Biology Module Chap 8

8/3/2019 Biology Module Chap 8

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o. I The Abiotic andii

Biotic Conrponents of the Environment

The abiotic and bioticI An ecosystem

components of an ecosystemconsist of the abiotic and biotic components

LEARNING OUTCOMESo Identify the abrotrc and brotic components of an ecosystenro Classify biotic corlponents into trophic levelso Explain the interactions berween biotic componenrs in rerationfeedingo Explain the interaction between biotic components in rerarioncompetition tn


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I

'fIThe abroirc Cor--rttr'-,=.rlS l

Most organisms cansurvive well in a neutralor nearlv neutralenvironment Examples.pi n ea ppl e pl ants preferacidic soil

Temperature- Most organisms survivewilhin the temperaturerange of 0"C to 45'C.- A drop in temperaturewithin a certain rangeresults in a decreasern the mefabolicactlvifies of theorganisms.- Temperatures higherthan 45"C usuallylead to denaturationof enzvmes.- Certain species can livein extreme temperaturesFor example.thermophi!ic

Light intensityAffects lhe di stri b utio nand qrowth of pianis a.,,Janimals Examples cf -oroanisms:Hict"r ;ntensily tall trees in

_,tHumidity

Humrdity rs hiqher at nrghi butlower during the dayMost organisms prefer humrdhabitats. For examples, snakes,frogs and mosses.Some organisms regulate therractivities to avoid dehvdration.for instance, woodlice which areusually found under stones

Topography- The physical features of the landwhich concern the altitude,gradient and aspecf of a region- The higher altitudes, the lowerthe afmospheric pressures andtemperatures. These result in

defferent plants growing atdifferent altitudes. For instance,pine trees can be found growingal a hiqher altitude than tropicalplants.- Gradient or the sfeepness of aslope is another topographicfactor. Steep slopes result inrapid drainage and run-offTherefore, the soil layer is thinnerand drier.Another topographic factors isaspect. The slopes of mountainsfacinq the direction of the windreceive more rain than the slopesshaded from the wind. Thus, theorganisms from different slopesof a mountain are different.

Microclimate- Refers to the climate in a' microhabitat.

bacteria can survivein fi.ot spdngs.

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' .. r. , rt .r ' r L diliO rr 2006Food charnl1 shcws a secue'rce of organisms through whrch enerqv from lhe sun ist ra nsferredSxample

flrrcc -------------|(producers)

,: :'' ...).,1l,i. z- '-i-- -, ': - :i\1r..: >' - .r\--- ., : ; *L_j, '"-: ,E.-., 'i,N"-_sGrasshoppers

->frogs =-)

I primarv | (secondarv )( consurners ) ( consumers )snakes

Iteriiarv )( consumers )b) Each stage in a food chain is known

Example :Grass ---) Grasshoppers

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Firsttrophic level

as a trophic level.

f,Secondtrophic level

------+ snakes.)L]

Fourth

frogsU

Thirdtrophic level trophic level

a

c) Complete the table below :Trophic level Functional group Food chain 1 Food chain 2

A

Producers

Primary consurners

SecondarvconsumersTeriiarv consumers

GrassIRatsiSnakes

IlHawks

Water plantsITadpolesiiDraqonflvnvmphsl

f roqsDo activity 8.1 on page 103 of the practical book

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d) Pyramid of numbers representslevel of food chain at a parlicular

decreasesup the trophic levelstrophic level 4trophic level 3trophic level 2trophic level 1

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the number of indivrduals ai eac.' trophictrrne The number sf grganisrrrs

tertiarv consumerssecondary collsurnerspilmary consumersproducers

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J Food weba) A series of interrelated food chains.Construct a food web involving the following organisms found in afreshwater pond.

small fish water beetlesgreen algae mosquito larvaetadpoles water fleas

large carnivorous fishwater snails

Mosquitola rvae

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b) Energy Flowt The producers abscrb so/ar ene;gy;lc;:-. li,e s",a a.,o convert ri rnto

chemical enerqv stored in organrc molecules durrnc photosynfhesis,ii When a carnivore eats a herbivcre :t'c :=:: .l'= S 3',allable energy istransferred on to the carnivore. The carnivors aiso ,oseS Bnrgy throughrespiration excretion and {efaec ation.iii About 90% of the energy lost io iils 6nei13rp-'sr;into new tissue and storage material.

-:. t 1}Yo is converted

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Energy flow in a food vreb

Assume that the grass contains 20 00C ki of en=rgyl calculate the energyflow in the food charn below .j

GrassTrophic 1level

grasshopper.Z

sorderi

Energy lost to the environmenl

Herbivores Carnivores Top carnivores

excretion anddefaecation excretion anddefaecation

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The interactions between biotic conrponents iri relation to feedirrg

One partner benefits (commensal) while the other (host)benefit nor harm.Tivo types of commensalisms are epiphvtes and epizoicsEpiphvtesr plants which grow on other plants to obtain sunliqht and support. example: pigeon orchids, staghorn ferns and bird's nest ferns.

Pigeon orchids

Bird's nest fernsstaghorn fern

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Parasitism

lnteractions between organisms )

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1. SymbiosisA close interaction between different species which live toqether and interacf witheach other for an extended period of time.

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Epizoics. Epizoics are animals which live on the. Example 1 Barnacles which

attach therrselves to the shell

l\i.r 5(:ulre lecrclrcr's ['diricn ?i'r.ir

body of other animals.Barnacles fl

iof crab get a free ride while lookingfor food

Example 2' A remora fish gets freetransportation and feeds on foodscraps left behind by the shark.

remora fish

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Mutualismo A relationship between two species of organisms in which bottb benefit.

Example 1: Association of leguminious plants and Rhizobium.

Leguminous plant. provide theenergy-richcompounds.

bacteria withorqanic

Rhizobium sp.. lives inside the root nodules of aleguminous plant. the nitroqen fixinq bacteria convertatmospheric nitrogen inlo ammoni umcompounds that are used by the plants

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Example 2" Lrchen (Associatron of fungus ano aiga)

Funqus. supplies carbon dioxide and AIqA. The green a,ga r:::-.:s foodforitself and for lne r,:io,-;sltrogenous compounds

the a/qa to manufacturefood.. profecfs the alga from dryingout

ParasitismOne organism benefifs (parasite) while the other is harmed (host)Types : a. Ectoparasites

b. Endoparasites

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Ectoparasites. parasites that feed on theexternal surface of a host.. obtain food and shelterfrom the host.. Examples: lice,mosquifoes,rafflesia sp. and aphids

$f.(-$ ,Rafflesia sp

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Endoparasltesparasites that live within the tissue of theirhost.For example, tapeworms attachthemselves to the linings of the digestivesystem of the host and obtain digestedfood and shelter. The hosts, which areeither animals or nurnans. /ose nutrients tothese parasites.

Tapeworm

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I Liuing organrsil2.

- ^^r^;^;^^-;-^-Saprophytism

ciead ana decavinq orEanic matter.Saprophytic bacteria a^C funqiare organisnrs that secrete digestive enzymeq todrgest deaC clganisnrsExantples cf saprsp'r',n-Ss a:e SaSrophytic bacteria, mlcor Sp. and mushrooms.

Mucor sp Mushrooms

3. Prey-predatorAn organism (prey) rs haunted and eaten- by a stronger and bigger organism (predator)

An increase in prey population followed by an increase in the predatorpopulation.When the prey population decreases due to increasing predation or otherfactors such as the spread of diseases, the predator's tood supplv becomeslimited and this leads to a decline in the population of predators.The prey-predators regulate each other's population in a cyclical manner whichmaintains the populaiions of both organisms in a dvnamic equiblibrium.

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Haunted by the credaio;.Smaller in size compared to the predatorThe prey populaiion is biqqer than thepredator pbputai,onThe prey ;'ei:es c:. speed ::'camouflaqeto avoid be;:c cal,.:1.: c),, :r= 3--caicrs

Predators usually have longcanine teeth, sharp vision andsharp claws to capture and killtheir prey.Have hooked beaks to tear theflesh of their prey.

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Types of cornpetition

I ntraspecific com petitionMenrbers of the samespecies compete for thesame resources.Examples:1. Paramecium aurelia

among themselves.2. naize plants among

themselves.

lnterspecific competitio nCompetiiion betweendifferent speciesExamples1. Paramecium aurelia

and Parameciumcaudatum

2. maize plants andpaddy plants.

Do activity 8.3 on page108 of the practicalbook

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8.2 COLONISATION AND SUCCESSION IN AN ECOSYSTEMLEARNING OUTCOMESo State what an ecosystem iso Identify the niche, habitat, community and population o. anoooooooo

ecosystemExplain the process of colonisation and successionIdentify the pioneer: species in an ecosystemIdentify the successors in an ecosystemIdentify the dominant species in an ecosystemIdentify the adaptive characteristics of pioneer species.Identify the adaptive characteristics of successors.Explain the changes in habitat caused by pioneer species.Explain the changes in habitat caused by successo:-s at ever,,,succession until a climax community is reachecjRelate the abiotic components with the biotrc coniponents in ar-ecosystem during the process of colonizatio: :nC succession

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Do activity 8.2 on page104 of the practicalbook

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EEcosystemt--.;.-*_lL____J

SpecresMEANING

r. grouD of organisnrs ihat look alike and have similar;hai'a;iei-isiics, share the same ecological niche and arecacari: oi rnterbreedinq and producing fertile offsprina.For example, duckweeds and water lilies are two differentspecies of water plants.A group of organisms of the same species living in thesame habitat at the same time.For example, a population of elephants living in a jungleSeveral populations of different species living in the samehabitat in an ecosystem.For example, a freshwater pond community.A communily of livinq organisms interactina with eachother and with the non-livinq environment.Examples '. a rainforest, a wetland and a pondThe role of an organism in the ecosystem. Organisms thatunCergo metamorphosis in their life cycles occupy differentnicnes.For example, a tadpole lives entirely in water and utilizesdifferent resources from those of an adult frog which livesmainly on land.A. naiiial environment where organisms /iye.Fcr eran-,cie. a srngle tree can be a habitat for caterpillars^ ^ ) L:_)^5 ! UllLJs.

Populatron

Community

Ecosystem

Habital

Conrntunrty

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Colon rsation and succession-cosyslenis underco changes inColonisation

tirerr structure and function as tinre passes

Colonisation occurs in newlvformed areas where no life existed previously.Pioneer speciesa The first colonizers, typically hardY plants such as grasses and fern'b Generally produce large nunrbers of easily dispersed seeds' have /eaves

which reduce transpiration and dense root systems to bind the sandparticles and hold water and humus

c.Haveashortlifecycle.Whenltreydie,theirremainsaddtothecontent of the soil.d Modify the environment, creat;pg conditions which are less favourable to

humus

4.spectes.

Successor speciesa. Grows larger and gradually shades out the original pioneer species,eventually replacinq it altogether'b. Examples of successor species are herbaceous plants such asdandelions and weeds. These plants have small wind-dispersible seeds,which are able to spread, germinate and qrow rapidly They also chanqethe structure and aualitv of the soil, making it more conducive for largerplants to grow.

Dominant speciesa. species that grow faster and out-compete the slower-growing pioneerand successorspecies.b. As time passes, the shrubs in turn modify the environment which allowsIarqertreesto grow, which lIs6 replaced by forest-floor species'Successiona. The gradual process where one community changes its environment so

that it is replaced by ar-rother "e6munity'b. Ecological succession leads to 2 relatively stable community which is inequilibrium with its environment'

themselves' but establishing sg!@that are more conducive to otherI{

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Clinrax conrnrunitya A stable and mature communitYspecies struciure. For example

that undergoes little cr no change ,. lstlre tr opical rarnforest

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(A) Colonisation and succession in a mangrove swamp

Protman1

)lems faced bygrove plantsSoftsoil muddv

Adaptations Functions

Avicenniabranchedroots.

sp. haveunderground

long,cable

To support themselves

Theroots

z Waterloggedconditions ofthe soildecrease theam.ount ofoxvqen.

. Avicennia sp. has breathing i . Allow gaseousroots called pneumatophores exchanqe to take place.

. Pores called lenticets found onthe bark of mangrove trees.

aJ Direct exposureto the sunleads to a hiqhrate oftranspiration.

A thick layerthe leaves.The leavessucculent.

cuticle covers ryt'ransPiraticnTc siore water(e thick ard

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Problenrs faced byntangrove plants

Adaptations F u nctions

Thesurroundingwater in the soilhvpertonic ascompared tothe cell sap ofthe root cells

. The cell sap of ihe roofs c3!lshas a hloher osrncsi,c c'3ssurethan tne soi/ \.,,aie:' :na:surrounds them.

. Have pores on the leaves called I .hvdathodes. j Excrete the excess saltin the hypertonic waterof the soil which entersthe roots

. To ensure thatcio nol loseosnlosis,

the rootswater by

Seeds whichfall onto theground diebecause theyare submergedwithin the softandwaterloggedsoil

. Seeds havecharacteristic.

. Able to qerminafe whilestill attached to themother plants.

. Can float horizontallyon the water

viviparv

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S;tr ' S: or e IcL :

Avicennia sp..Sonneratia sp

Pneumatophores-

tvluddy bank

A profile transect of a mangrove swamp

Do activity 8.4 on page 109 of the practical book

Prop rools

Kevsi--.l Avicennia sp. jiiii{ i 'r lvluddy bank

Sonneratia sp.rr!!j, ir:! li{i r!ir.l'fu..-j::iirijl

Rhizophora sp.B Bruquiera sD.H Land species

2000X

--

I 2020XZonation of mangrove swamps

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-/' \- Avicennia sp and Sonneratia sp. zone ( pioneerI

Bruguiera sp. zone. Replace lhe Rhizophora sp. II. The.roots frap more silt and mud. i

. Modify the sofl structure. II. Terrestrial plants like the nipah patm andIpandanus sp. then replace the bruguiera sp. II. Terrestrial forest and then a tropical I

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irainforest is formed after hundred years )l

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The soi/ becomes more compact and firmThe ground becomes hiqher

Rhizophora sp. zone (successor species). Replace the pioneer species. The prop roots trap silt and mud.. The soil firmer, drier and less submerged by seawater

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(B) Colonisation and succession in a pond,.lrlLliil -r')L'rL\

Colonization b,v pioneei' soecies- orsusecj pcno. proniif SC3c,:S(phvtoplankton. algae) and' submerqedplant ihydrlia sp caSornba sp e/odeagp.i begin ic Eict, an: caii-v ourphotosynthesis.when they die anC decornpose crganicmatter converieJ :;itc humus at the pondbase. tne cond ce,:ci::= shallow

Succession by floating plants- the condition becomes favourable forfloatinq plants such as water hyacinths(eichornia sp.) and duckweeds (lemnasp.)- they spread covering water surface andprevent sunliqht from reaching thesubmerged plant causing these plants todie since they cannot phofosynthesise.- the decomposed plants add more organicm.atter and the pond becomes more

Succession by land plants- ihe conditron becomes suitable for landplants like small herbaceous weeds.- gradually. the land becomes much drier- more lani piants (snrubs.bushes,woody-i--:-

Climax communitya iunale emerges axo r'Jrns into a tropicalrai nfOfeSt-.!yr'1!a:r :Ci'-,. a Cli m aXrnmm:rnilrr

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Succession by emergent plants- the emerqent plants (sedges. cattails)replace the floating plants.- they grow from the edqe of the pondtowards the middle of the pond as thepond becomes more shallow.- when these plants die. their decornposedremains are added as sediments to thebase of the pond thus reduces the depthoi the pond

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What is myname?\Alhere do I live?

. i,,ie:Unc.un-: Sc. Tlze surf ace ofthe water lpondj! i-..------\ ,'\ /'\.

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Successor

. Eichornia sp.. The surface of thewater (pond)

Cabomba sp.At the pond base

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The sampling technique to study the population size of organism

1. Quadrat sampling techniquea. A quadrat is a square or rectanqular frame made of metal, wood or string

A sguare quadrat A rectanqular quadratThe size of the quadrat depends on the size, distribution and density of theorganisms.For example, a quadrat of 10 cm x 10 cm is suitable forestimating the populatronof smallorganisms such as lichens.This technique can be used to determine :

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POPULATION ECOLOGYLEARNING OUTCOMES,- Identify the appropriate sarrpling technique ttL study tire populationsize of organism.o Estimate the population size of an organism in a habitat.o Determine the distribution of organisms in a habitat based on thedensity, frequency and percentage coverage of the specres.c Correlate the change in population distribution of an organism wi[hthe changes in each of the abiotic factors.o Design an experiment to investigate the eflect of a changc rn any oneof the abiotic factors on the population growth rate of an organism.

Quadrat samplingtechnique. to study andestimate thepopulation sizeof p/anfsSamplingtechniques

to estimate the population sizes and densiffes of organisms.

Capture, mark,. To estimate thepopulation sizeof animals

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(i) Percentage coverage

aerral coverage of all quadrats (mr)number of quadrats x quadrat area

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Formula :Percentagecoverage

(ii) DensityFormula :

Density

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(iii) FrequencyFormula:

Frequency

total number of individuals of a species in alt quadratsnumber of quadrats x quadrat aiea

number of quadrats coriaininq the scec;esv 1r^tt^Icr

number oi quacrats

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A quadrat to calculate the percentage coverage of

A large/big plant A small organtsm


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Steps to estimate the distribution of plants1 Selec: i i:: ::: iientifu the soecies of olanls2. P:ace 5 c,t ::"-re luadrats randomlvI t'\ ^',^. tisnis wfthin the boundary of the

quadratiesiii:=:e lhe population size of the planlsq Caicuiate tne averaqe number of Dlants per sctuare metreestimate the Censitv/calculate the percentaqe coveraqe

Capture, Mark, Release and Recapture TechniqueFormula :Population (number of individuals in the first sample) x(number of individuals in the second sample)srze number of marked individuals reoaptured

A biologist did a study on a type of bird species in a fruit orchard lt is found that thesebirds feed on the insect pests. This is useful to the farmers because these birds can helpcontrcl the ocpulaticn of insect pests. With the assumption that these birds can becaptured easily or can be represented by small objects, design an experiment than can becarrieci cut rn the fieic cr ir ihe laboratory to estimate the size of the bird population."Your field work or experimental planning need to include the following aspects :r Hii'n of investlcaiion. Staien^rer,i of hypothesis. Variables. List of apoaratus and materials. Technique usedr fvl;rim3nt3i 9;.1131,-.1.e Of methOd; aoriecied oaia. ?l:s:nt:ijor:i

Do activity 8.5 on page 11 1 of the practical book

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ilio Score Iecrcirt'

Prcblenrsta te trlet--ri:.n_

_[v1c_9Jne1ist"i ai'ra bles

What is the effect of increasinq the habitat area to the poputation size ofI-lLTo esthate the eopl, rhe hraer the habi lManipulated . habitat areaIResponding : the populatron size of birds I____iIBird, birds trap, birds foodRinqI' Capture, mark, release and recapture technique I1. Se/ect a suifable habitar iI2. Capture 20 or more birds usins a birds trap I

What is the effect of increasinq the habitat area to the population size ofLTo estimate the population size of the birds.The larqer the habitat area. the biqqer the population size of the birds.

\{aie rialsTechnrqueProcedure

3. Mark each bird captured with a rinq4. Record the number of birds in the first sample5. Release the birds back to their habitat6. After three davs, a second sample of birds is captured at the same

habitat. Count the number of birds captured in the second sarnpfe.7. Count the number of, marked birds in the second sample8. Tabulate the data and estimate the population size of the birds usinq

the formula:(number of birds in the first sampld x(number of birds in the second sample)number of marked birds recaptured

Keys.'a : number of birds in the first sampleb : numbeir of birds in the second samplec : number of marked birds recaptured

9. Repeat the experiment with a larqer habitat areaAssumption :. The marks used must not easilv be detected bv the predators orare poisonous/harmful to the orqanisms, The orqanisms are captured randomlv. The marked orqanisms are qiven enouqh time to mix with the restof the population, The orqanisms are captured in larqe samples. No mortalitv or migration of the orqanisms

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Collected idata I r"ot" tiiiaoitat buds {rornlhe firsl second caDture

An experiment toinvestigate the effect ofthe abiotic factors onthe population groMhrate of an organism.(investigate thepopulation d istributionof Pleurococcus sp.)

Humidity- a hioher humidilis more suitableiCr ilre gropth ofPieurccc;cus sp

Do activity 8.7 on page114 of the practical book

Nuntber oimarked brds 19

Hvpothesis accepted. The /arger the habitat area, the bigger thepopulation size of the birds.

Do activity 8.6 on page 113 of the practical bookThe effect of the abiotic factors on the population groMh rate of an organism

Temperature- the population distribution of Pleurococcus sp rshiaher at a mild temperatures

Totalnumber (b)

ilttttilAspects- the aspects such as lower temperatures and loiv lightintensities are not suitable for the groMh of Pleurococcussp

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LEARNING OUTCOMEShxplarn the meanrng of 'bto,iivei.siayExplain the need for classification of orqanismsState the five kingdoms used 1n in; _i;;;'tai,on of organismsidentiFy the main characterist,cs cr.il-r,,sii s ii each kingdomLrst examples of organisms in eacr \ n,::Jn. State the hierarchy in the cias:i::,:::.::. :: :r-:anisrns, using examplesExplain through exarnp!es, the rre:::..: tf naming organisms usingthe Linnaeus binomial s.vsten,Explain the importans3 sf iii6ir.'-:;5 it

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8.4 BIODIVERSITY

Biodrversity refers to lhe diverse species of plants and animals interactinqwith one another on earth.Organisms need for a classification because there are many of them in the world.

Classification of organisms into the five kingdoms

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ItMonera- composed of prokaryotic

org anisrns- unicellular, have cell vralls.no mem brane-bound nucleiand organelles- ohotosvnthetic and non-photosynthetic- typical shapes: rod,round,spiral- examplesCyanobacteria, I

Protis- unic- merF- auto- exansorroc

Kingdom

aulotropnrc euKaryotesimmobile,photosynthetichave cellulose cell;,\:?::S- evamples -fl,3i',,;rrn; 5,i3n;5

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Fungi- multicellu lar eukaryotes- saprophwic, have hyphaecalled mvcelium.- they have no chlorophvll- examples : yeast

.1ucor sp. mushrooms

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Hierarchy in the classification of organisms1 Lrvrng organlsms are classrfiedinto seven hlerarchrcal levelsaccording to their basicc haracteristics.2 The largest unit is thekinqdom, contains the lgggslnuntber of organisms.3 The number of organisms ineach unit decreases fromkinqdoms to species

4. Example : The hierarchical levels of some organlsmsCateqory House flv Human Corn Mouse

Kngdom An'rmalia Anhalia Plantae AnrnalnPhyl.rnr Aflfrropoda Chordata Irrchaeophyta ChordataClass Insecb Mammala Angrospermae MammalraOrder Dptera Prmates Gbmniflofbrae RodenbFamily Muscidae Homonidae Maydeae MurodaeGenus lvlusca Homo Zea Rattus

Speces dcmestta sapens mays rattus

Each organisms is given a scientific name based on the Linnaeus binomial system./ Each organism has fwo names in Latin../ The first name begins with a capital letter, refers to the genus../ The second name begins with a small letter, refers to the specfes.,/ Examples :Organisms Human Wolf Frog

Genus homo Canus RanaSpecies sapiens lupis pipiensScientific name Honn sapiens Canus luttis Rana nipiens

f-- lri"sd"- f*--l--ir.-Phvr.,n;__)-_--r_-_"r--a;-_l-___'r___-f-- oE--lL_I"*rvJr---c"i""---l(_ sp"c."s_J

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The importance of biodiversity1 Provide varrous brological products to humans

timber.Provide environnrental services. For example,Maintain a balanced nature so that no speciesDiversitv in the genetic pool.

For example, medicine, food rubbernutrient cycling, climate. pollinationwill extinct.

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irt8.5 THE IMPACT OF MICROORGANISMS ON LIFE

LEARNING OUTCOMESo Classify various types of microorganisms based on their basiccharacteristicso State the abiotic components affecting the activitv of microorganismso Explain the effect of a ihange in each abiotic .omponeni on theactivity of microorganismso Explain the role of useful microorganismso Explain the effect of harmful microorganismso Explain the rneaning of pathogeno Identify the pathogen, vector and symptoms of one particurar diseaseo Explain how the disease spreado Describe the methods for controlling pathogensc Explain the use of microorganisms in bioteChnology, using examplesTypes of microorganisms

To which organisms do the following descriptions apply?X : Yeast j Y : Bread mould Z : Baciilus

1 Parasite w:z i2 Saprophyte3 Form spores IX-AT] z ii-r-t-i4. A multicellular organismt Genetic material is a single strand of RNA6 Reproduces by binary fission

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Fu ngi ,spc res' BacteriaCell lvall\

ribosor"nes./ ^t^^^^/ /Pto>",J/ ---a : membrane\nucleoid region (DNA)

- unicellular, have cell wal/s (nrace cipolymer called peptidoglycan) plasmanrenrbrane DNA not encloseci in amembrane.- larqer than viruses, visible under a hohtmicroscope- reproduce by binarv fission- form spores under unfavourableconditions.- typical shapes: rod (bacillus), sphericai

( coccus),spial (s piril I u m)- examples : Staphy/ococcus sp.,Lactobacillus sp.

.^^-^^^,,'{ - ,] |;,sPoranqtum ) -'t'/-l " -.._:T--.- ,- .l .. Ijeveioping / " -rsporangiumhyphae of the mvceliumnucor sp- saFroph ytes/paras ite s.n uliiceliular eukarvotes have nochlorophvll, stenrs, leaves orrootsr- cellwalls of chitin- some are visible to the nakedeye- secrete enzymes that breakdown grqanlrc matter before theyare absorbed.- reproduce by formino spores orbuddinq (yeasts)- examples : mucor sp.. veast

Protozoa

- unicellular, have nucleus, cytoplasmand plasma membrane.- carry out life processes such asrespiration, reprod uctio n andexcretion.- move using f/aqel/a, cilia ormrcrotubules.- examples Amoeba sp.,Paramecium sp.

Algae spiral chloroplastvegetative cell

spuogyra sp.- photosvntheti c, eukaryotic plant-likeorganisms.- cell walls made of cellulose.- have chloroohvll and chlorop:asts. ncleaves, stems or roots.- reproduce by forminq spores- examples phvtoplankton. spiroqvrasp.

csbuglena sp.Microorganisms

Viruses----'capsid

- the srnallest microorganism, visible only under anelectron microscope.te;i incapable of carrying out anyi:v:rg t:'3cesses outsfde a living cell (host)- r-fa.'1cr. r-.-,s: r'rfect living cells lo reproduce.- ::a je :: :: l\i cr RrVA(genetic material)s-:::-:.:-: =, z protein coal.Do activiii, E '1C cn page 1i8 r,ithe practicat book

- -4. .a .^r.'C:=..,:Cr.{=.(3i::3:3s T4 bacteriophaae, tobacco mos?ic

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The effects of abiotic components on the activity of microorganismsABIOTICCOMPONEN EFF ECTS

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I Ci ii--r= d t- - - inactive at low temperature- the optimum temperature is between 35"C - 40'C- beyond 60'C, the growth of microorganisrns is inhibited- microorganisms and their spores can be destroved ala temperature of about 121"C.l The activity of yeast is optimal at a temperatureof 35'C.- prefer dark or low light intensities- hiqh intensities of sunlight or ultraviolet rays can kill

microorganisms- alqae and photosynthetic bacteria need light to

photosynthesise.i The activity of yeast is higher al a lower intensityof light.most bacteria prefer slightly alkaline conditions (pH7.4)

- moulds, yeast and protozoans prefer acidic conditions(pH a.5 - pH 5.0)

- extreme pH can kill the microorganisms.:. The -activity of yeast is optimum in the gcificmedium.- all microorganisms except yiruses need nutrients andwater for reproduction and groMh

- without nutrients or water, microorganisms will die orform spores

.l The higher the concentration of nutrients, the" hiqher the activity of yeast.

Light intensity

pH value

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The role of useful microorganisms1. Decorttpositiona Carrred out by a group of saprophvtic bacteria and fungi, called decomposers.b. Secrete enzvmes that break down conrplex organic nutrients into sintp/e

inorganrc substances such as carbon droxide, water and mindrals, this redricespollution by preventing the accumulation of the remains of decaying organismsc Maintain life on earth by recycling and release nutrients into the soil

2. Nitrogen cycleAtmospheric fixation

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Nltrates are taken up by the roots of plants and conveiledWhen the animals eat tl-re plants, the organic nitrcger, ;s :

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of animals and beconres aninral proteinWaste matter, p/ants and anrnrals which die and Ceccmpcs-. a.: ..r.,,ened intoammonium compoundsAmmonium compounds are converted into nitrites anj ni';'3'-= :.: nitrifVinqbacteria through a process called nitrification.Ammonia converted into nrtrites (NO:-) by Nitrosomonas sp.Nitrites converted into nrtrates (NO:-) by Nitrobacter sp.Tite cycle is balanced by a contrnuous return of nitrogen tc lhe arrnosphere bydenitrifvinq bacteria which break down nitrates and release nrtrogen back intothe atmosphere.Digestive system in hurnan. Symbiotic bacteria in human colon synthesise vitamrn Brz'and vitamin K. Deficiency in vitamrn Brz lead to anaemia. vitamin K needed for blood

clotting.

Alimentary canal of termitesTermites feed on woodwhich contains cellulose, they do noi have theenzymes (cel/u/ase) to digest the cellulose. Trichonympha sp. is a mutuafistic protozoans present rn the alimentarycanal of termites and secrete cellulase.

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The effect of harrlful microorganismsi 'naiiri- ::r,.ic^iganisms can spol the food and substances2 Mrcroorganrsnrs that cause drseases are called pathogens.-1 O:ca-:sr-s inal tr'ansmit the pathogens are called vector.

(Direct contact

a contagious disease can be spread by contactwith aninfected person or using their persona/ items such as towels,c othrng

' examples ringworm caused by fungi, AlDS and syphilis- lhrouqlr sexual intercourse.

Vectors- malaria ts causedI

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Food and water- microorganismsentei the alimentaryca nal th roug hcontaminaied foodanc'waterunwashed handsano lhe faeces ofinfected people.exar-nples; cholera,lv phoid

by plasmodium sptransmitted by themcrsquitoanopheles sp. as aver:torhouseflies cancause foodpoisoning andspread cholera

Airborne and droplet transmissionairborne transmission is a method where the pathogenscan change inio spores ancl then transmitied by air.croplet transmission is a method where liquid dropletr; ofthe infected person enter other people respiraiory system

How thediseasesspread

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PAT

Hurnan Acqurredintntunodefic&o,11-.--...- tmmune. I t-.lofivit us (Htv) uerlclencyI SyndromeIi (AtDS)

A T HOGENSi DISEASEVECTORS

Virus Dengue fever

METHOD'OFTRANSMISSION

Vector . Aedes sp.-t*+ _--- urrprotected sex withan infected partner- blood transfusionfrorrt an infectedperson- preqnant mother toan unborn child- use of contaminated-%contaminated food orwater and personalcontact

SIGNS & SYMPTOMS

Fever witlt severe bodv pain-drcsl'"sDiseases of the lunqs, brain,eves, weighl /oss and diarrhea

J a undic e, dimi nishecJ ap p etite,nausea, liver cancer

Hicth fever, drv couqh.pneumonia- profuse andwaterv diarrhea,vomitinq and leqcramps

- rapid /oss ofbodv fluids teadsto dehVdrationand shock

Viruses Hepatitis A.

Hepatitis Bcontaminated bloodgr needles, sexualintercourse

Coronavirus

Bacterium(vibriocholerae)

Severe acuterespiratorysyndrome(sARS)Re,spiratory dropletsl.el-eased when antnfected person couohsor sneezes

Cholera contaminated food orwaterthe faeces of infected

Bacteria I Foodl"'rel?ted food I RoisoningPotsonrnd II(examnle : IISalntonella I

contaminated foodcontamination ofcooked f ood fromcontact with utensilsthat were not

Diarr,4,ea, nausea, ,l.,illr,vomitinq and fever witnn tZto 24 ltours

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PATHOGENS/VECTORS

DISEASE

Malaria

Ringworm(Tineacorporis\

METHOD OFTRANSMISSIONproperlv washedafter cantact withraw foad Productssuch as fish, meaf

Veclor : Anopheles sp.mosquito

Contaqious and isspread throuqhinfected pets or directcontact with inf ectedindividuals.

SIGNS & SYMPTOMS

Hiqh fever. violent shiverinctq@9.., Rashes on the bodv whiclt 'Iookmt,, with a scalv border.

I_lAntibiotics

Penrcillrn and streptomycin areproduced bv microorganismswhlch inhibit the growth or killother microorg anisrns. esp.bacteria

Methods of controlling pathogensVaccines- a suspension of dead or

weakened bacteria or viruseswhich is inoculated into the bodyto lnduce the production ofantibodies. Example . BCG

Dis infectantssolutions used to sterilizesurgical equipment krllmicroorganisms on the floor.Examples . phenol. formaldehyde

Antisepticsused cn cuts and woundsand inhibti ir,e gi'o'"r.n cfrnicrcorganrsns E:xan-ipiesacrifiavrn, iodine solution

to kill

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J'lre use of microorganisms in brotechnologyi Brotechnclooy is lls_spp. glLe.s__ptof ryaterialsforyin d u strv.

anttbioiics are cbtainec,:::r :r::roorganisnrsstreptomvcin is produced oy Slreplontyces sp., peniciltin tsproduced by Peniciilrurrr cr;rysogerrurn, both used to treat infectrcnsSabine vaccine used to treal potiomvelitis.Modrfied bacteria are used to produce the hormon e insurin on alarge scale. I

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genetlcally engineeredthese bacferia convertenr",ironment friendly.

bacteria are used to clean the oil spills.the orl into less harmful molecules'which are

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usvvdgv rurrr rrousenolds and industries is piped into largesettling ianks in sewaoe treatment plants.Aerobic b""t.ri, rn lhe ser^.,age decompose organic matterThe s/udqe that setiles ei tne bottom of the setiling tanks ispumpec' intc the sedimentation tanks where fermentation takes^t^^^iJrdue.Her"e , anaerobic bacteria continue to decompose the organicmatler lo methane and carbon dioxiclefhe methane gas cc-llecie: is useC as a fuel.ihe otgeste: siL:cge js:i:r-, ,;^, n,iiates and phosphates, and rs driedto be usea as f ertilizers c; iaiirers

Drnd"^ri^^t VUUU-'L ! .accrnes and hormones

Cleaning of oil spills

Waste treatmentSewage from households and industriessettling ianks in sewage treatment plants.

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Food processtng _)carbonermentation by the yqSJ in bread making produces

dioxide which helps ihe dough to rise.Beer is brewed tront barlev grains.Wine i.s nrade by the fermentation of qrape jurces ethanol andcarbon dioxide are released.Soy sauce is nrade from fermented sova beans by the fttnqi.Y_oqhurl is made from fermentation of milk using bacteriaLa ct o b ac il I u s b u lg a rr cus a nd Strep t ococc u s t h e rnt o p l't i I I us wh tcirconveri sugar into lactic acid that coagulates casetn (milkprotein)Cheese is made by mrxing bacteria (for exanrple, Streptococcussp.) with the enzyme rennin. The bacteria ferrlent trilk sugar tolactic acid The solid part of the milk (the curd) is serparated fromthe liquid portion (ihe whey) The curds are pressed and mouldedand then lelt to matrrre or npen

Produciion of brodegradable plastic (broplastrc)

Bioplastic such as Biopol can be broken down into inorganrccompounds h,y bacteri a.Bioplastic is produced by culturing bacieria such as Envina sp rnnutrients (glucose)A specific nutrient (nitrogen) rs then depleted from the culturemedium.The bacterra react by prodr-rcing plastic as a storage componenltheir cellsBioplastic is used to make credit cards bottles, medical gLlxs.

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Two sources of energy that are generated through the activrtresof nticroorganisms are bioqas and -gasoho/.Btogas is a gas produced by the anaerobic fermentation of organrcnratter or waste in a bioreactorGasohol or biofuel is a conrbinalion of lO % ethanol and 9g%petrolSuqar cane and maize are the nrain sources of gasohol.The cane or maize is crusheci and sucrose is extracted to form asyrup contains glucose and fructose, the fermentation of this syrupby yeast will produce ethanol.

8_6 APP REC IATING BIODIVERSITY

LEARNING OUTCOMESo Justify the importance of preservation and conservation ofbiodiversity.o Preserve and conserve various living things around us.

The lmportance of Preservation and conservation of Biodiversity' organisms and ecosystems provide many useful products such as

Iood, medicines and sites for recreational actrvities and research.' Hunlan activities such as defo;estation have drsturbed the ecologtcai

equilrbrium which leads to the extinction of many species of organism. conseryation refers to the efforts made in maintaininq the quality of thenatural environments and their bioloqical resources For example replanting

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the trees. Preservation refers to the efforts tnecosystems and wildlife species which are

protectinq ine eafih s diver-sethreateneo r.r,,i:n ex lln c tlon.

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Biology Module Chap 8

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