Detailed Grade 12 IEB Life Sciences Evolution 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!
time
gradualchangeover
areinheritedovertimeduetonaturalselectionresultinginnewspecies
BIOLOGICALEVOLUTIONgeneticchangesin populationthat
evolution'satheory
HYPOTHESIS vsTHEORY microevolution
that
typothesisinformedassumption anexplanation
gives that
variation withinspeciessmall
occurs o riginatein
changes the pool
gene insmall
resulting
of specificphenomenonthatcanbetested changesinthegenotypeofthe
spec arepassedontooffspring
changes Fossil Records
THEORY well explanationsupported evidence
substantiated
by macroevolution organismorthe or
remainsimprints footprints
that senseof naturalp henomenon
makes developmentofnewlifeformsorspeciesfromearlierlifeformsovermanygenerations ofanorganisms
asnewevidenceisdisovered
develops changes the
forms
speciation basis ofmacroevolutionwherenewspeciesdevelopfromexistingspeciesovertime of
evidence the
provide of
history extinctorganisms
is
records the
fossil accumulation
ofall
listed knownloss
ofdifferentagesthathavebeendiscoveredbypalaeontolog
ERASMUSDARWINstudiedfossils
life
roposed fromcommon
descended ancestor ofbiogeography
father ModificationbyDescent
modified adaptto
one
species from
developed anotherovertime
of
mechanism evolution natural
selection
body plansoforganismsare to
artificial
in
selection animals
in
metamorphosis tadpoles their
differentenvironments
the
similarstructureswith same body thatperform
plan
manemporantos Infdffistishis different
functionshomologousstructures
JEANBAPTISTEDELAMARCK explains existed
evolution n atural
t hrough selection
body thatperformthe
structures samefunctionbut
Lowofuseodisuseiuseodisuseoforgonsmaycouseorgansize.to from
originate different
ancestoranalogousstructures
or
increasedecrease disappear
ighi li
tinki inoreoespringtnonrequired
of characteristics
Lowofinneritance acquired
certancnongesin.gg ihfhhf.iefhhhfrocedbocktoacom
are
characteristics
by
inherited offspring
of occuredensuressurvivalofpopulation
amount variation
alarge
sthe
in of 74848418 tospecificenvironmentreproducemore
are adapted
d riving some
change population formation new
species
3 individuals better ancestor
a t ransferred
characteristics
tooffspring
fromsurvivingparents
LAMARCKISM phenotypic inherited
c hange
atthe
g enotype
Biogeography
DARWINISM of speciesinspecific
distribution existing extinct
noofoffspringproduced
large that
species proves
geographical related
closely species
polyploidy meiosis usually inthesamegeographicalregionsuggestsa
occur
sexual
reproduction variationinoffspring mutations ancestor
common
leadtofor irafl.es
random
assortment over
crossing biogeographical c onbeisolatedbybarriers
regions
gpygep.org
had
short toreachleaves
them
necks frequentlystretched
yg ofnewspeciesgflightlessbirds
necks stronger longer
become
me selection
is to
down next
ongneckcharacteristic passed generation natural survival ofthefittest GENETICS
thatcloselyrelatedorganismshave
evidence
provides more
favourable
FORREJECTION
REASON of
inheritance characteristics similarities
intheirDNA
assessed
gene forlongstrongnecks of is
iexplainssource variationthat
cquiredgenesconnotbeinneritedtoo.fi pthg changes'overtime
forevolutiontooccur
necessary
newspeties
in or
change are
genotype phenotype trans
formed
to
successive
generations
set
common of20aminoacidssomemetabolicprocesses
Giraffe havedifferent
p opulations due
necks
length to resultofgeneticvariation VESTIGIALORGANS
environmental
changecompetition forresourcesoccurredshorternecksdielongerneckssurvive structures
organs withdisusedecreased
that insizeovertime
natural
selection
occurs structures evidence
homologous of commonancestorshared
genotype
forlongernecksispassedonnextgenerations eswisdomteethappendix
each has
futuregeneration thanpreviousgenerations
necks
longer
COMPARATIVEEMBRYOLOGY
chase
www.m.gow.grauacnongengpeciese
gradualism punctuated
Equilibrium.gg
asisspecies in of
unchanged state equilibrium
remains go.ee
species egg
natuatedrapid interrupted
c hanges
aeswereinequilibriumun.itsudden
rapid their
interrupted
changes existence species
favourable
mutations species
many
herfailedtoadaptobecomeextinct.ir experienced
new
atenabledthemtoadapt.to environments PUNCTUATEDEQUILIBRIUM
www.ngggpegegpoengunaniugaagenneaneaurgegemu anemp www.nongesaang species
species
leadto speciation for
o ccurrapidlyaccounts
speciation
of
absence
transitional
of
consist both
fossils a ncestors time time
modern
s pecies
microevolution macroevolution divergencersconvergence
mall
scale togenotypebelowspecieslevel
c hanges echangesabovespecieslevel
large.ca convergentorganisms not
are no
related commonancestors
to
sub
accumulate produce species
hanges headtospeciationovertime
fnyggggmessgg.gg
developANAlooousstructures
independently ofeachother
forceNatural
driving selection
to
due environmental
pressure Genomes different
d istinctly cannot besome
species
anymore butsome
differentanatomy insimilarenvironm
function
Peppered.gg gniAhffigticresistantbacteria
forcemacro
Driving mutation radiation
a daptive
d ivergence
egbutterflywings birdwings
regig
g of
evolution modern
horse evolution ofbirdsfromdinosaurs
divergent arerelatedcommonancestors
organisms
Homologous
develop structures
to
due different o rmodeoflifeel.ci
habitats
same butdifferentfunctionsindifferentenvironme
anatomy
pentadactyllimb
Ihh i.isnueaarossisiona
variation
onnew
based
s elected habitats
speciationnew sharesimilar
species traits
butaredif .beakssuitedtodietoft.me
finch
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