生物学简介英文版.ppt
2-Introduction to Biology1-Why a Study of Biology is Important?lSocietalMedicinePublic Health Worldwide Water Crisis1-Why a Study of Biology is Important?lPhilosophicalEvolutionGenetics1-1-1-Why a Study of Biology is Important?PersonalTo be informedSupport your causeMake it your life work1-bahy-ol-uh-jeelBio = lifel.ology = the study oflBiology is the science that studies life1-The Scientific Method in ActionlA systematic way of gaining information1-The Scientific Method: ObservationlAn observation is a thoughtful and careful recognition of an event or a fact.lThe careful observation of a phenomenon leads to a question.How does this happen?What causes it to occur?1-The Scientific Method:The HypothesislHypothesizing question an observationpropose possible solutions to questions based on what is already understood about the phenomenon lHypotheses must:be logicalaccount for all current informationmake the least possible assumptionsbe testable1-Testing Hypotheses lHypotheses need to be tested to see if they are supported or disproved.Disproved hypotheses are rejectedHypotheses can be supported but not provenlWays to test a hypothesis:Gathering relevant historical informationlRetrospective StudiesMake additional observations from the natural worldExperimentation1-The Scientific Method: ExperimentationlExperimentsrigorous tests to determine if the solutions are supportedlExperiments attempt to recreation an occurrencetests whether or not the hypothesis can be supported or rejectedlThere are many types of experimentslaboratory, clinical trials, surveys, statistical analyses 1-Experimental DesignlAll experiments have key elements in common:Experiments must be controlledlthis means that all aspects except for one variable must be kept constantlusually include any two groups.Experimental group: variable is altered, independent variable Control group: variable is not altered, dependent variableExperiments use models to recreate occurrences, but in a controlled settinglmodel organisms, ISS, cohorts1-Experimental DesignlExperiments must:use large numbers of subjects and/or must be repeated several times (replication)be independently reproduciblelThe validity of experimental results must: be tested statisticallylchi-squared test for statistical significancebe scrutinized by other scientistslpeer reviewed1-TheorylIf the hypothesis is supported by ample experimental data, it leads to a theory.lA theory may be defined as a widely accepted, plausible general statement about a fundamental concept in science.The germ theory states that infectious diseases are caused by microorganisms.lMany diseases are not caused by microorganisms, so we must be careful not to generalize theories too broadly.Theories continue to be testedlExceptions identifiedlModifications made1-A Scientific LawlA scientific law is a uniform and constant fact of nature that describes what happens in nature.An example: All living things come from pre-existing living things.lScientific laws promote the process of generalization.Inductive reasoningSince every bird that has been studied lays eggs, we can generalize that all birds lay eggs.lOnce a theory becomes established, it can be used to predict specific facts.Deductive reasoningWe can predict that a newly discovered bird species will lay eggs.1-Scientific Communication lData is shared with the scientific community through research articles published in scientific journals.peer reviewlScientists present preliminary data at conferences.lScientists collaborate directly by phone and e-mail.1-A Sample ExperimentScientific American August 20101-A Sample ExperimentlArticle: Hardt, Marah J. and Safina, Carl. “Threatening Ocean Life from the Inside Out.” Scientific American August 2010: Vol. 303 2.lWhat types of observations were being made?lState a hypothesis that was tested.lDescribe an experiment that was conducted.lDiscuss a variable that was studied and describe how constants where maintained in the experiment. lHow was a model system was used to simulate the conditions being studied. lHow were the complex processes being studied reduced to their simplest parts?lWhat was learned from the experiments?20The Science of Biology Chapter 1211.1 The Science of Life Biology unifies much of natural life Biology attempts to define life Biology Living reveals a hierarchical organization of living systems222Properties of Life Living organisms:are composed of cells (Cellular Organization)are complex and ordered (Ordered Complexity)respond to their environment (Sensitivity)can Grow, Develop and Reproduceobtain and use energy (Energy Utilization)maintain internal balance (Homeostasis) allow for Evolutionary Adaptation The definitions of life are adapting with the field-where do viruses fit in?23Levels of Organization1. Cellular Level Atoms molecules organelles cells2. Organismal LevelTissues organs organ systems 3.Population LevelPopulation species biological community4. Ecosystem LevelBiological community + physical habitat (
