1-3 The study of Biology

Objectives Outline the steps of the scientific method Summarize how observations are used to form hypothesis List the elements of a controlled experiment Describe how scientists use data to draw conclusions Compare a hypothesis and theory State how communication & peer review prevent dishonesty

Scientific Method Organized approach –Natural causes Not supernatural Have to be able to disprove something –Uniformity: The laws of nature are the same everywhere

Steps of method 1.Observation 2.Hypothesis 3.Prediction 4.Exeperiment 5.Analyze data 6.Communicate findings

Experimental design Control Groups: provide a normal standard Experimental Group: Different from control by 1 factor  the independent variable Dependant variable: what is affected by independent variable

Quantitative vs. Qualitative

Analyzing Data Is the data reliable? Does it support your hypothesis or not?

Conclusions Can’t prove much Theories: when hypothesis is confirmed many times and it explains a lot Law: Theories that have been confirmed many many times Beyond a doubt

Scientific Method Bacon ( ) and Descartes ( ) –were not scientists but did invent new habits of scientific thought scientific method as habits of disciplined creativity, careful observations, logical thinking & analysis of observations way of seeking trends & drawing generalizations Convinced governments of England & France to form academies of science that still exist today Scientific way of thinking based on assumptions & methods that are reliable, objective & testable

Inductive Method Making observations until capable of drawing generalizations and making predictions –anatomy is a product of inductive method Proof in science can not go past “proved beyond reasonable doubt” –reliable methods of observation –tested and confirmed repeatedly –not falsified by any credible observation In science, all truth is tentative

Hypothetico-Deductive Method Physiological knowledge gained by this method Ask a question and formulate a hypothesis -- an educated possible answer Good hypothesis –consistent with what is already known –capable of being tested and falsified with certain evidence If nothing could prove it wrong, it is not a scientific belief Hypotheses are written as If-Then predictions –modified and rewritten after testing

Experimental Design Sufficient sample size to prevent chance event Control group and treatment group receive the same treatment except for the variable being tested Prevention of psychosomatic effects –use of placebo in control group Experimenter bias –prevented with double-blind study Statistical testing to be sure the difference between groups was not random, but was due to variable being tested

Peer Review Critical evaluation by other experts in the field –prior to funding –verification and repeatability of results Ensures honesty, objectivity & quality in science

Health Minister Manto Tshabalala-Msimang of South Africa, known for putting vegetable remedies ahead of anti-retrovirals, endorses Dr Matthias Rath's vitamin treatments.

Dr. Rath and his cure for AIDS: Mega Doses of Vitamin C A doctor who worked with Nobel Prize winner Linus Pauling has taken the advocacy of vitamins into all-out war on the pharmaceutical companies Buys ad space in the NY Times, and fills them with editorials masked as facts Without getting confirmation of his studies is taking his cure to the people of Africa Problems: Too much Vitamin C can lead to Diarrhea which can kill an AIDS patient.

Facts, Laws and Theories Scientific fact is information that can be independently verified by any trained person –iron deficiency leads to anemia Law of nature is a description of the way matter and energy behave –resulting from inductive reasoning & repeated observations –written as verbal statements or mathematical formulae Theory is a summary of conclusions drawn from observable facts –it provides explanations and predictions –sliding filament theory of muscle contraction

Logic is the anatomy of thought -John Locke Conditional arguments: the basis of hypothesis forming. Two parts Part 1: If p then q –P = antecedent –Q = Consequent Part 2 allows us to draw conclusions –If P happens then Q happens (Modus Ponens –If Q did not happen, P did not happen (Modus Tollens)

There is a claim that lycopene, the reddish substance in tomatoes and peppers, is of value in protecting people from Alzheimer Disease. How would you, as a scientist, go about substantiating or refuting this suggestion?