What is What is Biology?Biology?

Unit 1: Get a Life… Unit 1: Get a Life…

Chapter 1: “The Chapter 1: “The Science of Biology”Science of Biology”

Goals of ScienceGoals of Science• Science—the use of evidence to Science—the use of evidence to

investigate the natural worldinvestigate the natural world

• Science has 3 goals: Science has 3 goals: –To investigate and understand To investigate and understand

naturenature

–To explain events in natureTo explain events in nature

–To use those explanations to To use those explanations to make useful predictionsmake useful predictions

The Scientific MethodThe Scientific Method

• ObserveObserve

• State a Question (Define the State a Question (Define the Problem)Problem)

• Research (Gather Background Research (Gather Background Information)Information)

• Form a HypothesisForm a Hypothesis

The Scientific MethodThe Scientific Method

• Experiment (Test the Experiment (Test the Hypothesis)Hypothesis)

• Record DataRecord Data

• Analyze DataAnalyze Data

• Draw a ConclusionDraw a Conclusion

ObservationObservation

• The first step in the scientific The first step in the scientific method is observation.method is observation.

• This involves collecting data This involves collecting data using one or more of one’s using one or more of one’s senses.senses.

• Data = evidenceData = evidence

InferenceInference

• Once observations have been made, one must make inferences in order to understand the data.

• Inference = the use of logic to interpret knowledge

HypothesisHypothesis• Hypothesis = an educated guess; Hypothesis = an educated guess;

a possible explanation for a possible explanation for observationsobservations

• In science, hypotheses are only In science, hypotheses are only useful if they can be tested.useful if they can be tested.

• Hypotheses may arise from prior Hypotheses may arise from prior knowledge, logical inferences, knowledge, logical inferences, or imaginative guesses.or imaginative guesses.

ExperimentExperiment• Experiment = a controlled test of Experiment = a controlled test of

one’s hypothesisone’s hypothesis• Variable = “to change,” a factor in Variable = “to change,” a factor in

an experiment that changesan experiment that changes• Control = that to which results Control = that to which results

can be compared; a constant; a can be compared; a constant; a factor that is NOT factor that is NOT changed/manipulatedchanged/manipulated

VariablesVariables• Two types of variables:Two types of variables:

–Independent Variable—a Independent Variable—a variable that is purposefully variable that is purposefully changed changed

–Dependent Variable—a variable Dependent Variable—a variable that is changed BECAUSE of that is changed BECAUSE of the independent variablethe independent variable

TheoryTheory

• Theory = a well-tested Theory = a well-tested explanation that unifies a broad explanation that unifies a broad range of observationsrange of observations

• To become a theory, a To become a theory, a hypothesis must:hypothesis must:

–Be tested MANY timesBe tested MANY times

–Be VERY well supportedBe VERY well supported

BiologyBiology

• ““Bio” = lifeBio” = life“ology” = study of “ology” = study of

• Biology—the scientific study of Biology—the scientific study of lifelife

• It is the study of living things It is the study of living things and the world around them.and the world around them.

Characteristics of LifeCharacteristics of Life

• All living things share several All living things share several characteristics:characteristics:

• They are made up of units They are made up of units called cellscalled cells

• They reproduceThey reproduce

• They are based on a universal They are based on a universal genetic code (DNA)genetic code (DNA)

Characteristics of LifeCharacteristics of Life

• They grow and developThey grow and develop

• They obtain and use They obtain and use materials and energymaterials and energy

• They respond to their They respond to their environmentenvironment

Characteristics of LifeCharacteristics of Life

• They maintain a stable They maintain a stable internal environment (called internal environment (called homeostasis)homeostasis)

• As a group, they change over As a group, they change over time (evolve)time (evolve)