Roma Unit 1 Chapter 4 PDF

7/29/2019 Roma Unit 1 Chapter 4 PDF

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RomaKhanna,Lecturer,CMCA(TMU)

Course- BBA

Subject code- BBA 301

Subject- Environmental studies

Faculty- Roma Khanna

Syllabus of unit 1Introduction to Environmental Studies: Introduction: Meaning, Definition and Scope of Ecology. Eco System

Interaction between living and non living components, Structure and Function. Energy flow through ecosystem

(Food Chain, Food Webs).

Unit1

Chapter4

Ecosystem

ThetermecosystemwasproposedbyA.G.Tansleyintheyear1935.

AnEcosystemincludesagroupofbioticcommunitiesofaspeciesinteractingwithone

anotherinanarea,andtheirsurroundingsandallthewaysinwhichtheyinteractwitheach

otherandexchangingenergyandmatter.

Anecosystemwasdefinedasadynamicentitycomposedofabiologicalcommunityandits

associated

abiotic

environment.

Thereexistnutritionalrelationshipamongthelivingorganism.Keepingthisinviewearth

canbeconsideredasagiantecosystemwhereabioticandbioticcomponentsareconstantly

actingandreactinguponeachotherbringingstructuredandfunctionalchangesinit.

sun

Plants

Herbivores

carnivores

omnivores

soil

Excretionanddecayproducts


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Kindsofecosystem

Anecosystemcanbenaturalorartificial,temporaryorpermanentandlargeortiny.Thus,

variousconstituentsofecosystemfallintothefollowingcategories.

1NaturalEcosystem:Theseoperatebythemselvesundernaturalconditionswithoutant

majorinterferencebyman.Basedupontheparticularkindofhabitatthesearefurther

dividedasterrestrialandaquaticecosystem.

i)TerrestrialSuchas Desert,Forest,Grasslandetc.

ii)Aquaticecosystem whichcanfurtherbeclassifiedas

a)FreshwaterecosystemThesemaybelotic(runningwaterasspring,streams,rivers)or

lentic(standingwateraslake,pond,pool,ditchetc).

b)Marineecosystem Theseincludesaltwaterbodieswhichmaybedeepbodiesasocean,

seaetc.

2ArtificialEcosystem: Thesearealsoknownasmanmadeormanengineeredecosystem.

HumanshavemodifiedsomeecosystemsfortheirownbenefitsandtheseareArtificial

Ecosystem

i.e

they

are

maintained

artificially

by

man

.

They

can

be

terrestrial

(crop

field,

gardenetc.)oraquatic(aquarium,dam,manmadepondetc.).

Structureandfunctionofecosystem

Thetwomajoraspectsofanecosystemarestructureandfunction.Bystructurewe

mean i) The composition of biological community imcluding species, number, life

historyanddistributioninspaceetc. ii)Thequantityanddistributionofthenonliving

materialssuchasnutrients,wateretc.iii)Therangeofconditionsofexistencesuchas

temperature,light

etc.

By function we mean i) The rate of biological energy flow ii) Biological regulation

includingbothregulationoforganismbyenvironmentandregulationofenvironment

byorganism.

Structureofecosystem


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Therearetwocomponentsofanecosystem;Livingcomponentsandnonlivingcomponents.

1NonLivingComponents:NonlivingcomponentsarealsocalledAbioticcomponents.They

directlyorindirectlyaffectthelivingcomponentsandinclude

i)

Physical

factors

and

climatic

conditions

e.g.

soil,

temperature,

light,

moisture,

wind

,

wateravailability

Soil Soil contains a mixture of weathered rock fragments, soil mineral particle, organic

matterandlivingorganism.Soilprovidenutrients,waterforphotosynthesis.

Solarradiations areusedtoheattheatmosphereandtoevaporateandtranspirewaterinto

theatmosphere.Itisalsonecessaryforplantgrowth.

Wateravailability

Living

tissue

is

composed

of

avery

high

percentage

of

water,

upto

and

evenexceeding90%.Theprotoplasmcannotsurvivebelowthispercentage.Throughwater,

mineralsaretranslocatedinplants.Itisalsonecessaryforphotosynthesis.

ii) Inorganic substances such as water, nitrogen, phosphorus, sulphur imvolved in the

cyclingofmaterialsintheecosystem.Theamountofinorganicsubstancesatanygiventime

inanecosystemisdesignatedasstandingstate.

2LivingComponents:Theyarealsocalledbioticcomponents.Ecosytemsarecomposedofa

variety

of

living

organism.

The

plants,

animals,

microorganisms

present

in

the

ecosystem

form the biotic component. These organism have different nutritional behavior in the

ecosystem and are known as producers or consumers based on how they get their food.

Producerscanproduceorganiccomponentse.g.plantscanproducestarch,carbohydrates,

cellulose from a process called photosynthesis. Consumers are the components that are

dependentonproducersfortheirfoode.g.humanbeingsandanimals.

i)ProducersorAutotrophiccomponentAutomeansselfandtrophicmeansnourishingso

thesearetheorganismwhichpreparetheirfoodthemselves.Theyconvertsolarenergyinto

chemicalenergywiththehelpofsimpleinorganicsubstancessuchasH2o,co2andorganic

substancessuchasenzymes.Therearebasicallytwokindsofautotrophs,chemoautotrophs

andphotoautogrophs.

a)Chemautotrophsarebacteriathatobtainenergybyoxidizinginorganiccompoundssuch

asammonia,nitrites,andsulfides,andtheyusethisenergytosynthesizecarbohydrates.


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B)Photoautotrophsarephotosynthesizers suchasalgaeandgreenplantsthatproduce

mostoftheorganicnutrientsforthebiosphere.

ii)ConsumersorHeterotroph Heteromeansotherandtrophicmeansnourishing.They are

unable

to

produce,

are

constantly

looking

for

source

of

organic

nutrients

from

elsewhere

i.e

dependonothersfortheirfood.

Theconsumersareofthefollowingtwomaintypes

a)MacroconsumersThesearecalledphagotrophsandincludeorganismwhichimgestother

organism.Dependingupontheirfoodhabitconsumersmaybeeitherherbivores,arnivores

andomnivores.

Herbivores livesonplantsandareknownasprimaryconsumers.Herbivoreslikegiraffeare

animalsthat

graze

directly

on

plants

or

algae.

CarnivoresAlsoknownassecondaryconsumersandtheyfeedonherbivores.Carnivores

aswolffeedonotheranimals;birdsthatfeedoninsectsarecarnivores,andsoarehawks

thatfeedonbirds.

Omnivoresareanimalsthatfeedbothonplantsandanimals,ashuman.

E.g.Bearseatfish,insects,deeraswellashoneyandgrass,

Squirreleatinsects,birdseggaswellasfruits.

b)Microconsumers

Detritivoresareorganismsthatrelyondetritus,thedecomposingparticlesoforganic

matter,forfood.Earthwormsandsomebeetles,termites,andmaggotsareallterrestrial

detritivores.

Nonphotosyntheticbacteriaandfungi,includingmushrooms,aredecomposersthatcarry

outdecomposition,

the

breakdown

of

dead

organic

matter,

including

animal

waste.

Decomposersperformaveryvaluableservicebyreleasinginorganicsubstancesthatare

takenupbyplantsoncemore.

Relationships within ecosystem


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Functions of Ecosystem

Thestudyofecosystemcannotbecompletedwithoutthouroughlyunderstandinghowan

ecosystemfunctionsandwhatkeepitinbalance.Fromtheoperationalviewpoint,theliving

andnon

living

component

of

an

ecosystem

are

so

interwoven

that

their

separation

from

eachotherispracticallyimpossible.

Theproducersfixradiantenergyandwiththehelpofmineralstakenfromthesoil,buitup

complexorganicmatter.Thetwoecologicalprocessofenergyflowandmineralcycling,

whichinvolveinteractionbetweenthephysiochemicalenvironmentandthebiotic

communities,maybethoughtofastheheartofecosystemdynamics.Severaltypesof

biogeochemicalprocessestakesplaceinanecosystem.Thefunctionsofecosystemcanbe

studiedinthefollowingforms

Energyflow Foodchian,Foodweb,Ecologicalpyramid

Biogeochemicalcycles

Energyflowinanecosystem

Ecosystems maintain themselves by cycling energy and nutrients obtained from external

sources.Atthefirsttrophic level,primaryproducers(plants,algae,andsomebacteria)use

solar energy to produce organic plant material through photosynthesis. Herbivores

animals that feed solely on plantsmake up the second trophic level. Predators that eat

herbivorescomprisethethirdtrophic level; if largerpredatorsarepresent,theyrepresent

stillhigher

trophic

levels.

Decomposers,

which

include

bacteria,

fungi,

molds,

worms,

and

insects,breakdownwastesanddeadorganismsandreturnnutrientstothesoil.

Onaverageabout10percentofnetenergyproductionatonetrophiclevelispassedonto

thenextlevel.Processesthatreducetheenergytransferredbetweentrophiclevelsinclude

respiration,growthandreproduction,defecation,andnonpredatorydeath(organismsthat


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diebutare not eaten by consumers).Thenutritional qualityof material that isconsumed

also influenceshowefficientlyenergy istransferred,becauseconsumerscanconverthigh

qualityfoodsourcesintonewlivingtissuemoreefficiently. Thelowrateofenergytransfer

between trophic levels make decomposers generally more important that producers in

termsof

energy

flow.

Decomposers

process

large

amounts

of

organic

material

and

return

nutrients to the ecosystem in inorganic forms, which are then taken up again by primary

producers. Energy is not recycled during decomposition, but rather is released, mostly as

heat (this is whatmakescompostpiles and fresh garden mulchwarm).Figure shows the

flowofenergy(darkarrows)andnutrients(lightarrows)throughecosystems.

Energyflowmodels

Theflow

of

energy

through

various

trophic

levels

in

an

ecosystem

can

be

explained

with

the

helpofvariousenergyflowmodels.

Universalenergyflowmodel energyflowthroughanecosystemwasexplainedbyE.P

odum.Astheenergyflowtakes placethereisagraduallossofenergyateverylevel,thereby

resultinginlessenergyavailableatnexttrophiclevel.

Singlechannelenergyflowmodel theflowofenergytakesplaceinasinglechannelplants

orproducerstoherbivoresandcarnivores.

Double`channel

or

yshaped

energy

flow

model

in

nature,

both

grazing

food

chain

and

detritus food chain operate in the same ecosystem. However sometimes it is the grazing

foodchianwhichpredominates.Ithappensinmarineecosystemwhereprimaryproduction

intheopensea is limitedandamajorportionof it iseatenbyherbivorusmarineanimals.

Ontheotherhand,inaforestecosystemthehugequantityofbiomassproducedcannotbe


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allconsumedbyherbivores.Rather,alargeportionofthelivebiomassentersintodetritus

compartmentintheformoflitter.Hencethedetritusfoodchainismoreimportantthere.

Thetwochannelsoryshapedmodelofenergyshowsthepassageofenergythroughboth

foodchaini.egrazinganddetritusfoodchain,whichseparatedintimeandspace.

.

Theflowofenergycanbebestunderstoodbyfoodchain,foodwebandthroughEcological

pyramids.

Foodchains

CharlesElton

is

apioneer

of

the

study

of

animals

and

plant

forms

in

natural

environments,

andoftheanimalbehavioraspartofcomplexpatternoflife.Hedefinesdtheconceptof

foodchainandoriginatedtheconceptofecologicalpyramids.

Foodiscontinuallybeingpassedthroughanecosystem.Withinanecosystem,nutrientsare

recycled as living things go about their daily business of eating food and excreting waste

products. All living things exist as part of a nutrient recycling chain an enormous chain

definedbywhateatswhat.Thisiscalledthefoodchain.

Thetransferoffoodenergyfromtheproducerthroughaseriesoforganism(herbivoresto

carnivore to decomposers) with repeated eating and being eaten is known as food chain.

Foodchains

are

the

pathways

along

which

nutrients

pass

through

an

ecosystem.

Producers utilize radiant energy of sun which is transformed to chemical form during

photosynthesis. Thus, green plants occupy first trophic level or nutritional level and are

calledtheprimaryproducers.Theenergystoredintheplantsinthenutilizedbytheplants

eaters which constitute the secondary trophic level primary consumers (


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herbivores).Herbivoresaretheneatenbycarnivoreswhichconstitutethirdtrophicleveland

secondaryconsumerswhicharetheneatenbytertiaryconsumers.

Therearetwotypesofchain

1Grazingfoodchain

2Detritusfoodchain

GrazingFood

chain

This

food

chain

is

also

known

as

prey

Predator

Food

Chain.

This

type

of

food chain is generally seen in ecosystem such as grassland, pond or lakes where a

substantialpartofthenetprimaryproductionisgrazedonbyherbivores.Examples:

i) Foodchaininaforestcommunity:

Radiantenergyofthesun >Greenplants >Ungulates >Tigers(Autotrophs)

ii)Foodchainingrasslandecosystem:

Radiantenergyofthesun >Grasses >Grasshopper>Frog>Snake >Hawk


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ii)Detritus

food

chain

Also

known

as

saprophytic

food

chain.

This

type

of

food

chain

goes

fromdeadorganicmatter intomicroorganismsandthen toorganismsfeedingondetritus

andtheirpredators.Suchecosystemsarethuslessdependentondirectsolarenergy.These

dependchieflyontheinfluxoforganicmatterproducedinanothersystem.


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DifferencebetweenGrazinganddetritusfoodchain

Thedetritusfoodchaindiffersfromthegrazingfoodchaininseveralways:

o The organisms making it up are generally smaller (like algae, bacteria, fungi,

insects,&centipedes)

o

The

functional

roles

of

the

different

organisms

do

not

fall

as

neatly

into

categorieslikethegrazingfoodchain'strophiclevels.

o Detrivoresliveinenvironments(likethesoil)richinscatteredfoodparticles.As

aresult,decomposersarelessmotilethanherbivoresorcarnivores.

o Decomposersprocesslargeamountsoforganicmatter,convertingitbackinto

itsinorganicnutrientform.

SignificanceofFoodChain:

1)

Food

chains

are

important

for

maintaining

&

regulating

population

size

of

different

animals&thusareinstrumentalinmaintainingecologicalbalance.

2) Food chain show a unique property of accumulation of certain chemicals. There are

severalpesticides,heavymetals&otherchemicalswhicharenonbiodegradableinnature

&arenotdecomposedbymicroorganisms.Theykeeponpassingfromonetrophiclevelto


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another& each successive trophic level, their concentration keeps on increasing their

phenomenonisknownasbiomagnifications.

Food Web: Food chains are interconnected with each other forming some sort of

interlocking

pattern,

which

is

referred

to

as

food

web.

In

food

web

there

are

a

number

of

optionsofeating&beingeatenateachtrophiclevel.

InFoodweb,therearenumberofoptionsofeatingandbeingeatenateachtrophiclevel.

Thus, Food web is a set of interconnected food chains by which energy and materials

circulate within an ecosystem. The food web is divided into two broad categories the

Grazing fod web, which typically begins with green plants, algae or photosynthesizing

planktonandthedetritalwebwhichbeginswithorganicdebris.Thesewebsaremadeupof

individualfoodchains.

EcologicalPyramids:Graphicrepresentationoftrophicstructureatsuccessivetrophiclevels

formingtheapexisknownasecologicalpyramids.Inecologicalpyramids,producerslevel

constitutethebaseofpyramid.

TypesofEcologicalPyramids:

1) PyramidofNumber Showingnumberofindividualorganismateachlevel.

2) PyramidofBiomass Showingthedryweight.

3) PyramidofEnergy Showingtherateofenergyflowsateachsuccessivelevel.


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Thepyramidofnumberandbiomassmaybeuprightorinvertedbutpyramidofenergy

arealwaysupright.

PyramidsofNumber

They show the relationship between producers, herbivores and carnivores at successive

trophiclevelsintermsoftheirnumber.Heretherewillbeagradualdecreaseinthenumber

ofindividualsfromthelowertothehighertrophiclevels.Thismaybestudiedbytakingthe

exampleoftrophiclevelsingrassland.

The grasses occupy the lowest trophic level and they are abundantly present in the

grassland ecosystem. The deers occupy the second level; their number is less than

comparedtothegrasses.

The

wolves,

which

feed

upon

the

deers,

are

far

less

in

number

when

compared

to

the

numberofdeers.Thelions,whichoccupythenexttrophiclevel,feeduponwolves,andthe

numberofindividualsinthelasttrophiclevelisgreatlyreduced.

Intheparasiticfoodchain,thepyramidofnumbersisfoundstobeinverted.Here,asingle

plant or tree might support varieties of herbivore. These herbivores like birds in turn,

supportvarietiesofparasiteslikelice,bugsthatoutnumbertheherbivores.

Subsequently each parasite might support a number of hyperparasites like bacteria and

fungi,which

will

outnumber

the

parasites.

Thus

from

the

producer

level

onwards,

towards

the consumers, in the parasitic food chain there is a gradual increase in the number of

organisms,insteadoftheusualdecrease.


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PyramidofBiomass:

Theyarecomparativelymorefundamental,asthey,insteadofthegeometricfactor,shows

thequantitativerelationshipsofthestandingcrops.Heretherewillbegradualdecrease in

the biomass from the autotrophs to the higher trophic levels. This may be illustrated by

studyingthetrophiclevelsinapond.

Thebiomass inautotrophs likealgae,green flagellates,green plantsetc. is themaximum.

Thebiomassisconsiderablylessinthenexttrophicleveloccupiedbysecondaryconsumers

likesmallfishes.Theleastamountofbiomassispresentinthelasttrophiclevel.

1.Thispyramidshowsthetotalbiomassateachtrophiclevelinafoodchain.

2.Pyramidinerect.

3. It indicates a decrease in the biomass at each trophic level from the base to apex of

pyramid.

Example:Totalbiomassthanherbivores,whichisagainmorethancarnivorous.


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e.g Forestecosystem

ThePyramidofEnergy

Theenergypyramidsgivethebestpictureoftheoverallnatureoftheecosystem.

Heretherewillbegradualdecreaseintheavailabilityofenergyfromtheautotrophshigher

trophic levels. In other words, there is decrease in energy flow from autotrophs on\ at

successivetrophiclevels.

Inthecourseofenergyflowfromoneorganismtotheother,isconsiderablelossofenergy

intheformofheat.Moreenergyisavailableintheautotrophstintheprimaryconsumers.

Theleastamountofavailableenergywillbeinthetertiaryconsumer.Therefore,shorterthe

foodchain,greateristheamountofenergyavailableatthetop.

carnivores

Herbivores

producers


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1.Theenergypyramidalwaysuprightanderrect.

2.Itshowstherateofenergyflowsatdifferenttrophiclevels.

3.Itshowsthatenergyismaximumatproducerlevelandminimumatthecarnivores'level.

4.Ateverysuccessivetrophiclevelthereisalossofenergyintheformofheat,respiration

etc.

Biogeochemicalcycles

The cyclic flow of nutrients between nonliving environment (soil, rocks, air, water) and

livingorganismsisknownasbiogeochemicalcycle.Themajornutrientelementi.e.carbon,

hydrogen, oxygen and nitrogen, which form about 95% mass of the living organism, are

circulatedagainandagainbetweenlivingandnonlivingcomponentsoftheecosystem.

Organic materials synthesised by the producers are eaten and assimilated by the

consumers.

With

the

help

of

decomposers,

all

the

organic

materials

in

the

bodies

of

the

consumersareeventuallybrokendownintoinorganicmaterials.Thesearethenrebuiltinto

organiccompoundsbythesyntheticactivitiesoftheconsumers.Thus,mattercirculates in

nature.Thoughitmayconstantlychangeit'sform,thereisnooveralllossorgain


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Nitrogen cycle -

Thenitrogencycle iscomplexas itdependsontheactivitiesofvariousbacteria.Nitrate in

thesoil

is

built

up

by

plants

into

protein

which

is

then

passed

on

to

animals,

which

eat

the

plants. The nitrogen from the protein is returned to the environment as ammonia

(ammonification), either from excretory matter or through the action of decomposing

bacteria on dead bodies. Various nitrifying bacteria convert the ammonia back to nitrate

(nitrification).Thenitrifyingbacteriaplayanimportantroleinreplenishingtheenvironment

with nitrate upon which plants are dependent for their protein. Another class of bacteria

called denitrifying bacteria liberate free nitrogen from nitrate which leads to the pool of

nitrogengasbeingbuiltupintheatmosphere.Someofthisnitrogenisconstantlyremoved

bynitrogenfixingmicroorganisms,whichbuilditupintonitrateandultimatelyprotein.


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Carbon cycle

TheatmospherecontainsapoolofCO2.CO2isremovedfromthepoolbythephotosynthetic

activitiesof

plants.

It

is

released

back

into

the

environment

by

respiration

which

is

carried

out by all organisms including those microorganisms (decomposing bacteria) responsible

for the decay of dead plants and animals. Not all dead material decays. Sometimes dead

plants and animals form fossil fuels such as peat, coal, petroleum and petroleumbased

gases. Man uses these materials as sources of energy and when they are burned CO2is

returnedtotheCO2pool.

Water

Cycle

TheWaterCycle(alsoknownasthehydrologiccycle)isthejourneywatertakesasit

circulatesfromthelandtotheskyandbackagain.

TheSun'sheatprovidesenergytoevaporatewaterfromtheEarth'ssurface(oceans,lakes,

etc.). Plants also lose water to the air (this is called transpiration). The water vapor


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eventuallycondenses,formingtinydroplets inclouds.Whenthecloudsmeetcoolairover

land,precipitation(rain,sleet,orsnow)istriggered,andwaterreturnstotheland(orsea).

Someoftheprecipitationsoaksintotheground.Someoftheundergroundwateristrapped

betweenrockorclaylayers;thisiscalledgroundwater.Butmostofthewaterflowsdownhill

asrunoff

(above

ground

or

underground),

eventually

returning

to

the

seas

as

slightly

salty

water.

TypesofEcosystem

Ecosystem can be broadly classified in to natural & artificial ecosystem. The natural

ecosystemoperatesautomaticallyundertheactivitiesofnaturalconditions,buttheartificial

ecosystemarecontrolled&manipulatedbyhumanbeings.Adetailedclassificationisshown

below.

Ecos stem

Natural ArtificialNatural


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GrasslandEcosystem:

Therabioticfactorsofthegrasslandbasicallyconsistsofthefollowing:

Climate:

It

is

one

of

the

most

crucial

aboitic

factors

that

shape

the

ecosystem

and

includes

rainfall, temperature, wind flow, ground moisture etc. Natural grasslands have a

precipitaionof 500 900mmperyear,whereas,thedesertshavearainfallofabout

250mm/year.Thisrainfallmaintainsthemoistureandinteractswiththeabioticand

bioticfactorsofthegrassland.

The tropical rainforests, however, have rainfall of more than 2000mm per year.

Grasslands can occur in high rainfall areas whereother growths are not that

successfulduetoheavyrainfall.

The

climate

of

the

grasslands

range

from

cool

to

hot

summers

and

may

even

range

to

iceinwinterinhigherlatitudes.

Temperature has a wide spectrum of distribution throughout the world .the average

temperatureofthegrasslandisform 20Cto30C.

BIOTICFACTORS

The biotic factors of the grassland ecosystem includes the autotrophs, and the

heterotrophs,

that

is

the

producers,

pirmary

consumers,

secondary

consumers

and

thetertiaryconsumers.

Primary producers:The primary producers include the autotrophs that can

photosynthesize and includes the grasses, sedged, rushes, cyanobacteria. lichens,

mosses,treesetc.

TerrestrialAquatic

Marine Fresh Esturine Grassland Desert TundraForest Polar


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Theprimaryandthesecondaryconsumers includesthe rabbits,moles ,hares,elks,

small deers insome places along with the phytophagous insects , snakes, preying

birds, insect feeders and in some grassland ecosystems like in Africa where there

are carnivores like the panthers. lions, foxes, wild dogs, etc

Thebacteria

,fungi

and

other

microorganisms

form

the

detritus

food

chain

that

is

involvedinthenutrientcyclingofthegrassland.

PondEcosystem:

PondEcosystem Anecosystem isadynamiccomplexofplant,animal,andmicroorganism

communities and the nonliving environment, interacting as a functional unit. Remember

that the organisms living in an ecosystem are broken down into categories: producers,

consumers, and decomposers. A pond is a quiet body of water that is too small for wave

actionandtooshallowformajortemperaturedifferencesfromtoptobottom.Itusuallyhas

amuddy

or

silty

bottom

with

aquatic

plants

around

the

edges

and

throughout.

However,

it

isoftendifficulttoclassifythedifferencesbetweenapondandalake,sincethetwoterms

are artificial and the ecosystems really exist on a continuum. Generally, in a pond, the

temperaturechangeswiththeairtemperatureandisrelativelyuniform.Lakesaresimilarto

ponds, but because they are larger, temperature layering or stratification takes place in

summer and winter, and these layers turnover in spring and fall. Ponds get their energy

fromthesun.Aswithotherecosystems,plantsaretheprimaryproducers.Thechlorophyll

in aquatic plants captures energy from the sun to convert carbon dioxide and water to

organic compounds and oxygen through the process of photosynthesis. Nitrogen and

phosphorus are important nutrients for plants. The addition of these substances mayincreaseprimaryproductivity.However,toomanynutrientscancausealgalblooms,leading

toeutrophication(ReadPonds&Eutrophicationformoreinformation).

Producers

Phytoplankton,literallywanderingplants,aremicroscopicalgaethatfloatintheopen

waterandgiveitagreenappearance.Theycarryoutphotosynthesisusingcarbondioxide

thatisdissolvedinthewaterandreleaseoxygenthatisusedbythebacteriaandanimalsin

thepond.

Periphyticalgaearemicroscopicalgaethatattachthemselvestosubstratesand

givetherocksandsticksagreenishbrownslimyappearance.Theyalsocarryout

photosynthesisandproduceoxygen,oftennearthebottomofthepondwhereitcanbe

usedbydecomposers.

Submergedplantsgrowcompletelyunderwater

Floatingplantsincludeplantsthatfloatonthesurfaceandplantsthatarerootedonthe

bottomofthepondbuthaveleavesand/orstemsthatfloat.


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Emergentplantsarerootedinshallowwaterbuttheirstemsandleavesareabovewater

mostofthetime.

Shoreplantsgrowinwetsoilattheedgeofthepond.

Consumers

Zooplanktonare

microscopic

animals

that

eat

phytoplankton

or

smaller

zooplankton.

Some

aresinglecelledanimals,tinycrustaceans,ortinyimmaturestagesoflargeranimals.

Zooplanktonsfloataboutintheopenwaterportionsofthepondandareimportantfoodfor

someanimals.

Invertebratesincludeallanimalswithoutbackbones.Macroinvertebratesarebigenoughto

beseenwiththenakedeye.Someofthemareonlyfoundincleanwater.

Vertebratesareanimalswithbackbones.Inapondthese mightincludefish,frogs,

salamanders,andturtles.

DecomposersAnimalwasteanddeadanddecayingplantsandanimalsformdetritusonthebottomofthe

pond.Decomposers,alsoknownasdetritovores,arebacteriaandotherorganismsthat

breakdowndetritusintomaterialthatcanbeusedbyprimaryproducers,

thusreturningthedetritustotheecosystem.Asthismaterialdecomposesitcanserveasa

foodresourceformicrobesandinvertebrates.Duringdecaymicrobeslivingondetrituscan

pullnutrientsfromtheoverlyingwaterthusactingtoimprovewaterquality.Intheprocess

ofbreakingdowndetritus,decomposersproducewaterandcarbondioxide.


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ForestEcosystem:

AbioticComponents:

It

consist

the

organic

&

inorganic

substances

present

in

the

soil

&

the

atmosphere.Mineralsarefoundinforestsaredeadorganicmatter&lightconditionsare

differentduetocomplexstratificationofplantcommunities.

BioticComponents:Theorderoffoodchaininforestecosystemamonglivingorganismare

givenbelow

Producers: Theproducersaretreesofdifferentkindsdependinguponthekindsofforest

formationdevelopinginthatclimate.Theshrubs&groundvegetationarealsopresentin

thatarea.

Consumers:

PrimaryConsumers:Primaryconsumersareherbivoresthatincludetheanimalsfeedingon

treeleaves,orfruitofproducerlikeant,bugsspider,deer,giraffes,elephantsetc.


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SecondaryConsumers:Thesearethecarnivoreslikesnake,birds,lizard,wolfandfoxetc.

feedingonherbivores.

TertiaryConsumers:Thesearetopcarnivoreslikelion,tigeretcwhichdependupon

secondaryconsumers.

Decomposers:Awidevarietyofdecomposerspresentinforestecosystemlikefungi,

bacteriaetc.


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Roma Khanna Lecturer CMCA( TMU)

References

www.ecostudies.org/chp/module1/1b3_pond_ecosystem_reading.pdf

ptuas.loremate.com/evs/node/4

globecarboncycle.unh.edu/CarbonCycleBackground.pdf

www.enchantedlearning.com/subjects/.../earth/Watercycle.shtml

Shrivastava,Smita,Environmentandecology,S.K.Katariaandsonspublisher,secondEdition,

2009.

KaushikAnubhaandKaushikC.P.,Environmentalstudies,NewAgeInternationalpublishers,

ThirdEdiion,2008.

Benny Joseph ,Environmental Studies, Tata McGraw Hill, Second Edition, 2005

Roma Unit 1 Chapter 4 PDF

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