Welcome toBiol 178Principles of BiologyCourse goalsCourse informationTextGradingSyllabusLabChapter Organization

Chapter OrganizationConcept OutlineTextConcept ReviewTest Your UnderstandingTest Your Visual Understanding

Lecture OutlineDefinition of LifeProperties of LifeHierarchical OrganizationUnifying Themes of ScienceScientific Method

What is Biology?Study of life

Search for order in the natural world

Discovery of new relationships

Learn working rules that allow life to exist

Properties of LifeCellular organizationOrderSensitivityGrowth, development, and reproductionGenetic system DNAEnergy utilizationEvolutionary adaptationHomeostasis

Hierarchical Organization of LifePopulation LevelOrganism LevelCell Level

LifeLevels of OrganizationPopulationsAmong OrganismsBiosphereEcosystemCommunityPopulation

LifeLevels of OrganizationWithin OrganismsOrgan systemsOrgansTissuesCells

LifeLevels of OrganizationWithin CellsOrganellesMacromoleculesMolecules & Atoms

LifeLevels of OrganizationAmong organismsWithin OrganismsWithin Cells

Consequences of Hierarchical organization Emergent propertiesNew properties arise at each higher levelMake life difficult to define

Unifying Themes of Science1. Cell theoryAll living organisms are made of cells, and all living cells come from other living cells.

2. Molecular basis of inheritanceDNA encodes genes Genes make-up & control living organisms.

Unifying Themes of Science3. Evolutionary changeLife-forms have evolved varying characteristics to adapt to varied environments.

4. Evolutionary conservationSome characteristics of earlier organisms are preserved and passed on to future generations.

Summary: Unifying Themes of Science1. Cell theory2. Molecular basis of inheritance3. Evolutionary change4. Evolutionary conservation

Scientific Inquiry How is Science Done?Discovery ScienceObservingMeasuring

Hypothesis-based ScienceScientific MethodProposing & Testing hypothesesInductive & deductive logic

ReasoningDeductive reasoningApply general principles to predict specific results

Inductive reasoningUse specific observations to construct general principles

How Science Is Done1. Observation: Begins science2. Hypothesis: accounts for observationsEducated guessInductive Reasoning Generalization3. Prediction: Allows test of hypothesis validityDeductive Reasoning specific outcome4. Experiment: Tests hypothesis validity5. Controlled experiment:One variableControl

How Science Is Done

Limitations of ScienceHypothesis can NOT be proven true

Truth TableHypothesisPredictionTrue TrueFalse False or True

Limitations of ScienceScience does not prove hypotheses are true.

Science proves that some hypotheses are not true.

Hypotheses not proven false are conditionally accepted.

Hypotheses, Theories & LawsHypothesis a tentative explanation.

Scientific TheoryAccepted explanation.Supported by experimental evidence.Solid ground of science.A well-supported hypothesis.

Scientific LawScientific knowledge accepted as true.An extremely well-supported hypothesis.

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