Ecosystem

concept of an ecosystem – structure and function of an ecosystem – producers, consumers and decomposers-Oxygen cycle and Nitrogen cycle – energy flow in the ecosystem – ecological succession processes – Introduction, types, characteristic features, structure and function of the (a) forest ecosystem (b) grassland ecosystem (c) desert ecosystem (d) aquatic ecosystems (ponds, streams, lakes, rivers, oceans, estuaries)

1. Ecosystem
By
V. S. SaravanaMani
Head & Assistant Professor
Department of Chemistry
Annapoorana Engineering College, Salem 636 308

2. Ecology
Alllivingorganism,whetherplantoranimalor
humanbeingissurroundedbytheenvironment,onwhich
itderiveitsneedsforitssurvival.
Eachlivingcomponentinteractswithnon–living
componentsfortheirbasicrequirementsformdifferent
ecosystem.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

3. Definition
Ecologyisthestudyofinteractionsamongorganism
orgroupoforganismswiththeirenvironment.The
environmentconsistsofbothbioticcomponents(living
organisms)andabioticcomponents(non–livingorganisms).
orEcologyisthestudyofecosystems.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

4. Ecosystemisthebasicfunctionalunitofecology.Theterm
ecosystemiscoinedformaGreekwordmeaningstudyof
home.
Definition
Agroupoforganismsinteractingamongthemselves
andwithenvironmentisknownasecosystem.Thusan
ecosystemisacommunityofdifferentspeciesinteractingwith
oneanotherandwiththeirnonlivingenvironmentandone
anotherandwiththeirnon-livingenvironmentexchanging
energyandmatter.
Example
Animalscannotsynthesistheirfooddirectlybut
dependontheplantseitherdirectlyorindirectly.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

5. TYPESOFECOSYSTEM-Naturalecosystem
Naturalecosystemsoperatethemselvesundernaturalconditions.
Basedonhabitattypes,itcanbefurtherclassifiedintothreetypes.
1.Terrestrialecosystem
Thisecosystemisrelatedtoland.
Example
Grasslandecosystem,forestecosystem,desertecosystem,etc.,
2.Aquaticecosystem
Thisecosystemisrelatedtowater.Itisfurthersubclassifiedinto
twotypesbasedonsaltcontent.
•Freshwaterecosystem
(i)Runningwaterecosystems.
Examples
Rivers,Streams
(b)Standingwaterecosystems
Examples
Pond,lake
(ii)Marineecosystem
Example:
Seasandseashores
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

6. Man –made (or) Artificial ecosystems
Artificial ecosystem is operated (or) maintained by
man himself.
Example
Croplands, gardens
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

7. STRUCTURE (or) COMPONENTS OF AN ECOSYSTEM
Thetermstructurereferstothevariouscomponents.
Sothestructureofanecosystemexplainstherelationship
betweentheabiotic(non–living)andthebiotic(living)
components.
Anecosystemhastwomajorcomponents
•Biotic(living)components
•Abiotic(nonliving)components
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

8. Bioticcomponents
Thelivingorganisms(or)livingmembersinan
ecosystemcollectivelyformitscommunitycalledbiotic
components(or)bioticcommunity.
Examples
•Plants(producers),
•animals(consumers),
•microorganisms(decomposers).
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

9. Membersofcomponentsofanecosystem(or)
Classificationbioticcomponents
The membersofbioticcomponentsofan
ecosystemaregroupedintothreebasedonhowthey
getfood.
•Producer(plants)
•Consumer(Animals)
•Decomposers(Micro-organisms)
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

10. 1.Procedures(Autotrophs)
Proceduressynthesizetheirfoodthemselvesthrough
photosynthesis
Example:
Allgreenplants,trees.
Photosynthesis
Thegreenpigmentscalledchlorophyll,presentinthe
leavesofplants,convertsCO
2
andH
2
Ointhepresenceof
sunlightintocarbohydrates.
6CO
2
+12H
2
O---->C
6
H
12
O
6
+6O
2
+6H
2
O
Thisprocessiscalledphotosynthesis
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

11. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

12. Consumers (heterotrophs)
Examples
Plant eating species
Insects, rabbit, goat, deer, cow, etc.,
Classification of consumers
Consumers are further classified as
(i) Primary consumers (Herbivores) (Plant eaters)
Primary consumers are also called herbivores, they directly
depend on the plants for their food. So they are called plant
eaters.
Examples :
Insects, rat, goat, deer, cow, horse, etc.,
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

13. (ii) Secondary consumers (primary carnivores) (meat eater)
Secondaryconsumersareprimarycarnivores,theyfeed
onprimaryconsumers.Theydirectlydependonthe
herbivoresfortheirfood.
Example
Frog, cat, snakes, foxes, etc.,
(iii) Tertiary consumers (Secondary carnivores) (Meat-eaters)
Tertiary consumers are secondary carnivores, they feed
on secondary consumers. They depend on the primary
carnivores for their food.
Examples
Tigers, lions, etc.,
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

14. 3.Decomposers
Examples
Microorganismslikebacteriaandfungi.Decomposers
attackthedeadbodiesofproducersandconsumersand
decomposethemintosimplercompounds.Duringthe
decompositioninorganicnutrientsarereleased.
Theinorganicnutrientstogetherwithotherorganic
substancesarethenutilizedbytheproceduresforthe
synthesisoftheirownfood.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

15. Abiotic(non-living)components
Thenon-livingcomponents(physicalandchemical)of
ecosystemcollectivelyformacommunitycalledabiotic
components(or)abioticcommunity.
Examples
Climate,soil,waterlair,energy,nutrients,etc.,
1.Physicalcomponents
Theyincludetheenergy,climate,rawmaterialsand
livingspacethatthebiological
communityneeds.Theyareusefulforthegrowthand
maintenanceofitsmember.
Examples
Air,water,soil,sunlight,etc.,
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

16. 2.ChemicalComponents
Theyarethesourcesofessentialnutrients
Examples
•Organicsubstances:Protein,lipids,carbohydrates,etc.,
•Inorganicsubstances:Allmicro(Al,Co,Zu,Cu)andmacro
elements(C,H,O,P,N,P,K)andfewotherelements.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

17. FUNCTIONOFANECOSYSTEM
Tounderstandclearlythenatureofecosystemits
functioningshouldbethoroughlyunderstood.
Thefunctionofanecosystemistoallowflowof
energyandcyclingofnutrients.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

18. TypesofFunctions
Functionsofanecosystemareofthreetypes.
1.Primaryfunction
Theprimaryfunctionofallecosystemis
manufactureofstarch(photosynthesis).
2. Secondary function
The secondary function of all ecosystem is
distribution energy in the form of food to all consumers.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

19. TertiaryFunction
Alllivingsystemsdietataparticularstage.Thesedead
systemsaredecomposedtoinitiatethirdfunctionof
ecosystemsnamely“cycling”.
Thefunctioningofanecosystemsmaybeunderstood
studyingthefollowingterms.
•Energyandmaterialflow.
•Foodchains
•Foodwebs
•Foodpyramids
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

20. ENERGY FLOW IN THE ECOSYSTEMS
Energyisthemostessentialrequirementforallliving
organism.Solarenergyistheonlysourcetoourplanetearth.Solar
energyistransformedtochemicalenergyinphotosynthesisbythe
plants(calledasprimaryproducers).Thoughalotofsunlightfallson
thegreenplants,only1%ofitisutilizedforphotosynthesis.Thisisthe
mostessentialsteptoprovideenergyforallotherlivingorganismsin
theecosystem.
Someamountofchemicalenergyisusedbytheplantsfor
theirgrowthandtheremainingistransferredtoconsumersbythe
processofeating.
Thustheenergyenterstheecosystemsthroughphotosynthesis
andpassesthroughthedifferenttropiclevelsfeedinglevels.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

21. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

22. EnergyflowandThermodynamics
Theflowofenergythroughanecosystemfollowsthetwolawsofthermodynamics.
1.Ilawofthermodynamics
It states chat “energy can be created nor destroyed, but it can be considered from one from to
another”.
Illustration
Energy for an ecosystems comes from the sum. It is absorbed by plants, herein it is converted
into stored chemical energy i.e., solar energy in converted into chemical energy.
2. II law of thermodynamics
Statement
It states that, “Whenever energy is transformed, there is a loss of energy through the
release of heat”.
Illustration
This occurs when energy is transferred between tropic levels. There will be a loss of
energy (about 80-90%) in the form of heat as it moves from one tropic level to another tropic
level. The loss of energy takes place through respiration, running, hunting etc.,
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

23. Relationshipbetweenstructureandfunction(flowmodel)
Fromtheaboveitisclearthat,thebioticcomponents
andabioticcomponentsarelinkedtogetherthroughenergy
flowandnutrientcyclingasshowninthefollowingfigure.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

24. NutrientFlow(OR)NutrientCycling(Or)BiogeochemicalCycleInThe
Ecosystem
Nutrients
Theelements,whichareessentialforthesurvivalofbothplantsand
animalsarecalledarecallednutrients.
Macronutrients
Theelementsneededinlargeamountsarecalledmacronutrients
Examples
Oxygen,nitrogen,carbon,calcium,magnesiumandphosphorus.
Micronutrients
Theelements,neededinsmallamountsarecalledmicronutrients.
Example
Boron,cobalt,strontium,zinc,copper
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

25. NutrientCycles
Thecyclicflowofnutrientsbetweenthebioticandabiotic
componentsisknownasnutrientcycle(or)biogeochemicalcycles.
Thenutrientsenterintoproceduresandmovethroughthe
foodchainandultimatelyreachtheconsumer.Theboundnutrients
oftheconsumers,afterdeath,aredecomposedandconvertedinto
inorganicsubstances,whicharereadilyusedupbytheplants
(procedures)andagainthecyclestarts.
ThemajornutrientslikeC,H,OandNarecycledagainand
againbetweenbioticandbioticcomponentoftheecosystem.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

26. HydrologicalCycle
Movementofwaterinacyclicmannerisknown
ashydrologicalcycle.
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Chemistry, AEC Salem

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Chemistry, AEC Salem

28. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

29. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

30. Carboncycle
Carbonisthebasiccomponentinalltheorganiccomponents.The
carbonispresentin
allbioticcomponentsindifferentformsasfood.
Examples:
Carbohydrates,proteins,fatsandaminoacids.Carbonispresent
intheatomosphereasCO
2
.TheCO
2
takenupbythegreenpalntsasa
rawmaterialforphotosynthesisofdifferentfood.Thisfoodmoves
throughfoodchain,finallythecarbonpresentinthedeadmatteris
returnedtotheatmosphereasCO
2
bymicroorganisms.
SourcesofCO
2
inatmosphere
•Duringrespiration,plantsandanimalsliberatesCO
2
intheatmosphere.
•CombustionoffuelsalsoreleaseCO
2
.
•VolcaniceruptionsalsoreleaseCO
2
.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

31. Nitrogencycle
NitrogenispresentintheatmosphereasnN
2
inlargeamounts(78%).The
nitrogenispresentinallbioticcomponentsindifferentformsasfood.
Examples
Proteins,vitamins,aminoacids,etc.,
TheN
2fromtheatmosphereistakenupbythegreenplantsasarawmaterial
forbiosynthesisofdifferentfoods(aminoacids,proteins,vitamins)andusedin
metabolism.Thesefoodmovethroughthefoodchain.Afterdeathoftheplants
andanimals,theorganicnitrogenindeadtissuesindecomposedbyseveral
microorganismsammonifyingandnitrifyingbacteria)intoammonia,nitrites
andnitrates,whichareagainusedbytheplants.Somebacteriaconvertnitrates
intomolecularnitrogen(N
2)whichisagainreleasedbackintoatmosphereand
thecyclegoeson.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

32. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

33. Nitrification
Theconversionofammoniaintonitratesistermedasnitrification.
Thisisbroughtaboutbynitrifyingbacteria.
Examples
Nitrobacter,Nitrosomonas.
Denitrification
Theconversionofnitratesintonitrogen(N2)istermed
dentrification.
Thisprocessisbroughtaboutbycentrifyingbacteria.
Examples
Pseudomonas,flurescence.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

34. Phosphoruscycle
Phosphorusismainlypresentintherocksandfossils.The
phosphorusispresentinallbioticcomponentsindifferentforms.
Examples
Bones,teeths,guanodeposits.Phosphaterocksisexcavatedby
manforusingitasafertilizers.Farmersuseexcessoffertilizersforthe
crops.Theexcessphosphatefertilizersmovewiththesurfacerun-off
reachestheoceansandarelostintothedeepsediments.Seabirdseat
sea–fishes,whicharephosphorusrich,andtheexcretaofthebirds
returnthephosphorustotheland.Thustheseabirds,areplayingan
importantroleinphosphoruscyclinganimalsandplantsusethese
dissolvedphosphatesduringthebiosynthesis.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

35. V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

36. ECOLOGICAL SUCCESSION
Inanareaonecommunitymaybereplacedby
anothercommunityorbyaseriesofcommunities.
Thustheprogressivereplacementofone
communitybyanothertillthedevelopmentofstable
communityinaparticularareaiscalledecological
succession.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

37. Stages of ecological succession
1. Pioneer community
The first group of organism, which establish their
community in the area is called ‘Pioneer’ Community.
2. Seres(or) Seralstage
The various developmental stages of a community is
called ‘seres’.
Community
It is the age group of plants or animals living in an area
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

38. Typesofecologicalsuccession
Ecologistsrecognizetwotypesofecologicalsuccession,
usedontheconditionspresentatthebeginningoftheprocess.
1.Primarysuccession
Itinvolvesthegradualestablishmentofbiotic
communitiesonalifelessground.
a.Hydrarch(or)Hydrosere
Establishmentstartsinawateryarealikepondandlake.
b.XerarchorXerosere
Establishmentstartsinadryarealike,desertandrock
2.Secondarysuccession
Itinvolvestheestablishmentofbioticcommunitiesinthe
area,wheresometypeofbioticcommunityisalreadypresent.
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Chemistry, AEC Salem

39. ProcessofEcologicalSuccession
Theprocessofecologicalsuccessioncanbeexplainedinthefollowingsteps.
1.Nudation
Itisthedevelopmentofabareareawithoutanylifeform
2.Invasion
Itistheestablishmentofoneormorespeciesonabareareathroughmigrationfollowedby
establishment.
Migration-Migrationofseedsisbroughtaboutbywind,waterorbirds.
b.Establishment
Theseedsthengerminateandgrowonthelandandestablishestheirpioneercommunities.
3.Competition
Asthenumberofindividualspeciesgrows,thereisacompetitionwiththesamespeciesand
betweendifferentspeciesforspace,waterandnutrients.
4.Reaction
Thelivingorganismstakewater,nutrientsandgrowandmodifytheenvironmentisknownas
reaction.Thismodificationbecomesunsuitablefortheexistingspeciesandfavoursomenewspecies,
whichreplacetheexistingspeciesthisleadstoseralcommunities.
5.Stabilizations
Itleadstostablecommunity,whichisinequilibriumwiththeenvironmentV.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

40. FOODCHAINS
Definition
“There sequence of eating and being eaten in an ecosystem is known as food
chain”
(or)
“Transfer of food energy from the plants through a series of organisms is
known as food chain”
Whentheorganismsdie,theyarealldecomposedbymicroorganism
(bacteriaandfungi)intonutrientsthatcanagainbeusedbytheplants.At
eachandeverytransfer,nearly80-90%ofthepotentialenergygetslostas
heat.Afoodchainalwaysstartswithplantlifeandendswithanimal.
Herbivores
Animalthateatonlyplantsarecalledherbivores.
Carnivores
Animalsthateatotheranimalsarecalledcarnivores.
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Chemistry, AEC Salem

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Chemistry, AEC Salem

42. Foodchaininapond
Foodchaininaforest
TropicLevels(T1,T2,T3,T4,T5)(or)Feedinglevels
Thevariousstepsthroughwhichfoodenergypassesinan
ecosystemiscalledastropiclevels.
Thetropiclevelsarearrangedinthefollowingwayas
Where,
ThegreenplantsorproducersrepresentfirsttropiclevelT1,
TheherbivoresorprimaryconsumersrepresentsecondtropiclevelT2.
ThecarnivoresorsecondaryconsumersrepresentthirdtropiclevelT3.
ThetertiaryconsumersarefourthtropiclevelT4.
FinallydecomposersrepresentlasttropiclevelT5
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

43. Typesoffoodchain
Foodchainsareclassifiedintotwomaintypes
1.Grazingfoodchain
2.Detritusfoodchain
1.Grazingfoodchain
FoundinGrasslandecosystemsandpondecosystems.Grazingfoodchain
startswithgreenplants(primaryprocedures)andgoestodecomposerfoodchain
ordetritusfoodchainthroughherbivoresandcarnivores.
2.Detritusfoodchain
FoundinGrasslandecosystemsandforestecosystems.Detritusfoodchain
startswithdeadorganicmatter(plantsandanimals)andgoestodecomposerfood
chainthroughherbivoresandcarnivores.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

44. Flowdiagram
Thefollowingflowdiagramofgrazingfood
chainanddetritusfoodchainshowsthattheyare
interconnectedtoeachotherbutarenotisolated.
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

45. FOOD WEB
Definition
The interlocking pattern of various food chains in an ecosystem
is known as food web. In a food web many food chains are
interconnected, where different types of organisms are connected at
different tropic levels, so that there is a number of opportunities of
eating and being eaten at each tropic level
Example
Grass may be eaten by insects, rats, deer's, etc., these may be eaten by
carnivores (snake, tiger).
Thus there is a interlocking of various food chains called food webs
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Chemistry, AEC Salem

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Chemistry, AEC Salem

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Chemistry, AEC Salem

48. Differencebetweenfoodchainsandfoodweb
Inalinearfoodchainsifonespeciesgetsaffected(or)
becomesextinct,thenthespeciesinthesubsequenttropiclevelsare
alsoaffected.But,inafoodweb,ifonespeciesgetsaffected,itdoest
notaffectothertropiclevelssoseriously.
Therearenumberofoptionsavailableateachtropiclevel.
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Chemistry, AEC Salem

49. Significance of food chains and food webs
1.Food chains and food webs play a very important role in the
ecosystem. Energy flow and nutrient
2.cycling takes place through them.
3.They maintain and regulate the population size of different
tropic levels, and thus help in maintaining ecological balance.
4.They have the property of bio-magnification. The non –
biodegradable materials keep on passing from one tropic level
to another. At each successive tropic level, the concentration
keep on increasing. This process is known as bio-magnification.
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Chemistry, AEC Salem

50. ECOLOGICAL PYRAMIDS
Definition
“Graphical representation of structure and function of tropic levels
of an ecosystem, starting with producers at the bottom and each
successive tropic levels forming the apex is known as an ecological
pyramids.”
In food chain starting from the producers to the consumers,
there is a regular decrease in the properties
(ie.,, biomass and number of the organisms). Since some energy is
lost as heat in each tropic levels, it becomes progressively smaller
near the top.
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Chemistry, AEC Salem

51. Types of Ecological pyramids
1. Pyramid of numbers.
2. Pyramid of energy.
3. Pyramid of biomass.
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Chemistry, AEC Salem

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Chemistry, AEC Salem

56. PyramidsofBiomass
Itrepresentsthetotalamountofbiomass(massoweight
biologicalmaterialororganism)presentineachtropiclevels.
Aforestecosystem
Theabovefigureshowsthatthereisadecreaseinthebiomass
fromthelowertropicleveltothehighertropiclevel.This
becausethetrees(producers)aremaximumintheforest,which
contributeahugebiomass.Thenexttropiclevelsareherbivores
(insects,birds)andcarnivores(snakes,foxes).topofthetropic
levelcontainsfewtertiary
consumersSandtigers),thebiomassofwhichisverylow.
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Chemistry, AEC Salem

57. It represents the number of individual organisms present ach tropic levels.
A grassland Ecosystem
Example
• The producers in the grasslands are grasses, which are in size and large
in numbers. So the producers occupy lower tropic level (1St tropic level).
The primary consumers (herbivores) •are rats, which the 11rid tropic level.
Since the number of rats are lower Compared to the grasses, the size of
which is lower.
The secondary consumers (carnivores) are snakes, which occupy the 1I1
tropic levels. Since the number of snakes are1 lower when compared to the
rats, the size of which is 1ower.The tertiary consumers (carnivores) are
eagles, which the next tropic level. The number and size .of the last
V.S.Saravana Mani, Head & AP /
Chemistry, AEC Salem

58. FOREST ECOSYSTEM
Introduction
A forest ecosystem is the one in which a tall and trees grow that support many
animals and birds. The forest are found in undisturbed areas receiving
moderate to hi rainfall. The forest occupies nearly 40%
of the world’s land area. In India it occupies only 19% of its total land area.
Types of forest ecosystem
Depending upon the climate conditions, forests can be classified into the
following types.
1. Tropical Rain forests.
2. Tropical deciduous forests.
3. Tropical scrub forests.
4. Temperate rain forests.
5. Temperate deciduous forests.
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Chemistry, AEC Salem

59. Featuresofdifferent.typesofForests
1.TropicalRainforests
Theyarefoi.indneartheequator.Theyarecharacterizedbyhightemperature.They
havebroadleaftreesliketeakand1.andtheanimalslikelion,tigerandmonkey.
2.Tropicaldeciduousforests
Theyarefoundlittleawayfromtheequator.Theyarecharacterizedbyawarmclimate
andrainisonlyduringmonsoon.Theyhavedifferenttypesofdeciduoustreeslike
maple,oakandhickaryandanimalslikedeer,fox,rabbitandrat.
3.TropicalScrubforests
Thesearecharacterizedbyadryclimateforlongertime.Theysmalldeciduoustrees
andshrubsandanimalslikemaple,oakandhickoryandanimalslikedeer,fox,etc.,
4.TemperateRainForests
Theyarefoundintemperateareaswithadequaterainfall.Theyarecharacterizedby
coniferoustreeslikepines,firs,redwoodetc.,andanimalslike,squirrels,fox,cats,bear
etc.,
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Chemistry, AEC Salem

60. 5. Temperate deciduous forests
They are found in areas with moderate temperatures. have major trees
including broad leaf deciduous trees like oak, hickory and animals like
deer, fox, bear, etc.,
Characteristics of forest ecosystems
1.Forests are characterized by warm temperature and adequate rainfall,
which make the
2.generation of number of ponds, lakes etc.,
3.The forest maintains climate and rainfall.
4.The forest support many wild animals and protect biodiversity.
5.The soil is rich in organic matter and nutrients which support the
growth of trees.
6.Since penetration of light is so poor, the conversion of organic matter
into nutrients is very fast.
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Chemistry, AEC Salem

61. Structure and Function of forest ecosystem
I. Abiotic components
Climatic factors (temperature, light, rainfall) and minerals The abiotic
components are inorganic and inorganic and organic substances found in the soil
and atmosphere. In addition minerals, the occurrence of litter is characteristic
features, majority of forests.
II. Biotic components
1. Producers: The plants absorb sunlight and produce photosynthesis
Trees, shrubs and ground vegetation..
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Chemistry, AEC Salem

62. 2. Consumers
(a)Primary consumers (herbivores) :They directly depend on the plants for
their food.
Example : Ants, flies, insects, mice, deer, squirrels.
b. Secondary consumers (primary carnivores):They directly depend on the
herbivores for their food
Examples: Snakes, birds, fox.
c. Tertiary consumers :They depend on the primary carnivores for their food
Examples : Animals, like tiger, lion, etc.,
3. Decomposers
Bacteria and fungi.
They decompose the dad plant and animal matter., of decomposition in
tropical and subtropical forests is in rapid than in the temperate forests.
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Chemistry, AEC Salem

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Chemistry, AEC Salem

65. GRASSLAND ECOSYSTEM.
Introduction
Grasslandoccupiesabout20%ofearth’ssurfaceadditiontograss
species,sometreesandshrubsare/alsopreingrasslands.Limited
grazinghelpstoimprovethenetprimaryproductionofthegrasslands.
But,overgrazingleadsdegradationofthesegrasslandsresultingin
desertification
Typesofgrasslandecosystem
Dependingupontheclimateconditionsgrasslandcalclassifiedinto
threetypes
1.Tropicalgrasslands.
2.Temperategrasslands.
3.Polargrasslands.
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Chemistry, AEC Salem

66. Featuresofdifferenttypesofgrassland
1.Tropicalgrasslands
Theyarefoundnearthebordersoftropicalrain.forests.arecharacterized
byhightemperatureandmoderaterainfall(40to100cm).Itisalso
knownasSavannatype.Theyyetallgrasseswithscatteredshrubsand
stuntedtreesandanimalslikezebras,giraffes,antelopes,etc.,
2.Temperategrasslands
Theyareusuallyfoundinthecentersofcontinents,oilslopedhills..They
arecharacterizedbyverycoldwintersandhotsummers:Intensegrazing
andsummerfires,donotWshrubsortreestogrow.
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67. 3.Polargrasslands
Theyarefoundinarcticpolarregions.Theyarecharacterizedby
severecoldandstrongwindsalongwithiceandsnow.Insummers
severalsmallannualplantsgrow.They‘eanimalslikearcticwolf,
weasel,arcticfox,etc.,
CharacteristicsofGrasslandEcosystems
Grasslandecosystemisaplainlandoccupiedbygrasses.Soilisvery
richinnutrientsandorganicmatter.Sinceithastallgrass,itisideal
placeforgrazinganimals.Itischaracterizedbyloworunevenrainfall.
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68. Structure and function of the grassland Ecosystems
I. Abiotic components
Nutrients, , H, 0, A, P, S, etc.,
These abiotic components are supplied by C0
2, H
2, C, Nitrate, phosphates and
sulphates.
II. Biotic Components
1. Producers: They produce food.
Example :Grasses, forbs and shrubs.
2. Consumers:.
Primary consumers (herbivores) :They depend on grasses for their food
Examples: Cows, buffaloes, deer, sheep, etc.,
Secondary consumers (carnivores):They feed on herbivores.
Examples: Snakes, lizards, birds, Jackals, fox, etc.,
Tertiary consumers: They feed on secondary consumers
Examples :Hawks, eagle, etc.,
3. Decomposers :They decompose the dead organic matter
Examples :Fungi and bacteria.
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71. DESERT.ECOSYSTEMS
Introduction
Desertoccupiesabout35%ofourworld’slandarea.Itis
characterizedbylessthan25cmrainfall.Theatmosphereisdryand
henceitisapoorinsulator.
Typesofdesertecosystems
Basedontheclimaticconditions,desertsareclassifiedthreetypes.
1.Tropicaldeserts.
2.Temperatedeserts.
3.Colddeserts.
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72. Features of different types of deserts
1. Tropical deserts: Tropical deserts are found in
•Africa: Sahara desert.
•Rajasthan: Thar desert.
They are characterized by only few species. Wind blow sand dunes are
very common.
2. Temperate deserts
They are found in
South California: Majave.
They are characterized by very hot summer and very Winter time.
3. Cold deserts
They are found in -
China: Gobi desert.
They . are characterized by cold winters and was summers.
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73. Characteristics of Desert ecosystem
The desert air is dry and the climate is hot. Annual rainfall is less
than 25 cm. The soil is very poor in nutrients and organic matter,
Vegetation is poor.
Structure and functions of the desert systems ecosystems
1. Abiotic Components
Examples : Temperature, rainfall, sunlight, water, etc.,
The temperature is very high and the rainfall is very low. The
nutrient cycling is also very low.
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74. II.BioticComponents
Procedures
Examples:Shrubs,bushes,somegrassesandfewtrees.Indeserts
mostlySucculent(e.g.,cacti)plantsarefoundavailable.Theyhavewater
insidethemtostayalive.Theyhave.rontheoutsidetoprotectthem
fromthesun.
Consumers
Examples:Squirrels,nicefoxes,rabbits,deerandreptiles.
Theseanimalsdigholesinthegroundtolivein.Theycomeoutatnight
tofindfood.Mostoftheanimalscanextractwaterfromtheseedsthey
eat.
Decomposers
Examples:Fungiandbacteria
Deserthaspoorvegetationwithaverylowamountofdead
organicmater.Theyaredecomposedbyfewfungiandbacteria.
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77. AQUATICECOSYSTEMS
Theaquaticecosystemdealswithwaterbodies.Themajortypes
oforganismfoundinaquaticenvironmentsaredeterminedbythe
water’ssalinity.
Typesofaquaticlifezone
Aquaticlifezonesaredividedintotwotypes.
•Freshwaterlifezones
Examples:Pounds,streams,lakes,rivers.
•Saltwaterlifezones
Examples:Oceans,estuaries.
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78. FRESHWATERECOSYSTEM
PONDECOSYSTEMS
Introduction
Apondisafreshwateraquaticecosystems,wherewaterisstagnant.It
receivesenoughwaterduringrainyseason.Itcontainsseveraltypesofalgae,
aquaticplants,insects,fishesandbirds.
Characteristicsofpond
•Pondistemporary,onlyseasonal.
•Itisastagnantfreshwaterbody.
•Pondsgetpollutedeasilyduetolimitedamountofwater.
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79. Structureandfunctionsofpondecosystems
I.Abioticcomponents
Examples
Temperature,light,waterandorganicandinorganiccompounds
II.BioticComponents
•Producers
Theseincludegreenphotosyntheticorganism.Theyareoftwotypes.
•Phytoplankton
Thesearemicroscopicaquaticplants,whichfreelyfloatonthesurfaceof
water.
Example:Algae,smallfloatingplantslikevolvox,pandorinaanabaena,
consmarium.
Microphytes
Examples:Largefloatingplantsandsubmergedplantslikehydrilla,
Jussiaea,wolfia,demna.
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80. Consumers
•Primary consumers (Zooplanktons): These are microscopic animals which
freely float on the surface of water. Zooplanktons are found along with
phytoplankton. They feed on plants (phytoplankton).
Examples :Protozoa, very small fish, ciliates, flagelaltesand protozoans.
•Secondary consumers (Carnivores):They feed on zooplankton
Examples :Insects like water beetles and small fish.
•Tertiary consumers :They feed on smaller fish
Examples :Large fish like game fish.
Decomposers: They decompose the dead plant and animal matter and their
nutrients are released and reused by the green plants.
Examples :Fungi, bacteria and flagellates
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83. LAKEECOSYSTEM
Lakesarelargenaturalshallowwaterbodies.Lakesareusedfor
variouspurposes.Lakesaresuppliedwithwaterfromrainfall,meltingsnow
andstreams.
Typesoflakes
Someimportanttypesoflakeare
•Oligotrophiclakes:Theyhavelownutrientconcentrations
•Eutrophiclakes:TheyareovernourishedbynutrientslikeNandP
•Dystrophiclakes:TheyhavelowpH,highhumicandcontentand
brownwaters.
•Volcaniclakes:Theyreceivewaterfrommagmaaftervolcanic
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84. ZonesofLake
Dependingupontheirdepthanddistancefromtheshore,likes
consistsoffourdistinctzones.
1.Liftoaizones: It is the top layer of the Lake. It has a shallow water.
2.Linineticzone: Next to the littoral zone is limneticzone, where
effect penetration of solar. light takes place.
3.Préfundalzone: The deep open water, where it is too dark.
4.Benthic zone: This zone is found, at the bottom of the lake.
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87. Characteristics of lake ecosystem
1. Lake is a shallow fresh water body;
2. It is a permanent water body with large Water resources.
3. It helps in irrigation and drinking.
Structure and function of lake ecosystem
I. Abiotic components
Temperature, light, proteins and lipids, O
2
CO
2
II. Biotic Consumers
Producers: They are green plants, may. be submerged, free floating
ad amphibious plants.
Examples: Phytoplanktons, algae and flagellates.
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88. 2. Consumers
(a). Primary Consumers (Zooplanktons): They feed on
phytopankton
Examples: Cilictes, protozoans, etc.,
(b) Secondary consumers (carnivores): They feed on zooplankton.
Examples: Insects and small fishes.
(c) Tertiary consumers: They feed on smaller fish
Examples: Large fishes like game fish.
3. Decomposers
They decompose the dead plants ad animals
Examples: Bacteria, fungi and aclinonrcetes.
.
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90. V.S.Saravana Mani, Head & AP /
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91. RIVER (or) STREAM ECOSYSTEM
Introduction
The running water of a stream or a river is usually well
oxygenated, because it absorb’soxygen from the air. The number of
animals are low in river or stream.
Characteristics of River or Stream.
•It is a fresh water, and free flowing water systems.
•Due to mixing of water, dissolved oxygen content is. more.
•River deposits large amount of nutrients.
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92. Structure and function of River or Stream Ecosystem
I. Abiotic components
Examples : River, Light, Temperature, Chemistry, Substrate
II. Biotic Components
Producers: Phytoplankton, algae, water grasses, aquatic masses
other amphibious plants.
Consumers
(i) Primary consumers: They feed on phytoplankton.
Examples : Water insects, snails, fishes:
(ii) Secondary consumers: They feed on primary consumers
Examples : Birds
Decomposers: They decomposes the dead animals and plants.
Examples :Bacteria and fungi.
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95. SALTWATERECOSYSTEMS.
OCEAN(MARINE)ECOSYSTEMS
Introduction
Oceanscovermorethantwothirdsoftheearth’ssurface.ocean
environmentischaracterizedbyitshighconcentrationofsaltsandminerals.
Itsupplieshugevarietyofproductsanddrugs.Italsoprovidesusiron,
magnesium,iron,naturalgas.
ZonesofOceans
Theoceanshavetwomajorlifezones.
(a)Coastalzone:Itisrelativelywarm,nutrientrichshallowwater.Ithas
highprimaryproductivitybecauseofhighnutrientsandsunlight.
(b)Opensea:Itisthedeeperpartoftheocean.Itisverticallydividedinto
threeregions.
(i)Euphoticzone:Itreceivesabundantlightandshowshigh
photosynthetic
(ii)Bathyalzone:Itreceivesdimlightandisusuallygeologicallyactive.
(iii)Abyssalzone:Itisthedarkzoneandisverydeep(2000tometres).
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97. Characteristics of Ocean Ecosystem
1.It occupies a large surface area with saline water.
2.Since ship, submarines can sail in ocean, commercial activities
may be earned out.
3.It is rich in biodiversity.
4.It moderates the-temperature
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98. Structure and function Ecosystems
I. Abiotic components
Examples
Temperature, light, NaCl, K, Ca, and Mg Salts alkalinity
II. Biotic components
1. Producers :
Phytoplanktons(diatoms, unicellular algae, etc., ) and marine
plants (sea weeds, chlorophycela, phaeophyceae).
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99. 2. Consumers
These are heterotrophic macro consumers. They depend on
producers for their nutrition.
•Primary consumers (herbivores):They feed on producers
Examples :Crustaceans, moiluscs, fish
•Secondary consumers (carnivores) : They feed on herbivores
Examples :Herring sahd, mackerel, etc.,
•Tertiary Consumers: They are the top consumers. They feed on small
Examples :Cod, Haddock, -etc.,
3.Decomposers: They decompose the dead organic matter.
Example s:Bacteria and some fungi.
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103. ESTUARINE ECOSYSTEM
Introduction
An estuary is a partially enclosed coastal area at the’ mouth of a
river, where sea water mixes with freshwater. It is strongly affected by
tidal action. Estuaries are generally : abundant of nutrients. Estuaries
are useful to human beings due to their high food potential. It is
essential to protect the estuaries from pollution.
Characteristics of Estuarine ecosystem
1.Estuaries are transition zones, which are strongly affected by tides
of the sea.
2.Water characteristics are periodically changed.
3.The living organism in estuarine ecosystems have wide tolerance.
4.Salinity remains highest during the summer and lowest during the
winter.
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104. Structure and function of Estuarine Ecosystem
I. Abiotic Components
Examples :Temperature, pH, sodium and potassium salts and
various nutrients.
II. Biotic Components
•Producers
Examples :Marsh grasses, seaweeds , sea-grasses and
phytoplankton.
•Consumers
Examples :Oysters, crabs, seabirds, small fishes
•Decomposers
Examples :Bacterias, fungi and actenomycetous.
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