lecture 3 - flow of energy

8/9/2019 Lecture 3 - Flow of Energy

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Lecture 3:

Energy Flow in anEcosystem

1Bonifacio B. Magtibay, CE, SE, MSEM


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Energy FlowEnergy Flow

• EnergyEnergy in an ecosystem originallyin an ecosystem originallycomes from the suncomes from the sun

• Energy flows through EcosystemsEnergy flows through Ecosystemsfromfrom producers to various levelsproducers to various levelsof consumers to decomposersof consumers to decomposers

2Bonifacio B. Magtibay,E, !E, M!EM


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"roducers"roducers

• !unlight!unlight is the mainis the mainsource of energysource of energyforfor mostmost life onlife onearth.earth.

• "roducers"roducers containcontain

chlorophyllchlorophyll # can# canuse energy directlyuse energy directlyfrom the sunfrom the sun



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$utotrophs$utotrophs

• $n $utotroph is any organism$n $utotroph is any organismthatthat can produce its own foodcan produce its own food supply%supply%

• $utotrophs are also called$utotrophs are also called"roducers"roducers

•"lants, algae, some protists, #"lants, algae, some protists, #some bacteria are e&amplessome bacteria are e&amples



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'iche of a $utotrophs'iche of a $utotrophs

• aptures energyaptures energy and transformsand transformsit intoit into organic, stored energyorganic, stored energy forforthe use of living organisms.the use of living organisms.

• May beMay be photoautotrophsphotoautotrophs usingusinglight energy (e.g.light energy (e.g. plants plants ))

•May beMay be chemoautotrophschemoautotrophs usingusingchemical energy (e.g.chemical energy (e.g.cyanobacteri cyanobacteri a)a)



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"hotoautotroph"hotoautotroph

$ producer that captures energy$ producer that captures energyfrom the sun by:from the sun by: –"hotosynthesis"hotosynthesis

• $dds$dds *&ygen*&ygen to theto theatmosphereatmosphere

• +emoves+emoves arbon io&idearbon io&ide fromfrom

the $tmospherethe $tmosphere

7$lgae$lgae

Bonifacio B. Magtibay,E, !E, M!EM


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hemoautotrophshemoautotrophs

• apture energy from the bondsapture energy from the bondsof inorganic molecules such asof inorganic molecules such as-ydrogen !ulfide-ydrogen !ulfide

• "rocess is called"rocess is called hemosynthesishemosynthesis•*ften occurs in deep sea vents or*ften occurs in deep sea vents orgut of animalsgut of animals

Bonifacio B. Magtibay, CE, SE, MSEM 9


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onsumersonsumers

onsumers or heterotrophsonsumers or heterotrophseat other organisms toeat other organisms toobtain energy. (e.g.obtain energy. (e.g.animals animals ))•-erbivores-erbivores

–Eat *nly "lantsEat *nly "lants•arnivoresarnivores –Eat *nly *therEat *nly *ther

$nimals$nimals



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onsumersonsumers

• *mnivores*mnivores (-umans)(-umans) – Eat "lants # $nimalsEat "lants # $nimals

• etritivores (!cavengers)etritivores (!cavengers)

– Feed *n ead "lant # $nimal +emainsFeed *n ead "lant # $nimal +emains(bu00ards), e.g. vultures, hyena(bu00ards), e.g. vultures, hyena

• ecomposersecomposers

– Brea1 down dead organic matter intoBrea1 down dead organic matter intosimpler substances2 recycle nutrients,simpler substances2 recycle nutrients,e.g., Fungi # Bacteriae.g., Fungi # Bacteria



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Feeding +elationshipsFeeding +elationships

Energy flowsEnergy flowsthrough anthrough anecosystem inecosystem inoneone directiondirection

fromfrom producersproducers

toto variousvariouslevels oflevels ofconsumersconsumers



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Feeding +elationshipsFeeding +elationships

• Food hainFood hain –!imple energy path through an!imple energy path through an

ecosystemecosystem

• Food ebFood eb –More realistic path through anMore realistic path through an

ecosystem made of many foodecosystem made of many foodchainschains



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Food hainFood hain

Bonifacio B. Magtibay, CE, SE,MSEM 14

"roducer"roducer ((trapped sunlight # stored food)trapped sunlight # stored food)

44stst orderorderonsumeronsumer

55ndnd *rder*rderonsumeronsumer

33rdrd *rder*rderconsumerconsumer

66thth *rder*rderonsumeronsumer


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'ame the "roducer, onsumers #'ame the "roducer, onsumers #

ecomposers in this food chain:ecomposers in this food chain:



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Bonifacio B. Magtibay, CE, SE,MSEM 17


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/rophic Levels/rophic Levels

Each level in a food chain or foodEach level in a food chain or foodweb is aweb is a trophic Leveltrophic Level..

• "roducers"roducers

–$lways the first trophic level$lways the first trophic level

–-ow energy enters the system-ow energy enters the system

• -erbivores-erbivores –!econd trophic level!econd trophic level



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/rophic Levels/rophic Levels

• arnivores7*mnivoresarnivores7*mnivores –Ma1e up the remainingMa1e up the remaining

trophic levelstrophic levels

Each level depends on theEach level depends on theone below it for energy.one below it for energy.



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Ecological "yramidsEcological "yramids

8raphic representations of the8raphic representations of therelative amounts of Energy orrelative amounts of Energy orMatter at each trophic levelMatter at each trophic level

May be:May be:Energy "yramidEnergy "yramid

Biomass "yramidBiomass "yramid"yramid of 'umbers"yramid of 'umbers



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Energy "yramidEnergy "yramidBonifacio B. Magtibay, CE, SE, MSEM

21


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Biomass "yramidBiomass "yramid



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"yramid of 'umbers"yramid of 'umbers


lecture 3 - flow of energy

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