THE SCIENTIFIC METHOD

HYPOTHESISTentative explanation to account for an observation

Testable

Falsifiable

In accord with all dataCannot be proven!

Fairies cause warts.Toads cause warts.

HYPOTHESISHypothesis making and testing

Inductive reasoning

•Take many specific facts to come up with a general statement

Deductive reasoning

•If . . . . then . . .

HYPOTHESISHypothesis 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.

HYPOTHESISHypothesis 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.

THE SCIENTIFIC METHOD

THE TESTExperiment or Observation

You can't prove your hypothesis, but you can disprove your null hypothesis

H0 versus H1

EXPERIMNENTAL DESIGNChange only one variable

Experimental Variable

Dependent Variable

Have something to compare it to

Experimental Groups

Control Groups

Numbers

Quantify data

Have replicates

THE SCIENTIFIC METHOD

PUBLISH YOUR DATAPrimary publication

Peer review

Evaluate, confirm, repeatReview articles

Popular literature

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

AVOID FAULTY REASONING

Cause and Effect-Fire trucks

Linked Variables-Cold weather causes the flu

Anecdotal Evidence-Toads cause warts

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.”

WHAT SCIENCE SHOULDN'T DO

Avoid faith-Avoid ethical decisions

THE SCIENTIFIC METHOD

Scientific Principles

Scientific Laws

BIOLOGICAL THEORIESThe Cell Theory

Robert HookeAntonie van LeeuwenhoekSchleiden & Schwann

Theory of BiogenesisThe Gene TheoryTheory of Evolution

Charles Darwin & Alfred Wallace