Organisms and their environment

Name: __________________ Topic: Organisms and their environment LO: Briefly describe the non-cyclical nature of energy flow ● Energy flows in alinear manner. It does not flowin a cycle. Hence energy cannotbe recycled.● Chemical energy is transferred from one trophic level to another upon predationand finallyreleased as heat.● Energy flow can be represented by a food chain:Producers(plants)primaryconsumer (herbivore)secondary consumer (carnivore)tertiary consumer(carnivore / omnivore) LO:Explainthetermsproducer,consumerandtrophiclevelinthecontextoffoodchains and food webs ● Foodchain:aseriesoforganismsthroughwhichenergyistransferredintheformof food.● Food web is made up of many interconnecting food chains. Concepts Summary NotesNan Hua High School Biology 1

Name: __________________ Topic: Organisms and their environment ● Trophiclevel:feedingpositioninafoodweborchain,beginningwithproducersat trophic level one.● Producer:Organism,whichproducestheir own food,glucosethroughphotosynthesisbyabsorbinglightenergyandconvertingitintochemicalenergyin food.Producersarethefirstorganismsin thefoodchainorfoodwebandoccupy the first trophic level.● Consumer: Organism thatobtains energy by feedingon other organisms. Eg: Concepts Summary NotesNan Hua High School Biology 2

Name: __________________ Topic: Organisms and their environment LO:Explainhowenergylossesoccuralongfoodchains,anddiscusstheefficiency of energy transfer between trophic levels ● As energy is passed on from one trophic level to another, 90% of it is lostasheatenergy due to respirationandchemical energy in excretedor egested wasteproductssuch as uneaten body parts, faeces, etc.● Only10% of energy stored as tissuesis transferredto the next trophic level.● Theshorter the food chain, the less energy is lostto the environment. Hencemore efficient in energy transfer. Concepts Summary NotesNan Hua High School Biology 3

Name: __________________ Topic: Organisms and their environment LO: Describe and interpret pyramids of numbers and biomassPyramid of numbers● Allowsforcomparisonofthenumberoforganismspresentineachtrophiclevelat a particular time.● Can be inverted (narrow – based) or upright (broad-based). Pyramid of biomass● Allowsforthecomparisonofthedrystandingmassoforganismspresentineachtrophic level at a particular time.● Mostly upright (broad–based)● Canbe invertedif the producerreproducesfastenoughto supporttheconsumersdespite theirsmaller biomass at any onetime. Concepts Summary NotesNan Hua High School Biology 4

Name: __________________ Topic: Organisms and their environment LO:Describehowcarboniscycledwithinanecosystemandoutlinetheroleofforests and oceans as carbon sinks Removal of carbon dioxide from the environment:● Green plantsabsorb carbon dioxide during photosynthesisto manufacture glucose. Concepts Summary NotesNan Hua High School Biology 5

Name: __________________ Topic: Organisms and their environment ● Throughfeeding, carboncompoundsaremovedthroughthefoodchainsof theecosystem.● Preserved as fossil fuels Release of carbon dioxide into the environment:● Respiration● Combustion● Decomposition Importance of the carbon cycle:● Ensuresthat thereis a continuoussupplyof carbondioxidefor plantstophotosynthesise.Thus,foodcanbeproducedandfeduponbyotherorganismstostay alive.● Enablesenergy to flow through the ecosystemin theform of carbon compounds. Role of forests and oceans as carbon sinks:● A carbon sink is an area thatstores carbon compoundsfor anindefinite period oftime.● Itstores more carbon than it releases.Oceans (largest carbon sinks)● Thecarbon dioxide that dissolves in the ocean’s wateris absorbed and used byphytoplankton and algae in photosynthesis to make carbon compounds/ glucose.● A portion of the carbon compounds found in oceans is buried in the seabed and is inthe form offossil fuelssuch as natural gas and oil.Forests● Atmospheric carbon dioxide is absorbed by the plants and used in photosynthesis.● A large amount of carbon compounds is stored in trees.● Remains of dead trees form coal, a fossil fuel. LO: Evaluate the effects of● water pollution by sewage and by inorganic waste● pollutiondueto insecticidesincludingbioaccumulationupfoodchainsand impact on top carnivores Water pollution by sewage:● Sewage is waste matter from homes or industries.● Untreated sewage is agood source of food for bacteria.● Bacteria grow and multiply rapidly, depleting the oxygenin the water.● Thus, other organisms may die due to insufficient oxygen. If sewagecontainsexcessivefertilizers(inorganicwaste),eutrophicationmayoccur.Concepts Summary NotesNan Hua High School Biology 6

Name: __________________ Topic: Organisms and their environment ● Excessnitratesandphosphatespromoterapidgrowthofalgaeonthesurfaceofthe water body(river, lake or sea).● Thisprevents sunlight from reaching the submergedplants.● Submerged plants cannot photosynthesise and die.● Dead plants aredecomposed by bacteria.● Bacteria thus grow and multiply rapidly, using up the oxygen in the water.● Other organisms die due to lack of oxygen.Water pollution due to excessive insecticides● InsecticidessuchasDDTarenon-biodegradable(cannotbebrokendownbymicroorganisms)● DDTcannotbeexcretedduetoitsinsolubilityinwater,thusitisstoredinthefattytissues of the organismand willaccumulate in thebodies of consumers.● This process is known asbioaccumulation.● Asit getspassedalongthefoodchainalongthetrophiclevels, it increasesinconcentrationas theorganismshigherup thetrophiclevelsconsumemoreorganisms of the lower trophic levels.● Organismsinthetoptrophiclevelusuallyhavethehighestconcentrationoftheinsecticideand suffer or die from its harmful effects.● This is known asbioamplification. Bioaccumulation Bioamplification LO:Outlinetherolesofmicroorganismsinsewagetreatmentasanexampleofenvironmental biotechnology ● Bacteriais usedto secreteenzymesthatdigestorganicwasteintoharmlesssoluble substances. Concepts Summary NotesNan Hua High School Biology 7

Name: __________________ Topic: Organisms and their environment ● Environmentalbiotechnology:makinguseof biologicalscienceto provideenvironmentallyfriendlyor ‘green’solutionsto reducepollutionandkeeptheenvironment clean.● Thesewagetreatmentprocesstakesplaceinwaterreclamationplantsthroughseveral stages:i. Settlingtanks: Heavierandbiggerparticlessettleatthebottomandareremoved as sludge.ii. Aerationtanks:Bacteriaismixedwithsewage.Bacteriasecreteenzymesto digestorganicwasteintoharmlesssolublesubstancesandcarbondioxide.iii. Finalsettlingtank: Microogranismsare removedfromthe treatedsewage before being discharged into the sea.iv. Anaerobic digesters: Sludge from settling tank istreated.v. Treated sludge is dewatered and disposed of as a soil conditioner. LO: Discussreasonsfor conservationof specieswithreferenceto themaintenanceofbiodiversityandhowthisisdone,e.g.managementoffisheriesand management of timber productionConservation:protection and preservation of naturalresources. 1. Maintenance of biodiversity2. Prevent extinctionof plant and animal species3. Maintain astable and balanced ecosystem Co