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Patrick Dampare 1Lecture 1 – What is Biology?Biology - the science of living things and their interactions with each other and the physical world. Science attempts to explain nature by generating and testing alternative explanations.Do climatic differences cause biome differences? (Alphonse de Candolle 1855)• Wladimir Köppen:–temperature ranges: cold, warm, hot–moisture ranges: dry, moist, wet• Nine climate types–cold/dry, cold/moist, cold/wet, warm/dry, warm/moist, warm/wet, hot/dry, hot/moist and hot/wet;• Searched for “link” between climate and biome typeLecture 2 – How do experiments test hypotheses?• controlled experiment “Fair" test - values of only one independent variable differ; others held constant ("controlled“).• independent variable: Input, manipulated, causal variable; stimulus; values vary to see if this causes a change in outcome.• dependent variable: Outcome variable, effect; response; values may vary in response to changes in values of independent variable.• in math: x is independent variable; y dependent variable; y = f(x), values of y a “function” of values of xWhy do we want to test alternative hypotheses?• Biological research is often motivated by curiosity• Basic research is designed to describe or explain nature to satisfy one’s curiosity–Such research may lead to important applications–Or generate new questions (e.g. list species in an area)• Hypothesis testing for practical reasons is called applied researchTypes of evidence• circumstantial evidence: circumstances usually linked to cause (e.g., wet street is usually caused by rain, thus wet street in morning supports the hypothesis that the pitter patter on roof lastnight was caused by rain)• correlational evidence: extent to which values of two variables, which have been predicted to be “linked,” are correlated• experimental evidence: direct or indirect manipulation of independent/causal variablesLecture 3 – Why do gazelles leap when being chased?• causal question: Question about cause of puzzling• observation: e.g., Why does vegetation change from place to place? Why do giraffes have long necks?• hypothesis (plural, hypotheses): Possible cause of puzzling observation – possible explanation.• planned test: Conditions to test a hypothesis.• prediction: Statement of expected (future) outcome of test - assuming that hypothesis is correct.--• Bias – a tendency or inclination in favor of one explanation or belief that prevents unprejudiced consideration of alternatives• variable: Characteristic/property/trait with values that differ; e.g., the number of times the gazelle stotts; student heights; Opposite of constant.• value: Quantity, magnitude, number or rank of a variable; e.g., values of the gender variable are male and female; values for the height variable are 5’10”, 6’2”.• deduction: If/and/then reasoning, hypothesis + planned test gives prediction (expected result).• observed result Outcome, evidence, data (compare with prediction).• conclusion: hypothesis supported, contradicted, or not sure.• constant Characteristic with values that do not differ; e.g., number of noses in a group of students.• correlation: Mutual or co-relation of two or more things, parts, variables.The placebo effect• Placebo = Latin for ’I will please’• Defined in 1811 as "any medicine adapted more to please than to benefit the patient”• Was widespread in medicine, before real medicine became more reliable• The end of practicing placebo as treatment may have ended in 1890How do experiments test hypotheses (II)?Clinical research• Extremely important applied research•Medical researchers must know everything about how to run controlled experiments• Why is this important? Because, if they mess this up, people may die!• Goal: To obtain information about adverse drug reactions and efficacy of drug• Health authorities must give approval before a clinical trial starts• This is evidence-based medicine--• Pre-clinical studies: before testing in humans–In vitro: Test drug on cell cultures in test tubes–In vivo: Test drug on animals• Phase 0 – pilot studies–First human trial–A very low dose is given to 10-15 volunteers to see if there are any unexpected effects on the human body or how the body affects the drug–Sometimes many similar drugs are tested in the same trial, and then ranked by performance• Phase 1 – First real clinical human trial•Safety•Tolerability•Effect•Dose-ranging–Takes place in a clinic, usually independent of the pharmaceutical company•Test subjects are observed continuously–Test subjects usually 20-100 healthy volunteers•Occasionally also tested on terminally ill cancer- or HIV patients• Phase II–Larger test group (100-300) of volunteers and patients–Assess efficacy–Assess dosing requirements–Monitoring safety• Some tests may be randomized clinical trials–subject receives either the drug or placebo/standard treatment• Phase III–The final assessment–Randomized clinical trials on large groups (300-3000)–Expensive and time consumingPatrick Dampare 2• Minimum two Phase III trials are usually needed to get approval from federal agencies• Phase IV–Post-marketing surveillance–Ongoing technical support–Try to detect rare or long-term adverse effectsIt takes time•It takes years from a new medication is discovered until you can get it prescribed•E.g., a new cancer drug–6 years pre-clinical studies–8 years clinical trials•Why?–It takes time to see effects on chronically ill patients–It takes time to gather enough volunteers•Weak medications need large sample size to detect effects•The target group may be small, limited number of patientsLecture 5 – Who discovered oxygen?• theory: Statements (claims, postulates,propositions) that together explain a class ofrelated phenomena.• How do hypotheses and theories differ?How are they similar?– complexity– generality– abstractnessModern Combustion Theory1. Matter consists of atoms and combinations of atoms called molecules.2. Atoms combine with and separate from other atoms.3. During combustion (burning) oxygen atoms from the air combine with atoms of the burning material.4. Combustion stops when a sufficient supply of oxygen atoms is gone.Lecture 6 – Is there a vital force?The theory of spontaneous generation•They believed that a vital force gave life to dead or

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ASU BIO 100 - Lecture notes

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