Chapter2

ECOLOGY AND ECOSYSTEMECOLOGYANDECOSYSTEM

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ECOLOGYECOLOGY

The word ecology is derived from two greekwords oikos meaning house habitation orwords oikos meaning house, habitation orplace of living and logos meanings study.

Ecology is the study of interrelationship betweenEcology is the study of interrelationship betweenliving organisms and their physical and biologicalenvironment.

Ph i l i i l d li h d hPhysical environment includes light and heat orsolar radiation, moisture, wind, oxygen, carbondioxide, nutrients is in soil, water and, ,atmosphere.

The biological environment includes organismsf ll ki d ll l t d i lof all kind as well as plants and animals.

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OBJECTIVE OF ECOLOGYOBJECTIVEOFECOLOGY

The interrelationship between organisms in population and diverse communities. Th t l ( ti l) h ( l l i l t ) The temporal (sequential) changes (seasonal, annual, successional etc) The behavior under natural condition The structural adaptations and functional adjustments of organisms to their

physical environment. The development in the course of evolution. The biological productivity and energy flow in natural system The development of mathematical models relate interaction of parameters and

to predict the effects.p

The main objective:

Uncontrolled interference with natural population Uncontrolled interference with natural population Unchecked felling of trees Environmental pollution

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SCOPE OF ECOLOGYSCOPEOFECOLOGY

Ecology helps to tackles of problems of pollution:1. Air, water, land erosion, ,2. Floods3. Famine variation in seasonal patterns4. Green house effects5 Ozone layer depletion5. Ozone layer depletion6. Ice melting of poles7. Acid rains8. Deforestation9. Provide people knowledge of environment protection

Maintain ecological balance Understanding different cycle like N C P O H O Understanding different cycle like N2, C, P, O2, H2O Helps protecting flora and fauna Helps in finding productivity of the area Proper and deep study maintain balance in nature and prevent ecological disaster

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CONTCONT

Ecology plays important role in:Ecologyplaysimportantrolein:1. Humanwelfare2 Agriculture2. Agriculture3. Managementofgrasslands4. Forestryy5. Biologicalsurvey6. PestcontrolandinconservationofwildlifeTheinternationalproblemofenvironmentpollutionalsoneedsecologicalassistance

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CLASSIFICATION OF ECOLOGYCLASSIFICATIONOFECOLOGY

1. Autecology: It deals with study of individual organism oran individual species. In other words it is the study ofinter relationship between individual species or itspopulation and environment.

E.g. tree in the forest

2. Synecology: It deals deals with study of group of organismor species which are associate together as a unit. It isconcerned with structure, nature, development andconcerned with structure, nature, development andcauses of distribution of communities

E g ForestE.g. Forest

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SUBDIVISION OF ECOLOGYSUBDIVISIONOFECOLOGY

Based on Taxonomic: PlantEcologyBasedonTaxonomic:

d biAnimalEcology

BasedonHabitats:Ecology

AquaticEcology TerrestrialEcology

MarineEcology

FreshwaterEcology

GrasslandEcology

ForestEcology

StreamEcology DesertEcology7

CONTCONT

Basedonleveloforganization:

DesertEcology

Autecology Synecology

PopulationEcology

CommunityEcology

EcosystemEcology

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BRANCHES OF ECOLOGYBRANCHESOFECOLOGY

Productive EcologyProductiveEcology PopulationEcology Community Ecology CommunityEcology EcosystemEcologyMi bi l E l MicrobialEcology

RadiationEcology PollutionEcology SpaceEcology

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ECOSYSTEMECOSYSTEM

Ecosystem is made up of two words eco and system. Ecoi t d t i t ti dmeans environment and system means an interacting and

interdependent complex.

Definition of EcosystemDefinition of Ecosystem1. The organisms of any community besides interacting among

themselves, always have functional relationship with theenvironment. The structural and functional system ofenvironment. The structural and functional system ofcommunities and environment is called ecological system.

2. It is a community of interdependent organisms together with theenvironment.

3. Any unit that includes all of the organisms in a given areainteracting with the physical environment, so that a flow ofenergy leads to clearly defined trophic structure, biotic diversityand material cycles within the systemand material cycles within the system.

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TYPESOFEOSYSTEMORKONDS OF ECOSYSTEMKONDSOFECOSYSTEM

Types of EcosystemTypesofEcosystem

NaturalEcosystem ArtificialEcosystem

e g

TerrestrialEcosystem AquaticEcosystem

e.g. cropland ecosystem

e.g. Forest, grass land, Desert

e.g. Fresh water Lotic (running water as e.g. spring, stream and river) or lentic (standing water as lake ponds pools puddles ditch Desert water as lake, ponds, pools, puddles, ditch, swam)Marine water (e.g deep body ocean, shallow one seas or estuary) 11

IMPORTANCEOFSTUDYINGECOSYSTEM

Provides information about the amount of solarenergy in an area

Provides data about the availability of mineralelements their utilization and recyclingelements their utilization and recycling

Provides information about relation betweenorganisms as well as between organism andorganisms as well as between organism andabiotic environment

Provides information of productivity and numberf d dof producers and consumers

The knowledge about pollution, naturalresources and the conservation also can beresources and the conservation also can begathered

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CHARACTERISTICSOFANECOSYSTEM Major structural and functional unit of Ecology Structure is related to species diversity Functional is related to energy flow and material cycling through andgy y g g

within the system The relative amount of energy is needed to maintain an ecosystem

depend on its structure The more complex structure, the lesser the energy it needs to maintain

itself It matures by passing from lesser complex to more complex states.

l f h i h f i l d Early stages of each succession have an excess of potential energy andrelatively high energy flow per unit biomass.

Later stages have less energy accumulation and its flow through morediverse componentsdiverse components

Both environment and the energy fixation in any given ecosystem arelimited and cannot be exceeded without causing serious undesirableeffects

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STRUCTURE OF ECOSYSTEMSTRUCTUREOFECOSYSTEMEcosystem

Abiotic Components BioticComponents

P d OR C ORPhysicalFactors

InorganicSubstance

Organicsubstance

ProducersORAutotrophs

ConsumersORHetrotrophs

Decomposers ORDecomposersORSatrotrophsRain

Light

Water

Minerals

Carbohydrates

Proteins

PrimaryconsumersORHerbivores

Secondary consumersWind

Temperature

Soil

Gases Lipids

SecondaryconsumersORPrimarycarnivores

TertiaryconsumersOR Large consumers

HumicbSoil

Topography

ORLargeconsumers

QuaternaryconsumersOROmnivores

substances

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ECOLOGICAL BALANCEECOLOGICALBALANCE

In the natural environment there exists aIn the natural environment there exists aperfect balance or equilibrium between thevarious organisms, this balance is called asecological balanceDefinition: A state of dynamic equilibriumwithin a community of organisms in whichgenetic, species and ecosystem diversity

i bl bj bl bjremains stable, subject to stable, subject togradual changes through natural succession

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ECOLOGICALBALANCE

The ecological balance may however get distributed due tointroduction of new species, sudden death of some species,introduction of new species, sudden death of some species,natural hazard or mane made causes like deforestation, pollutionetc.

If the numerical ratio balance between different organisms isdi ib d h ll h ill b h f f d fdistributed, then naturally, there will be shortage of food forcertain species which may ultimately lead to large scale mortalityof that species.

A new equilibrium is finally reestablish in the changed condition A new equilibrium is finally reestablish in the changed condition In an ecosystem if there is large number of species of a particular

type, there will be shortage of food for that species and after sometime due to shortage of food death rate of that particular speciesg p pwill increase.

This will also effects the species which feeds on that particularspecies, this is turn would effect the species of next trophic leveland so on as in an ecosystem every species are interconnected Soand so on, as in an ecosystem every species are interconnected. Soultimately the whole ecosystem gets disturb or becomes unstable.

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ENERGY FLOW IN AN ECOSYSTEMENERGYFLOWINANECOSYSTEM

To maintain life energy is required Energy enter from solar radiations Earth atmosphere present solar energy : 15 X 108 cal/m2/year Out of which, 47% of energy reaches earth surface and only 15 %

f h h d d h lof energy reaching the ground is converted into chemical energyby green plants.

The plant make food by own by using raw material( water, salts,CO2 sunlight) through photosynthetic organisms and passes onCO2, sunlight) through photosynthetic organisms and passes onfrom one organism to another in the for of food.

The flow of energy is unidirectional and non cyclic Energy enter ecosystem in form of solar convert into chemical Energy enter ecosystem in form of solar convert into chemical

energy by chemical energy by producers, from them energy passesto the lower trophic level to higher one.

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ENERGY FLOW IN AN ECOSYSTEMENERGYFLOWINANECOSYSTEM

This is the way energy is governed by laws ofy gy g ythermodynamics which state that:

1. Energy is neither created nor destroyed but maybe transferred from one from to anotherbe transferred from one from to another.

2. During energy transfer there is degradation ofenergy from a concentrated form (mechanical,energy from a concentrated form (mechanical,chemical or electrical etc) to dispersedform(heat).

N f i i 100% ffi iNo energy transformation is 100% efficient. It is always accompanied by some dispersion orloss of energy in form of heatloss of energy in form of heat.

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MODELFORENERGYFLOWINECOSYSTEM

Singlechannelenergyflowmodel

NU NATrophic level Green plant Herbivores Carnivores

Total light

I and La

A

APg or A PnI and La

PP

A= Total assimilationPn= Net primary

d ti

Unidirectional energy flow

d lproductionPg=Gross primary productionP=Secondary productionNU=Energy not used

model

Heat R15

R R

3000 - 1500 15 0.3L La Pn P2 P1

NU Energy not usedNA=energy not assimilated by consumersR=Respiration

Kcal/m2/day19

YSHAPEDORDOUBLECHANNELENERGYFLOWMODELFLOWMODEL

Common boundary for light, heat, import, export andstorage of organic matter

Decomposers are placed in separate box to partiallyseparate the grazing and detritus food chain.

Yshaped energy flow is more realistic and practical thanthe single channel energy flow model because:

1. It conforms to the basic stratified structure of ecosystem1. It conforms to the basic stratified structure of ecosystem2. It separates the two chains i.e. grazing and detritus food

chain in both time and space3 Micro consumers(bacteria and fungi) and the macro3. Micro consumers(bacteria and fungi) and the macro

consumers (animals) differ greatly in sizemetabolismrelation in two models

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UNIVERSAL ENERGY FLOWMODELUNIVERSALENERGYFLOWMODEL

As the energy takes place there is gradual lossAs the energy takes place, there is gradual lossof energy at each level as indicated bynarrower pipes and smaller boxesnarrower pipes and smaller boxes

The loss of energy which is not utilized is NU.Th l i i i hi h f The energy lost in respiration which s formaintenance. The remaining energy is usedf d ifor production.

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ECOLOGICAL PYRAMIDSECOLOGICALPYRAMIDS

Graphical representation of trophic structure and function ofp p pecosystem, starting with producers at the base and successivetrophic levels forming the apex is known as ecologicalpyramidpyramid.

Typesyp

1. Pyramids of numbers

2. Pyramids of Biomass

3. Pyramids of energy

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1. PYRAMIDS OF NUMBER1.PYRAMIDSOFNUMBER

Topcarnivores

Hawks other birdsHyperparasites Fleas,microbes

Hawks,otherbirds

Frogs,birds

InsectsHerbivores

CarnivoresParasitesHerbivores

Lice,bugs

Birds

GrasesProducers

Producers

Trees

Drawbacks

Grassland Parasiticfoodchain

1. The pyramid does not take in to account the size of theindividuals. All considered to be equal

2 The number of individual of a trophic level depends upon2. The number of individual of a trophic level depends upontheir biomass.

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2. PYRAMIDS OF BIOMASS2.PYRAMIDSOFBIOMASS

TopcarnivoresTertiarycarnivores Bigfish

Frogs,birds,snakes

squirrl,rabbitHerbivores

CarnivoresCarnivoresHerbivores

Small fish

Insects

GrasesProducers

Producers

Phytoplankton

Drawbacks1 Each trophic level indicates standing crops which is different in different seasons For eg a deciduous

GrasslandPond

1. Each trophic level indicates standing crops, which is different in different seasons. For eg, a deciduoustree has more biomass durring spring but less in autumn and winter

2. Life span of individual is not taken in to consideration, short life span organism may have high turn over

3. In aquatic ecosystem pyramid of biomass is often inverted in unfavourable periods(winter) and uprightin favourable period (spring)p ( p g)

4. Biomass differs in its energy content in different organisms

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3. PYRAMIDS OF ENERGY3.PYRAMIDSOFENERGY

carnivores

Herbivores

Herbiivores

Producers

Advantage1. Always uprighty p g

2. Based on productivity

3. Give idea of actual amount of energy received at a trophiclevel

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BIOGEOCHEMICAL CYCLESBIOGEOCHEMICALCYCLES

The cyclic exchange of nutrient materials between livingy g gorganisms and their non living environment is called asbiogeochemical cycles

It includes1 Hydrologic or water cycle1. Hydrologic or water cycle

2. Gaseous cycle (include O2 cycle, N2 cycle)

3. Sedimentary cycles( includes S, P, C)y y ( , , )

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C cycleCcycle

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O2 cycleO2 cycle

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N2 cycleN2 cycle

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P cyclePcycle

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FOODCHAIN

In food chain each organism eats the smaller organisms and iseaten by larger one. All those organisms which are interlinkedwith each other through food together constitute theecosystem

There are mainly 3 trophic levels: Producers level consumers There are mainly 3 trophic levels: Producers level, consumerslevel, decomposer level.

Sunlight > Producers (grass) primary consumers(rabbit) Secondary consumers(Fox) Tertiaryconsumers(Wolf) Quaternary consumers (tiger)death decomposers (bacteria, fungi etc) inorganicdeath decomposers (bacteria, fungi etc) inorganicsubstancesgrass

10% loss energy every stage Food chain depend on number of trophic level. Shorter food chain more available energy 34

TYPES OF FOOD CHAINTYPESOFFOODCHAIN

1 Predator food chain or Grazing food chain :1. PredatorfoodchainorGrazingfoodchain:startfromproducersandendwithhigherconsumer levels In energy trophic level theconsumerlevels.Inenergytrophic level,thesizeoftheorganismincreasewhiletheirnumber decreasesnumberdecreases.

E.g :Grass Grasshopper ToadSnake

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CONTCONT

2 Parasitic food chain: This type of food chain2.Parasiticfoodchain:Thistypeoffoodchainstartsfrombighostsandendswithparasiticorganismsorganisms

Cow worm Protozoa3 S h i f d h i d i f d h i3.Saprophyticfoodchainordetritusfoodchain:Startfromdeadorganismsandendwithd h b idecomposerssuchasbacteria

Leaflitter algae crabs SmallfishLargefish

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SIGNIFICANCE OF FOOD CHAINSIGNIFICANCEOFFOODCHAIN

Food chain help to understand feedingFood chain help to understand feedingrelationship and interaction betweenorganisms in any ecosystemorganisms in any ecosystem

It helps to understand the energy flowmechanisms and circulation of toxicmechanisms and circulation of toxicsubstances in the ecosystem and the problemof biological magnificationof biological magnification

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BIOLOGICAL MAGNIFICATIONBIOLOGICALMAGNIFICATION

Definition: It is tendency of pollutants to concentrated insuccessive tropic levels Large concentration of pollutantssuccessive tropic levels. Large concentration of pollutantscould be detrimental if they are toxic.

Biomagnifications occurs when organisms at the bottom ofthe food chain accumulate the toxic materials greater thanthat available in the environment around it.

As DDT heavy metal resemble inorganic nutrients these will As DDT, heavy metal resemble inorganic nutrients these willtaken up by plants along with the essential nutrients.

If there is shortage of essential nutrients accumulation ofgthese toxic material will be more and more

This first step of biomagnifications is known asBIOACCUMULATIONBIOACCUMULATION

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CONTCONT

The second type of biomagnifaction occurs when producersyp g pare eaten by consumers. The energy availability decreasesfrom one trophic level to other. Thus successive trophic levelconsumes more and more toxic materialsconsumes more and more toxic materials.

This toxic material are not broken down in the body easily butthey get quickely accumulated in the tissues.

For e.g. toxic material like DDT soluble in fat easily. When consumers eat another consumers fat is digested and

h ll f f hthe pollutants move fats of another consumers.

For water soluble toxic material, biomagnifaction cannotoccur as they are dissolved in body fluids of the consumersoccur as they are dissolved in body fluids of the consumersand get exerted easily.

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CONTCONT

Man is omnivores and has all trophic level of food, heMan is omnivores and has all trophic level of food, hereceives toxic substances large amount. Secondaryand tertiary consumers at the top of the food chainalso accumulate toxic materials in their body.

Biomagnifaction of pollutant can be estimated withthe help of biological concentration factor (BCF)

BCF =Concentrationoftoxicmaterialinorganism

Concentrationoftoxicmaterialinenvironment

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TROPHIC LEVELTROPHICLEVEL

All organisms feeding their food from plantAll organisms feeding their food from plant.And plant make their food by own so plant is afirst trophic levelfirst trophic level.

Then plant is eaten by another primaryconsumers so it is called second trophic levelconsumers so it is called second trophic level.

Like this successive trophic level is occur. e.g1. WheatMan2. Algae Insects FishMan

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FOOD WEBFOODWEB DEFINATION: Various food chain are often interlinkedat different trophic levels to form a complexat different trophic levels to form a complexinteraction between different species from the pointof view of food. This network like interaction is calledas food web.

It provides more than alternative of food, thereforeincreases their chances of survival.

Charles Elton, a British ecologist, concluded thatnumber of links a chain rarely exceeds five becausein this process loss of energy occur.

It is the energy transfer mechanisms determinenumber of links in food chain. 42

CONTCONT

It maintain stability of ecosystem It maintainItmaintainstabilityofecosystem.Itmaintainthedifferentpatchwayofecosystem

Snake Hawks

ToadRabbit

Grass Grasshopper Birds

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FORESTECOSYSTEM

Forest ecosystem includes trees, shrubs, algae andy , , gvariety of animals, plants and birds.

Forest found moderate to high rain fall area

Function of forest ecosystem Enhance water resources both quantity and quality.Hydrological cycle depend on it

It gives shelter to wild life It gives shelter to wild life It acts as sink for reducing CO2 content in toatmosphereatmosphere

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COMPONENTOFFORESTECOSYSTEM

Abiotic Inorganic and organic substances, soil, atmosphere, climate

Biotic Producers

Plants, species, shrubs, fruits, trees

componentsConsumersPrimary Flies, leaf hoppers, bugs, spider, large animalsconsumersSecondary consumers

Lions, tigers etc

Decomposers Microorganisms, bacteria, virus, fungi

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GRASS LAND ECOSYSTEMGRASSLANDECOSYSTEM

Includes :trees and shrubs Rainfall is average About 4.6 X 10 ^7 km2 of earth surface is covered with grass

lands which occupy 32% of the plant cover of the world.py pOvergrazing of grass land converts into desertification

Three types of grass landyp g

Temperature grassland (25100 cm of annual rainfall) Tropical grassland( 150 cm of annual rainfall) Tropical grassland( 150 cm of annual rainfall) Polar grassland (serve very cold, strong and fridge winds along

with ice and snow)

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COMPONENTOFGRASSLANDECOSYSTEM

Abiotic Soil and atmosphere like elements (C, H, O, N. P, S) which r supplied CO2, H2O, nitrates, phosphates and sulphates

Biotic Producers

Grasses, shrubs and few forbs

componentsConsumersPrimary Cow buffalo, rabbit, mouse, incestsconsumersSecondary consumers

Snakes, lizard, birds, fox, jackal

Decomposers Microorganisms, bacteria, virus, fungi

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DESERT ECOSYSTEMDESERTECOSYSTEM Precipitation exceed less than 25 cm per year. Atmosphere is dry, poor insulator.p y, p Desert soil make cool quickly, night is cool

3 major types3 major types

Tropical dessert like sahara and Namibia in Africa and Thardesert in Rajasthan They have only few species Wind blowdesert in Rajasthan. They have only few species. Wind blowsand dunes are very common

Temperature dessert like Mojave in south California wheretemperature are very hot in summer but cool in wintertemperature are very hot in summer but cool in winter.

Cold desert like Gobi desert in China has cold winters andwarm summers

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COMPONENTOFDESERTECOSYSTEM

Abiotic Temperature in very high and rainfall is very low

Producers Grasses, shrubs, treesConsumers Insects, reptiles, rodents, birds, camels etcDecomposers Poor vegetation deed organic matter fungi bacteria etcDecomposers Poor vegetation, deed organic matter, fungi, bacteria etc

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AQUATIC ECOSYSTEMAQUATICECOSYSTEM

Pond EcosystemPondEcosystem LakeEcosystem

i MarineEcosystem EstuarineEcosystem

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PONDECOSYSTEM

Abiotic Temperature, light, water several inorganic and organic elements (C, H, O, N. P, S, Ca, Mg), carbohydrates, protein, li idlipids

Biotic Producers components

Green plants, alage, fungi

components

Consumers

( fPrimary consumers

Zooplankton (ciliates, flagellates, other crustacean like copepods and daphnia etc)

Secondary Carnivores: they feed harbivores like fish and insectsyconsumers

y

Tertiaryconsumers

Large fishes they feed smaller fishes

Decomposers Microorganisms, bacteria, fungi51

LAKEECOSYSTEM

W li ht i l ti fWarm, lighter, circulating surface area

Sharp drop in temperature

Cold, viscous, non circulating bottom layer

52

RIVER ECOSYSTEMRIVERECOSYSTEM

Large stream flow down wards.

3 phase of river

The mountain high land part has cold clear water rushingdown as water dalls with large amount of DO. The plants areattached to rocks and fishes are cold water, high O2 requiring.

In second phase gentle slopes, the water warmer and supporta growtth of plants and less O2 requiring fishesa g o tt o p a ts a d ess O equ g s es

In third phases, river eater are very rich in biotic diversity.Moving down the hills, river shape the lands.

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MARINE ECOSYSTEMMARINEECOSYSTEM

It includes ocean, estuaries and coral reef ecosystem

OCEAN ECOSYSTEM

Covers 7071 % earth surface. Survive 2,50,000 species. Serve food for human and other

organisms huge variety of sea products and drugsorganisms, huge variety of sea products and drugs. Ocean provides us iron, phosphorus, magnesium, oil, natural

gas, sand and gravel Major sinks of CO2 play important role in biogeochemical Major sinks of CO2 play important role in biogeochemical

cycles

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OCEAN2MAJORJONE

COASTALZONE:warm,reachshallowwater,highnutrients,sunlight high primary productivitysunlight,highprimaryproductivity

OPENSEA:deeperpartofocean.

Furtherdividein3parts

Euphoticzone Benthiczone

Ab l Abyssalzone

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OCEANECOSYSTEM

Abiotic Salt, Ca, Mg, K salts water is buffered, dissolved nutrients

Biotic Producers components

Phytoplankton, marine plants

componentsConsumers

Primary Fish, molluscs, crustanceansconsumers

Secondary consumers

Carnivores fishes (herring, shad, Mackerels)

Tertiaryconsumers

Top consumers like fishes (Cod, Haddock)

Decomposers Fungi dead organic compoundDecomposers Fungi, dead organic compound

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TUTORIAL 2

1. Write definition : (1) Ecology, (2) Ecosystem,(3) Producers or Autotrophs,(4) Consumers or Hetrotrophs, (5) Herbivores, (6) Decomposers orReducers, (7) Ecological balance, (8) Ecological pyramid, (9)Biogeochemical cycles, (10) food chain, (11) food web, (12) biologicalmagnification, (13) bioaccumulation, (14) trophic level.

2. What are the classification of ecology?

3. What are the types of ecosystem and explain structure of ecosystem?

4. Explain energy flow in an ecosystem.p gy y

5. Write a short note on Ecological pyramid

6. Write a short note on (1) hydrological cycle (2) Carbon cycle (3) O2 cycle(4) N2 cycle (5) Phosphorus cycle (6) sulfur cycle(4) N2 cycle (5) Phosphorus cycle (6) sulfur cycle

7. Explain food chain and food web

8. Write a short note on (1) Forest Ecosystem (2)Pond Ecosystem (3)MarineEcosystemEcosystem

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ENDEND

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