NCERT Solutions | Class IX | Science (Biology) | Chapter 15 | Improvement in Food Resources

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1. NCERT
SOLUTIONS
BIOLOGY
CLASS –IX

2. Improvement in
Food Resources

3. Did youKnow ?
Eating2kiwionadailybasiswaslinkedtosubstantial
improvementstobothsleepqualityandsleepquantitybecause
kiwifruitishighinSerotonin,theHappyHormone!
Thedesirableagronomiccharacteristicsforcropimprovementsare:
i.Tallnessandprofusebranchinginanyfoddercrop.
ii.Dwarfnessincereals.
Thesedesirableagronomiccharacteristicshelpinincreasingcrop
productivity.
In-text Exercise 1
Whatdowegetfromcereals,pulses,fruitsandvegetables?
i.Cerealsprovideuswithcarbohydrates.Also,theyarearichsource
ofenergy.
ii.Pulsesgiveusproteins.
iii.Fruitsandvegetablesarearichsourceofvitaminsandminerals.A
smallamountofproteins,carbohydrates,andfatsarealsopresent
inthem.
Avarietyofbioticfactorssuchaspests,nematodes,diseases,etc.can
reducethenetcropproduction.Apestcausesdamagetoagricultureby
feedingoncrops.Forexample,bollweevilisapestoncotton.Itattacks
thecottoncrop,therebyreducingitsyield.Weedsalsoreducecrop
productivitybycompetingwiththemaincropfornutrients,light,and
space.Similarly,abioticfactorssuchassalinity,temperature,etc.affect
thenetcropproduction.Somenaturalcalamitiessuchasdroughtsand
floodsareunpredictable.Theiroccurrencehasagreatimpactoncrops
sometimes,destroyingtheentirecrop.
BiswarupMajumder| Bio-World
1.
1.
2.
Howdobioticandabioticfactorsaffectcropproduction?
Whatarethedesirableagronomiccharacteristicsforcrop
improvements?
In-text Exercise 2

4. Whataremacro-nutrientsandwhyaretheycalledmacro-
nutrients?
BiswarupMajumder| Bio-World
1.
2.Howdoplantsgetnutrients?
In-text Exercise 3
Macro-nutrientsarenutrientsrequiredinrelativelylargequantitiesfor
growthanddevelopmentofplants.Theyaresixinnumber.Sincethey
arerequiredinlargequantities,theyareknownasmacro-nutrients.The
sixmacro-nutrientsrequiredbyplantsarenitrogen,phosphorus,
potassium,calcium,magnesium,andsulphur.
Plantsrequiresixteenessentialnutrientsfromnaturefortheirgrowth
anddevelopment.Allthesenutrientsareobtainedfromair,water,and
soil.Soilisthemajorsourceofnutrients.Thirteenofthesenutrientsare
availablefromsoil.Theremainingthreenutrients(carbon,oxygen,and
hydrogen)areobtainedfromairandwater.
In-text Exercise 4
Comparetheuseofmanureandfertilizersinmaintainingsoil
fertility.
1.
Manuresincreasesoilfertilitybyenrichingthesoilwithorganicmatter
andnutrientsastheyarepreparedbythedecompositionofanimal
excretaandplantwastes.Ontheotherhand,fertilizersaremostly
inorganiccompoundswhoseexcessiveuseisharmfultothesymbiotic
micro-organismslivinginthesoil.Theirexcessiveusealsoreducessoil
fertility.Hence,fertilizersareconsideredgoodforonlyshorttermuse.
Applescontain80%waterand
arevirtuallyfatfree.
Oneappleequalsoneportionof
thefivefruitandvegetables
requiredfordailyintake.
Importantminerals,notably
potassium,whichisneededfor
regulationofwaterbalanceand
musclefunction.
Applescontain8-14%natural
fruitsugarthatgetsconvertedto
energy.
Excellentsourceofvitamins,
especiallyvitaminC.
Thisfruithaslowsodiumcontent.

5. (c)Farmersusinggoodqualityseeds,adoptingirrigation,using
fertilizers,andusingcropprotectionmeasureswillderivemost
benefits.
Reason:
Theuseofgoodqualityseedsincreasesthetotalcrop
production.Ifafarmerisusinggoodqualityseeds,thena
majorityoftheseedswillgerminateproperly,andwillgrow
intoahealthyplant.
Properirrigationmethodsimprovethewateravailabilityto
crops.
Fertilizersensurehealthygrowthanddevelopmentinplants
byprovidingtheessentialnutrientssuchasnitrogen,
phosphorus,potassium,etc.
Cropprotectionmeasuresincludevariousmethodstocontrol
weeds,pests,andinfectiousagents.Ifallthesenecessary
measuresaretakenbyafarmer,thentheoverallproduction
ofcropswillincrease.
Whichofthefollowingconditionswillgivethemostbenefits?
Why?
a)Farmersusehigh-qualityseeds,donotadoptirrigationor
usefertilizers.
b)Farmersuseordinaryseeds,adoptirrigationanduse
fertilizer.
c)Farmersusequalityseeds,adoptirrigation,usefertilizer
andusecropprotectionmeasures.
BiswarupMajumder| Bio-World
1.
In-text Exercise 5
Did youKnow ?
WHITE
REVOLUTION

6. Preventivemeasuresandbiologicalcontrolmethodsshouldbe
preferredforprotectingcropsbecauseexcessiveuseofchemicalsleads
toenvironmentalproblems.Thesechemicalsarealsopoisonousfor
plantsandanimals.Preventivemeasuresincludepropersoilandseed
preparation,timelysowingofseeds,intercroppingandmixedcropping,
usageofresistantvarietiesofcrops,etc.Ontheotherhand,biological
controlmethodsincludetheusageofbio-pesticidesthatarelesstoxic
fortheenvironment.Anexampleofbio-pesticidesisBacillus
thuringenesis,whichisaninsectpathogenthatkillsawiderangeof
insectlarvae.Therefore,bothpreventivemeasuresandbiological
controlmethodsareconsideredeco-friendlymethodsofcrop
protection.
2.
Whyshouldpreventivemeasuresandbiologicalcontrol
methodsbepreferredforprotectingcrops?
1.
Whatfactorsmayberesponsibleforlossesofgrainsduring
storage?
Duringthestorageofgrains,variousbioticfactorssuchasinsects,
rodents,mites,fungi,bacteria,etc.andvariousabioticfactorssuchas
inappropriatemoisture,temperature,lackofsunlight,flood,etc.are
responsibleforlossesofgrains.Thesefactorsactonstoredgrainsand
resultindegradation,poorgermination,discolouration,etc.
BiswarupMajumder| Bio-World
In-text Exercise 6

7. WHYARESOMEMEATCHICKENSYELLOWINCOLOUR?
Insomecultures,chickenswithyellowfatandskinareconsideredtobebetter
quality.However,thisisnottrue.Theyellownessoftheskin,fatandeggyolk
dependsonthelevelofbetacaroteneinthediets.Sotheseyellowchickensare
fedwithacorn-baseddiet,whichishigherinbetacarotene.
Cattlefarmingiscommonlyusedforimprovingcattlebreeds.The
purposeofcattlefarmingistoincreasetheproductionofmilkand
draughtlabourforagriculturalwork.Dairyanimals(females)areused
forobtainingmilkanddraughtanimals(males)areengagedin
agriculturalfieldsforlabourworksuchascarting,irrigation,tilling,etc.
Crossbreedingbetweentwogoodvarietiesofcattlepotentially
producesanewimprovedvariety.Forexample,thecrossbetween
foreignbreedssuchasJerseyBrown,Swiss(havinglonglactation
periods)andIndianbreedssuchasRedSindhi,Sahiwal(havingexcellent
resistancepoweragainstdiseases)producesanewvarietyhaving
qualitiesofbothbreeds.
1.
Whichmethodiscommonlyusedforimprovingcattlebreeds
andwhy?
1.
Discusstheimplicationsofthefollowingstatement:
“ItisinterestingtonotethatpoultryisIndia’smostefficient
converteroflowfibrefoodstuff(whichisunfitforhuman
consumption)intohighlynutritiousanimalproteinfood.”
PoultryinIndiaisthemostefficientconverteroflowfibrefoodstuffinto
highlynutritiousanimalproteinfood.Inpoultryfarming,domesticfowls
areraisedtoproduceeggsandchicken.Forthis,thefowlsaregiven
animalfeedsintheformofroughage,whichmainlyconsistsoffibres.
Thus,byfeedinganimalsafibrerichdiet,thepoultrygiveshighly
nutritiousfoodintheformofeggsandchicken.
BiswarupMajumder| Bio-World
In-text Exercise 7
In-text Exercise 8
Did youKnow ?

8. Layersaremeantforeggproduction,whereasbroilersaremeantfor
poultrymeat.Nutritional,environmental,andhousingconditions
requiredbybroilersaredifferentfromthoserequiredbyegglayers.A
broilerchicken,foritspropergrowth,requiresvitaminrichsupplements
especiallyvitaminAandK.Also,itsdietincludesproteinrichfoodand
enoughfat.Italsorequiresextracareandmaintenancetoincreaseits
survivalrateincomparisontoegglayers.
Commonmanagementpracticesindairyandpoultryfarmingare:
i.Propershelterfacilitiesandtheirregularcleaning.
ii.Somebasichygienicconditionssuchascleanwater,nutritiousfood,
etc.
iii.Animalsarekeptinspacious,airy,andventilatedplace.
iv.Preventionandcureofdiseasesattherighttimeisensured.
1.
Whatmanagementpracticesarecommonindairyandpoultry
farming?
1.
Howarefishobtained?
Fishcanbeobtainedbytwoways:
i.Capturefishing:Itistheprocessofobtainingfishfromnatural
resources.
ii.Culturefishery:Itisthepracticeoffarmingfishes.Farmingcanbe
doneinbothfreshwaterecosystem(whichincludesriverwater,
pondwater)andmarineecosystem.
BiswarupMajumder| Bio-World
In-text Exercise 9
In-text Exercise 10
Whatarethedifferencesbetweenbroilersandlayersandin
theirmanagement?
2.
Somefishesaresooily,theycanbedriedout
andusedascandles.
Did youKnow ?

9. BiswarupMajumder| Bio-World
Whataretheadvantagesofcompositefishculture?2.
Whatarethedesirablecharactersofbeevarietiessuitablefor
honeyproduction?
1.
Anadvantageofcompositefishcultureisthatitincreasestheyieldof
fish.Inacompositefishculture,fiveorsixdifferentspeciesaregrown
togetherinasinglefishpond.Fisheswithdifferentfoodhabitatsare
chosensothattheydonotcompeteforfoodamongthemselves.Also,
thisensuresacompleteutilizationoffoodresourcesinthepond.Asa
result,thesurvivalrateoffishincreasesandtheiryieldalsoincreases.
Whatispasturageandhowisitrelatedtohoneyproduction?2.
In-text Exercise 11
Beevarietieshavingthefollowingdesirablecharactersaresuitablefor
honeyproduction:
i.Theyshouldyieldhighquantityofhoney.
ii.Theyshouldnotstingmuch.
iii.Theyshouldstayinthebeehiveforlongdurations.
iv.Theyshouldbreedverywell.
Pasturageistheavailabilityofflowersfromwhichbeescollectnectar
andpollen.Itisrelatedtotheproductionofhoneyasitdeterminesthe
tasteandquantityofhoney.

10. BiswarupMajumder| Bio-World
Explainanyonemethodofcropproductionwhichensureshigh
yield.
1.
Whyaremanuresandfertilizersusedinfields?2.
Manuresandfertilizersareusedinfieldstoenrichthesoilwiththe
requirednutrients.Manurehelpsinenrichingthesoilwithorganic
matterandnutrients.Thisimprovesthefertilityandstructureofthesoil.
Ontheotherhand,fertilizersensureahealthygrowthanddevelopment
inplants.Theyareagoodsourceofnitrogen,phosphorus,and
potassium.Togetanoptimumyield,itisinstructedtouseabalanced
combinationofmanuresandfertilizersinthesoil.
NCERT Exercise
Croprotationisoneofthemethodsofcropproductionthatensures
highyield.Itisthemethodofgrowingtwoormorevarietiesofcropson
thesamelandinsequentialseasons.Acroputilizessomeparticular
nutrientsinlargerquantitiesfromthesoil.Then,ifthesamecropis
growninsubsequentseasons,thosenutrientswillgetdepletedinthe
soil.Therefore,cropshavingdifferentnutrientrequirementsarerotated.
Forexample,legumeswhichhavenitrogen-fixingbacteriaintheirroot
nodulessupplythesoilwithnitrogen.Therefore,theselegumesare
rotatedwithnitrogenrequiringcerealssuchaswheatandmaize.This
methodreducestheneedoffertilizers,therebyincreasingtheoverall
yieldofcropsanddecreasingsoilpollution.
Whataretheadvantagesofinter-croppingandcroprotation?3.
Inter-croppingandcroprotationbothplayanimportantrolein
increasingtheyieldofcrops.Inter-croppinghelpsinpreventingpests
anddiseasestospreadthroughoutthefield.Italsoincreasessoil
fertility,whereascroprotationpreventssoildepletion,increasessoil
fertility,andreducessoilerosion.Boththesemethodsreducetheneed
forfertilizers.Italsohelpsincontrollingweedsandcontrolsthegrowth
ofpathogensandpestsincrops.

11. Geneticmanipulationisaprocesswherethegeneforaparticular
characterisintroducedinsidethechromosomeofacell.Whenthe
geneforaparticularcharacterisintroducedinaplantcell,a
transgenicplantisproduced.Thistransgenicplantexhibits
charactersgovernedbythenewlyintroducedgene.
Forexample,letusassumethereisawildplantthatproducessmall
fruits.Ifthegeneresponsibleforalargerfruitsizeisintroducedin
thisplant,thisplantbecomestransgenic,andstartsproducinglarger
fruits.Similarly,genesforhigheryield,diseaseresistance,etc.can
beintroducedinanydesiredplant.Therefore,genemanipulation
playsanimportantroleinagriculturalpractices.Ithelpsinimproving
cropvariety.Itensuresfoodsecurityandinsectresistantcrops.It
alsoimprovesthequalityandyieldofcrops.
BiswarupMajumder| Bio-World
Whatisgeneticmanipulation?Howisitusefulinagricultural
practices?
4.
Howdostoragegrainlossesoccur?5.
Themainreasonforthelossesofstoragegrainisabioticandbiotic
factors.
Theabioticfactors:Moistureandtemperature.
Thebioticfactors:Insects,rodents,birds,mitesandbacteria.
Howdogoodanimalhusbandrypracticesbenefitfarmers?6.
Cattlefarmingisoneofthemethodsofanimalhusbandrythatismost
beneficialforfarmers.Usingthismethod,betterbreedsofdraught
animalscanbeproduced.Suchdraughtanimalsareengagedin
agriculturalfieldsforlabourworksuchascarting,irrigation,tilling,etc.
Whatarethebenefitsofcattlefarming?7.
Benefitsofcattlefarming:
i.Goodqualityandquantityofmilkcanbeproduced.
ii.Draughtlabouranimalscanbeproducedforagriculturalwork.
iii.Newvarietythatareresistanttodiseasescanbeproducedby
crossingtwovarietieswiththedesiredtraits.

12. BiswarupMajumder| Bio-World
Forincreasingproduction,whatiscommoninpoultry,fisheries
andbee-keeping?
8.
Howdoyoudifferentiatebetweencapturefishing,mariculture
andaquaculture?
9.
Thecommonfactorforincreasingproductioninpoultry,fisheries,and
beekeepingisthepropermanagementtechniquesthataretobe
followed.Regularcleaningoffarmsisofutmostimportance.
Maintenanceoftemperatureandpreventionandcureofdiseasesisalso
requiredtoincreasethenumberofanimals.