CHAPTER 1 Introduction: Themes in the Study of Life

1 CHAPTER1 introduction : Themes in the Study of Life2. Evolution and the Diversity of Life3. The Process of Scientific Inquiry1. Unifying Themes in Themes in BiologyChapter Reading pp. 1-9 OrderEvolutionary adaptationResponseto theenvironmentReproductionGrowth anddevelopmentEnergyprocessingRegulation Characteristics of LifeThe biosphereEcosystemsTissuesOrgans andorgan systemsCommunitiesPopulationsOrganismsOr ganellesCellsAtomsMoleculesLevels of Biological OrganizationAnimals eatleaves and fruitfrom the take incarbon dioxidefrom the airand fall tothe ground andare decomposedby organismsthat returnminerals to andminerals inthe soil aretaken up bythe treethroughits absorblight energy fromthe of Chemical NutrientsHEATP roducers absorb lightenergy and transform it intochemical energy infood is transferredfrom plants toconsumers.(b) Using energy to do work(a) Energy flow from sunlight toproducers to consumersSUNLIGHTAn animal s musclecells convertchemical energyfrom food to kineticenergy, the energyof energy is usedto do work, someenergy is converted tothermal energy, whichis lost as plant s cells usechemical energy to dowork such as growingnew Flow through EcosystemsEnergy flow through ecosystems is one way.

2 Sunlight producers HEATHEATHEAT(a) Wings(c) Neurons(b) BonesInfoldings ofmembraneMitochondrion(d) m100 mStructure Correlates w/Function1 mOrganellesNucleus (contains DNA)CytoplasmMembraneDNA(no nucleus)MembraneEukaryotic cellProkaryotic cellCells are the Basic Unit of LifeNucleusDNACellNucleotide(a) DNA double helix(b) Single strand of DNADNA is the Basis of InheritanceNucleicontainingDNAS perm cellEgg cellFertilized eggwith DNA fromboth parentsEmbryo s cells withcopies of inherited DNAO ffspring with traitsinherited fromboth parentsSexual Reproduction providesGenetic DiversitySexual reproduction involves the union of gametes seen in the Kingdoms Animalia, Plantae, FungiNegativefeedback Excess Dblocksa stepDDDABCE nzyme 1 Enzyme 2 Enzyme 3D(a) Negative feedbackWEnzyme 4 XPositivefeedbackEnzyme 5Y+Enzyme 6 Excess ZstimulatesastepZZZZ(b) Positive feedbackRegulation ofBiologicalProcessesNegative Feedback counteract change in order to restore original statePositive Feedback proceed further in direction of change toward new state2.

3 Evolution & the Diversity of LifeChapter Reading pp. 10-14 SpeciesGenusFamilyOrderClassPhylumKingdo mDomainUrsusamericanus(American black bear)UrsusUrsidaeCarnivoraMammaliaChorda taAnimaliaEukaryaClassification by Taxonomy(a) Domain Bacteria(b) Domain Archaea(c) Domain Eukarya2 m2 m100 mKingdom PlantaeKingdom FungiProtistsKingdom AnimaliaThe Domains of LifeDiversity via EvolutionEvolution explains the diversity of life, both past and present descent with modification through Natural Selection explains the diversity of lifetoday as well as the fossil record first proposed by Charles Darwin and Alfred WallacePopulation withvaried inheritedtraitsElimination ofindividuals withcertain traitsReproduction ofsurvivorsIncreasing frequency oftraits thatenhancesurvival andreproductivesuccess1234 The Process of Natural Selection selective factorsin the environment favor thesurvival of individuals with certain traits and the transmission of those traits to the next generationCOMMONANCESTORW arbler finchesInsect-eatersSeed-eaterBud-eaterI nsect-eatersTree finchesGreen warbler finch Certhidea olivaceaGray warbler finch Certhidea fuscaSharp-beakedground finch Geospiza difficilisVegetarian finch Platyspiza crassirostrisMangrove finch Cactospiza heliobatesWoodpecker finch Cactospiza pallidaMedium tree finch CamarhynchuspauperLarge tree finch Camarhynchus psittaculaSmall tree finch

4 Camarhynchus parvulusLarge cactusground finchGeospiza conirostrisCactus ground finchGeospiza scandensSmall ground finchGeospiza fuliginosaMedium ground finchGeospiza fortisLarge ground finchGeospiza magnirostrisGround finchesSeed-eatersCactus-flower-eatersAn Evolutionary Tree3. The Process of Scientific InquiryChapter Reading pp. 16-21 The Scientific MethodObservation > Hypothesis> Experiment> Conclusion predicts an answer to the question of , Does vitamin D help prevent colds? A good hypothesis is a statement that: contains only objective, well-defined terms can be tested or challenged experimentally scientific investigation begins with an observationthat leads to a question (ideally Yes/No ) People who take vitamin D are less likely to get colds. *A good hypothesis doesn t have to be correct, just testable!*Variables in ExperimentsHypotheses are tested experimentally, and experiments contain variables:DependentVariables (DV) outcome being measured or recorded , occurrence of coldsIndependentVariable (IV) the single factor that varies in an experiment , whether or not one takes a vitamin D supplementStandardizedVariables (SV) all other factors that remain constant , age, gender, location, stress level, DesignIdeally experiments have 1 independent variable.

5 In this way any changes in the results (dependent variable) can beattributed to the singleIV you tested >1 IV makes it unclear which IV affected the DV!**In an experiment, the IV is tested for its effect on the DV**ObservationQuestionHypothesis #1:Dead batteriesHypothesis #2:Burnt-out bulbPrediction:Replacing bulbwill fix problemTest of predictionTest of predictionTest falsifies hypothesisTest does not falsify hypothesisPrediction:Replacing batterieswill fix , if she changes boththe batteries andthe bulb (2 IVs), she won t be able to determine which, if either, wasn t workingControl ExperimentsEvery experiment should ideally include a testin which the IV is set to zero or some default value, a test referred to as a control: leave out the IV ( , no Vitamin D) if IV can t be left out ( , temperature), set it to adefault or background level ( , room temperature)This sort of test is also called a negative control. Positive controls(tests that give a known positiveresult) are also appropriate for some experiments.

6 **Controls provide a reference for comparison in additionverifying that the experimental results are reliable**Interpreting Experimental ResultsExperimental results (data) are then interpreted to either supportor disprovethe hypothesis: a hypothesis can neverbe proven, only supported an experimental result that is inconsistentwith ahypothesis reveals it to be incorrect!Scientific Theories in contrast to a hypothesis, a theoryis a very general, broad concept that is supported by a vast body of evidence and experimentation , Theory of Evolution , Cell Theory , Germ Theory South CarolinaNorth CarolinaKeyScarlet kingsnake (nonpoisonous)Scarlet kingsnake (nonpoisonous)Eastern coral snake (poisonous)Range of scarletkingsnake onlyOverlapping ranges ofscarlet kingsnake andeastern coral snakeCase Study in Scientific Inquiry(a) Artificial kingsnake(b) Brown artificial snake that has been attackedTesting the HypothesisHypothesis: Kingsnakemimicry of coral snakes provides protection from predators onlywithin the coral snake habitat.

7 Experiment (test):Plant equal amounts of fakekingsnakesand control snakes in habitats with and w/ocoral snakes, determine percent of fake snakes groupcontrol groupArtificialkingsnakesBrownartificial snakesPercent of total attackson artificial snakes83%84%100806040200 Coral snakesabsentCoral snakespresent17%16%RESULTSR esults and ConclusionHypothesissupported!Key Terms for CHAPTER 1 hypothesis vstheory variables: independent, dependent, standardized homeostasis positive & negative control experimentsRelevant CHAPTER Questions 1, 2, 5-8, 10