Abiotic factors

This PPT is useful for 12th biology as well as Life Science students

1. Dr. Archana Bajirao Mantale
Assistant professor
Department of Zoology
Shri Muktanand College,
Gangapur

2. Abiotic Environmental Factors
Each&everylivingorganismhasitsspecificsurrounding,medium
ofenvironmenttowhichitcontinuouslyinteracts&remainsfully
adapted.
Theenvironmentisthesumtotalofphysicalandbioticconditions
influencingtheresponsesoftheorganisms.
Theenvironmentismadeupoftwofactors/components:
a)Bioticcomponents:includesalllivingorganismsinteractingwith
theirabioticenvironment.
b)Abioticcomponents:includesatmosphere,hydrosphereand
lithosphere.

3. 1. Temperature
Temperatureisoneoftheessentialand
changeableenvironmentalfactor.
Itpenetratesintoeveryregionofbiosphereand
influencesallformsoflifebyincreasingor
decreasingsome important activitiesof
organisms.
Itislimitingfactorforthegrowthordistribution
ofanimalsandplants.
Normallifeactivitiesgoonsmoothlyataspecific
temperaturecalledoptimumtemperature.

4. 1.1. Temperature fluctuation in
different environment
Environmentaltemperaturefluctuatebothdaily&
seasonally.
Differentenvironmentshavevariableresponsesto
fluctuatingtemperature.Freshwater,marinewater,
terrestrialenvironmentetc
Temperaturefluctuationarecomparativelylessinthe
aquaticenvironment thanintheterrestrial
environment.
Thereisdifferenceintheresponseoflivingorganisms
offreshwaterandmarinewatertotemperature
fluctuations.

5. 1.2. Thermal stratification of
freshwater media
Epilimnion–upperlayeroffreshwater.
Constantlystirredbywind.Temperaturemay
riseupto22
0
Cinsummer.
Metalimnion–middleintermediatezone.
Temperaturemayrangebetween10
0
C-20
0
C.
Ithasrapidchangeinverticaltemperature.
Hypolimnion–bottomzone.Stagnantwater.
Ithastemperature5
0
C-9
0
C

6. 1.2.Terrestrial Environment
Intheterrestrialenvironment,theseasonal&daily
fluctuationintemperaturearevariableand
marked.
Thelowesttemperaturerecordedforanylandmass
is-70
0
C.
Highertemperaturegoesupto85
0
Cincertain
desertsatafternoon.
InThardesertofRajasthan,India,temperature
exceeds50
0
Candlowestupto15
0
C.
Differenceinlatitudesoftencausevariationinthe
annualtemperaturecycleswithvisibleeffectson
theorganism.

7. 1.3. Range of Temperature Tolerance
Normallifepersistswithinnarrowtemperature
limitsofabout-10
0
Cto50
0
C.
Manynematodes,rotifersandtardigradeshave
showntowithstandcoolingto-272
0
C.
LarvaeofchironomidsandDipteraliveat55
0
C.
Prayingmantisisreportedtoliveinbared
groundsat62
0
Cindeserts.
Somealgaeandbacteriaarereportedtolivein
hotspringsat88
0
C.
Nonphotosyntheticbacteriacanactivelygrowat
90
0
C.

8. 1.3. Range of Temperature Tolerance
Euthermalorganism–Theorganismswhich
cantolerateverylargefluctuationsin
temperaturearecalledEuthermalorganisms.
Ex-microbes,plantsandanimalslikecyclops,
toads,walllizard,grasssnake,manetcarethe
Euthermalorganisms.
Stenothermal organisms–Theorganisms
whichcantolerateonlyasmallvariationin
temperaturearecalledstenothermalorganisms.
Ex-fishes,snails,coralreefsetc.are
stenothermalorganisms.

9. 1.4. Effect of Temperature on Animals
1)Temperature &Cell–theminimum or
maximum temperatureshavelethaleffectson
thecellsandtheircomponents.
2)Temperature &Metabolism –increasein
temperatureuptocertainlimitbringsabout
increasedenzymaticactivitywhichresultinan
increaseinrateofmetabolism.
3)Temperature&Reproduction–thematuration
ofgonads,gametogenesis&liberationofgametes
takesplaceataspecifictemperaturewhich
variesfromspeciestospecies.

10. 1.4. Effect of Temperature on Animals
4)Temperature&sexratio–incertainanimals
theenvironmentaltemperaturedeterminesthe
sexratioofthespecies.
5)Temperature&Ontogeneticdevelopment–
completedevelopmentofeggsandlarvaeismore
rapidinwarmtemperature.
6)Temperature &Growth–itaffectsonthe
growthoftheorganisms.
7)Temperature&Coloration–thecolorationof
animalsareinfluencedbytemperature.

11. 1.4. Effect of Temperature on Animals
8)Temperature &Morphology –temperature
affectsthesizeofananimalandrelative
propertiesofvariousbodyparts.Birdsand
mammals livingincolderregionsattaina
greaterbodysize.Theextremitiesofmammals
aretail,snout,earandlegsarerelativelyshorter
incolderpartsthaninwarmerparts.
9)Temperature&Cyclomorphosis–thecyclic
changeinmorphologicalstructureoforganisms
inrelationtoseasoniscalledcyclomorphosis.It
isobservedinDaphnia.

12. 1.4. Effect of Temperature on Animals
10)Temperature&animalbehavior-temperature
generallyinfluencesthebehavioralpatternof
animals.
11)Temperature&animaldistribution–temperature
isalimitingfactorinthedistributionofanimals.
12)Temperature&Regeneration–whentemperature
increases,theregenerationpowerincreases.
13)Temperature&Mutation–hightemperaturecauses
mutation.
14)Temperature&Death–whenanimalsexposedto
extremetemperature,theywilldie.

13. 1.5. Thermal Adaptations of Animals
FormationofheatresistantCysts–someofthe
animalsproduceheatresistantcystswhichcan
tolerateextremesoftemperature.
Removalofwaterfromtissue–driedcystsavoid
freezingbecausethereremainsnoliquidinthem
thatcanfreeze.
Dormancy–itincludestwophenomenoni.e.
a)Hibernation:someanimalsrespondby
becomingdormantatlowtemperature.
b)Aestivation:iftemperaturebecomeshigh
someanimalsundergoaestivation.

14. 1.5. Thermal Adaptations of Animals
Dormancy–itincludestwophenomenoni.e.
a)Hibernation:someanimalsrespondbybecoming
dormantatlowtemperature.
b)Aestivation:iftemperaturebecomeshighsome
animalsundergoaestivation.
Duringbothkindofdormanciesmetabolicrate
becomesreduced,bodytemperaturebecomeslow
andheartbeatrateisalsoreduced.
Thermalmigration–itoccurinanimals.The
journeystakenbyanimalsthatenablethemto
escapefromextremelyhotorcoldsituationsare
referredtoasthermalmigrations.

15. 2. Light
Lightisan importantfactorofecosystem
becauseitconstitutesthemainsupplyofenergy.
Itinfluencesvariousactivitiesofplantsand
animals.
Themainsourceoflightissunlight.
Radiantenergyfromthesunisthebasic
requirementfortheexistenceoflifeontheearth.
Althoughwegenerallythinkonlyintermsof
visiblelight,emittedbysun,thesunemitsother
formofenergyofdifferentwave-lengths.

16. Light
Sinceanimalsdependonlightfororientation,
diurnalmigrationandrhythmicactivities,the
lightreceptionismostimportantsensory
modalityintheexplorationoftheenvironment.
Manyhomoeothermicanimalswithnormalvision
donotcommonlyrespondtoultravioletorinfra-
redrays,sincetheirretinasarenotstimulated.
Theyalsodonotproperlydistinguishbetween
thedifferentcolorsofvisiblespectrum.

17. Light
Dogs,cats,hamstersandopossums are
colorblind.Whilehornedcattlecannotidentify
redlight.
Horses,deer,sheep,pigsandsquirrelscannot
distinguishclosetoredandgreen.
Primatescandistinguishcolors.Someinsects
likehoneybeecanseeultravioletradiation.

18. 2.1. Light variation in different Environment
Lightenergyvarieswithdifferentmedia.The
transparencyofairandwaterisimportantin
regulatingtheamountandquantityoflightthat
maybeavailableinparticularhabitats.
Example–theintensityoflightreachingthe
earth’ssurfacevarieswiththeangleofincidence,
degreeoflatitudeandaltitude,season,timeofday,
amountabsorbedanddispersedbyatmosphere
andanumberofclimaticandtopographicalfactors
suchasfog,clouds,suspendedwaterdrops,dust
particlesetc.

19. 2.1. Light variation in different
Environment
Whentheangleofincidenceissmallerlight
rayshavetotravelbyalongerdistancethrough
theatmosphere.
Likewise,sun’saltitudechangesdueto
differencesinlatitude,changesintheseason
andinthetimeofday.
Whensunremainsoverheadtheintensityof
sunlightovertheearth’ssurfacewillbe
greatest.
Athigherlatitudestheintensityoflight
becomesreduced.

20. 2.1. Light variation in different
Environment
Theintensityofdaylightisgreatlydiminished
bymoisture,cloudsanddustinthe
atmosphereandalsobyforestvegetation.
Thedirectionandslopeofthemountainalso
effectlightintensity.
Mostorganisms respond tomoonlight
particularlyonafullmoon.

21. 2.1. Light variation in different
Environment
Thelight,whichentersintheaquaticmedia,
comesfromsunbypassingthroughthe
atmosphereexistingabovethewatersurface.
About10%ofthesunlightwhichfallsoverthe
watersurface,isreflectedbackandresult90%of
thatpassdownwordsinthewaterandis
modifiedinrespecttointensity,spectral
compositionandtimedistribution.
Thephytoplankton,zooplankton,suspended
organicandinorganicparticleseitherreflector
absorbthelightrays.

22. 2.1. Light variation in different
Environment
Further,inwaterthereisaselectiveabsorptionof
lightatvariousdepths.
Thelongerlightraysareabsorbednearthesurface
andingeneraltheshortestlightrayspenetrates
deepest.
Thus,longinfra-redraysareabsorbedintheupper
layersofwater,redandorangeraysarecompletely
absorbeduptothedepthof20meters.
Yellowrayspenetratesupto80-100metersandno
anylightraypenetratesbeyond200meterofdepth.

23. 2.1. Light variation in different
Environment
Each plant perform optimum
photosynthesisincomplementarycolors.
Example-greenpigment-redrays,
brownpigment–greenrays,
Redpigment–bluerays
Inocean,algaearedistributedaccording
tolengthoflightraysthattheircolorsare
bestsuitedtoabsorbandtoutilize.

24. 2.1. Light variation in
different Environment
Photosynthesisindeeperwatersoccurswith
blueandgreenrays,whichareabsorbedby
thebrownandredpigmentsofredalgae.
Theredandbluegreenalgaeusepigmentsof
photo-cyanine and photoerythrin for
photosynthesis.

25. 2.2. Effect of Light on Animals
Effectoflightonprotoplasm:sometimes,
thesunrayspenetratesthebodycoveringand
causeexcitation,activation,ionizationand
heatingofprotoplasmofdifferentbodycells.
Ultravioletrayscausemutationalchangesin
theDNAofvariousorganism.
LightandMetabolism:themetabolicrateof
differentanimalsisgreatlyinfluencedbylight.
Theincreasedintensityoflightresultsinan
increaseinenzymeactivity.

26. 2.2. Effect of Light on Animals
Effectoflightonpigmentation:thesynthesis
ofskinpigmentsisdependentonthesunlight.
Theorganismslikeinsects,birdsandmammals
livinginwarmerregionaredarkincolordueto
formationofmorepigmentsandanimalslivein
coolanddryplacesarepaleorlightincolor.
Effectondevelopment:insomeorganisms,
lightacceleratesdevelopment.e.g.Salmon
larvae.Inotherorganisms,lightretardsthe
development.e.g.Mytiluslarvae.

27. 2.2. Effect of Light on Animals
Effectonanimalmovement:theinfluenceof
lightonthemovementofanimalsisevidentin
loweranimals.
Orientedlocomotarymovementoftowardsand
awayfromasourceoflightiscalledphototaxis.
Animalslikeeuglena,ranatraetc.movetowards
thesourceoflight,suchanimalsarepositively
phototacticanimals.
Whilesomeanimalslikeplanaria,earthworm,
slugs,copepodsetc.moveawayfromthesource
oflight.

28. 2.2. Effect of Light on Animals
Thelightdirectedgrowthmechanism are
calledphototropism,whichoccurinsessile
animals.E.g.movement offlagellumof
euglenatowardslightandmovements of
polypsofmanycoelenterates.
Someanimalslikearthropods,birdsandfish
usethesun,moonorstarsasacompass.

29. 2.2. Effect of Light on Animals
PhotoperiodismandBiologicalclocks:the
response ofdifferentorganisms to
environmentalrhythmsoflightanddarkness
iscalledPhotoperiodism.
EffectofReproduction:insomeorganisms
lightisnecessaryfortheactivationofgonads
andininitiatingannualbreedingactivities.In
birds,gonadsbecomeactivewithincreased
intensityduringsummerandviceversa.

30. 2.2. Effect of Light on Animals
Effectonvision:eyesareusefulonlywhenlight
ispresent.
Inabsenceoflight,reducedeyesaredeveloped.
e.g.inamphibianproteusanurinuslivingindark
caves,eyesareabsent.
Animalswhicharelivingindarkseawater,have
largereyes.
Sizeofeyesincreaseswithincreasingdepth.
Somefishesareprovidedwithtelescopiceyes.
Innocturnalanimalseyesarelargeand
powerful.E.g.owl,bat,Lorisetc.

31. 2.2. Effect of Light on Animals
Protectivecoloration:someanimalsdevelop
differentcolorpatternstoescapefromtheir
predators.Thecolorofbodymatcheswiththe
colorofanyobjectintheenvironment.such
formofcolorisinfluencedbythenatureof
lightreceivedfromthebackground.
EffectiveonMutation:ultravioletlight
inducesgenemutation,whichcauses
abnormality.

32. 4. Salinity
Purewatercontainsonlyoxygenandhydrogen,
butinthenaturalworldsolidsubstancesare
oftendissolvedinwater.Whentheydissolve,
thesolidsdissociateorbreakupintoelectrically
chargedions.Thepresenceofdissolvedsolids
orionsinaliquidiscalledsalinity.
Salinityisdefinedasthetotalamountofsolid
materialdissolvedinonekilogramofwater.

33. Salinity
Alltypesofnaturalwatercontainvarious
amountsofdifferentsalts,suchasNa,K,Mg,
Cl,SO4,PO4,HNO3,NO3etc.andallthese
saltsareresponsibleforsalinityofwater.
Oneofthemostfamiliarandabundant
dissolvedsolidsinoceanwaterisNaCl,but
otherdissolvedsubstancesarealsofoundin
smallerconcentrations.
Thesalinityofmarinewaterisabout3.5%.

34. Salinity
Thesalinityoffreshwatervariesgreatly.
Salinityoffreshwaterisverylow.
Thebodyfluidoffreshwateranimalsishighly
concentratedanditishypertonicandmedium
ishypotonic.
Asaresult,endosmosisoccurs.Theyhave
capacityofosmoregulation.

35. Salinity
Theanimalswhichcantoleratenarrowrangeof
saltconcentrationarecalledstenohaline.
e.g.Spider,crab,snailsetc.
Theanimalswhichtoleratewiderangeofsalt
concentrationarecalledeuryhaline.
e.g.Mytilus,aplysiaetc
Someanimalspossessbothstenohalineand
euryhalinepower.
E.g.Anguilla

36. Salinity
Seawaterishypertonicashighsaltcontentand
bodyfluidishypotonic.Asaresultexosmosis
occurs.Bodylosewaterandmarineanimalsare
exposedtodehydration.Tocompensateforthe
lossofwater,marineanimalsdrinkwater.
Estuarineanimalsareeuryhaline.Mostofthese
animalsareosmoregulators.Theymaintaina
constantconcentrationoftheirbodyfluidwith
respecttochangeinexternalmedium.
eg.Platyhelminth,carcinuscrabetc.

37. 4. Moisture
Amountofwatervaporpresentintheairis
calledmoistureorhumidity.
Humidityaffectsthelifeofplantsandanimals
indirectly.Bothexcessiveandlessmoisture
affectorganisms.

38. Variousactivitiesofanimalsareaffectedby
humidity.
Someanimalslivemorecomfortablywhenairis
saturatedwithmoisture.
Desertanimalslivemorecomfortablyinlow
humidity.
Relativehumidityalsoaffectsthereproduction,
developmentandgrowthofmanyanimals.
4.1. Effect of Moisture on animals

39. Colorationofinsectsareinfluencedby
humidity.
Excessivemoistureandcloudyweatherkill
insectsnymphs.
Prolongedwetspellscausedeathamongbirds
andmammals.
Inlocustandeggsofhousefly,speedof
development increaseswithincreasein
humidity.
4.1. Effect of Moisture on animals