The Science of The Science of BiologyBiology

Chapter 1Chapter 1

Mrs. MeggsMrs. MeggsFall 2011Fall 2011

What is Science?What is Science?The goal of science The goal of science is to is to investigateinvestigate and and understandunderstand nature, to explain nature, to explain events in nature, events in nature, and to use those and to use those explanations to explanations to make useful make useful predictions. predictions.

Biology= The Study of LifeBiology= The Study of LifeBio- (Life) -logy (Study Bio- (Life) -logy (Study

of)of)

ObservationObservation• Scientific thinking usually begins with Scientific thinking usually begins with

observationobservation– the process of – the process of gathering info about events or gathering info about events or processes in a careful and orderly processes in a careful and orderly way. way. – Generally uses the senses. Generally uses the senses.

DataData- information gathered from - information gathered from observations.observations.There are 2 types of data:There are 2 types of data:1. 1. Quantitative-Quantitative- expressed as numbers expressed as numbers found by counting or measuring.found by counting or measuring.

2. 2. QualitativeQualitative- descriptive and involve - descriptive and involve characteristics that can’t be counted.characteristics that can’t be counted.

Scientists use data to make Scientists use data to make inferencesinferences – a logical – a logical interpretation of data or interpretation of data or evidence collected.evidence collected.

Scientific MethodScientific Method1.1. Define the problemDefine the problem2.2. Form a hypothesisForm a hypothesis3.3. Test the hypothesis (controlled Test the hypothesis (controlled

experiments)experiments)4.4. Analyze dataAnalyze data5.5. Draw conclusions and Record resultsDraw conclusions and Record results

Defining Scientific MethodDefining Scientific Method• Hypothesis – possible explanation of Hypothesis – possible explanation of

a problema problem– It must be testableIt must be testable– Stated as “If ……then……” formatStated as “If ……then……” format

Controlled ExperimentControlled Experiment• An experiment in which a single An experiment in which a single variablevariable is is

changed in one set up but not in the other.changed in one set up but not in the other.• ControlControl – the standard in which all – the standard in which all

conditions are kept the sameconditions are kept the same• Independent VariableIndependent Variable – the condition that – the condition that

is changed. is changed. – (Manipulated variable, x-axis)(Manipulated variable, x-axis)

• Dependent VariableDependent Variable – the measurable – the measurable condition that RESULTS from changing the condition that RESULTS from changing the Independent variable. Independent variable. – (Responding variable, y-axis)(Responding variable, y-axis)

ReplicationReplication• Repeating investigations: a key idea Repeating investigations: a key idea

in science is that experimental in science is that experimental results can be repeated--- if the results can be repeated--- if the results change each time, then the results change each time, then the experiment is not considered valid. experiment is not considered valid.

Scientific TheoriesScientific Theories A theory attempts to explain A theory attempts to explain

everything about a phenomenon everything about a phenomenon including it’s cause.including it’s cause.

• Examples: Examples: – The Big Bang TheoryThe Big Bang Theory– EvolutionEvolution

Scientific LawScientific Law•A statement that describes A statement that describes

some aspect of a some aspect of a phenomenon that is TRUEphenomenon that is TRUE

•Does not explain how or why Does not explain how or why – Example: The law of gravityExample: The law of gravity

Studying Life- Branches of Studying Life- Branches of BiologyBiology• Botany – study of plantsBotany – study of plants• Zoology – study of animalsZoology – study of animals• Ecology – study of interactions between Ecology – study of interactions between

living things and their environmentliving things and their environment• Genetics – study of heredityGenetics – study of heredity• Microbiology – study of microorganismsMicrobiology – study of microorganisms• Evolution – study of living things Evolution – study of living things

changing over timechanging over time• Biochemistry – study of organic Biochemistry – study of organic

molecules molecules

Spontaneous GenerationSpontaneous GenerationPasteur- tested the hypothesis of spontaneous Pasteur- tested the hypothesis of spontaneous generation. generation. – He showed that living things come from other living He showed that living things come from other living

things. things.

8 Characteristics of Living 8 Characteristics of Living ThingsThingsComposed of CellsComposed of Cells Have a genetic codeHave a genetic code

ReproduceReproduce Respond to their Respond to their environmentenvironment

Obtain and use Obtain and use materials and energymaterials and energy

Grow and developGrow and develop

Change over time- Change over time- “Evolution”“Evolution”

Maintain homeostasisMaintain homeostasis

Made up of CellsMade up of Cells• Cells – smallest unit of lifeCells – smallest unit of life1.1. Unicellular organisms- consist of Unicellular organisms- consist of

only a single cellonly a single cell2.2. Multicellular organisms- contain Multicellular organisms- contain

more than one cellmore than one cell- The human body has over 85 The human body has over 85

different types of cells.different types of cells.

ReproduceReproduce2 types of reproduction:2 types of reproduction:1.1. Sexual ReproductionSexual Reproduction- cells from two - cells from two

different parents unite to form the different parents unite to form the first cell of a new organismfirst cell of a new organism

2.2. Asexual ReproductionAsexual Reproduction- new - new organism has a single parent (ex.- organism has a single parent (ex.- hydra)hydra)

Genetic CodeGenetic Code• Directions for Directions for

inheritance come inheritance come from DNAfrom DNA

Grow and DevelopGrow and Develop• Life cycles involve growth and development

Obtain and Use Obtain and Use Materials and EnergyMaterials and Energy

1.1. Metabolism:Metabolism: chemical reactions chemical reactions through which organisms break down through which organisms break down materialsmaterials

2.2. Photosynthesis:Photosynthesis: the way plants, most the way plants, most algae, and some bacteria obtain their algae, and some bacteria obtain their energy- process of converting light energy- process of converting light energy into stored energy.energy into stored energy.

3.3. Decomposers:Decomposers: obtain materials from obtain materials from remains of dead organismsremains of dead organisms

Respond to the environmentRespond to the environment• Organisms respond to stimuli from the Organisms respond to stimuli from the

environment – (ex: light, temperature, environment – (ex: light, temperature, food) food)

Ex- hungerEx- hunger Maintain internal balanceMaintain internal balance

•Homeostasis-process by which organisms Homeostasis-process by which organisms maintain a stable internal balance– to stay the maintain a stable internal balance– to stay the same.same.Ex. – body temperatureEx. – body temperature

Change over timeChange over time• Evolution- a Evolution- a

change in an change in an organism organism over time over time

Levels of Organization in Levels of Organization in BiologyBiology(See graphic on pg. 21) - From smallest to largest (See graphic on pg. 21) - From smallest to largest

and least complex to most complexand least complex to most complex1.1. MoleculesMolecules2.2. CellsCells3.3. Groups of CellsGroups of Cells4.4. OrganismOrganism5.5. PopulationPopulation6.6. CommunityCommunity7.7. EcosystemEcosystem8.8. BiosphereBiosphere

MeasurementsMeasurements• Scientists use a Scientists use a

universal system of universal system of measurement measurement called called Systeme Systeme InternationalInternational (SI) or (SI) or the the Metric Metric SystemSystem

• Importance of a Importance of a common system – common system – allows scientists all allows scientists all over the world to over the world to communicate with communicate with each other and each other and share data.share data.

Units of Measurement- SI Units of Measurement- SI UnitsUnitsDistanceDistance MeterMeter

VolumeVolume LiterLiter

TemperatureTemperature Kelvin– Degree Kelvin– Degree Celsius is commonly Celsius is commonly used in Scienceused in Science

MassMass GramGram

Common PrefixesCommon PrefixesKiloKilo 1 000 X (thousand)1 000 X (thousand)HectoHecto 100 X (hundred)100 X (hundred)DecaDeca 10 X (ten)10 X (ten)UNITUNITDeciDeci 0. 1 X (tenth)0. 1 X (tenth)CentiCenti 0.01 X (hundredth0.01 X (hundredthMilliMilli 0.001 X (thousandth)0.001 X (thousandth)

Sample ProblemsSample Problems• 25.8 g = __________ kg25.8 g = __________ kg• 1000 g = _________ kg1000 g = _________ kg• 45.9 cm = ________ m45.9 cm = ________ m• 100 m = __________ mm100 m = __________ mm• 75.2 mL = ________ L75.2 mL = ________ L• 10 dm = __________ m10 dm = __________ m• 27 L = ____________ kL27 L = ____________ kL

Sample ProblemsSample Problems• 25.8 g = .0258 kg25.8 g = .0258 kg• 1000 g = 1 kg1000 g = 1 kg• 45.9 cm = .459 m45.9 cm = .459 m• 100 m = 100 000 mm100 m = 100 000 mm• 75.2 mL = .0752 L75.2 mL = .0752 L• 10 dm = 1.0 m10 dm = 1.0 m• 27 L = .027 kL27 L = .027 kL

Analyzing DataAnalyzing Data• Scientists often use graphs to Scientists often use graphs to

analzye data:analzye data:Line graphs, pie charts, bar graphsLine graphs, pie charts, bar graphs

Line graphsLine graphsWhen graphing the data from an experiment--

•The graph should have a title•The graph should be drawn to scale•Independent variable (manipulated variable)- goes on the X axisDependent variable (resulting variable) –goes on the Y axis

Tools of the Trade:Tools of the Trade:The MicroscopeThe Microscope

• Allows scientists to Allows scientists to see objects that see objects that would never be would never be seen with the seen with the unaided eyeunaided eye

Three Types of MicroscopesThree Types of Microscopes• Simple MicroscopeSimple Microscope

– Consists of only a – Consists of only a single lenssingle lens

• Light MicroscopeLight Microscope – – consists of two lens. consists of two lens. One lens magnifies One lens magnifies the object and the the object and the other magnifies other magnifies image.image.

• Electron MicroscopeElectron Microscope – electron beams are – electron beams are passed through the passed through the specimen and the specimen and the image is projected image is projected onto a monitor. onto a monitor. Better resolution and Better resolution and magnification. Two magnification. Two types – TEM and SEMtypes – TEM and SEM

Lab TechniquesLab Techniques

1.1. Cell cultures- single cell in a Cell cultures- single cell in a nutrient solution– then that cell nutrient solution– then that cell produces many cellsproduces many cells

2.2. Cell fractionation- cell is separated Cell fractionation- cell is separated into different cell partsinto different cell parts