BIOLOGY 1030

SUMMER 1999

UNIT I. AN INTRODUCTION TO BIOLOGICAL SCIENCE

 

science vs pseudoscience vs not science	controlled experiment vs experimental control
inductive vs deductive reasoning	dependent vs independent variables
null hypothesis vs alternative hypothesis	mean and standard deviation
placebo effect	t-test

1. What is science?
1. way of knowing
2. tries to explain the universe on the basis of measurable forces causing measurable changes
3. contrast with social sciences and religion
1. reliance on observation not authority
2. reliance on explanation not acceptance
4. contrast with pseudoscience
1. pseudosciences claim that phenomenon is caused by an as yet unknown, unmeasurable force
2. forces known to science include
1. gravity
2. electromangetic forces
3. strong nuclear force
4. weak nuclear forces
3. examples of pseudoscience
1. creation science
2. astrology
3. esp, telekinesis, etc
4. science seeks to explain not exclaim
1. are the forces measurable, therefore understandable
2. do alternative explanations exists involving measurable forces
3. extraordinary claims require extraordinary evidence
1. are UFO's piloted by extraterrestrials
2. Scientific method
1. process to explain phenomenon in terms of measurable forces
2. typically proceeds in four phases
1. inductive step--formulating explanations
1. formulate a problem
2. gather information and observations
1. great care must be taken at this step
1. what is the position of the moon
2. flatworm mazes
3. praying mantis eats mate
4. The Mismeasure of Man by S. J. Gould
3. formulate an explanation of the observations
1. the sun will rise tomorrow is not a hypothesis; the sun will rise tomorrow because the sun orbits the earth is a (wrong) hypothesis; the sun will rise tomorrow because the Earth rotates on its axis is a (correct) hypothesis
2. there is a progression in the fossil record because organisms have evolved over time
2. deductive step--testing competing explanations
1. often we test the ability of the explanation or hypothesis to predict the outcome of additional observations
1. the position of the sun and the planets at any time is predictable
2. evolution should be evident in things besides the fossil record
2. controlled experiments allow direct tests
1. define variables involved; usually many independent variables influencing a few dependent variables
2. set up an experiment where only one indepedent variable is allowed to change, measure the effects of that change on the dependent variable
3. analyze the results
1. experimental controls - used for comparison
1. placebo effect
2. statistical and graphical analysis
1. mean, median, mode, and standard deviation
2. scatterplots and histograms
3. t-tests and more advanced statistical analysis
3. modify hypothesis in light of the results from the test as necessary and repeat the deductive step
4. publish findings so can be evaluated by others
1. scientific reports must include the following information
1. the purpose of the investigation or experiment including information concerning the hypotheses to be tested
2. the methods used in the investigation
3. the results of the investigation in a readable form (graphs, tables, etc., are especially helpful)
4. the conclusions drawn from the results: what do the results mean, what changes do we need to make in our hypotheses
5. a few refinements and warnings
1. hypothesis should be simple (Occam's Razor)
2. some experiments may never give clear results
1. are there any untouched field sites - earth ecology?
3. repeat experiments as often as possible; this is especially important in biology where it is very difficult to hold all variables but one constant, and not all variables can be measured precisely
1. often effects are minimal (cancer) so look for statistical effects
2. aspirin and heart
6. examples
1. medical experiments
2. why are there so many species?
1. four hypotheses
1. special creation in the Garden of Eden (Biblical)
2. special creation in multiple Gardens of Eden (de Buffon)
3. Lamarckian evolution evolution by means of acquired characteristics
1. ultimately relies on unmeasureable, unknown force
2. inheritance of acquired characteristics -- doesn't happen
4. Darwinian evolution evolution by means of natural selection
1. forces known
2. survives tests
1. fossil record -- evolution
2. homology -- relatedness and evolution
3. embryology -- relatedness and evolution
2. Darwinian evolution accepted as the scientific explanation

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