Unit 6 Exemplar v3

8/3/2019 Unit 6 Exemplar v3

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Exemplar Material

Unit 6 (6BI06)

December 2010

GCE

GCE Biology 6BI06/1a/1b

Edexcel Limited. Registered in England and Wales No. 4496750Registered Office: One90 High Holborn, London WC1V 7BH


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Contents

General Points / Introduction (by Principal Examiner) ........................................1

Exemplars 1 to 15 (by Principal Examiner) ................................................... 2-32


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1

Unit6BI06IndividualInvestigationfurtherexemplification.

Thisdocumenthasbeencompiledinthelightofareviewofinvestigationssubmittedforthefirst

awardofthisunitinJune2010.Itshouldbereadinconjunctionwiththeexaminersreportfor6BI06

June2010.Thecommentshereapplytoboththeexternallyexaminedandinternallyassessed

options.

Thisdocumentcontainsadditionalcommentsoneachcriterionfollowedbyextractsofcandidates

workwithexaminersassessments.

GeneralPoints

ThisunitseekstotestskillswhichhavebeenacquiredthroughouttheAlevelcourse.Itisexpected

thattheseskillswillbedevelopedthroughuseofthecorepracticalsandarecloselylinkedtothe

requirementsofHowScienceWorkscriteria. Examinersandmoderatorsthereforeplaced

particularemphasis

on

seeking

evidence

of

these

skills

in

candidates

reports.

Itwasdisappointingtoseethatevidenceforanumberoftheseskillswasfrequentlyabsentfrom

reports.Themostcommonomissionswere;

Assessmentofpracticalskills(b)(ii)Identifiesandexplainspossiblesystematicorrandom

errorsinresults.

Analyseandinterpretdatatoprovideevidence,recognisingcorrelationsandcausal

relationships(usingdescriptivestatisticssuchasstandarddeviationanddiscussingthe

problemsofcorrelationandcausationasillustratedinUnit1.3.18)

Research&Rationale

R(a)Whilstthisrequiressomeexplanationofthebasicreasonswhythismightbearelevant

questiontoinvestigate,itisimportantthattherearesomesoundbiologicalprincipleswhichactually

explainthebasisofthehypothesistobetested.Thesourcesusedtoresearchtheseprinciplesneed

tobeclearlyindicatedinthebodyofthetext.

R(b)NOTEtobeawardedmorethan6markscandidatesneedtoshowthattheresearched

informationhasbeenusedtoinform theplanningorexecutionoflaboratoryorfieldworkANDto

informtheinterpretationofresults.Asurprisingnumberprovidedverylittleevidenceofthisin

attemptingtocommentontheirdata.


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2

Ex.1Theeffectoflightintensityonstomataldensityonlaurelleaves.

Rationale:Stomata

are

responsible

for

the

exchange

of

gases,

such

as

carbon

dioxide,

oxygen

and

water

vapour,between theplantand itsenvironment.Carbondioxideandoxygenareexchangedduring

photosynthesisandwatervapour is lostduringtranspiration.Astoma isapore intheepidermisof

theplantwhich opens and closes in response to the surrounding conditions. The two cellswhich

control the opening of thepore are called guard cells. Research has shown that guard cells are

ensuring regulation of stomata apertures and the gas exchange between the leaf and its

environmentZeigeretal (1987).Theguard cellsopenwhenpotassium ionpumpsactivelybegin

pumpingpotassium ions into theguardcellsfrom theepidermalcells thereforemaking thewater

potentialmorenegative.Waterthenentersthecellbyosmosisandtheguardcellsswell.Onesideof

the

guard

cells

is

has

a

thicker

cellulose

cell

wall

and

will

not

stretch,

so

when

the

cell

is

turgid

it

causestheporetoopenbetweenthem.Stomatausuallyopenwhentheyareeitherexposedtolight,

have low concentrations of carbon dioxide in the air,when temperatures aremoderate orwhen

thereissufficientwateravailable.

Duringtranspirationtheairspacesaroundtheplanttissuesarefilledwithwatervapourmolecules

making theconcentrationofwatermoleculeshigher than theconcentrationofwatermolecules in

theairsurrounding theplant.Thismaintainsaconcentrationgradientensuring thatwatervapour

movesoutoftheopenstomata.Asthewatermoleculesmoveoutoftheplantmorewaterispulled

upfromtherootsbycohesion.Whentheleafswaterpotentialdropstheguardcellsclosetoprevent

further

water

loss.

However

by

closing

the

stomata

photosynthesis

is

compromised

as

no

carbon

dioxidecanentertheplant.

Lightasafactorcaneffecttranspirationinthefollowingways:Ahigherlightintensityusuallymeans

a higher temperature, a higher temperature increases transpiration as the air around theplant

containslesswatervapoursothedifferenceinconcentrationsisgreater.Thismeansplantstranspire

upto3timesmorethan itcanatatemperaturewhichis10degrees lower.However,anextremely

high light intensitycausesahightemperaturewhichwillcausetheplanttohave lessstomawhich

reduceswaterlossthroughevaporation.Havinganincreasedrateoftranspirationwouldmeanmore

stomatawould be needed in order to accommodatefor the increased amount ofwater vapour

needing

to

escape.

This

adaption

of

stomata

is

common

in

many

species

of

plants

which

need

to

survive in hotter conditions and copewith thewater lossproblem. They do this by havingfewer

stomata,orbyhavingthestomataonlyopenatnightwhenitiscooler.Alloftheseadaptationshelp

toreduceevaporationandtranspirationofwaterwhengasexchangeisoccurring.Thisdemonstrates

thatplantscanadapttheirstomataandthereforesupportsthehypothesis.


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3

Ex.1Comments

This isaratherweakexample forA2.Themainproblem isthatthecandidatedoesnotaccurately

focus on the hypothesis. The main part of this concentrates on the mechanism of stomatal

movement and then makes some basic errors of assuming light intensity is equivalent to

temperature,

which

is

subsequently

not

measured.

What

is

needed

is

some

research

into

thepossible explanation of how different light intensities might have an effect on density and how

densitymightbelinkedtoleafareaetc.

Overall this is limited and a weak R(b)36. The exact mark would depend upon how well this

informationhadbeenusedtoexplainthedata.ThemarkforR(a)wouldbesimilarsinceitwouldbe

expectedthatthismightbeplacedinanecologicalcontextwithreferencetoniche,competitonetc..


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4

Ex.2 WhichmicrohabitatisbestsuitedtoBeadletseaanemones?

RESEARCHANDRATIONALEThisstudywillaimtofindasignificantassociationbetweenBeadletanemonesandthespecific

microhabitatin

which

they

prefer

to

live.

More

specifically,

it

is

designed

to

examine

the

extent

to

whichthenumberofBeadletanemonespresentinrockpoolsonthemiddleshorevariesunderthree

distinctconditions.

TherearefourprincipalfactorsthatplayamajorpartindeterminingtheprevalenceofBeadlet

anemonesonthemiddleshore.Theseare:competition,food,desiccationandpredators.

Rationale

Ecologicalstudiessuchasthisaddtoourunderstandingofinteractionsbetweenlivingthingsin

ecosystems.

This

type

of

knowledge

is

becoming

increasingly

important

as

there

are

many

discussionsaboutexactlywhatmighthappentonaturalhabitatswhensomechangesaremade.This

mightbenaturaldisasterssuchasstormsandfloodsortheeffectsofhumanactivities.Many

predictionsarebasedoncomplicatedmodelswhichcanonlybemademoreaccuratebyadding

smallerpiecesofinformationfromstudiessuchasthis.RecenteventssuchastheGulfofMexicooil

spillshowhowimportantitistounderstandthepossibleeffectsonshoreorganisms.

Competition.InBritain,theonlyotheranemonecommonlyfoundontheseashoreistheSnakelockanemone,Anemoniaviridis.Eachofthesespecieshasastickymuscularbasaldisc,bothfor

attachmentto

asubstrate

and

for

movement.

This

means

they

can

grip

rock

so

that

they

are

not

movedbythetides.ButSnakelocksaremorecommonlyfoundonthelowerratherthanthe

middleshore,whereasBeadletsareknowntoliveonboth.

Beadletsarealsoincompetitionwithseaweed.LikeBeadletanemones,seaweedneedsa

substratetoattachitselftoifitisnottobemovedbythetides.LikeBeadletanemonestoo,

seaweedneedswatertoavoiddesiccation.ButBeadletsaremorecommonlyfoundinthe

shallowerpartsofrockpools,whereasseaweedismorecommoninthedeeperparts.

Food.WhenBeadletanemonesfeedupto192stingingtentaclesemerge,arrangedin6circlesaround

the

mouth

(1).

These

tentacles

are

used

to

feed

mainly

on

shrimps

and

other

small

speciesthatlivehighupshore.Theyhaveagastrovascularcavitywhichworkslikeastomach,

butwithonlyoneopeningtotheoutsideworkingasboththemouthandtheanuswhichis

referredtoasanincompletegut.Theycanonlyfeedandreleasewasteproductswhenunder

water.

Desiccation.TheBeadletanemoneisoftenfoundoutofwater.WhenexposedtoairtheBeadletrecallsitstentacles,therebyreducingitssurfacearea.Itthenappearsasabrightredblobofjelly

andcansurviveassuchforhoursatatime(1).Thedangeritfacesinthisconditionisthatof

desiccation.Thisistheprocessofextremedryingand,ifitcontinuesbeyondacertainpoint,

eventuallyresultsindeath.AsHorton(1982)indicates,asthedegreeofexposuretothe

atmosphereincreases,

the

abundance

of

Beadlet

anemones

decreases

(2).


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5

Predators:AccordingtoAndyHorton(1982)themainpredatorofBeadletanemonesisthegreyseaslug,Aeolidiapapillosa,whichfeedsexclusivelyonBeadlets(3).Thesluglivesonthebottom

andsidesofrockpools.However,itisunabletoliveoutofwaterduetoitsrelianceonseawater

asotherwiseitwilldiefromdesiccation.HencethereisanimportantadvantageforBeadletsin

beingabletosurviveforlimitedperiodsoutofwater.

TheBeadlethasotherdefencemechanismsavailable.Itcan,forexample,useitstentaclesto

deterpotentialpredatorsaswellascaptureitsprey.Itcanalsowithdrawthemmakingitharder

forpotentialpredatorstograb. Inadditionitisabletoreduceitssizeandshapesothatit

appearsasaslipperyredblobwhichoffersmuchreducedpurchase.Therearenoknown

predatorsintheUKthataredeterredbythesemechanisms,butthatmaysimplybebecausethe

Beadletanemonesdefencemechanismshaveprovedsoeffective.

AnotherfactorthatmayaffectBeadletdistributionishowtheymove.Theycanmoveintwoways:

1. Bycreepingaroundontheirbasaldiscs.Thismovementissoslowandtimelapsephotography

isrequiredtoseeit(3).

2. Theycanalsoinflate,disconnectfromtherocktheyareattachedtoandusethetidesand

currentstotakethemtoanewlocation.However,thisisbelievedtoonlyhappenwhenthe

conditionsbecome

extremely

unfavourable

for

the

anemone

(3).

ThisabilitymeansthatBeadletscanmoveclosertowateriftheyarestartingtodesiccate.Italso

allowsthemtomovetoamorefavourablesurroundingwhenthetideisin.

Summary:TheseobservationssuggestthatBeadletanemonesaremorelikelytoinhabitthemiddleshore.Beadletanemoneshaveadaptedsothattheyareabletosurviveforhoursatatimeoutofthe

waterwithoutdesiccating.Itwouldappearthatthereisanevolutionaryadvantageinbeingableto

dothis,becauseoutofthewatertheyhaveanimportantdefenceagainstattackfromtheirmain

predator.Atthesametimetheyarevulnerabletodesiccation.ThissuggeststhatBeadletanemones

flourishin

aspecific

ecological

niche.

Ex.2Comments

IncontrasttoEx.1,thisexampleisconciseandaccuratelyfocusedontheactualhypothesis.Itplaces

theinvestigationintoaclearecologicalcontextandexplains itspossiblerelevanceaswellasgiving

sufficientinformationfromsomeacademicsourcestoexplainthebiologicalprinciples.Italso

providesinformationforplanningbysuggestingothervariablessuchasalgalcoverthatmightbe

worthwhilemonitoring.Inthiscasethesedetailswereusedwelltoexplainthedata.Henceoverall

thisiscomfortablyintheR(a)(b)79range.Alittlemoredetailwouldjustifythetopofthisrange.


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6

Planning

P(a)Itisusefultoidentifythestepsoftheactionplanclearly.Thisismostoftendonebyuseof

logicalsubheadings.Thinkingaboutthemostimportimportantvariablescanoftenyieldgoodideas

forgenuinetrialinvestigations.

P(b)Thereareseveralwaysofapproachingriskassessmentsbutitmustbeanassessmentnota

simplelist

of

precautions.

P(c)was,byfar,themostdiscriminatingsectionofthiscriterion.Manyweresimplysuperficial

justificationsofapredeterminedrecipe.Higherscoringcandidatessoughttocheckcarefully

exactlywhattheyweretomeasureandtotestanyassumptionsthatmightbemade. Infieldwork

somedetailedsiteobservationmightanswervitalquestionsaboutsamplingtechnique.Isitlikelyto

introduceothervariablessuchasarockpoolorapatchofbrambles?Whatmightbedonetoavoid

this?

IMPORTANTNOTEExaminersandmoderatorsassumedthatthesignedrecordsheetfor

assessment

of

practical

skills

meant

that

candidates

had

already

been

given

detailed

protocols

for

all

corepracticalsandhaddiscussedtheminsomedepth.Thereforetheycouldonlysupportvery

modestmarksforplanninginvestigationswhichwereessentiallythesameunlesstherewasclear

evidenceofthecandidatesindividualplanningskillinusingthetechniqueinamoreinnovativeway.

Forexample,merelysubstitutingdifferentcompoundsintoabasictestforantibacterialactivity

wouldprovidelittleevidenceofindividualskill.


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7

Ex.3Investigatingtheeffectofmineraldeficienciesontherateand

overallheightofoatseedlings

Method

1) Placethe57inchflowerpotsonatrayandlabeleachwiththenameofthemineraldeficiency

2) Add20gofvermiculitesoiltoeachpotanddifferentculturesolution(roughly20sprays)toeach.Mixtogetherevenlyusingafork.

3) Placethevermiculitesoilwithculturesolutiontothetopofthepotusingaspade4) Usingindexfinger,mark5holesinthesoil,deepenoughtocoveryournail5) Place5oatseedlingsintheholes

6) Lightlycovertheoatseedswithvermiculitesoilandculturesolution.7) Repeatsteps26,byremovingadifferentmineraleachtimefromthesolution.

8) Placeall

5pots

in

the

same

place,

ideally

by

awindow

with

good

source

of

sunlight

9) Waterseedlingsandaddnutrientsverylightlyinpotseverytwodaysandrecordtheheights

Resultsfrompilotstudy

Day1

Seed Nitrate deficiency

heightofseedling

(mm)

Phosphate

deficiency height

ofseedling(mm)

Potassium

deficiency height

ofseedling(mm)

Calcium

deficiency height

ofseedling(mm)

Magnesium

deficiency height of

seedling(mm)

1 0.00 0.00 0.00 32.50 45.00

2 0.00 0.00 20.00 10.50 10.00

3 0.00 10.00 24.00 0.00 50.00

4 0.00 0.00 25.50 40.50 25.00

5 0.00 10.50 0.00 0.00 0.00


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8

Day3

Seed Nitrate

deficiency

heightof

seedling(mm)

Phosphate

deficiencyheight

ofseedling(mm)

Potassium

deficiencyheight

ofseedling(mm)

Calcium

deficiencyheight

ofseedling(mm)

Magnesium

deficiencyheight

ofseedling(mm)

1

0.00

0.00

0.00

35.50

50.00

2 0.00 0.00 25.00 15.50 13.00

3 0.00 11.00 24.50 0.00 54.50

4 0.00 0.00 28.50 44.00 31.00

5 0.00 12.50 0.00 0.00 0.00

Day5

Seed Nitratedeficiency

heightofseedling

(mm)

Phosphate

deficiencyheight

ofseedling(mm)

Potassium

deficiency

heightof

seedling(mm)

Calcium

deficiencyheight

ofseedling(mm)

Magnesium

deficiencyheight

ofseedling(mm)

1 0.00 0.00 0.00 38.50 55.00

2 0.00 0.00 27.50 19.50 18.50

3

0.00

13.50

25.00

0.00

57.50

4 0.00 0.00 31.50 45.50 33.00

5 0.00 13.00 0.00 0.00 0.00


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9

Day7

Seed Nitratedeficiency

heightofseedling

(mm)

Phosphate

deficiencyheight

ofseedling(mm)

Potassium

deficiency

heightof

seedling(mm)

Calcium

deficiencyheight

ofseedling(mm)

Magnesium

deficiencyheight

ofseedling(mm)

1

0.00

0.00

0.00

41.50

59.50

2 0.00 0.00 30.50 22.50 21.50

3 0.00 14.50 29.00 0.00 59.50

4 0.00 0.00 32.00 47.50 36.50

5 0.00 15.00 0.00 0.00 0.00

StatisticalTest

ThestatisticaltestthatwillbeusedtoevaluatemyresultswillbetheMannWhitneyUtest

Modificationsofpilotstudy

Theinvestigationwillbeovertwoweeksratherthanone,sotheprogressoftheoatseedlingscanbe

recordedoveralongerperiodoftime,givingmemoredatatoworkwith.Thereforethevolumesof

solutionswillneedtobedoubledformyfinalinvestigation. Onlyafewseedlingsgrewinmypilot

study,thereforeIwilluseatleast20oatseedlingsforeverypotinordertogetadecentnumberof

readings,whichwillallowgreatercomparisonstobemade.Havingamuchlargeramountof

readingswillalsoallowmetomakestatisticalanalysise.g.MannWhitneyUtestwhichneedsat

least7measurements.Acontrolwithall5nutrientswillalsobeincludedinordertoseetheeffectof

havingallthenutrientsontheoverallheightofoatseedlings.

FinalExperimentVariables

Independent:mineraldeficiencyinculturesolution

Dependent:Heightoftheoatseedlings

Controlledvariables:mustbecarefullymonitoredandkeptconstant,otherwisetheresultswouldbe

unreliable.Theseusingthesamepotsizeforeachofmymineralnutrientdeficiencies,withsame

sizeddrainageholes.Ifthepotsizeswerenotequaltheneachpotmayreceivedifferentamountsof

sunlight;someseedsinasmallerpotmayhavetobedistributedclosertogetherwhichcouldaffect

theirgrowthduetocompetition.Samesizeddrainageholesensureequalamountsofwaterand

nutrientscanbedrainedout.Iwouldkeeptheamountofvermiculitesoiladdedtoeachpotequal.A

balance(2.d.p)wouldweighoutexactlythesamemassofsoil.Equalamountsofthedifferent

nutrientmineralswouldbeusedtomakeitafairtest.Tocontroltheamountofnutrientsineachpot,

Iwillspray5timesineachpot.Thesamequantityof20oatseedlingswiththesameshape,sizeand

weightwouldbeneeded,soIwillhandpickthembecauselargersizedseedswouldabsorbmore


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10

nutrientsthusexperiencemoregrowth.Theseedlingsshouldbedistributedwiththesamepatternin

everypotandatthesamedepthinsoil,otherwisesomeseedlingsmayhavetocompetewithsunlight

andnutrients,distortingtheresults.Thesamevolumeofwaterandmineralnutrientswouldbe

addedevenlyacrossthesoil,byrotatingmyarmaroundeachpotinanidenticalmanner.Thepots

shouldbeplacedinthesamelocationtoreceivethesameamountofsunlight.Ifeachseedlingdidnt

getthesameintensityofsunlightthenthiscouldaffecttheirgrowthrates.Abioticfactorsshouldalso

bekeptconstantsuchasthesolarenergyinputandroomtemperature.Withthevermiculitesoil,

EdaphicfactorssuchassoilpH,soiltextureandtemperatureshouldalsobekeptconstant(14).In

ordertoensureacidityofthesoilisthesameIwilluselitmuspapertotesteachpot.Keepingall

thesefactorsthesamewillensureanyresultsIproduceareduetotheindependentvariablealone,

enablingmyresultstobebothvalidandreliable.

Ex.3Comments

Thisisaweakplanoverall.

P(a)Thelargemajorityofthisisbasedonasimpleapproachtoacorepractical.Thereislittle

evidencethatthecandidatehasarealunderstandingofwhatisbeinginvestigated.Thereis

commentonvariablesbuttheircontrolisextremelyweakspray5times!Thevitalvariableofheight

isignored.Exactlywhatheight?Howisthismeasuredreliablygiventhismethod?Isheightauseful

measureofgrowthinthisinstance?Howdoweknowthevermiculiteisionfree?

Thismightjustmeet36butisveryweak

P(b)thereisasensibleriskassessment.

P(c)

It

is

possible

to

give

some

credit

for

a

trial,

but

not

a

great

deal,

as

this

is

typically

simply

carryingoutthesameprotocolanddoesnotleadtoverymeaningfulchanges.Whyshouldthe

nitratedeficientseedsnotgrow?Seedscontainmanyionsandthereforethereasonfortheirfailure

togerminateatallneedsinvestigating.Againthereisnothingaboutexactlywhatheightmeans

exactly.12ofthe25samplesfailtogrow.Thetablerecordsaheightof50mmforsomeafterday1

whichseemshighlydubious.Thechangesmadeareverysuperficialanddonotalwayslogically

followfromthedatasupplied.

Againthiswouldbeaveryweak36.

OverallitwouldbedifficulttosupportmorethanP=3


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Ex.4 - The effect of aspect on moss distribution on tree trunks

Plan

Dependant variable: moss distribution

Independent variable: aspect

The following are variables that may affect the dependent variable specified above:

Time of day

Light levels

Position of tree (where rain gathers)

Soil richness (moisture and nutrients) Trees age

The location will stay constant throughout. This will be at Slapton Woodland Nature Reserve,

and within the same area if possible. The process of collecting data will be as follows:

1. Using a tape measure, mark 40cm above ground level on a tree trunk. 40cm shouldbe high enough to avoid roots getting in the way and low enough to avoid branches.It is important I keep this constant, as moss is known to be low on the trunk.

2. Measure the circumference of the tree trunk from the 40cm mark and record it. Thiswill ensure all variables have been taken into account. If tree circumference seems to

have a dramatic affect, this can be tested and then changed to make the experimentmore reliable.3. Using a compass, find the northern and southern points of the tree trunk and mark

the points with blue-tac, again 40cm above ground level. Place a 10x10cm2 griddedquadrate at the north point of the tree, directly above the tape measure (marking40cm above ground level) and stick it there with the blue-tac already placed. Countthe squares of the quadrate covered in moss and record findings. Include squareswith any moss in at all, so that the method of data collection is kept constant. A10x10 gridded quadrate should give enough detail and accuracy, which is why it waschosen. Repeat this process for the southern side of the tree.

4. Repeat steps 14 for 30 trees if there is time; 20 trees is an acceptable number ifnot.

5. Use the statistical test to measure findings (in this case the T-test). It will be used totest my null hypothesis to a 5% significance level.


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12

Risk assessment

Woodland areas are not without safety risks. These risks can be avoided or minimized if the

appropriate precautions are taken.

Risk Steps taken to avoid/minimize the risk

Tripping on tree trunks/vegetation/rocks Always take clear thought out walking routes

and stick to paths where possible

Getting lost in the woodlands Be aware of landmarks and always be in

shouting distance of others

Falling branches/trees Always be aware of the stability of the trees

above, if they look weak avoid them

Hypothermia Warm clothes/thermal clothing

Nettles/thorns Wear clothing that covers all lower body skin

Risk assessment table

* risk rating = (probability) x (worst case outcome)

As the highest risk is only 6 out of a possible 25, the experiment is determined safe enough

to continue.

Hazardsidentified

Worstcase

outcome

Probability

minorinjury

(1)

injury(2)

majorinjury

(3)

cripplinginjury

(4)

fatality(5)

very rarely(1)

rarely(2)

infrequently(3)

sometimes(4)

often(5)

riskrating*

Tripping ontree trunks/vegetation/

rocks

/ /

Getting lost

in thewoodlands

/

Slipping onslippery

rocks andsteps

/ /

Fallingbranches/

trees

/ /

Hypothermia / / 5

Nettles/thorns

/


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13

Preliminary Results (1)

tree number moss south (cm) moss north (cm) tree circumference (cm)

1 50 30 240

2 80 90 136

3 10 40 120

4 20 95 132

5 0 5 133

6 3 100 111

7 100 96 137

8 71 84 142

9 0 4 129

10 28 88 161

After collecting data from 10 trees as a preliminary test, I noticed that there was often ivy and

other vegetation getting in the way of the quadrate I used to measure the moss. This meant I

had to use estimations when determining the percentage of moss in each quadrate. I also

noticed that on some trees there was in fact just as much, or sometimes more light on the

north side.

Preliminary results (2)

In my second set of preliminary results, I improved on my investigation method by measuring

canopy cover. I used a 20x20cm2 gridded quadrate to estimate canopy cover on both the

north and south sides of the trees I collected data from. I placed the quadrate directly above

the tree on each side and estimated what percentage was covered by canopy. To try to stop

vines and grass getting in the way of my view of the moss, I decided to stop measuring moss

40cm above ground level and started measuring it at 70cm above ground level.


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14

tree

number

moss south

(cm)

moss north

(cm)

tree circumference

(cm)

canopy cover

south(%)

canopy cover

north (%)

1 34 2 180 60 75

2 61 13 112 40 60

3 21 0 216 10 90

4 2 30 147 30 45

5 0 0 167 90 90

6 32 36 141 70 60

7 60 6 265 35 30

8 82 37 102 60 40

9 13 0 283 80 50

10 6 2 62 85 65

Measuring 70cm above ground level helped me measure moss more accurately. However, I

then noticed that on larger trees the vines and ivy grew further up the tree, making it still

difficult to see the moss. The larger trees were also a problem as measuring the

circumference of the tree was less accurate because the vines were often in the way of the

tape measure. The trunks also had large ridges and groves (unlike the flat surfaces of

smaller trees) which moss would fill. In essence, there was a higher density of moss, but it

only fit into a few squares. On the smaller trees it was hard to measure accurately because

the face of the quadrate didnt lie flat on the tree, so I had to estimate the number of squaresfilled at each side. I also noticed that canopy cover was a very inaccurate way of measuring

light, as the tree was often slanted, meaning it was shaded even when the canopy was

largely open.

Preliminary results (3)

To make my data collection more accurate and amend the problems I faced in my second

set of preliminary results, I decided to only collect data from trees between 110cm and

140cm in circumference. The smoother surfaces of these trees made it a lot easier to

measure quantities of moss accurately. To make my measurement of light and shade more

accurate, I used both light meter and estimation of canopy cover. I placed the light meter

where the moss was being measured on each side of the tree and recorded the results.


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15

tree

number

moss

south

(cm)

moss

north

(cm)

tree

circumference

(cm)

canopy

cover south

(%)

canopy

cover

north (%)

light

south

(lux)

light

north

(lux)

1 87 96 118 70 50 125.3 95.8

2 0 55 110 80 40 32.4 45.6

3 6 40 125 80 60 87.5 58.2

4 21 13 113 75 70 148.8 173.6

5 50 36 136 40 90 45.2 14.2

6 80 82 114 75 60 12.3 84.3

7 0 2 138 80 70 15.8 178.8

8 6 21 114 60 50 189.8 124.7

9 77 32 135 60 55 148.2 185.6

10 0 35 139 40 75 15.3 134.4

In this set of preliminary results, I felt that the methods by which the data was collected

controlled as many variables as possible. Therefore, this is the method that will be used in

the collection of data for my investigation.

Summary of change in method

Restriction on tree circumference of trees being measured (110140cm only) Use of a light meter on both sides of the tree

Estimations of canopy cover on both sides of the tree

Measuring 70cm above ground level (rather than 40cm)

EX.4Comments

Thiscontainsmanyoftheelementsthatwewouldliketoseeinagenuinetrial.IncontrasttoEX.3it

concentratesonthemostimportantvariablestobemeasured,lightandcoverofmoss.The

candidatestarts

with

abasic

ecological

procedure

but

then

uses

the

trial

to

check

how

to

collect

reliabledata.Manycandidatesmeasurelightintensityinthefieldbutfewshowanunderstandingof

howunreliablethiscanbeortestdifferentmethodstomakethisasaccurateaspossible.

P(a)Thereissomeconsiderationofimportantvariablesbutnotall.Thereportshowsaclear,logical

sequencefrominitialtechniquethroughseveralstagestosomesensibleamendmentstothe

method.

ItwouldmeetP(a)79butnotstronglysincewecouldexpectsomesiteobservationstoensurethat

assumptionsaboutsoilorgradientetcwerevalidandmoreimportantlywereallyneedsome

considerationoftreespeciestomakethisahigh79ormaximum1011.However,thisisclearand

conciseandoverallkepttothesuggestedwordlimit.


18/34

16

P(b)Thistypeofriskassessmentiscommonlysuggestedbyfieldcentresandisasensibleapproach

whichcouldsupportagoodP(b)79andwouldnotbelimitingifothersectionsindicatedthehighest

range.

P(c)Thereisplentyofevidencehereofawellthoughtouttrialwhichhasbeenusedtomake

sensiblemodificationswithreasoningsupportedbythedata.ThisisagoodP(c)79

OverallitwouldbeharshnottoawardP8andthiswouldcertainlybeP9withalittlemoreevidence

ofconsiderationofothervariables.

Observing

O(a)ForthehighestmarksitwasexpectedthattableswoulduseSIunitswherepossibleandthat

significantfigureswouldbeconsistentandjustifiedbythemethodologyemployed.Similarly,

manipulateddatasuchasmeansshouldnotbequotedtoamuchhigherdegreeofaccuracythan

thatoftheoriginaldata.

O(b)AsurprisingnumberofcandidatesignoredtherequirementthatAnyanomalousresultsare

notedfor

36marks.

It

is

not

intended

that

candidates

find

anomalies

where

none

exist

but

it

was

commonfortheretobenocommentatallwheretherewereobviouslargevariations.Inextreme

casesthislimitsobservingmarkstoamaximumof2.

EX.5Investigatingspeciesdiversityunderdifferenttreecanopies

Tree ShannonWeinerDiversityIndex

Oak1 1.458

Oak2 0.876

Oak3 1.016

Oak4 1.094

Oak5 1.436

Oak6

1.004

Sycamore1 0.598

Sycamore2 0.815

Sycamore3 0.624

Sycamore4 0.822

Sycamore5 1.190

Sycamore6

0.705


19/34

17

EX.5Comments

O(a)Althoughthiscouldbeconsideredlimiteddatawithonly6samples,therawdatafromwhich

theseindiceswerecalculatedwerewelltabulatedinaseparateappendixandwereatleastasmuch

ascouldreasonablybeexpectedforthistypeofinvestigation.HencethiswouldqualifyforO(a)78

O(b)Unfortunatelythiscandidatemadenofurthercommentintheirreportaboutpossible

anomalies.InthisexampleitisclearthatSycamore5shouldatleastprovokesomecomment.Itis

higherthan4oftheoakindicesandistheonlysycamoretohaveahigherfigurethananyofthe

oaks.Ideallythismighthavebeenpickedupatthedatacollectionstagebutananalysisoftheraw

datawouldrevealpossiblereasonsforthisresultandwouldbeacceptedforahighmark.

AnyanomalousresultsarenotedisarequirementforO(b)36andthishasnotbeenmet.Hence

thiswouldbeawardedO2overall.

Examinersandmoderatorswillgivethebenefitofdoubttotablesofdatawherethereareno

anomaliesand

hence

no

comment

but

it

is

strongly

recommended

that

all

candidates

make

some

commentforO(b).Iftherearenoobviousanomaliesthenaverybriefexplanationofthereasoning

forthiscouldbegiven.

Ex.6Investigatingthedistributionofblackflylarvaeindifferentwater

velocities

Tableofmainexperimentresults

SampleNumber

Velocity

(revs

/min)

BlackflyAbundance

Temperature(C)

Light

Intensity

(Luxx103)

1 116 18 13.6 2.83

2 40 0 13.5 9.49

3 194 4 13.7 0.57

4 28 2 13.6 58.6

5 46 9 13.6 27.4

6 116 21 13.6 3.04

7 64 6 13.5 26.8

8 8 3 13.7 28.1

9 218 7 13.5 2.83

10

156

12

13.5

67.4

11 112 7 13.6 10.4

12 168 14 13.5 34.7

13 56 3 13.5 27.1

14 232 0 13.5 64.1

15 21 1 13.7 2.93

Fromobservingtheseresults,therearegenerallylargernumbersofBlackflylarvaeinareasof

highervelocitywater,withtheexceptionofSample14,whichhasthehighestflowratebutshowed

nolarvaeaftertakingakicksample.Thiscouldbebecausetheorganismscanonlysurviveataflow

ratethatisslowerthan232revs/min,butunlikelyasnopriorresearchhasindicatedthis.More

likelythat

amethodical

error

occurred,

such

as

an

inadequate

kick

sample

or

failure

to

spot

larvae

whencounting.Tocheckthisanomaly,thesameareacouldberesampledafteratimetoallow


20/34

18

organismstoreturntothedisturbedplaceandtomakesurefurtheranomalieswerenotcreated,

themethodofcountingbecomemorethroughafterthis.Evenwheneliminatingthisanomaly,

however,thereareawideenoughrangeofvaluestovalidateconclusionsmade.Allsamples

recordedhadtemperatureswithinarangeof0.3C,soitissafetoassumethatthevariableof

temperaturehashadlittleeffectonresults.

Ex.6Comments

O(a)AllcriteriaaremettoconsiderO(a)78

O(b)Theanomalyhasbeencorrectlyidentifiedandthereissomeinvestigation.Foramaximum

O(b)78howeverwewouldexpectthatthisanomalywouldhavebeeneasilyrecognisedatthedata

collectionstageandfurthersiteobservationscarriedouttofindpossiblereasonsandafurther

sampletaken.

ThisisagoodexampleandwouldmeritatleastO6orpossiblyO7

Interpretingandevaluation

I(a)

Most

candidates

gave

a

clear

indication

of

their

statistical

calculation

and

conclusion

but

sometimesignoredimportanttrendsintheirgraphsanddata.Manyneededtoshowthatthey

understoodthatastatisticaltestmerelydemonstratesasignificantdifference,correlationor

associationbetweentwodatasetsbutdoesnotproveanythingabouttheunderlyingbiological

principles.

I(b)Thiswasoftenverybrief.Themainrequirementhereisthatthereisevidenceoftheuseof

researchedbiologicalknowledgeandunderstandingtointerpretthedatacollected,notsimply

assertsomegeneralprincipleorrepeattheintroduction.

I(c)Thiswasaveryweakarea.Itisstronglyrecommendedthatcandidatesaregivenclearadviceand

trainingabout

objective

evaluation.

The

following

might

be

considered;

Whatisthevariabilityinthedata?(errorsbars,standarddeviationetc)

Arethereanyobvioussourcesofrandomorsystematicerrors?Isthereanyevidenceof

these?

Ifasignificantcorrelationisindicated,whataretheproblemsinsuggestingacausallink?

Overallwhatdoesthissuggestaboutthereliabilityofthedata?Rememberitispossibleto

drawaperfectlyvalidconclusionfromdatabutthismaywellbeunreliableifthedesignof

theinvestigationoraccuracyofdatacollectionisflawed.

Itwouldbeexpectedthatcandidatesatthislevelwouldhavesufficientunderstandingof

HSWcriteriatoensuretheyusecautiouslanguagewhendiscussingconclusions.Datamay

supporttheideathat...butisunlikelytoproveanything.


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19

Ex.7 Investigatingtheeffectoftemperatureonthegrowthofalgae

ConclusionTheresultsinbothcoloniesandtheaveragebetweenthemquiteclearlyshowthat25Cis

thefavouredtemperatureand35Cisanintolerabletemperature.Theothertemperatures

showmorevariation.Growthishighestat25Candstopsat35C,whereasincolonytwo

the20Csamplewashighlysuccessfulwhilethe30Csamplesufferedgreatly.15Cwasalso

successful,thoughinnocaseshigherthan20or25Cbytheendofweek4.Dataonthe15C

samplesisunreliablehowever(seeevaluation).

Thetrendsfromtheaveragecountsshowthecoloniesin20and25Cincreasingrapidly,

15Crisingslowly,30Cdroppingslowlyand35Cdroppingrapidly.

FromtheseresultsIcanconcludethattemperaturedoeshaveaneffectonChlorellaand

thatfor

the

best

growth,

temperatures

should

be

between

20

and

25

C.

This

is

slightly

lower

thanmyprediction.

Theseresultsaremostlikelytohavebeenduetoallcellslimitedtolerancetotemperatures

outsideanoptimumrange.Toowarmandtheenzymesinacelldenaturecausingthecells

tostopfunctioninganddevelopingnewproteinsandlipids.Activetransportandthe

synthesisofenergyprovidingATP(adenosinetriphosphate)wouldallshutdownasaresult

ofdenaturedproteins.Toocoolandthereactionstakingplaceinsidethecellswouldslow

downasagreaterproportionofparticlesdonotcollidewithsufficientenergyforactivation

enthalpies

to

be

overcome

and

bonds

to

be

broken.

This

again

would

result

in

vital

reactions

shuttingdown.25Cappearstobetheoptimumtemperaturebetweenthetwoextremesin

whichallproteinsandreactionsareworkingcorrectly.

AsIwascomparingfrequenciesIusedtothechisquaredtesttojudgereliability.Thiswas

calculatedfromtheaveragebetweenbothcoloniesexcluding15Ccolonyone(see

evaluation).Chisquaredwascalculatedasfollows.Withtheobservedreading(O)beingthe

datacollectedforeachcolonyonday28andtheexpectedreading(E)beingtheaverage

readingIwouldbelikelytogetiftemperaturehadnoeffectonthegrowthrates.


22/34

20

Temperature(C) Observed

reading(O)

Expected

reading(E)

OE (OE)2 (OE)

2/E

15 22.00 22.06 0.06 0.0036 0.00016

20 34.57 22.06 12.51 156.50 7.09

25

44.50

22.06

22.44

503.55

22.83

30 9.22 22.06 12.84 164.87 7.47

35 0.22 22.06 22.06 486.64 22.06

Total 110.29 59.45

OnceIhavemyChisquaredvalue59.45IthenreferredtoasimpleChisquaredtable[9]

havingcalculated

how

many

degrees

of

freedom

(n

(the

total

number

of

data

pieces)

1)

to

be4andcheckedwithwhatlevelofcertaintythattheresultswerenotdowntochance.

Pvalue

d.f. 0.25 0.20 0.15 0.10 0.05 0.025 0.02 0.01 0.005 0.0025 0.001 0.0005

4 5.39 5.59 6.74 7.78 9.49 11.14 11.67 13.23 14.86 16.42 18.47 20.00

WithaChi

squared

value

of

over

20,

Ican

say

with

over

99.9995%

certainty

that

the

results

werenotdowntochance.Iwillnowrejectmynullhypothesisandconcludethat

temperaturedoesindeedhaveaneffectonthegrowthofChlorella.

EvaluationInbothcoloniestherewasageneralincreaseincelldensityfor25Candadecreasefor

35C.Incolonyone,thesamplesof20Cand30Cappeartodipbeforerisingagainwhile

onlygrowing/decayingexponentiallyincolonytwo.

ValidityofresultsThereislikelytohavebeensomedegreeofinaccuracyinmyresultsdue

tofailure

to

control

some

of

the

variable

listed

on

page

4.

Most

notably,

despite

using

sterilisedequipment,theinvasionofthe15C,colonyoneflaskbyaninvaderknownas

parameciumwhichfeedsonChlorellaprobablyresultedinthemuchdecreasedcellcount

comparedtothe15Csampleincolonytwo.


23/34

21

Parameciumisasinglecelledprotozoon.Itconsumesitspreyinvesicles

beforedigestingitwithenzymesfromthecytoplasmsimilartophagocytosis.[7]

Theparameciuminfection,alongwiththeinabilitytokeeptemperatureconstantwould

havegreatlyreducedthereliabilityofthe15Ccolonydataalongwithnotactuallybeing

placedinawaterbathandthus,wasexcludedfromanyconclusionmaking.Thecell

countingitselfwaslikelytohavebeenquiteconsistentasIrepeatedtheprocessmanytimes

toensurehighreliability.

Anotherpossiblesourceofinaccuracywasmiscountingcellsinthehaemocytometer,when

dying;Chlorellacellswouldlosetheircolourbeforebreakingup.Attimesitcouldbedifficult

todecide

whether

the

cells

were

healthy,

dying

or

dead

which

lead

to

adegree

of

guessworkinsomecolonies.

Therewereseveralanomalousreadingsinmydatasuchasthe20Csampleonday28of

colonyonewhichwasmuchhigherthanexpected,thoughthismayhavesimplybeenthe

startoftheexponentialgrowthphase.Days7and21forthe15Csampleofcolonytwo

weremuchhigher/lowerrespectivelythanexpectedandthereislittlethatcouldpossibly

accountforsuchvariationandthiswouldaddtomyuncertaintywhendrawingconclusions

for15C.

Timewas

agreat

limitation

when

collecting

results.

In

order

to

collect

areasonably

accurate

andreliablesetIwouldhavehadtocountliterallyhundredsoflargechambers.Counting

fivecoloniestookabout90minutessoaddingmorecoloniesorrepeatingcountscould

extendthistimetoseveralhours.Thiswouldhavebeenveryinconvenientanddifficultto

achieve.

IfIwastorepeattheexperimentIwouldtakeevengreatercaretoensurethatnoinvading

bodieslikeparameciumcanentertheChlorella.Unfortunatelythetopcouldntbeblocked

offorCO2couldntenter.Iwouldalsousemorecolonies(3or4)forevengreateraccuracy

andcarry

on

the

experiment

for

longer.

The

experiment

would

have

continued

anyway

but

waslimitedduetotermtimesandschoolclosuresduetoadverseweatherconditions.

SummaryofinvestigationTemperatureclearlyhashadaneffectonthegrowthratesofChlorellacellsplacedinfive

differenttemperatureroundbottomedflaskswith25Cbeingtheoptimumtemperature,a

cleardislikefortemperaturesof30Candhigher,anduncertaintyunder20C.Thiscanbe

explainedbythetheorythatenzymeswilldenatureinwarmconditionsandnothave

enoughenergytofunctionincoolerconditions.


24/34

22

Fromtheresultsgathered,ifseasurfacetemperaturesdoraisebeyond30Cthenupto80%

ofthealgaecouldbedestroyed.Theresultofthiscouldbedevastating.Fortunatelythereis

alwaysapossibilitythatthealgaewouldsimplymoveawayfromtheequatorandcontinue

soakingupCO2.

Ex.7Comments

I(a)Thisisaverymodestattempt.Therearesometrendsandpatternsidentifiedbutmuchofthis

sectionissimplydescribingthedata.Alackofplanninghasledtoanattempttoapplyachisquared

test.Thisisnotcategoricaldataanditisobviousthatthetestdoesnottellusanythingaboutthe

hypothesis.Theactualconclusionfromitispredictablyveryvague.ThiswouldmatchaweakI(a)46.

I(b)Theattempttouseresearchedbiologicalknowledgeisalsoquiteweak.Thereisverylittlehere

thatextendstoA2levelormakesuseofresearchedinformation.Wemightatleastexpectthe

realisationthatChlorellaisatemperatefreshwaterspeciesandmightnotberepresentativeof

marinespecies

in

warmer

seas.

Again

this

is

avery

weak

I(b)

46

I(c)CommentshereregardingpossibleanomalieswouldbecreditedinO(b)anditwouldbe

expectedthatsomeactionwouldhavebeentaken.Therearesomeusefulcommentsbutthereisa

greatdealwhichdescribesverypoormethodologyorbasicerrorswhichwewouldexpecttobe

addressedinplanninge.g.anuncontrolled150C(assumedtoberoomtemperature!).Itisclearthe

candidatedoesnotunderstandwhatismeantbyanobjectiveanalysis.Cellcountingisdescribedas

consistentanditissuggestedthatIrepeatedtheprocessmanytimestoensurehighreliability

whenrepeatingcannotimproveonunreliabledatacollection.Thenextparagraphthensuggests

countingwasunreliableandexplainswhy!

ThiswouldalsobeI(c)46anditisdifficulttogofurtherthanI4overall


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23

Ex.8 Investigatingeffectofpostureonvitalcapacity

Conclusion:Mystatisticaltestresultshelpprovethatformalesandfemales,vitalcapacityisaffected

byposture.Myresultsandgraphs illustratehow.My initialfinding isthatmalesandfemaleshave

their

vital

capacities

reduced

in

bad

postures

compared

to

their

relative

good

positions,

with

bad

standing positions reducing vital capacity to a greater extent (4.77% for males and 3.47% for

females)thanbadsittingconditions.

Myresultspartiallysupportmyhypothesissayingthatagoodstandingposturewillresultinthe

highestvital capacitywhile the lowest vitalcapacities will be seen in bad seating positions. While

males and females saw their good standing positions produce their highest vital capacities, with

meanvalues of4.4l and 3.45l, males saw the biggest reduction in vital capacity in the bad sitting

position,withareductionof5.91%,while femalessawthebiggestreduction in the lyingposition,

withareductionof9.27%.Thisgenderdifferencemaybebecauseofobstructionstothemechanics

of

breathing

when

lying

down

due

to

females

breasts.

When

lying,

the

breasts

may

be

pushing

into

and reducing the amount the thoracic cavity is able to expand during inspiration and therefore

restrictingtheactionofthelungs.Thislimitsthepressurereductioninthecavityneededtodrawin

airfromtheoutside,reducingtheamountofairinspiredmaximally.

Mygraphshelpmeidentifyfurthertrends.TherangebarsinGraph1showthatalthoughthere

aredifferencesinmaleandfemalevitalcapacitiesforeachposture,thereisonlyarealdifferencefor

thelyingpositionwithitbeingtheonlyconditionwheretherangebarsdonotoverlap.InGraph2,I

can see how male and female percentage changes compared to the control are very different. It

appears males generally have their vital capacities reduced to a greater extent in all postural

positions

except

the

lying

position,

which

has

been

discussed.

This

gender

difference

in

the

other

three postures may be attributed to the fact males generally possess larger lungs. The differing

posturalpositionsmayincreasethepressureintheabdominalcavitypossiblyreducingtheextentto

whichthelargerdiaphragmisabletoflattentoincreasethepressureinthelungs.Thiswouldreduce

themalesmaximalexpiratoryvolume.

Evaluation: Aspectsofmyresultssuggestmyresultsarenotasreliable,preciseandaccurateasthe

statistical test and graphs imply. Three anomalous results imply reduced levels of accuracy and

validity inmyreadings.Thethreeanomalousresultsare;37%vitalcapacityreductions inthe lying

positionofmale5;thegoodandbadsittingreadingsbyfemale1whichbothshowedincreasesof

12.1%

and

8.4%.

I

ruled

these

readings

as

anomalous

as

although

they

were

consistently

achieved

overthreerepeats,theyallfellwelloutsidethegeneraltrendoftheother12results.Isubsequently

excluded them fromaverage vital capacity calculations in order to avoidaveragesbeing distorted

andreducedinvalidity,reliabilityandaccuracy.

Fluctuatingvalues forvitalcapacitiesacross threerepeatssuggestrandomerrors inmy results.

Althoughthesefluctuationsareverysmallandsuggestrelativelyhighprecision levels,therandom

errorscouldpointtoveryslight inconstancies inhow individualsareseatedcausingfluctuations in

readings. To overcome this, walls would be utilised for the goodstanding positions tocompletely

standardise theposition, reducingvariation. In sittingpositions, Icoulduse two different typesof

chairs,one

advocating

good

posture,

while

another

is

adjusted,

causing

the

person

to

sit

in

abad

posture.


26/34

24

Systematic errors appear to be present in that the 3rd

result of the three repeats frequently

appearstobethelowestofthethree,withthiseffectbeingmorenoticeableforfemales.Thistrend

suggestsacumulativeeffectofhavingthreereadingstaken.Itsuggestshavingtoconsistentlyinspire

andexpiremaximallymayhaveafatiguingeffectwhereonthe3rd

readings,theindividualfeelsless

able to do their potential. This suggests a limitation inmymethodology and were I to repeat the

experiment,Imayhavetoincorporateabreakinbetweeneachroundofreadings.Thisbreakwould

needtoremainconstanthowevertopreventthelengthofbreaksimpactingresults.

My average vital capacity readings of 4.4l for males and 3.45l for females are not far off the

values4.6land3.6lquoted inmyscientificresearch.Differencesbetweenmaleandfemalevalues

arealsoaround1litreinboth,suggestingmyresultsmaypossesshighlevelsofaccuracy,reliability

andvalidity in theirmatchingwith recognisedvalues.Readingsbetweenmalesand femalescould

however, be attributed to differing attitudes while carrying out readings. While males appeared

competitive in trying to achieve high vital capacities, females were hesitant about initially putting

the tube in their mouths and then trying their hardest, appearing selfconscious about how they

were perceived. This suggests that my subsequent female results may be lower than average

reducingmyvaliditywhencrosscomparingmalesand femalesdue todiffering levelsofperceived

commitment. Result accuracy is reduced as results are shifted away from true vital capacity

readings.

The implications of my investigation can help alleviate the problems of people with breathing

difficulties. By adjusting their posture, my results suggest that it may help maximise their vital

capacityandsubsequenttidalvolume.Myevidencethatsitting inabadconditioncanreducevital

capacity by 12% for males and females suggests efforts could be made to improve postures of

peopleworkinginofficesandstudents.Ifextendingmyinvestigation,Imayinvestigatehowposture

affects the vital capacities of people of varying heights, finding out whether height impacts

reductionsinvitalcapacities.

EX.8Comments

I(a)GoodandBadpostureswerewelldefined intheplanningforthisexemplarandtherewasa

welllaidoutttestformalesandfemaleswithaccurateconclusions.Thefirstsectionabovegoeson

tosupport the highest rangewithanobjectiveanalysisof the dataasawhole rather thansimply

relying on assertions fromastatistical test.Theuseofsomedatamanipulation (%differences) to

describetrendsandpatterns isgoodpracticefordataresponsequestions inunittests.Thiswould

supportI(a)79)

I(b)There

are

many

examples

here

of

attempts

to

make

sound

conclusions

with

objective

analysis

partiallysupportmy hypothesis.Theanalysis of theevidence from graphs and the actualdata is

good. It would have been helpful for this candidate to give a little more evidence of researched

biologicalknowledgebut,althoughconcise,thereisagoodlinkbetweenthedataandtheorywhich

is integrated into the analysis rather than simply repeating information in Research & rationale.

ComparedtoothercandidatesitwouldbeharshnottoplacethisinaI(b)79

I(c) There is a veryobvious link between conclusions and results here. The strongest point in this

section is theway inwhich theevaluationofthe investigationhasbeen linked toactualevidence

from the data rather than making general assertions. The comments on anomalies could well be

used

to

support

a

high

mark

in

O(b)

but

there

is

intelligent

reference

to

systematic

and

random


27/34

25

errors with examples and identification of an important problem in using human subjects. This

wouldmeetI(c)79

Overallthereisagoodlogicalflowtothissectionandsomestrongevidencethatthecandidatehas

reallyunderstoodthisaspectoftheHowScienceWorkscriteria.AmarkofI8wouldbeappropriate

and maximum 9 would have been supported had there been a little more use of biological

knowledge.

Communicating

C(a)Mostreportswerewellorganisedandtheuseofclearsubheadingsmatchedtothecriteriawas

abighelptomany.Theinclusionofabriefabstractisrecommendedbutthissectionwasnotthe

maindiscriminatorinthiscriterion.

C(b)Candidatesneedtothinkmuchmorecarefullyaboutselectingthecorrectgraphtoaidthe

interpretationoftheirdatainrelationtotheirhypothesis.Simpleplotsofrawdatadonotoften

meetthisrequirement.Itisimporttodistinguishbetweenbarchartsandhistogramsandtoensure

axes

are

correctly

labelled

with

units.

Many

choose

to

use

a

computer

programme

such

as

Excel

to

plottheirgraphbutonlyaminoritycandothiswithscientificaccuracy

.


28/34

26

EX.9

0

0.5

1

1.5

2

2.5

3

3.5

4

0 1 2 3 4 5 6 7

Diversity

Rating

Species Diversity Index

R

P

Ex.9Comment

Thisis

avery

common

example

of

abasic

graphical

error.

The

use

of

sample

number

as

an

axis

is

almostalwaysscientificallymeaningless.Inthefirstinstancethesearedatafromrandomkick

samplesintwodifferentareashencesample1fromoneareacannotbepairedwithsample1from

another.Thisisnotpaireddata.Thecandidatealsopresentstheseassomeformofcontinuousaxis

withasuggestionofalinegraphratherthanabarchart.BotherrorsdonotmeetC(b)34Datais

presentedinwellchosengraphs...andcannotaidinterpretationofdata.


29/34

27

How soil moisture levels affect species abundance

0

20

40

60

80

100

120

0-10% 10.01-

20%

20.01-

30%

30.01-

41%

40.01-

50%

50.01-

60%

60.01-

70%

70.1-

80%

80.01-

90%

Percentage soil moisture (%)

SpeciesAbundance(no.)

Abundance of Mercurialis perennis Abundance of competition plant species

EX.10

Ex.10Comment

Thisexampleis betterinthatthereisagoodchoiceofsensiblesizeclassesofmoisturecontentand

someveryusefulillustrationoftherelationshipbetweenspeciesabundanceandsoilmoisture.The

ideathatthiscanalsobeusefullycomparedwithcompetingspeciesisanexcellentstartingpointfor

someinterestingdiscussionofecologicalreasoningbehindwhatmightbethesignificantfactor

affectingthedistributionofDogsMercury(Mercurialisperennis).However,havingdecidedtouse

sizeclassesitisobviousthatthisshouldbeahistogramnotalinegraph.Thiswouldprecludea

maximumbutoverallthisintelligentdisplaycouldjustifyC(b)56


30/34

28

EX.11

Ex.11Comment

Thisgraphiswellchosentoillustratethecorrelationalthoughwewouldacceptasimple

scattergram. Itisonlylimitedbysomecarelessmistakes.Formaximumcreditwewouldexpect

accuratelabellingofaxesMeanareaof.......andConcentraionofchlorinesolutionaswellas

correctspellinginthetitle.HencethiswouldbeC(b)4

C(c)Although

there

were

some

careless

exceptions

alarge

majority

of

candidates

checked

their

reportsforbasicerrorsofspellingandgrammarandthiswasnotoftenalimitingfactorinthis

section.

C(d)GiventhattheseskillsweretestedatASlevelitwasdisappointingtoseemanyinaccurateor

meaninglessreferencesquotedandsomeverynaiveevaluationofsources.

ForC(d)56wewouldexpectthefollowinginformation;

BOOKS

Author,Initials.,

Year.

Titleofbook.Edition.(onlyincludethisifnotthefirstedition)Placeof

publication(thismustbeatownorcity,notacountry):Publisher.

e.g. McCafferty.W.P.1981,Aquaticentomology:thefishermen'sandecologists'illustratedguidetoinsects

andtheirRelatives,London,ScienceBooksInternational, Inc,

JOURNAL

Author,Initials.,Year.Titleofarticle.FullTitleofJournal,Volumenumber(Issue/Partnumber),Pagenumbers.


31/34

29

e.g.Boon.P.J.1978ThepreimpoundmentdistributionofcertainTrichopteralarvaeintheNorth

TyneRiverSystem(NorthernEngland),withparticularreferencetothecurrentspeed.,

hydrobiologia,57.2 2246.

WEBSITE

AuthorshiporSource,Year.Titleofwebdocumentorwebpage.[typeofmedium](dateofupdateif

available)

Available

at:

include

web

site

address/URL

(Uniform

Resource

Locator)

[Accessed

date].

e.g.DrAliciaWhite,2009,HowtoreadtheheathnewsNHSUK,availableat:

http://www.nhs.uk/news/Pages/Howtoreadarticlesabouthealthandhealthcare.aspx (accessed 20/11/10)


32/34

30

Ex.12

Source9 http://www.unc.edu/~farkouh/usefull/chi.html

http://www.natuurlijkerwijs.com/english/suikers.htm

http://www.oregoncounseling.org/ArticlesPapers/Documents/ETOHBIOFx.htm

http://findarticles.com/p/articles/mi_m0FCG/is_1_32/ai_n13670706/p

g_6/?tag=content;col

Ex.12Comment

Thesesareexamplesofsimplycopyingawebsitereferencebuttellusnothingaboutthesourceor

natureoftheinformationtheycontain.Wheresomejournalsareaccessedinthiswaythenthe

detailsofthejournalandarticle,asindicatedabove,mustbegivenpriorityinreferencing.Overall

thesewouldbeaweakC(c)34


33/34

31

Evaluating sources

For C(d) 5-6 evaluation of sources must be objective and give some evidence for any

assertions. This will be credited where there is evidence of this skill in evaluating a small

number of important references rather than every one from a long list

EX.13

Is an article written byRenato M.E. Sabbatini, who the site says holds a doctorate in

neurophysiology by the Faculty of Medicine of the University of So Paulo at Ribeiro Preto,

Brazil, and was a guest scientist and post-doctoral fellow at the Max Planck Institute for

Neurobiology in Munich, Germany. He is currently chairman of medical informatics and

adjunct professor at the Faculty of Medical Sciences of the State University of Campinas, in

Campinas, Brazil; associate editor and chairman of the editorial board of"Brain & Mind"

Magazine. Therefore he is well regarded in the scientific community, and his work would be

peer assessed and reliable.

Ex.13Comment

Thisisagoodstarttofindthecredentialsoftheauthorwithreferencetothepossibilityofpeer

reviewbutneedssomecommentonevidence.Doesthearticlequoteotherworkfromareliable

journal?Isthisworkmentionedinanyotherreference?Isitpossibletoquoteonepieceof

informationwhichcouldalsobefoundinanotherreliablesource?Anyofthesemightraisethisto

thehighestmarkrange.C(d)

Ex.14

EvaluationofSourcesAmongthesourcesusedinthisinvestigationwasascientificpaper:Thepreimpoundment

distributionof

certain

Trichoptera

larvae

in

the

North

Tyne

River

System

(Northern

England),

with

particular

referencetothecurrentspeed P.J.Boon.Ibelievethistoacrediblesourcewithinthewiderscience

communityasitisaprofessionalscientificpaperthatwillhavebeenpeerreviewed.Othersourcesused

includedtwobooks:Caddislarvae:larvaeoftheBritishTrichopteraByNormanE.HickinandCaddisflies:the

underwaterarchitectsByGlennB.Wiggins.ThroughoutmyreadingWigginshasoftenbeencited,hisbook

wasalsopublishedinassociationwiththeNationalResearchCouncilCanada(NRC)press.ForthesereasonsI

believehisbookisaverycrediblesource.NormanE.Hickinhaswrittenalargenumberofbooksonvarious

biologicaltopics,hisbookisextremelydetailedandcorroborateswithotherreadingIhavedone,thereforeI

toobelievethatthisbookisaverycrediblesource.

Ex.14Comment

Herethecandidatehasaclearideaofevaluationbuteachoneisratherbrief.Thefinalsentencesbeginto

addressC(d)56buttoawardthehighestmarkswewouldliketoseeatleastoneexampleofcorroborates

otherreadingInthiscaseanypieceofdetailedinformationquotedinthefirstsectionofthereportcould

easilybequotedbutwhatistheotherreading?

ThismightthereforebelimitedasanexampleofpartofC(d)4butcouldeasilybeimprovedforatleastone

sourcetojustifythe56range.


34/34

Ex.15

http://www.madsci.org/posts/archives/mar99/922685827.Gb.r.html (31/10/09)

Thisisamedicalstudentsresponsetoanenquiryandsobeingfromastudentmaynotbeentirely

factual

as

it

has

not

been

peer

reviewed

however

it

is

not

from

a

commercial

company

so

can

be

seen

asrelativelyreliable.

Ex.15Comment

Thisisobviouslymuchweakerexample.ItiscontradictoryanddoesnotdemonstrateA2levelHSW

awarenessandwouldbeamaximumC(d)3

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