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Topic D.1: Origin of Life on Earth

D.1.1 Describe the four processes needed for the spontaneous origin of life on Earth.

1) Non-living synthesis of simple organic molecules

a) Early Earth provided elements + chemicals needed for lifeb) Oceans mixture of inorganic molecules simple organic molecules

c) Organic chemicals from Earth or space

!) "ssembly of these molecules into polymersa) #olymeri$ation formation of larger% more complex organic chemicals in oceans

&) Origin of self-replicating molecules made inheritance possible

a) DN" re'uires protein en$ymes for replicationb) (N" capable of self-replication

i) ataly$e its formation from nucleotides *o proteins

ii) (N"-based catalyst ,ribo$yme)

c) apable of undergoing evolution by natural selection) #acaging of these molecules into membranes * internal chemistry different from surroundings

a) losed membrane vesicles form spontaneously from lipids

b) Different internalexternal environments cellular metabolism

D.1.2 Outline the experiments of /iller and 0rey into the origin of organic compounds.

1) Earths Developmenta) 2ormed .3 billion years ago from cloud of dust particles around 4un

b) 5eat from force of gravity + radioactive decay melted interior dense metallic core ,iron + nicel)

i) 4urrounded by cool li'uid mantlec) During cooling of crusts% gases from hot interior escaped through volcanoes atmosphere of

hydrogen% *ater vapor% methane% ammonia% nitrogen and hydrogen sulfide

d) 6aced of oxygen reducing atmosphere

e) /onomers of biological molecules formed in shallo* ocean *aters as products of reactions btsimple organic compounds in atmosphere + *ater

i) #rimeval soup or chemical soup!) /iller and 0reys Experimentsa) 4imulated early Earth conditions

b) Establish if chemical evolution could occur in primeval soup

c) 7ater ,5!O)% methane ,5)% ammonia ,N5)% hydrogen ,5!)d) 4ealed in sterile glass tubes + flass connected in loop

i) 2lass one *ater% one * pair of electrodes

e) 7ater heated to produce steam% spars produced bt electrodes ,lightning)

f) /ixture cooled*ater condensed + tricled bac into first flas continuous cycle

g) "fter 1 *ee% 138 of carbon organic compounds

i) 1& of !9 natural amino acids

ii) 5igh concentration of adenine

D.1.3 4tate that comets may have delivered organic compounds to Earth.

1) #anspermia

a) 5ypothesis that life on Earth may have originated by introduction of complex organicchemicalsbacteria via comets

b) omet small body in solar system orbiting 4un

c) 4ome bacteria + archaebacteria resistant to extreme conditions% possibly in deep spacei) 4emi-dormant bacteria deep in "ntarctic ice cores

d) osmic radiation energy for organic molecule synthesis


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i) omet spectra hydrocarbons% amino acids% peptides

D.1.4 Discuss the possible locations *here conditions *ould have allo*ed the synthesis of organiccompounds.

1) "biogenesis

a) :eneration of life from chemicalsb) 5ydrothermal ;ents

i)

iv) /artian meteorites ,possibly * fossili$ed bacteria) found in "ntarctica

D.1.5 Outline t*o properties of (N" that *ould have allo*ed it to play a role in the origin of life.

1) (N" 7orld 5ypothesisa)


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c) "ccumulation organisms *hich synthesi$ed protective en$ymes ,e.g. catalase)

d)


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iii) 4ome hybrids cannot mate * o*n ind but possibly * parent species

iv) ?n ring species% members of ad@acent populations interbreed successfully ,not if *idely separated)v) an be physically impossible for members of same species to mate

vi) ?ndividuals forming single gene pool

f) Evolutionaryi) :roup of organisms sharing uni'ue collection of structural + functional characteristics

g) ladistic

i) :roup of organisms sharing common ancestorii) /embers may diverge separate species

D.2.4 Describe three examples of barriers bet*een gene pools.

1) :enetic ?solationa) ommonest re'uirement for speciation

b) "ccumulation of different allele fre'uencies

c) /aintained by reproductive isolating mechanismsd) #re$ygotic ?solation

i) Bygotes not formed bc gametes dont meet + fertili$e

ii) =emporal ?solation /ateflo*er at different timesiii) Ecological ?solation occupy different same region but different habitats

iv)


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D.2.6 ompare allopatric and sympatric speciation.

1) 4peciationa) #rocess by *hich one or more species arise from previously existing species

b) One species ne* species intraspecific speciation

i) ?f occurs *hile populations are physically separated allopatric speciation,1) :eographical barrier blocs gene flo* adaptations to ne* environment changes in allele +

gene fre'uencies reproductive isolation

ii) ?f occurs *hile populations are occupying same area sympatric speciationc) ! speciesne* species interspecific speciation

D.2.7 Outline the process of adaptive radiation.

1) "daptive (adiationa) :roup of organisms share homologous structures *hich are differentiated to perform variety of

functions

b) Occurs in all taxonomic group except speciesc) 4hared features adaptations to particular environments

D.2.8 ompare convergent and divergent evolution.

1) onvergent Evolutiona) Distantly related organisms evolve similar traits as they adapt to similar environments or ecological

niches

b) (esult in analogous structuresc) 4imilarity due to pressure from natural selection

!) Divergent Evolution

a) =*o or more adaptations have common evolutionary origin but have diverged over time ,adaptiveevolution)

b) (esult in homologous structures

c) 4imilarity due to common origin&) #arallel Evolution

a) =*o species maintain same degree of similarity *hile each undergoes evolutionary changeindependently

D.2. Discuss ideas on the pace of evolution including gradualism and punctuated e'uilibrium.

1) #unctuated E'uilibrium

a) /any species sho* stasis throughout much of geological historyb) "ccount for observed gaps in fossil record

c) (apid evolutionary change occurs during speciation

d) Occurred in small portion of population at edge of geographical range ,higher selective pressure inperipheral populations) peripatric speciation

!) #hyletic :radualism

a) /ost evolutionary change relatively slo* but not uniform rateb) One species gradually transforms into another

&) 4tabili$ing 4election

a) Operates *hen environmental conditions favorable to particular phenotype + competition isntsevere

b) Eliminates extreme phenotypes maintains phenotypic stability% doesnt promote evolutionary

change

) Directional 4electiona) (esponse to gradual environmental changes

b) #ressure to move mean to*ard ne* mean


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c) 6eads to stabili$ing selection

3) Disruptive 4electiona) 2luctuating conditions favor presence of ! phenotypes

b) /ay split into ! sub-populations + later speciation

D.2.1! Describe one example of transient polymorphism.1) #olymorphism

a) Existence of ! or more forms of same species *in population

b) =ransient #olymorphismi) One allele displacing anotherii) ExC ?ndustrial /elanism in


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1) #rimates

a) 5umans% lemurs% moneys% gibbons% apes ,orangutans% gorillas% chimpan$ees)b) "pes + humans distinguished by being tailless + free motion of arms over head

c) :rasping limbs opposable thumb grip for po*er + precision

d) (otating forelimb hand can rotate through 1G9H

e) 4tereoscopic vision eyes close together on face * parallel optical axes

f) ;isual activity increased numbers of rodscones * o*n nerve cells

g) (educed olfaction reduced snout allo*ing flatter faceh) Enlarged sullexpanded area for cerebrum% ventral foramen magnum

i) 6arge brain increased sensorymotor areas% deeply fissured

@) 2e* offspring longer gestation

) 4ocial dependencycorporate activities% group cohesion

l) "dapted to arboreal ,tree-d*elling) life pre-adapted ,fortuitous) human ancestors to ne* niches

*hen "frican forests gave *ay to drier grassland savannas 3 mya

D.3.5 Outline the trends illustrated by the fossils ofArdipithecus ramidus%Australopithecus includingA.

afarensisandA. africanus% andHomoincludingH. habilis%H. erectus%H. neanderthalensisandH.sapiens.

1) 4ulls and


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f) 6ong life span

) 5ominid Evolution

'en#s of

ho$inid

(ge of

appearance

)$*a+

S,#&& -

a/s

0rain

capacit*

)c$3+

Teeth Diet ost#re Distri#tion Significance

Ardipithecusramidus

. 2lat @a* &A3 J 339 6argeupper +

lo*er

canines

2ruit%leaves%

insects

#ossiblybipedal

4pecimensin Ethiopia

urrentlyoldest

hominid

Australopithecu

s afarensis

6arge

@a*s

39 4mall

canines +

incisors%

moderatelylarge

molars

5erbivore%

some meat

2ully

erect

4outh + East

"frica

6ived in

trees +

savanna

Australopithecu

s africanus

!.3 ;entral

foramen

39 4mall

canines

arnivore 2ully

erect

4outh + East

"frica

4mall game

hunter

Homo habilis ! 6ighter @a*

A99 4mallcanines

arnivore 2ullyerect

4outh + East"frica

4tone tools%ma@or

increase in

brain si$e

Homo erectus 1.3 =hic

sull% lo*

forehead

bro*ridges

GG9 4mall

canines

Omnivore 2ully

erect

/igrated out

of "frica !.!

mya to "sia

+ Europe


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e) Neanderthals side branch of hominid evolution

i) "dapted to cold of ?ce "ge in Europeii) ommunity living + beginnings of religion at burial sites

iii) Extinct suddenly possibly bc of competition *H.sapiens,overlap for 9.3 my)

D.3.7 Discuss the incompleteness of the fossil record and the resulting uncertainties about human evolution.

1) 2ossil (ecord

a) /any species appear at early roc strata + disappear abruptly at later level origination + extinctionb) 6ac of continuous record missing linsc) #unctuated e'uilibrium gaps pauses bt speciation events

d) Dead organisms decompose rapidly + arent eaten by scavengerse) 4oft-bodied organisms dont fossili$e easily

f) 4mall fraction of organisms die under fossili$ation conditions

g) =iny fraction of fossils unearthed

h)


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i) oordination of lips% tongue% larynx + & areas of brainC speech motor cortical area ,delivery of

speech)% + ! areas on left side of cerebrumb) hanges in sexual behavior life-long relationships bt men + *omen% *ho lived together *

children

c) 2ood sharing benefit to communityd) =ransmitted bt people by communication% not genetics cultural evolution

e) ?ncreased brain si$e inHomo habilis stone tools

f) Homo erectus

hand-held axes * ! cutting edgesg) Homo sapiensflint% bone% *ood tools ,&3%999 ya)

h) 4cience + technology cultural evolution

i) :ene pool little different from firstHomo sapiensancestors ,ro-/agnon) !9%999 ya in 2rance

Topic D.4: The "ard*einerg rincip&e

D.4.1 Explain ho* the 5ardy-7einberg e'uation is derived.1) p dominant allele ,") "" p!

!) ' recessive allele ,a) aa '!% "a p'&) 1998 probability that gamete contains " or a p + ' 1.9)

1998 probability that offspring are genotypes ""% t*o "a% and aa p!

+ !p' + '!

1.93) #opulation in genetic e'uilibrium ,for ! alleles)) ?f 5ardy-7einberg assumptions not met% deviations from expected genotype fre'uencies occur

a) No random mating inbreeding increase in homo$ygosity for all genes

b) 4mall population si$e random changes in genotype fre'uencies genetic drift

c) "ssortative mating increase in homo$ygosity for genes involved in trait thats assertively matedd) Natural selection change in allele fre'uencies

e) (ecurrent mutation maintains alleles in population

D.4.2 alculate allele% genotype and phenotype fre'uencies for t*o alleles of a gene% using the 5ardy-

7einberg e'uation.

1) p dominant allele fre'uency!) ' recessive allele fre'uency&) p! homo$ygous dominant genotype

) !p' hetero$ygous genotype

3) '! homo$ygous recessive genotype

D.4.3 4tate the assumptions made *hen the 5ardy-7einberg e'uation is used.

1) /athematical "ssumptionsa) Organism diploid + sexually reproducing

b) =rait under consideration autosomal ,not located on sex chromosome)

c) Organism has discrete generations

!) ?nherent "ssumptionsa) (andom mating occurs *in single population

b) #opulation infinite si$e% or sufficiently large to minimi$e genetic drift

i) ?n smaller populations% some alleles may be lost bc of genetic drift in terms of fre'uencyc) No natural selection% mutation or immigrationmigration ,gene flo*)

Topic D.5: h*&ogen* and S*ste$atics

D.5.1 Outline the value of classifying organisms.

1) =axonomy


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a)


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d) ladists uses DN" se'uences% biochemical + morphological data

e) "ssumptionsi) hange in characteristics occurs in lineages over time ,only *hen characteristic change can *e

recogni$e different lineagesgroups)

ii) "ny group of organisms related by descent from common ancestor ,all life on Earth related)iii)


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a) ?nsufficient light hampers gro*th% possibly causes death

b) 4un plants adapted to receiving a lot of lightc) 4hade plants adapted to lo* amount of light

) 4oil p5

a) "ffects its capacity to retain mineralsb) "cid soil 5+replace positive ions clinging to clay particles + leach them out of soil

i) 5igher amount of iron

c) "laline soil

calcium becomes more soluble ,more available to plant roots)3) 4alinity

a) 4alt content of soil dissolves in *ater% giving it higher osmotic valuei) /ore difficult for plants to tae up ,bc they collect *ater by osmosis)

) 6evels of /ineral Nutrients

a) (oc from *hich soil is formed

b) 4i$e of particles maing up soili) /inerals + *ater drain rapidly thru large particles ,sand) + are held by small particles ,clay)ii) Negatively charged clay particles bind to a!+% +% /g!+

c)


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e) ount number of individual species in 'uadrat + move to ne* location

f) "verage number of individuals can be calculatedg) Divide by area of 'uadrat individuals per unit area

'.1.4 Outline the use of a transect to correlate the distribution of plant or animal species *ith an abioticvariable.

1) 6ine =ransect

a) 6ine across area of geographical variation ,e.g. slope or seashore)b) ?nvestigate all plants touching string or place 'uadrat at regular intervals

'.1.5 Explain *hat is meant by the niche concept% including an organisms spatial habitat% its feeding

activities and its interactions *ith other species.1) Niche

a) " species role in an ecosystem

b) 4patial 5abitat *here species livesc) 2ood supply% ho* species interacts * other species in ecosystem

d) ?nformation on abiotic + biotic factors

'.1.6 Outline the follo*ing interactions bet*een species% giving t*o examples of eachC competition%

herbivory% predation% parasitism and mutualism.

1) ompetition

a) Organisms attempt to exploit the same limited resource such as food or spaceb)


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ii) 4pecies competing * each other for everything + best adapted *ill remain

'.1.8 Distinguish bet*eenfundamentaland realizedniches.

1) 2undamental Niche

a) #otential mode of existence given a species adaptations!) (eali$ed Niche

a) "ctual mode of existence resulting from adaptations + competition * other species

'.1. Define biomass.1)


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b) /etabolism of consumer re'uires most of energy contained in its food little converted into

biomass available for next level

c)


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ii) 4ome soil holds minerals better than other types accumulation promotes plant gro*th

c) /ore plants less erosion

i) (oots hold soil in place% prevent *ind erosion

d) #lants provide shade more *ater in soil + reduces erosion

'.2. Distinguish bet*een biomeand biosphere.

1)


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E9a$p&e actus /il*eed (osemary Oa =ree Orchid

,Epiphyte)%


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a) 2oreign plants in 5a*aii cover native plants * shade increased erosion

!) #redation

a)


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c) 2ormed spontaneously *hen 0; light stries atmosphere

i) Energy of 0; radiation absorbed by oxygen molecule

ii) 4eparates O!molecule into highly reactive oxygen atoms

iii) Each combines * oxygen molecule to form O&

iv) (elease absorbed energy as heatd) ?n troposphere% is a pollutant

i) omponent of smog + greenhouse gas

ii) ?nhibits photosynthesis

'.4.1 Explain the use of biotic indices and indicator species in monitoring environmental change.

1) Environmental hange

a) /onitoring *arns us in advance of undesired changes + allo*s for preventative actionb) ExC Eutrophication rate of oxygen depletion biochemical oxygen demand ,


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b) "dvantages

i) 4ome species hard to breed in captivityii) #opulation remains adapted to original habitat

iii) ?ndividuals maintain natural behavior

iv) 4pecies interacts * others + fulfils role in ecosystemv) 5abitat remains available for endangered species ,and others)

vi) (e'uires larger gene pool but then conserves this variation bt individuals

'.4.6 Outline the use of ex situconservation measures% including captive breeding of animals% botanicgardens and seed bans.

1) Ex 4itu onservation $oos% captivity

a) aptive breeding difficulty capturing animals *o illing them

i) ;ariable reproductive success in captivity

ii) Koung deaths ,sea mammals)

b)


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b) (elease into original population mix * unmared individuals randomly

c) apture second random sample of population

d) "ssumes that natality% mortality% immigration% emigration $ero

e) 6incoln ?ndex

i)N

n

n

n1

!

&=

&

!1

n

nnN

=

ii) n1 number in first sample

iii) n! number in second sampleiv) n& number of mared individuals in second sample

v) N number of individuals of total populationvi) (e'uirements

,1) ;ery lo* natality% mortality% immigration and emigration

,!) /ethod of capturing has little to no effect on animal,&) /arings have little effect on animal

'.5.4 Describe the methods used to estimate the si$e of commercial fish stocs.

1) ?nternational ouncil for Exploration of the 4ea ,?E4)

a) Estimates of fish stoc on North "tlanticb) =ae sample of !99 fish for every 1999 tonnes of fish brought into port 1. milyr

c) Data on age% length% breeding condition of fishd) Normal stocs broad range of ages ,determined by si$e of ring bones on either side of brain)e) /ostly young fish lo*er stoc

f) =aes longer to catch certain number of fish lo*er stoc

g) 4cientists fish in standard coordinate matter in one spot + compare to other spots

h) Echo + sound e'uipment to detect schools of fishi) ;ery fine nets catch eggs + larvae as they float bt planton

i) Number of eggs indicates number of adult fish

'.5.5 Outline the concept of maximum sustainable yield in the conservation of fish stocs.

1) atching fish limited to leave enough to produce sufficiently large generation the next year

!)

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