高中英语必修5Unit3 Background informationVIP免费

Section2:BackgroundinformationaboutscienceversusnatureI.GeneticEngineeringFoodTheworld’spopulationcontinuestoincrease.Nowwehaveapproximately6billionpeopleintheworldtoday.Ifitgrowsattheconstantratein30years,itprobablywillbe8billionpeople,growingatafasterratethanenoughfoodtoconsume.Howwillwebeabletogetenoughfood?Now,there’snoneedtoworry.ScientistshavedevelopedamethodcalledGeneticEngineering.Scientistshavetakenthegenesfromonespeciesandputthemintoanother.GeneticallyModifiedfoodtendstogrowsfasterandismoreresistancetodisease.Geneticallyengineeredfoodsarebeneficialtooursocietyandenvironment,sosupportingsuchresearchishighlyrecommended.However,todayonlytheUnitedStatesandCanadaareinvestinginGMfood.Tousethistechniquerequiresalotoffunding.EuropealsoproducesGMfood,butEuropeansareafraidtoeatit.Theworld’shungriestcontinentisAfrica,butitdoesn’thavethistechniquebecauseitistooexpensiveforthemtoafford.ThisisashamesincefaminesarecommoninAfrica,wherethepopulationisincreasingatarapidrate.Theclimatethereisveryhot,mostplacesaredeserts,mountains,andtropicalrainforests.Thetypeofenvironmentisnotgoodforplantingthecropsandotherfood.Sotheydon’tgrowmuchfood.ButtheGMfoodcansurviveinhorribleandpoorsoilconditions.U.S.AhasbeensupportingAfricansbyshippingthefoodtothem,butthiscan’tsolvethehungerproblem.Also,thereisatransportationproblem,becauseofmountanpaths.Theroutesaredifficultforcarstodrivethrough.SoAfricansfeeltheyshouldgrowthefoodthem-selves,havingasenseofindependence.TheydispatchpeopletolearnthetechnologyaboutGeneticallyEngineeringfood.Theygettheseedstoplant,anditworks.Theplantseedschangeveryoften,companieshavetomakethebusiness.Theywillraisethepriceofseedssohigh.ButAfricanswillnotbeabletoaffordseedsforGMcropsduetopoverty.Onehopesthatcompaniescanmakeproductsatreducedcosttoimpoverishednations.GMfoodcanincreasefoodproduction,reducefoodprices,andkeepitfreshlongerandhavemorenutritiousvaluecomparedwiththetraditionalmethodcalledselectivebreeding.T用心爱心专心116号编辑raditionalkindsofmethodsneedraintokeepthesoilrich.Also,whenalandhasbeenplantedseveraltimes,thesoilwillgetworseandworseresultinginlowyields.However,usingtheGeneticallyEngineeredmethodnomatterhowmanytimesproducehasbeenplantedthesoilwillkeeprich.Crossbreedingmethodshavebeenusedformanyyears.Itisalsoeffective,butitisnotcheapanditdoesnotproduceenoughtofeedmanyhungrypeoplebecauseitdependsontheseasonsandsoiltogrow.Thismethodtakestimeandpeoplehavetolookafteritconstantly.Ontheotherhand,GeneticallyEngineeredfoodgrowsfaster.Also,GMfoodcangrowinsoilthatispooranddoesn’thavemuchmoisturein,andindry,coldweather.ButoneofthemostbeneficentaspectsofGMfoodisthatitcanresistinsectsthateatanddestroytheplants.Far--mers,so,canreducetheuseofchemicalpesticidesandherbicides.Theysavealotofmoneyfromthat.Thenewplantscarryagenethatcanmakeplantsproduceapoison,calledBTtoxinwhichisharmfulonlytoinsects,nottohumansorotheranimals.UsingGMfoodsisalsoeconomicallyadvantageous.Themorefoodafarmercanproducethehigherprofitshewillget.Theconsumers’costwillbelower.Becausegeneticengineeringofferswaystoresistinsectandreduceweeds,farmerscansavemuchmoneyfromthat.Therefore,theamountofproductioncanincreasetomakemoreprofits,withoutariseinthepriceoffood.ThepeoplewhosupportGMfoodalsosayithelpstheenvironment.BygrowingGMfood,farmerscanreducetheuseofpesticides.GMfoodhastheBTtoxinintheirgenes;itcanp...