The Science of Biology

Chapter 1

EarthBiosphere includes all living things and the

places they live.Biodiversity (variety of organisms)

increases from the poles to the equator.All species are included in an area’s

biodiversity.A species is a group of closely related

organisms that can successfully reproduce.

Goal of science Investigate and understand the natural

worldExplain events in the natural worldMake predictionsBiology is the study of living things and

their interactions with their environments.

Ancient ScienceAsians – herbal medicinesSouth Americans – developed crop

domestication and irrigationEgyptians – mummification of royaltyGreeks

Hippocrates – human body is made of humours

Aristotle – first classification of organisms

Scientific revolutionScience is limited by rules of society and

government15th century gave rise to study of human

and animal bodies; dissection of corpses aided the understanding of the human body

New technologies (microscopes) allowed discovery of cells and microorganisms

Characteristics of living things Organization – structured; made of cells Energy- energy needed for metabolism Reproduction – produce offspring Growth and development – increase number of

cells and change Respond to stimuli – react to changes Adaptation – adjust to changes in environment Homeostasis – control internal environment

HomeostasisControlling internal temperature, blood

sugar, acidity, and other conditionsMaintained by negative feedback

EvolutionChange in living things over timePart of unity and diversity (similarities and

differences) of lifeCan occur through natural selection of

adaptationsStructures, behaviors, internal processes,

and interactions result from evolutionDoes NOT occur during a single life span

Scientific MethodUsed by scientists to solve problemsHas 5 major steps

Observations Define the problemHypothesisPredictionExperimentResultsConclusions

Observations Using your senses to study the world

around youCan involve tools such as computers,

literature, measurement devices

Define the problemDeveloped from observations, previous

knowledge, and collected data or information

Data can be qualitative-observationsData can be quantitative-measurements

HypothesisProposed solution to a problem or

questionDeveloped from observations, data, and

scientific literature Involves 2 types of reasoning

Inductive-specific facts to general ruleDeductive-general information to specific facts

(If…then… statements)

Predictions Must be testableWhat would happen if the hypothesis is

valid?

Experiment A procedure to test the hypothesis under controlled

conditions Constants are conditions that don’t change during the

experiment Has 2 groups

Control group (used for comparison) Experimental group (test group)

Has 2 variables Independent variable (condition tested or

manipulated) Dependent variable (what is measured or responds)

ResultsGathering data from the experimentAll data must be recordedData can be

QuantitativeQualitative

Scientists looking forNonsignificant data-data with no effectStatistically significant data-large enough

effect that data don’t occur by chance

ConclusionsAnalyze your dataWas the hypothesis supported? Is more data needed?Data are confirmed after repeated

experiments.Supported hypotheses can become

theories.

Theory Proposed explanation for a wide range of

observations and resultsSupported by wide range of evidenceMay be broadly accepted but are never

provenAlways subject to change

ToolsCan be used to make measurementsUse the metric (SI) systemQuality of a measurement is described as

accuracy and precisionAccuracy-how close the measurement is to

the true value or quantityPrecision-is the exactness of the

measurement

Metric system (base measurements)

Length – meter (m)Volume – liter (L)Mass – gram (g)Temperature – CelciusTime – second (s)

Light MicroscopesUse a series of lenses to magnifyFirst used by Anton van Leewenhoek to

see microorganismsVisible light is passed through the object to

make it visibleCan magnigy up to 1500 timesOften use stains to make details stand out

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Electron microscopesBeams of electrons used in a vacuum instead of visible lightCan magnify up to 1,000,000 timesTwo types

SEM-scanning electron microscope passes electrons over surface of objectTEM-transmission electron micro. passes electrons through object

Medical imagingX-rays used to view the calcified portions

of the body (bones and teeth)Medical resonance imaging (MRI) used to

view soft tissues using strong magnetic fields

Computers and probewareAllow for easy collection of data and fast

analysisCan model systemsAdvanced knowledge in genetics

Study DNA molecule (molecular genetics)Compare genomes of different organisms

(genomics)

Biology and the FutureHealth

Healthy food choicesManaging allergiesControlling blood sugar / obesity

EcologyReducing pollutionControlling parasitesManaging water supplies

BiotechnologyUse and application of living things and

biological processesProduce medicinesProduce larger food cropsGenetic screening