testing, results b)Hypothesis, observation, testing, question, results c)Observation, question, testing, results, hypothesis d)Question, observation, hypothesis, testing, results

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