Ecology and Ecosystem

Ecology derived from two Greek word “oikos” means house, habitation or place of living & “logos” means study.
Definition: Ecology is the study of interrelationship between living organism and their physical and biological environment.

1. ECOLOGY
AND
ECOSYSTEM
Chapter 2
By : Yash Patel

2. Ecology
EcologyderivedfromtwoGreekword“oikos”
meanshouse,habitationorplaceofliving&
“logos”meansstudy.
•Definition:Ecologyisthestudyof
interrelationshipbetweenlivingorganismand
theirphysicalandbiologicalenvironment.
•Biologicalenvironment=Bioticfactors
•Physicalenvironment=Abioticfactors

3. Biotic Factors

4. Abiotic Factors

5. Objectives of ecological study
Theinter-relationshipbetweenorganismsin
populationanddiversecommunities
Thetemporal(sequential)changes(seasonal,
annual,successionaletc)
Structuraladaptationandfunctional
adjustments
Thebehaviorundernaturalconditions
Thedevelopmentinthecourseofevolution
Thebiologicalproductivityandenergyflowin
naturalsystem

6. Scope of ecology
Helpsustotackleproblemslikepollution,
floods,O
3depletion,globalwarming
Isnecessaryinmaintainingecologicalbalance
andunderstandingdifferentcycles(oxygen,
nitrogen,sulfur,carbonetc.)
Helpsinprotectingfloraandfauna
Wecanmaintainbalanceinnatureandcan
preventecologicaldisasters
Playsanimportantroleinhumanwelfare,
agriculture,conservationofwildlife.

7. Classification of ecology
1)Autecology
2)Synecology
Autecology:Itdealswiththestudyofindividual
organismoranindividualspecies.Inotherwordsitis
studyofinterrelationshipbetweenindividualspecies
oritspopulationandenvironment.e.g.atreeinforest
Synecology:itdealswiththestudyofgroupof
organismorspecieswhichareassociatedtogetherasa
unit.e.g.aforest.Itisconcernedwithstructure,
nature,developmentofthatcommunity

8. Further subdivisions of ecology is based on
following:
1)Based on the taxonomic affinities :
According to this ecology is divided in two part:
Plant ecology and animal ecology

9. 2) Based on the habitats
Ecology
Aquatic
Ecology
Terrestrial
Ecology
Marine Ecology
Fresh water
Ecology
Stream Ecology
Grass Land
Ecology
Forest Ecology
Desert Ecology

10. 3)Based On the level of organization:
Depending upon the level of organism
synecologycan be divided into may types :
Desert Ecology
Autecology Synecology
Population Ecology
Community Ecology
Ecosystem Ecology

11. The Ecosystem
Definitionsofecosystem:
1.Allorganisms,theirinteractionswithoneanother
andtheirenvironmentsmakeupanecosystem.
2.Itisacommunityofinterdependentorganisms
togetherwiththeenvironment.
3.Anyunitthatincludealloftheorganismsinagiven
areainteractingwiththephysicalenvironment,sothat
aflowofenergyleadstoclearlydefinedtrophic
structure,bioticdiversityandmaterialcycleswithin
theecosystem.

12. Ecosystem-populationsina
communityandtheabioticfactors
withwhichtheyinteract(ex.
marine,terrestrial)

13. Ecology
•Definition:EcologyderivedfromtwoGreek
word“oikos”meanshouse,habitationorplace
ofliving&“logos”meansstudy.
•Ecologyisthestudyoftheinterrelationship
betweenlivingorganismandtheirphysicaland
biologicalenvironment.

14. Types of ecosystem
Ecosystem can be Naturalor Artificial
a) Natural ecosystems:
Theseoperateunderthenaturalconditionswithout
anymajorinterferencebyman.Furtheritcanbe
classified:
1)TerrestrialEcosystem
2)AquaticEcosystem

15. b) Artificial Ecosystem
Thesearemaintainedartificiallybyman
wherebyadditionofenergyandplanned
manipulation,naturalbalanceisdisturbed
regularly.
E.g.Croplandecosystem

16. 1)TerrestrialEcosystem:Eg:Forest,Grassland,Desert
2)AquaticEcosystem:
a)Freshwater:-whichmaybelotic(e.g.running
waterasstream,rivers)orlentic(e.g.standing
wateraslake,pool)
b)Marineecology:-Deepbodiesasaocean

18. Characteristics of Ecosystem
Itisamajorstructuralandfunctionalunitof
Ecology.
Itsstructureisrelatedtoitsspeciesdiversity;
themorecomplexecosystemhavespecies
diversityandviceversa.
Therelativeamountofenergyneededto
maintainanecosystemdependonitsstructure.
Themorecomplexthestructure,thelesserthe
energyitneedstomaintainitself.
Itmaturesbypassingfromlesscomplexto
morecomplexstates

19. Structural features
1.Biotic structure
Theplants,animalsandmicroorganismpresent
inanecosystemformthebioticcomponent.
a)Producers:Theyaremainlythegreenplants,
whichcansynthesizetheirfoodthemselvesby
makinguseofcarbondioxidepresentintheair
andwaterthroughtheprocessof
photosynthesis.
‘Photoautotrophs’=(Photo=light,auto=self;
troph=food).

20. Structural features
b)Consumers:allorganismswhichgettheirorganic
foodbyfeedinguponotherorganismarecalled
consumers,whicharefollowingtypes:
i.Herbivores(planteaters):e.g.Rabbit,insect,
goat,cattle.
ii.Carnivores(meateaters):e.g.Snake,cat,foxetc.
iii.Omnivores:e.g.humans,rat,foxetc.
iv.Detritivores:(Detritusfeedersorsaprotrophs)
v.Predetor:(Killsotherorganizationforfood)
e.g.wolf,beer.

21. Structural features
c)Decomposers:Theyderivetheirnutritionby
breakingdownthecomplexorganicmolecules
tosimplerorganiccompoundandultimately
intoinorganicnutrients.
e.g.bacteria,fungietc.

24. primary consumers
•Also known as HERBIVORES , such as: mice,
deer, cows, and elephants
•Herbivores eat ONLY PLANTS

25. Secondary Consumers
•Are CARNIVORES –they eat only animals
•If the animal must be killed before it is eaten, the
secondary consumer is known as a predator.
•However, sometimes the animals does not have to
be killed to be eaten.

26. Secondary Consumers
O m n i v o r e s
they eat Both :
Plants and
Animals

27. Scavengers
Feedsonthebodiesof dead organisms.

29. Decomposers
Breakdownwastesanddeadorganisms,andso
completethecyclebyreturningnutrientstothe
ecosystem.(tothesoilorwaterandcarbondioxideto
theairandwater)

30. Transfer of
Energy in an
Ecosystem

31. Transfer of Energy in an Ecosystem
CONSUMER
Herbivores–eat
plants
Carnivores–
eat animals
Scavengers –
feed only on
dead organisms
Omnivores–
eat both
plants &
animals

32. Energy flow
•This pattern of energy flow among different
organisms is the TROPHIC STRUCTUREof an
ecosystem.
heat
Producers Consumers
Decomposers
heat

33. Energy Flow in Ecosystem
Tomaintainlifeenergyisrequired.Energyentersinanecosystem
fromsolarradiations.
Inearth’satmosphereabout15x10
8
cal/m
2
/yearofsolarenergyis
present.
Outofwhichonly47%oftheenergyreachestheearthsurfaceand
only1-5%ofenergyreachingthegroundisconvertedinto
chemicalenergybygreenplants.
Theplantsmakeuseofrawmaterialfromtheenvironmentinthe
formofwater,saltsandcarbondioxidetopreparefoodwiththe
helpofsunlight.
Thusenergyformthesunentersthelivingworldthrough
photosyntheticorganismsandpassesonfromoneorganismto
anotherinformoffood.

34. Theflowofenergyisunidirectionalandnon
cyclic.
Energyenterstheecosystemformsolarradiation
andconvertedintochemicalenergybyproducers,
fromthemenergypassestolowertropiclevelto
higherone.
Thisonewayflowofenergyisgovernedbylaws
ofthermodynamicswhichstatethat:
a)Theenergycannotbecreatednotdestroyedbutmaybe
transferredfromonefromtoanother
b)Duringtheenergytransferthereisdegradationofenergy
fromconcentratedformtoadispersedform(Heat)

35. Noenergytransformationis100%efficient;itis
alwaysaccompaniedbysomedispersionor
lossofenergyintheformofheat.
Heatenergyisnotutilizedbybiologicalsystem
andultimatelylostfromthebody

37. Models for energy flow in ecosystem
•The flow of energy through various trophic
levels in an ecosystem can be explained by:
1)Single channel energy flow model
2)Y shaped or double channel energy flow
model
3)Universal energy flow model

38. Ecological Pyramid
This shows how energy is
transferred and changed
when going up the pyramid.

39. Three Types of Ecological Pyramid
A.Pyramid of Energy –shows the amount
of energy in calories (Kcal / cal)
B. Pyramid of Biomass –shows the
biomass of all organismsand individuals
C. Pyramid of Numbers –shows the
number of individuals feeding at each
tropic level

40. Pyramid of Energy

41. Pyramid of Biomass

42. Pyramid of Numbers

43. Food Chain
Organisms in one level feed
upon organisms at the lower
level.

44. Trophic Levels
•Eachlinkinafoodchainisknownasa
trophiclevel.
•Trophiclevelsrepresentafeedingstepin
thetransferofenergyandmatterinan
ecosystem.

45. Trophic Levels
Producers-Autotrophs
Primary consumers-Herbivores
Secondary consumers-
small carnivores
Tertiary consumers-
top carnivores
E
N
E
R
G
Y

47. Types of Food chain

49. Significance of Food Chain
•Biological magnification (Biomagnification)
*Harmfulchemicalslikeinsecticidesandpesticides
whichareusedtoprotectcropsfrominsectsand
pestsareabsorbedbyplantsandenterthefood
chain.
*Sincethesechemicalsarenonbiodegradable,they
getaccumulatedateverytrophiclevelandtheir
concentrationincreases.
*Theincreaseinconcentrationofharmfulchemicals
inthebodiesoforganismsathighertrophiclevelsis
calledbiologicalmagnification.

50. Biological magnification (Biomagnification)
Biomagnification of DDT Biomagnification of Mercury

51. Biological magnification (Biomagnification)
•Thebiomagnificationofpollutantscanbe
estimatedwiththehelpofBiological
ConcentrationFactor(BCF).
Concentrationoftoxicmaterialinorganism
ConcentrationoftoxicmaterialinEnvironment
BCF =

52. Food Web
It is a network of interacting
food chains.

53. Food Web
•Foodweb-showsallpossiblefeeding
relationshipsinacommunityateach
trophiclevel
•Representsa network of
interconnectedfoodchains

54. Food web:-
Food web is a group of several interconnected food
chains. In a food web an organism gets food from more
than one group of organisms.
Examples of Terrestrial food web

55. Examples of Aquatic
food web

56. Biogeochemical Cycle
Theproducersofanecosystemtakeupseveral
basicinorganicnutrientsfromtheirnonliving
environment.
Thesenutrientsgettransformedintobiomassof
theproducers.
Thentheyareutilizedbytheconsumerpopulation
andultimatelyreturnedtotheenvironmentwith
thehelpofreducersanddecomposers.
Thecyclicexchangeofnutrientsmaterials
betweenlivingorganismsandtheirnonliving
environmentiscalledbiogeochemicalcycle.

57. 1)Biogeochemicalcycleshelpsastounderstand
theflowofpatternvariousnutrients,water,gases
etc.neededfordevelopmentoflife
2)Hydrologicalcycledealswiththeinterchange
waterbetweenlivingorganisms&environment.
3)Gaseouscycledealswiththeinterchangeof
gaseslikeOxygen,Nitrogen,CarbonDioxide.
4)Thesedimentarycyclesdealswiththe
interchangeofmineralslikesulphur,phosphorus.

58. Water cycle

59. Water never leaves the Earth. It is constantly being cycled
through the atmosphere, ocean, and land.
This process, known as the water cycle, is driven by
energy from the sun.
The water cycle is crucial to the existence of life on our
planet.

60. Evaporation
Evaporation:Process by which the sun heats up
liquid water and changes it to a gaseous form
(vapours).

61. Condensation
Condensation:Process by which water rises
into the atmosphere, cools and becomes a liquid
again.

62. Precipitation
Precipitation:Process by which water condenses and
falls back to the earth.

63. Transpiration
Transpiration: The process of evaporation from plants.
Factors affecting transpiration: Sun light intensity,
relative humidity, soil moisture availability, wind
movement, types of plants.

64. Runoff
Runoff:Water that collects in rivers, streams,
and oceans

65. Oxygen cycle
All Animals and Other Consumers Use Oxygen.
•Weuseoxygentobreakdownsimplesugarand
releaseenergy.
•Thiscanbedonethroughrespirationor
fermentation.
•Animalsmainlyuserespiration.

67. Respiration
Simple Sugar —Glucose
•The process that breaks apart simple food molecules
to release energy.
•It occurs inside cells.
The molecule most living things use for
energy —including us!
•We break down food into smaller molecules during
digestion. One of the small molecules is glucose.
•Glucose leaves your intestines, goes into your blood
and is taken to every cell in your body.

68. Photosynthesis
Plants take in carbon dioxide and water and
use them to make food. Their food is simple
sugar —glucose.
Plants pull the carbon off CO
2and use the
carbon in glucose. (They do not need the oxygen for this. They get
that from water, H
2O.)
Plants release the oxygen (O
2) back into the
atmosphere.
Other organisms use the free oxygen for
respiration.

69. How are photosynthesis and cellular
respiration similar?
•Photosynthesis uses carbon dioxide and
produces oxygen.
•Cellular respiration uses oxygen and produces
carbon dioxide.

70. Respiration
Photosynthesis

71. Everywhere
•This happens on land and in the water.
•Algae and aquatic plants produce food underwater
through photosynthesis.
•They use CO
2dissolved in the water.
•Other aquatic organisms use the dissolved oxygen
these plants release into the water.

72. Human Impact
•We keep destroying natural areas, especially
forested areas with many plants and replacing
them with buildings, parking lots, lawns, etc.
•Fewer plants mean less oxygen and more
carbon dioxide.
•This disturbs the balance of the natural cycle.

74. What Is Carbon?
•An element
•The basis of life of earth
•Found in rocks, oceans, atmosphere

75. Plants Use Carbon Dioxide
•Plants pull carbon dioxide from the atmosphere
and use it to make food –—photosynthesis.
•The carbon becomes part of the plant (stored
food).

76. Animals Eat Plants
•When organisms eat plants, they take in the
carbon and some of it becomes part of their
own bodies.
•C is also released back as CO
2after respiration
and combustion

77. Plants and Animal Die
•When plants and animals die, most of their
bodies are decomposed and carbon atoms are
returned to the atmosphere.
•Some are not decomposed fully and end up in
deposits underground (oil, coal, etc.).

78. Carbon Slowly Returns to Atmosphere
•Carbon in rocks and underground deposits is
released very slowly into the atmosphere.
•This process takes many years.

80. Carbon cycle

81. Carbon in Oceans
•Additional carbon is stored in the ocean.
•Animals die and carbon substances are
deposited at the bottom of the ocean.
•Oceans contain earth’s largest store of
carbon.

83. Human Impact
•Fossil fuels release carbon stores very slowly
•Burning anything releases more carbon into
atmosphere —especially fossil fuels
•Increased carbon dioxide in atmosphere
increases global warming
•Fewer plants mean less CO
2removed from
atmosphere

84. What We Need to Do
•Burn less, especially fossil fuels
•Promote plant life, especially trees

85. Nitrogen Cycle

86. Forms of Nitrogen
•Urea CO(NH2)2
•Ammonia NH3(gaseous)
•Ammonium NH4
•Nitrate NO3
•Nitrite NO2
•Atmospheric nitrogen N2
•Organic N (Amino acids--RCONH
2)

87. Roles of Nitrogen
•Plants and bacteria use nitrogen in the
form of NH
4
+
or NO
3
-
•It serves as an electron acceptor in
anaerobic environment
•Nitrogen is often the most limiting nutrient
in soil and water.

88. (1) Nitrogen Fixation
(3) Nitrification (2) Ammonification
(4) Denitrification
Nitrogen
Cycle
The Nitrogen Cycle

89. Atmospheric nitrogen (about 78% of our air)is converted
to ammoniaor nitrates.
Ammonia (NH
3)
Nitrogen combines
with Hydrogen to make
Ammonia
Nitrates (NO
3)
Nitrogen combines
with Oxygen to make
Nitrates
Atmospheric
Nitrogen (N
2)
N
N
N
N

90. It is one of nature’s
great ironies…
•Nitrogenis an essential
component of DNA, RNA,
and proteins
•the majority of the air we
breathe is nitrogenyet most
living organisms are unable to
usenitrogenas it exists in the
atmosphere.

91. “Nitrogen Fixation”is the process that causes the strong
two-atom nitrogen molecules found in the atmosphere to
break apart so they can combine with other atoms.
Nitrogen gets “fixed”when it is combined with oxygen or hydrogen.
N
N
N
N
N
Oxygen Hydrogen
Oxygen
Hydrogen
N

92. Free Living Bacteria (example of nitrogen fixation)
Highly specialized bacteria live in the soil and have the ability
to combine atmospheric nitrogenwith hydrogento make
ammonia (NH
3).
Free-living bacteria live
in soil and combine
atmospheric nitrogen
with hydrogen
Nitrogen changes
into ammonia
N
N
H
NH
3
(NH
3)
Bacteria

93. Symbiotic Relationship
Bacteria
Bacteria live in the roots
of legume family plants
and provide the plants
with ammonia (NH
3)in
exchange for the plant’s
carbon and a protected
home.
Legume plants
Roots with nodules
where bacteria live
Nitrogen changes into
ammonia.
NH
3
N
N

94. Ammonification: Bacteria (decomposers) break down amino
acids from dead animals and wastes intoammonium.
Bacteria decomposers break down amino acids into ammonium

95. Microorganisms convert the organic nitrogen to
ammonium. The ammonium is either taken up by the
plants (only in a few types of plants) or is absorbed into
the soil particles. Ammonium (NH
4)in the soil is stored
up to later be changed into inorganic nitrogen, the kind of
nitrogen that most plants can use.
Ammonium (NH
4) is
stored in soil.
Bacteria converts organic nitrogen to
ammonium (NH
4)
Ammonium (NH
4) is used by
some plants
Bacteria

96. Nitrification: Nitrifying bacteria in the ground combine
ammoniawith oxygento form nitrites. Then another
group of nitrifying bacteria convert nitritesto nitrates
which green plants can absorb and use.
Nitrifying bacteria in soil
combine ammonia with oxygen
Ammonia changes to nitrites
Nitrifying bacteria in soil
convert nitrites to nitrates
Plants absorb nitrates
and grow!
Ammonia NitritesNitrates
(NH
3) (NO
3)(NO
2)

97. Denitrification:The conversion of nitrates (NO
3)in the soil
to atmospheric nitrogen (N
2) thereby replenishing the
atmosphere.
Nitrates (NO
3)
in Soil
Nitrogen in atmosphere (N
2)

98. Denitrifying bacteria live deep in soil and in aquatic sediments
where conditions make it difficult for them to get oxygen. The
denitrifying bacteria use nitratesas an alternative to oxygen,
leaving free nitrogen gasas a byproduct. They close the nitrogen
cycle!
Denitrifying bacteria live
deep in soil and use
nitrates as an alternative
to oxygen making a
byproduct of nitrogen gas.
Nitrogen in atmosphere
closes the nitrogen cycle!
(NO
3)
(N
2)

100. Nitrogen cycle

101. Sulphur Cycle
Sources
•Available in free state
•Also as sulfides, sulfates like PbS, ZnS, BaSO4
•In gas--H2S, SO2

102. Acidic fog and
precipitation
Ammonium
sulfate
Ammonia
Sulfuric acid
Water
Sulfur trioxide
Oxygen
Hydrogen sulfide
Sulfur dioxide
Volcano
Industries
Dimethyl sulfide
Ocean
Metallic
sulfide
deposits
Decaying matter
Animals
Plants
Hydrogen sulfide
Sulfur
Sulfate salts

104. Dimethyl sulfide
•(CH
3)
2S
•Emissions from Phytoplankton
•Occurs over oceans
Sulfur dioxide
•SO
2
•Emission: Industries
•example : power plants
•Volcanoes

105. Sulfuric acid
Sulfur Trioxide
•SO
3
•Primary agent in acid rain
•Principal uses include: ore processing
•fertilizer processing
•Oil refining

106. Hydrogen Sulfide
•H
2S
•Emitted by volcanoes and hot springs
•Remains in atmosphere for 18 hours
•Changes into sulfur dioxide

107. Biomes
•Determined primarily by
precipitation
–Forests(> 75 cm rain per year)
–Grasslands(30-75 cm rain per year)
–Deserts(< 30 cm rain per year)

108. Tropical Forest: Vertical stratification with trees in
canopy blocking light to bottom strata. Many trees
covered by epiphytes (plants that grow on other plants).

110. Example of Tropical, Dry Forest

111. http://earthobservatory.nasa.gov/Laboratory/Biome/Images/picgrassland.jpg
Grasslands

112. Temperate Deciduous Forest: Mid-latitudes with moderate amounts of
moisture, distinct vertical strata: trees, shrubs, herbaceous sub-
stratum. Loss of leaves in cold, many animals hibernate or migrate
then. Original forests lost from North America by logging and clearing.

113. http://www.ccet.ua.edu/hhmi/images/Autumn.JPG
Deciduous forest

114. Coniferous forest: Largest terrestialbiome on earth, old growth
forests rapidly disappearing, usually receives lots of moisture as rain
or snow.

115. http://www3.newberry.org/k12maps/module_07/images/coniferous.jpg
Coniferous forest

116. Desert: Sparse rainfall (< 30 cm per year), plants and
animals adapted for water storage and conservation. Can
be either very hot, or very cold (e.g. Antarctica)

117. http://pangea.stanford.edu/~hsiao/desert.jpg
Desert

118. Temperate Grassland: Marked by seasonal drought and fires, and
grazing by large animals. Rich habitat for agriculture.

119. Estuary: Place where freshwater stream or river merges
with the ocean. Highly productive biome; important for
fisheries. Often heavily polluted from river input so many
fisheries are now lost.

120. Thank You