A summary of Population Size and Ecosystems chapter for WJEC A level Biology, containing the Carbon Cycle, Nitrogen cycle, Predator-prey relationships, ecological pyramids, Succession etc
Measuring obundarca: Caplure markrecqpture kick-sampling, for aquah
Opulalion Size and ecos ystems: using a quadrant to cdeulat he meean numbu ofindividuas in severd
esfimating Peruentagecover 9f a plant
Se of Populaton dtecmined by bil ate deof. ate, inmigcaton Ond emigra mesguradintervals;
lesuringdistribution line-transect-shows The organisms Tha le ona line aT
belt - transeci Shows abundancu dafa for a 3iven area ot messured
Fugilive species are poor a competton They aly thar ablt t on
distonces along fransect. A quadrat placed at esch freqweney.
ordinate olong the Trors et co-
reproduce quicly and readings may be faken for densiy ofspecies, Iransect s Tabl
speues costrol
steto
Equilbium5table fheir population by ompetlo Ph for assesing plants btnot mofile animss
a hobrtot. Teir usual patfeen of growth s
asiomod Curve called h e One -stop grot Curve
lo8 Phas
.
The intaraction o organisms wth ese ofher with the non-ing faotorsin
Log phaseperiod oP odapfotonor preparaton or growl (oponestial) Their
environment
comprisesan ecsystem Hab, Tat isan ecological o onvironmtal
Eponenial phase n o factor lmling rowih, hente mor indivduals area inhibtad by On organsm
ecome available
lag phes
eproduction.
Tat onary phase corrying capacty be a o Qvailable ood, overtrowding, corpebio n, predatantrivores and decomposers feed as
saProbontsty derive their ene37 rom
Deat phase thu Pactocs tat slo populsfioneatargrouthbecome more significast ond pulta dead Ond deca ing org anisms. Vefrivo res for example asrthwDims ) e d on smal fag
dereasess uatl death rat Than birth rate
organic debris. Vecomposers a r microbes Such 0s bacteri0 nd
and ogi t
Predator pre elationshps odbtainnutritds from dead organm Ond Qnimal waste
-Both Populatos etuate, bl. oe ed Lat tmphe level) (ad trophe el (ard tophe bel) (4 hophe kve
pp nan der
prey Food chains produce Prmaryconsume Secondary consumtrttry corsumar
Pledatar
- Bames tel popalata pe e4Energy slos at each trophiclevel energ7 flowihg Through fhe ecosyslo
TL be predabr popud Ceduca and ultimately fhe nerY leaves The 5Ystem as hesl. Three dimensions
environmenfs Such as 9qugti Systemsand forest an opies have aonger food
Bvioma5s-dry mass asseciakd wil orqmcb Cha than Two dimensi'onal habstots such as gasslands. |he more effiuent nary
molecles Pt Onimpl coastant t be. All the enery
chain, 1he lonqer flowing Fon
One organi'sm to another oniginated ssuligkt, but not all Sunlgkt
abunda.T food source by the photosynthehc piqmensbecaase may be he wrongavelangth.
casier te catch
P p prey Gross primary produetivily s he rate of producton of chemcal eneray by fb
Synthesis in agiven qiven tme. Whot comains nef
tim -becasef predater area in a
after respirat.on
1 predatons fecbrgotpdells. J}Htutt att Primary prod.cthiv.ty. GPP-opiration NPP 30 hat los
ttepee e .Seondary produetivty is The ocondery ered,
Densy dependent factors: uSually biohe factors uch as disease, paras.ttm, prdan con3umbs accumule e ener3y
afe ar
Onma5simlafd
food i biomass their ceds or tssus
Vonsity-independont factors: usually a6ote factors such aslood, fre ¥aecrs
Ieienc o egy toer = resyincoporatad i biom 10 ner
In anew ablat, physical feetures ore descrbed s t Gel tps, hopeatn than phob energ1 Qvailable in bonass belare
transfer.
Congmt
becase Plants aepend on The ph1Sicol feafures fhan Onimals because f depend on The
plonts.
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