THE SCIENTIFIC METHOD

1. THE SCIENTIFIC METHOD The Hypothesis

2. HYPOTHESIS Tentative explanation to account for an observation • Testable • Falsifiable • In accord with all data Cannot be proven! Fairies cause warts. Toads cause warts.

3. HYPOTHESIS Hypothesis making and testing • Inductive reasoning • Take many specific facts to come up with a general statement • Deductive reasoning • If . . . . then . . .

4. HYPOTHESIS Hypothesis making • Inductive reasoning • Specific  General Facts: Bacteria are made of cells, plants are made of cells, and animals are made of cells Hypothesis: All organisms are composed of cells.

5. HYPOTHESIS Hypothesis testing • Deductive reasoning • General  Specific Hypothesis: All organisms are composed of cells Test: If all organisms are composed of cells, then fungi and protist should be made of cells.

6. THE SCIENTIFIC METHOD

7. THE TEST Experiment or Observation • You can't prove your hypothesis, but you can disprove your null hypothesis H0 versus H1

8. EXPERIMNENTAL DESIGN Change only one variable • Experimental Variable • Dependent Variable Have something to compare it to • Experimental Groups • Control Groups Numbers • Quantify data • Have replicates

9. THE SCIENTIFIC METHOD

10. PUBLISH YOUR DATA Primary publication • Characteristics of the rhizobia associated with Dalea spp. in the Ordway, Kellogg–Weaver Dunes, and Hayden prairies • Prevalence and airborne spore levels of Stachybotrys spp. in 200 houses with water incursions in Houston, Texas • Genome-wide comparison of phage M13-infected vs. uninfected Escherichia coliPolarity within pM and pE promoted phage lambda cI-rexA-rexB transcription and its suppression • Antimicrobial susceptibility of lactic acid bacteria isolated from a cheese environment • Characterization and regulation of new secondary metabolites from Aspergillus ochraceus M18 obtained by UV mutagenesis • Overexpression of the ftsZ gene from Corynebacterium glutamicum (Brevibacterium lactofermentum) in Escherichia coli • Influence of carbon source and surface hydrophobicity on the aggregation of the yeast Kluyveromyces bulgaricus • Isolation and PCR amplification of a species-specific oxidoreductase-coding gene region in Listeria grayi • The presence of novel 3-hydroxy oxylipins on surfaces of hat-shaped ascospores of Ascoidea africana • Peer review Evaluate, confirm, repeat Review articles Popular literature

11. AVOID FAULTY REASONING Cause and Effect -Fire trucks Linked Variables -Cold weather causes the flu Anecdotal Evidence -Toads cause warts

12. AVOID FAULTY REASONING After training the flea for many months, the biologist was able to get a response to certain commands, such as jump. The professor would shout “jump”, and the flea would leap into the air . Before publishing, the professor decided to take his experiments one step further. He sought to determine the location of the receptor organ involved. He removed one leg and the flea continued to jump on command, but as each successive leg was removed, its jumps became less spectacular. Finally, with the removal of its last leg, the flea remained motionless. The professor decided that at last he could publish his findings. He set pen to paper and his conclusion was one intended to startle the scientific world: When the legs of a flea are removed, the flea can no longer hear.”

13. WHAT SCIENCE SHOULDN'T DO  Avoid faith -Avoid ethical decisions

14. THE SCIENTIFIC METHOD Scientific Laws Scientific Principles

15. BIOLOGICAL THEORIES • The Cell Theory • Robert Hooke • Antonie van Leeuwenhoek • Schleiden & Schwann • Theory of Biogenesis • The Gene Theory • Theory of Evolution • Charles Darwin & Alfred Wallace