I. Chapter 1: Life and the Scientific MethodThe Characteristics of LifeWhat is a living thing?Living things must:*have a different molecular structure than non living thingsproteins, carbohydrates, lipids, nucleic acids*take in, transform, and use energywe don’t make energy, but humans take energy*Composed of cellsa cell is the smallest unit of living*maintain homeostasis*respond to external envirement*have populations that evolve*growth & reproduceuse info stored in DNAViruses (not alive)Reproduce with a host cell, have DNA, other viruses have RNANot made of cellsCant take in/use energyFor something to be alive it must have all characteristicsBees- AliveWhere do humans fit in the world?3 domain classificationdivided into different domains according to cell typeDoes organism have cells with a nucleus (Eukaryotic) or with out a nucleus (prokaryotic)?Divided into different domains according to shared genetic.Domain bacteriaKingdom bacteriaDomain ArchaeaKingdom ArchaeaDomain EukaryaProtistaAnimaliaFungiPlantaeClassification of humas:Domain EukaryaKingdom AnimiliaPhylom Chordates (spinal cord)Order primatesFamily hominids (walk on 2 feet)Genus homoSpecies homo sapiensGO TO SIHuman Biology LectureJanuary 23rdChannel 16Smallest unit of classification system is speciesSimilar physical and functional characteristicsCan interbreed and produce fertile offspring2nd smallest unit is genusAll living human beings belong to the same genus and speciesHomo sapiensBipedalism - able to stand upright and walk on two legsOpposable thumbs - able to grasp objects between thumb and tips of fingersLarge brain - relative to body sizeCapacity for language - both spoken and writtenHuman Biology can be studied on many different levels of organization.AtomMoleculeCellTissueOrganOrgan systemCommunityOrganismEcosystemBiosphereScience Is Both a body of knowledge and a processScience is the study of the natural worldBiology specifically studies living thingsScience is two things:Knowledge about the natural worldThe process used to acquire knowledgeCalled the Scientific MethodSteps in the Scientific Method1. Observe and generalize2. Formulate a hypothesis3. Make a testable prediction4. Experiment or observe5. Draw a conclusion6. Modify the hypothesis as necessary and repeat1. Make observations about the natural world.Ask a question or make generalizations based on observations.“Every winter in the past was colder than the preceding summer.”“Winter will always be colder than summer.”2. A hypothesis is a tentative statement about how things may work in the natural world.A hypothesis must be testable and potentially able to be proven incorrect.3. Should be based on the hypothesis.Are often in the form of “if then statements”4. Used to test accuracy of the hypothesisAn experiment should be designed to eliminate other possible explanations for the results.For example: set up two experimental groups that differ in only one variableA good experiment uses controls as a basis of comparison.5. The conclusion may be that the experimental data supports or fails to support the hypothesis.We never say that the experiment “proves” the hypothesis.Why not?Because we may discover more data in future experiments or with more advanced technology that disproves the hypothesisModify the hypothesis as necessary and repeat steps 3 through 5If prediction is not supported, the hypothesis must be modified.If the prediction is supported, only one small part of the hypothesis has been tested. Further testing required.Findings can be disseminated in:Peer reviewed journalsExperts must approve articles before publicationExperiments are sometimes repeated or critiqued; conclusions are debatedPopular pressElectronic publicationsInternet is less regulated than print and broadcast media.For a hypothesis to become a Scientific Theory it must:Be broadBe extensively testedBe supported over timeExplain a broad range of factsHave a high degree of reliabilityTheories may be refuted in the future.In this course, learn to think like a scientist!Be a skepticAppreciate the value of statisticsLearn to read graphicsDistinguish anecdotes from scientific evidenceSeparate facts from conclusionsUnderstand the differences between correlation and causationRole of Science in SocietyScience improves technology and the human conditionScience has limitsScience helps us to make informed choicesStudy guide questions:List the 7 characteristics that all living things must have.If something has some of the characteristics of living things, but not all, is it still a living thing?Chapter 2: The Chemistry of Living ThingsAll matter on Earth is made of Elements:Cannot be broken down to a simpler form.Iron, gold, potassium, helium, carbonH: Hydrogen C: CarbonAtoms: Smallest functional unit of elementsAn atom is the smallest unit that has all an elements physical and chemical properties.Consist of protons, neutrons and electronsProtonsPositive charge, have massFound in nucleus, core of atomNeutronsNo charge (neutral) have massAlso found in nucleus of atomElectronsNegative charge, no massFound orbiting atom’s nucleus in shellsEach element has a unique Atomic Number (above the symbol)Defined by the number of protonsE.g., Hydrogen has 1 proton, Phosphorus (P) has 15 protonsAtomic Mass (below the symbol)Equal to number of protons + neutronsIn an electrically neutral atom, number of protons = number of electronsThat is, positive charges = negative chargesIsotopes have a different number of neutronsSame number of protons, different of neutronsIsotopes are forms of an element with a different number of neutrons than the usual numberSame atomic number (same number of protons)Different atomic mass (different number of neutrons)E.g., 3 forms of Hydrogen exist in natureUnstable isotopes are called radioisotopesRadioisotopes give off energy (radiation)Some are harmful to humansUsed for determining age of fossils (14C)Some are useful in medicine6  atomic number= ProtonsC12.011  atomic mass = Protons + neutronsLecture January 28thHuman BiologyIons have a different number of electronsAn atom may gain or lose electrons in chemical reactions.Therefor no longer has the same number of protons and electronsNo longer neutralCan be positively or negatively chargedThese charged atoms are called ions– H+, Na+,Example: Na (sodium)#11 = 11 protons11 electronsNa +11 protons +10 electrons –Ions – no longer have even number, how do you know?Positive or negative sign after