Detailed Grade 12 IEB Life Sciences Population Ecology notes, crafted by a matriculant who achieved a Life Sciences distinction. These thorough and easy-to-understand notes cover all essential topics, making complex concepts simple. Ideal for exam prep and mastering the IEB curriculum!
inLY.io populationsize in n Populationgroupoforganismsofthe
samespeciesfoundinaspecific
area canfreelycrossb
rateofapopulation
natality birth of
communitygroup differentpopulationsoccurringinaparticulararea
m I i fhem of
w
fanisms
ofplant animalcommunitiesininteractionwitheachotheraswellasnonlivingfactors
intoanareawheretheybecomeestablished Ecosystemunit
emigration oneway movement organismsout anareatobecomeestablished inaparticulararea
orclosedpopulation apopulationwhereemigration don'toccur
immigration Environmentexternalfactorsbiotic abioticsurroundingan
organism influencingitsdevelopme
egfishinadamanimalsonanisland survival
occur
onlynatality mortality
HabitatThespecificenvironmenthomeinwhichaplantanimalspeciesnormallyoccurs
individualsingleorganismthatformspartofaspecies
sulationsize
can be bydirectorindirectmethods
determined
esize mobilityoforganismsdeterminesthechoiceofmethod Nichesumofactivities relationshipsinwhichanindividualengagestosecure useresourcesnecessaryto
itssurvival reproductioneach hasaspecificroletoplayecologicalniche
species
ect ofall
totalcount inthe
individuals p opulation
censusforhumans aerialphotographsofgroupsofanimals 2 Quadrat aframeofmetalwoodorplasticofknownsizeeg1m
iareaisdemarcated thesurfaceareaisdetermined
irectcountingofonlypartofthepopulation quadratisrandomly ongroundindemarcatedarea
placed
i markrecapture organismsare
counted of
insideframeno individualsper
unitarea
ecificareaisdemarcated repeated few
a of
no individualsperquadratiscalculated
timesindifferentareasorg
of arecaughtcounted marked
number individuals 1ˢᵗSAMPLE
marked arereleased
individuals mustn't damageorganism
injure
timeallowedforindividualstomix
fficient mustbevisibleclearly populationsize noofindividualsperquadrat
dug 86888
2ndSAMPLE
Anothergroupiscaught counted tomustn'taffectmovementorbehaviour
canbeanyshape
quadrat
5 be
must closed
population
no immigration datamustbecollectedfromsomeshapedquadratstobecomparable
p MY oremigrationtakesplace sizeofquadratdependsonthetypeoforganismsconcerned
quadratissuitedtoplantpopulations sessileinvertebrates
estimatedpopulationsize briefperiodbetweentwosamplings
noofmarkedanimalsin1ˢᵗsample sonobirthsordeathsoccur reliabilityexactnooforganismsmustbeknown areaofdemarcatedarea
surface beknown
must
noofanimalsin2ⁿᵈsample areaofquadratmust
surface beknown be
Quadratmust placed
randomly
, eometricExponential JshapedGrowthform
opulationconreachunreproductive
p otential young
isMhh.Ewnh
nlimited
resources like water space no
food predators withsufficientfoodwaterspacelittlepredation LagPhaseinitiallypopulationgrows
slowly
eatconditionsmaximum
growthratipopulationrapidly to must
acclimatisesadapts environment individuals
population become motu
sexually
once seek
individuals p artnersformating
55 4ie nitashopeshorpincr ffffif.gg fffffffffff phasepopulationgrows
Accelerating rapidly reaches rate
growth
m aximum
favourable
again repeats
pattern
growth
phfse
phase littleto
noenvironmentalresistance
DeceleratingPhasegrowth
rate
is thanmortality
natality higher
resistance
duetoonincrinenvironment.at
d ecreases
still
natalityis than
higher m ortality
ameina.us n
insects
isIY I i
t.me
Ecuilibriumapopulationnumbersreach
c arrying of
c apacity environment stabilise
aroun
fungi can
factors transform curve
limiting s.snopeintos.sn areequal
natalitymortality
Aspopulationgrowsavailableresourcesdecrimore carryingcapacity Maximumno_ofindividualsthat specificenvironmentcansustain
competitionfor m embers
resourcesamongstp opulation
OPULATION REGULATORY FACTORS LIMITINGFACTORS
nsitydependantfactorsfactorsthat.toeeffectwhenpopulationsizedensityincrease Densityindependentfactorsfactorsthatlimitthesizeofpopulationregardlessofthepopulationden
shortage offoodwatershortageoflivingspace extreme in
c hanges temperature natural
disasters
asnortoseofsnelter.ci Yn
predation
am n
size
ceopopulationreachesits maximum thenumberswon'tremainconstantbutfluctuatewithinnarrowboundariesduetochangesinenvironmentalresistance
EEE.EE
incrbeyondcarryingcapacityenvironmentalresistancewillincri.popno.sc
sopulationno.s
ecr sopulationno.sdecrbelowncr egggy
c apacityenvironmental
resistancewilldecri.popno.si stablepopulation nos
fluctuatearoundcarrying
capacity
carrying
the
unstablepopulation nosexceed carrying
c apacity
habitatisdamageddeerinthe
carrying
capacity
carrying
a
seasonalfluctuation of
capacity environment time
incrordeerin population
to
sizedue seasonal
migration for availableresources
ommaswnentnerno.sexceedcomyngcapanya.name
ftp.ffffqggnfqfffffgffffffffffigff.gg
g
q yyggggg.gg
migration foravailableresources ofplantsanimals
environment
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