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Introductionntroductionto Biologyo Biology
The World of Biology
Chapter 1.2
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Biologyiology The Study of Lifehe Study of Life
New organisms arose from older kinds Today there are millions of species They inhabit almost every region of Earth today
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Themes of BiologyThemes of Biology
Cell structure and function Stability and homeostasis Reproduction and
inheritance Evolution Interdependence of
organisms Matter, energy, and
organization
Cell Structure and FunctionCell Structure and Function
Cell basic unit of life All organisms are made of and
develop from cells Some composed of only a
single cell ( unicellular ) which isusually identical to parent
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Cells Most organisms are
composed of many cells(multicellular ) Cells are different
(undergo differentiation ) Cells are small
Cells are highly organized
Cells contain specializedstructures ( organelles ) thatcarry out the cells lifeprocesses
Many different kinds of cellsexist
All cells surrounded by aplasma membrane
Contain a set of instructionscalled DNA (geneticinformation )
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Stability and Homeostasis Organisms must Maintain very stable
internal conditions - HOMEOSTASIS Temperature, water content, chemical
content, etc. must be maintained
Reproduction and Inheritance
All organisms produce new organismslike themselves REPRODUCE
Organisms transmit hereditaryinformation to their offspringINHERITANCE
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DNADNA Genetic Information in all cells Deoxyribonucleic Acid DNA contains instructions for traits
GENES Make the structures and complex
chemicals necessary for life
Reproductioneproduction
All species have the ability to reproduceability to reproduce Not essential to survival of individualNot essential to survival of individual but
is essential for continuation of a species
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Sexual ReproductionSexual Reproduction Hereditary information from
two different organisms of thesame species are combined
Egg and sperm zygote(fertilized egg)
Zygote contains hereditaryinformation from both parents
Asexual ReproductionAsexual Reproduction Hereditary information
from one, usuallyunicellular, organism thatdivides ( binary fission)
Resulting cells containidentical hereditaryinformation
Genetic information fromsingle parent
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Matter, Energy and Organization Living things are highly organized Require a constant supply of energy to
maintain their orderly state
In multicellularmulticellularorganisms,organisms, cells andgroups of cells(tissues) areorganized by theirfunction CellsCells tissues TissuesTissues organs OrgansOrgans
systemssystems SystemsSystems ORGANISMORGANISM
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Energy Use Use energy in a process called metabolismmetabolism
Sum of all chemical processes Sum of all chemical processes Require energy to maintain their molecular
and cellular organization, grow andreproduce
Energy ALL energy comes from the SUN (directly
or indirectly) Photosynthesis is the process by which
some organisms capture the energy fromthe sun (solar) and transform it into energy(chemical) that can be used by livingthings
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AutotrophsAutotrophs Organisms that make their
own food are calledautotrophs
Phototrophs use solarenergy (photosynthesis) toget energy
Convert H 2O and CO 2 intosugar and O2
Chemotrophs use differentchemical processes to getenergy
HeterotrophsHeterotrophs Organisms that must take in food to meet
their energy needs are called heterotrophsheterotrophsConsume autotrophs ( (herbivoresherbivores ),), otherheterotrophs ( (carnivorescarnivores )) or both((omnivoresomnivores )) for their energy needs
Complex chemicals are broken down andreassembled into chemicalsreassembled into chemicals and structuresneeded by organisms
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EvolutionEvolution Populations of organisms
change (evolve) overgenerations (time)
Explains how many differentkinds of organisms cameinto existence SPECIES
Explains how modernorganisms are related topast organisms
Explains whyorganisms look andbehave the way theydo
Provides a basis forexploring therelationships amongdifferent groups oforganisms
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Evolve
Ability to adapt to their environment through theprocess of evolutionevolution
Favorable characteristicsFavorable characteristics are selected for andpassed on to offspring
Called adaptationsadaptations Driven byDriven by
natural selectionnatural selectionor survival of theor survival of thefittestfittest
Natural SelectionNatural Selection
Natural selection is the drivingforce in evolution
Organisms that have certainfavorable traits are better ableto successfully reproduce thanorganisms that lack these traits
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Natural SelectionNatural Selection
Survival of organisms withfavorable traits cause a gradualchange in populations overmany generations
Also Called Survival of theFittest
Interdependence ofOrganisms
Interaction of organismswith one another andwith their environmentECOLOGY
Insects depend andflowers DEPEND oneach other for food &pollinationCOEVOLUTION
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All organisms need substances suchas nutrients, water, and gases from theenvironment
The stability of the environmentdepends on the healthy functioning oforganisms in that environment
Responsiveness Respond to stimuliRespond to stimuli in the
external environment
Detect and respond tochanges in light, heat,light, heat,sound and chemical andsound and chemical andmechanical contactmechanical contact
Coordinates itsresponses
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Scientific MethodChapter 1.3
ObservationObservation STEP 1STEP 1
Employing your five sensesfive senses toperceive objects or events
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Asking a Question Based on observations; one or more
questions are generated
Forming a Hypothesis STEP 2
A statement is testabletestable if evidence can becollected that either does or doesnt supportit
It can never be proven beyond doubt Often must be refined and revised orrefined and revised or
discardeddiscarded
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The HypothesisThe Hypothesis --- ---
Is a statement made in advanceIs a statement made in advancethat states the results that will bethat states the results that will beobtained from testing theobtained from testing thehypothesishypothesis
Often written in the form of an ifif--thenthen statement statement
Experimenting STEP 3
Testing a hypothesis or prediction by gatheringdata under controlled conditions conducting acontrolled experiment Based on a comparison of a control group
with an experimental group
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Measuring Involves quantitative dataquantitative data that can
be measured in numbersnumbers &/orqualitative dataqualitative data information thatisnt numbers
Sampling
Technique of using a samplesample asmall part to represent the entirerepresent the entirepopulationpopulation
Organizing Data STEP 4
Involves placing observations andmeasurement (data) in order Graphs, charts, tables, or mapsGraphs, charts, tables, or maps
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Analyzing Data STEP 4 cont) Collected and organized data must be analyzed
Process of determining whether data aredetermining whether data arereliable or whether they support or do notreliable or whether they support or do notsupport a hypothesissupport a hypothesis or prediction
Conclusion STEP 5
Conclusions are made on the basisof facts, not observations
drawn from data gathered from astudy or experiment Should support the hypothesis Should be re-testable
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Communication STEP 6
Scientists must share the results of theirshare the results of theirstudiesstudies with other scientists (peers)
PublishPublish findings in journals journals Present their findings at scientific meetingsscientific meetings Scientists must be unbiasedunbiased
Should not tamper with their data Only publish & report tested & proven ideas
CommunicationCommunication
Sharing of informationSharing of information is essential to scientificprocess
Subject to examination and verificationverification byother scientists
Allows scientists to build on the work ofothers
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TheoriesTheories A theorytheory may be formed
after many relatedhypotheses have beentested and supported withexperimental evidence
A broad and comprehensivebroad and comprehensivestatement of what is thoughtstatement of what is thoughtto be trueto be true
Supported by considerableconsiderableevidenceevidence
Ties together relatedhypotheses
LawsLaws
A Statement of fact that conciselyA Statement of fact that conciselyexplains an action or group of actionsexplains an action or group of actionse.g. Law of Gravitye.g. Law of Gravity
Accepted to be trueAccepted to be true UniversalUniversal
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