Biology and You

Chapter 1 Pages 1 - 21

Nature of Science

Chapter 1 Sections 1.1- 1.4Written HomeworkWritten Homework: Do Check & Challenge on Page 4

What is Science?

Science tries to understand the natural world by explaining how and why things are as they are.

Scientific Method

Scientific MethodScientific Method - the organized approach used by scientists to solve problems and acquire information.

Steps of Scientific Method

PProblemOObservationsHHypothesisEExperimentationCConclusion

Problem

a question about natural worlddefines specific area to study

Observation

thorough search for information

examine others work in the area of interest

collect data from experimentslook for patterns

Hypothesis

identify patternform possible explanation

for observationseducated guess to explainable to predict new patternsIf ………then……

Experiment

tests hypothesisat least two groups: Experimental GroupExperimental Group

Control GroupControl Group

Experimental Group

has the independentindependent variablevariable which will causes an observable difference (effect) in the dependent variabledependent variable

If If independent variable then dependent variable

Control Group

identical to the experimental group except:it does not contain the

independent variableis used for comparisoncomparison to

verify the affect of the variable

Conclusion

if experiment verifies hypothesis

report results

publish report so others can

repeat experiment to verify work

Conclusion

if experiment does not verify the

hypothesis:

reformulate hypothesis

or

redesign experiment

Theory

explanation for many different observations

explanation supported by repeated experimental evidence

Law

describes one observationis always truedoes not explain howhow or

whywhy

Lamarckian and Darwinian Theories of Evolution

Evolution

Slow change with timeGeological Evolution – slow

change of Earth over timeOrganic Evolution – change of

life over time

Theory of Evolution

Fossil organisms were different from living organisms

Organisms of past gave rise to current organisms

Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck

French biologistProposed first hypothesis of how

evolution workedTWO (2) Laws:

Law of Use and DisuseLaw of the Inheritance of Acquired

Traits

Law of Use and Disuse

Change in environment forms barrier to survival

organism needs to change to survive

Use body part to over come barrier; part becomes bigger

Doesn’t use body part to over come barrier; part becomes smaller.

Law of Inheritance of Acquired Traits

Acquired Traits – the changes achieved during lifetime from use and disuse can be passed on to offspring

Validity?

Use and Disuse seems truePractice makes perfect

Inheritance of Acquired Traits not trueWeismann experiment with miceDoberman dogs in textbook

Charles Lyell

Geologist Forces today same as those in

pastTime forces working cause

changes on earth’s surfacesInfluences Charles Darwin

Charles Darwin

HMS BeagleGalapagos IslandsDiversity

impressiveGentleman farmer

Pigeon breeder

Theory of Natural Selection

Overproduction – more produced than survive

Competition – struggle for limited resource

Variations – individual differencesAdaptations – differences that favor

successNature “chooses” variations that

become adaptations – “natural selection”

Scientific Attitude

Scientific Perspective

Observation & ExperimentsRepeatable & VerifiableRefutableNatural world can be

investigated and explained

Pseudoscience

“false” science because research does not meet rigid criteria accepted by scienceCreationismAstrologyMiracle diets and cures