The system resulting from the interaction of all the
living and non-living organisms is called “eco system”.
The study of the eco systems is called – ecology it derived from Greek
words oaks + logos
Oaks
home
logos
study
Various scientists proposed various definitions to describe the eco
system
The term ecosystem was first proposed by “A G Tansies ACC to him
“An ecosystem is a self- regulating group of biotic communities of species
interacting with one another and with their non-living environment
exchanging energy and matter”
Michael Allay defined as “eco system is a community of independent
Organisms to ether with the environment”.
Structure of the Ecosystem:An ecosystem has two major components
The living organisms including micro organisms (like bacteria
&fungi) plants &animals that are present in an eco system forms the biotic
components.
Based on the system the biotic components can be classified into 3
types.
1. Producers/auto trophy
2.consumers
3.decomposers
:-
All plants in the eco system are called producers self
food producing organisms are known as autotrophy they depend on the
environment for new materials & utilize sun light for the production of their
own food material hence called as products.
2
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(Auto –self , trophy-nourishing)
:- [Hetero = other, trophy=nourishing]
Those organism which depend on other [producer]for their
Energy requirement are Known as consumers / heterophsto .
Here consumers means animals
Depending on the food habits the consumers are divided into 3 types
Primary consumers/ Herbivores:They are totally dependent on producers (plants)
Here (herb=plant; vorous=eater)
In herbivorous are the consumers that eat plants for energy &
nutrients.
Examples:-Insects ,zoo, plankton (or) animals deer ,cattle elephant.
The organisms that feed on herbivores are called carnivore
sometimes carnivores can also consume other carnivores they may be like
animals lion & tiger. These are also called secondary consumer.
Fox, cat, snake etc
Tertiary consumers\omnivores:Tertiary consumers dependent on both primary and secondary
consumers .
These are the top most consumers.
Omnivores:-
Omnivores (such as humans) eat both plants & animals.
Examples:-lion, tiger.
Group of organisms consisting of small animals like worms
,insects, bacteria & fungi which break down dead organic material into smaller
particles & finally into simple substance that are used by plants as nutrition
Decomposition is a vital function in nature as without this, all the
nutrients would be tied up in dead matter & no new life would be produced.
Decomposes also called “Reduces” because they decomposes
&remain the dead bodies.
Decomposes also called as “saprotrophs” because they feed on dead organic
Types of ecosystem
Artificial/man-made
ecosystem
Natural ecosystem
Eg:-crop
field,aquarium
Terrestrial
ecosystem
Aquatic ecosystem
matter
Terresterial
ecosystem
Forest
Grass
Aquatic
ecosystem
flesh water
marine
ecosystem
esterarine
ecosystem
Ecosystem-structure & function
Phycial organisation of biotic & abiotic components characterises the
structure of an eco system.
The major structure features of an eco system
In species composition of each ecosystem is different.
Pond ecosystem & marine ecosystem have different species in them.
In desert ecosystem have only a few species where in forest
ecosystem a great variety of species.
In an ecosystems organisms are arranged in one (or) many layers
called strata.
v Formation of strata is called stratification
Tropical rainy forest- there are3 strata
Trees shrubs & herbs & these are occupied by different species
The non living things in the ecosystem that are involved in the
material cycle are collectively called as biotic components
The non living things enter into body of living organism, take part in
metabolic activities and then return to the environment
The biotic components of the ecosystems are
rainfall, etc.
solar radiation, temperature, wind, water, current,
light, pressure, humidity etc
acidity, serenity, organic nutrients.
climate factors
physical factors
chemical factors
inorganic
substance
exampels:water,carbon,
nitrogen,sulph
er,phosphor
etc.
organic
substance
examples:protein,carbohydrates,
lipids,humic substance
etc.
The topic structure of an ecosystem is one kind of producerconsumer arrangement where each food level is known as trophic level.
Producers
1
herbivores
2
primary
Consumers
3
2
cornivores
4
3
cornivores
5
The transfer of energy from the source in plants through
a series of organism, by eaten and being constitute food chain(or)The series of
organism fixing energy by eating and eaten is called food chain .
The last stage of many food chains are “ scarengers” which feed on the
dead animals like vultures& crows.
At each properties the energy is last in the form of heat.
When all the trophic levels are linked they form a food chain .
+H2 Raw
2
Material
producers
Primary
consumers
Secondary
consumers
Tertiary
consumers
In nature three types of food chains have been distingushed
.
This food chain begins from green plants at the base and the
primary consumer is herbivores.
Examples:- 1. Grasslandseco system.
Gasses
grasshopper
frog
snake
hawk
2. pond ecosystem:Aquatic plants
aquatic insects
small fishes
large fishes
(photo plankton)
C. marsh ecosystem
Green plants
butterflies
dragon fly
2. detritus food chain:-
frog
snake
The food chain starts from dead organic matter of decaying
animals &plant bodies to the micro-organisms and then to detritus feeding
organisms and to other predators.
Detriters feeding organisms are called detrivores
Detriters are consumers of dead organic matter
In the given example the organic matter is eaten by microbles like bactriea,
Fungi , &agar, which are in turn eaten by a group of small crabs, shrimps etc
These are detritus consumers these are eaten by small fishes which are in turn
eaten by large fishes.
Detritus
detritivores dead &
crabs &
small
decaing organic matter
shrimps
fishes
(vores –microbes)
This is an example in an aquatic medium.
grass
hopper
grass
lizard
hawk/fox
/even
man,if
present
rabbit
mouse
snake
large
fishes
Relation ship between the components of the food chain are very
complex. The net work like interation of organisms is called as the food web.
There are interconnected network of feeding ralationship, that take the form
of food webs.
1. Food chain &food wes play avery significant role in the eco system
because the two most important function of energy flow and nutrirnt
cycling takes place throggh them
2. Food chains also halp in maintaining & regulating the population size of
different animels & thus help maintain the ecological balance.
3. Food chains show a unique property of biological magnification.
Ecological succession is defined as the process in which
communities of plants & animals species in a particular area are
replased over time by a series of different often more complex
communities.
Ecological succession may be defined as an orderly process of
changes in the community structure & function with time through
modification in the physical environmant which ultimatly eluminates in
a stable eco system is known as “climax”.
Odum called this orderly process as ecosystem developmant.
The relationship & ineractions of all these organisms change
from time to time due to.
1. Physical factor like temperature, wind, speed & direction.
2. Chemical factor like concentration of nutrients & pollutants.
3. Biological factors like population of various species & their
behaviour
Theries of seccession.
1. Mono climax theory
2. Poly climax theory
3. Climax pattern theory
:According to this theory. There is only one climax community in agiven
climatic geographical region.
:According to this theory there is ano. Of different climax
communities may be present in a climatic (or) geographical region
:According to climax pattern theory the structure composition &
other characters of the climax communities are determined by the total
environment of the ecosystem & not by a single factor.
The first group of organisms establishing these are
known as pioneers/ primary communiy /primary colonies.
Its states from previously built up community where a
sudden change in climatic factor biotic intervention, fire etc causes the
existing community to dis appear.
After succession vegetation modified its own environment
attracting new community.
condition.
It is the replacement of existing communities by external
It is characterised by early & continued dominance of autotrophic
organism likegreen plants.
It is characeterized by early dominance of hetrotrophs such
as bacteria , actinomycetes fungi& animals.
Eco system have some functional attributes due to which
components parts remain running together.
The tendency of every eco system to persist is ensured by the
various functions performed by the structural components of the eco
system.
1. Productivity & decomposition
2. Energy flow
3.Nutrient cycling
4. Development & stabilization.
1.
The rate of production of organic matter /biomass is
called productivity.
The productivity of an eco system is of two types.
1. Primary productivity
2. Secondary productivity.
The ratio at which solar energy is absorbed by the producers for the
synthesis of organic compounds through photosynthesis is called primary
productivity. It is expressed as gm-2year-1 for dry matter & k cal m-2 y-1 for
organic matter
The primary productivity is of two types.
1. Gross primary productivity(GPP)
2. Net pramay productivity(NPP)
Gpp means the rate of total capture of energy (or) rate of total
production of organic matter per unint area & time.
Npp means the rate at which energy (or) organic
matter stored by the producers after respiration & maintanance per unit
area and time
NPP=GPP-Loss due to resperation and maintenan.
time.
It is the rate of increase in biomass of consumers per unit area &
Decomposition refers to the process by which complex organic
material are broken down into inorganic raw material like co2,H2o &
various nutrients by the decomposers after decomposition in organic
raw material become available for utilisation by the plants.
The nutrients like carbon, nitrogen, oxygen, phosphorous,
sulphur , move along the circle through biotic & abiotic components and
this cycle arecalled as Bio-geochemical cycle.
The various earths water- sources get their supplies from
precipitation while the precipitation in it self is the evaporation from
these sources. Water is lost to the atmosphere as vapour from the earth
which is then precipitate back in the form of rain, snow, hail, dew,
sleet(or) frost etc the precipitation & evaporation continuoues forever
and there by a balance is maintainad between two this process is
known as hydrological cycle.
∑ Carbon is the major chemical constituent of most organic matter
from fossil fuels to the complex molecules that contrcgenetic
reproduction in organism.
∑ The chief reservoirs for co2 are in the oceans & in rock carbon dioxide
dissolves readily in water
∑ Once it may precipitate as a solid rock known as calcium carbonate
(lime stone ) corals & alga encourage this reaction & built up lime stone
reef in this process
∑ On land & in water plant take up co2 & converted into carbon hydrates
through photosynthesis.
∑ This carbon in the plants now has three possible fates.
∑ It can be liberated to the atmosphere by the plants through respiration
∑ It can be eaten by an animal
∑ It can be present in the plant when the plant dies.
∑ In animals the carbon also has the same three possible fates.
∑ Carbon from plants (or) animals that is released to the atmosphere
through respiration
∑ When an animal (or) plant dies two things can be buried intact and
ultimately from coal, oil(or)natural gas
∑ This fossil fuel can be mined & burned & releasing co2 to the
atmosphere otherwise the carbon in lime stone (or) other sediments
can only be released to the atmosphere when they are subduted &
brought to volcanoes
∑ Human have a great impact on the carbon cycle because when we burn
fossil fuels we release excess co2 into atmosphere.
∑ Oxygen is relesed to the atmosphere by autotrophs during
photosynthesis & taken up by both autotrophs & heterotrophs during
respiration.
∑ All the oxygen in the atmosphere is biogenic i.e. it was released from
water through photosynthesis by autotrophs so o2 cycle is linked to
carbon cycle deforestation reduces the o2 level in the atmosphere
∑ Sulphur is mainly found on earth as sulphates in rocks sulphur also
occurs in combination with several metal such as lead & mercury
sulphur appears as the yellow aspects of soil in many region.
∑ Sulphur is released into atmosphere through burning of fuels especially
high sulphur coal & this is a primary constituent of rain
∑ Sulphur dioxide & carbonyl sulfide (COS) occur in small quantities in
the atmosphere, but due to its high reactivity sulphur is deposited as
compound sulfater (so42-) on land and surface.
∑ Sulphur components can also be transferred from the higher altitudes
from tall smoke stacks & contribute to acid rain far from the source.
∑ Only small amount of sulphur are necessary for biological system
∑ Phosphorous is in the form ofphosphate is present in rocks when rocks
with po4 is exposed to water the rock is weathered out and goes into
solution.
∑ Autotrophy take this Phosphorous up & use it in a variety of uses. It is
an important constituent of cell membranes.
∑ The obtained Phosphorous from the plant they eaten by the one type of
heterotopes.
∑ Animals may also use Phosphorous as a component of bones ,teeth &
shell.
∑ When animals (or) plants die, the phosphate will returned to soil (or)
water by the decomposers.
∑ This mining of phosphate & use of the phosphate as fertilizer greatly
accelerates the phosphorous cycle.
∑ Total abundance of phosphate can cause over growth of algae in the
water. The algae can use up all the oxygen & kill other aquatic life.
The other animals that play a unique role in the phosphorous
cycle are marine birds.
These birds take phosphorous containing fish out of the ocean
and return to land.
Their guana contains high levels of phosphorous & in this
way marine birds return phosphorous from the ocean to the land. The
guano is often mined and may from the basis of the economy in some
area.
An ecological pyramid is a graphic representation of an
ecological parameter like number of individuals present in various
trophic level of a food chain with producers forming the base & top
carnivores the tip.
Ecological pyramids were developed by charales Elton.
Producers
herbivores
carnivores.
Are shown graphically the picture is called “Ecological pyramids”.
Here the producers (plant) constitute the base with tertiary
carnivores occupying the apex of the pyramid
Ecological pyramids are 3 types
1. Pyramids of numbers (showing number)
2. Pyramids of biomass(showing total mass of organism)
3. Pyramid of energy.
It is agraphical representation of the no. of individuals per unit
area of various trophic levels stepwise with producers being kept at the
base & carnivores kept at the tip.
3 consumers very
big fish
2 consumers (carnimores)
some largefish, water
bottles
primary consumers herbivores, small
fish, rotifers
zoo planktons
producers phyto plankton, like algae, plants Bacteria.
∑ The no. of pyramids in a higher trophic level is generally smaller than
that the lower trophic level because the organism of the higher trophic
level are dependent for Their food & energy on the organism of the
lowers trophic level.
∑ During transfer of food 90% of it is wasted (or) consumed up in
respiration & only 10% become part higher trophic level.
The amount of living (or) organic matter present in an
organism is called biomass.
It measured both fresh & dry weight
Pyramid of biomass is a graphic representation of biomass
present sequence wise per unit area of different trophic level with
producers at the base & top carnivores kept at tip.
Miximum biomass occer in producers there is a progressive
reduction of biomass found in herbivores primary carnivores &
secondary carnivores.
∑ Here 1000kg of vegetation support a biomass 100 kg of Herbivores
which in its turn shall form 10 kg only of biomass in the primary
carnivores & only 1kg in secondary carnivores.
∑ Therefore cost of production of food from animals are much higher than
the one obtained directly from plants.
∑ It is a graphic representation of amount of energy tropped per unit time
& area in different tropic levels of a food chain with producers forming
the base & top carnivores.
Maximum energy content is present in producers the energy
obtained from solar radiation this energy is converted in chemical form
& stored inside organic matter
As the energy pass into higher tropic level along with food its
amount decreases.
2 carnivores
126 kj/m2/yr
1 carnivores
1260 kj/m2/yr
herbivores 1980 kj/m2/yr
producers 31080
Terrestial ecosystem are classified no basis of predominant type of
vegetation. The broard classification of major terrestrial ecosystem is forest ,
grassland deserts
∑ Different temperatures & rainfall conditions may occur in almost any
combination to give wide variety of forest ecosystem.
∑ Rainfall about 90cm or more per year will support forest ecosystem
∑ Tropical rain forests dominate in areas with high rainfall out the year
Tropical rain forests are mainly found in central america along amazon
& orinco river.
Temperature , rainfall , soil, air , organic & inorganicmatter, they play
important role in the development of the forest community a number of grass
especially biogenetic gases(co2&o2) which occur in plenty in forest ecosystem
regulate the productivity & energy processes.
Trees, ground vegeation , herbs , shrubs(small tree) climbers, flowering &
non-flowering plants(Gymo sperms) (angio sperms).
Primary consumers
small animals feed on leaves
(grass hopper, insects, spider)
Large animals feed on leaves & stems
(deer monkey squirrel)
Secondary consumers:- fox, birds, snake, lizard.
Teriatory consumers:- lion ,tiger , hawks
Micro organism & fungi are decomposers
Depending on eco system forest of different types
It is ever green forest found near the equator. These are
characterised by high rainfall, temperature, humidity, & rich in biodiversity
Top most layer is emergent layer low this canopilayer is
present (the branches of tree form an umbrilla like cover)
In canopilayer birds, insects & buds are present lower these small
trees are present in it (shurb layer) ground floor it contains micro organism
like bacteria & fungi it is a darken layer some climbers are attached to
branches of some trees . the bigger flower Rafflesia (7kg) and it gives rotten
meat smell The forest also contains colourful large fragnant flowers
Eg:- sailent valley in kerala is the only tropical rain forest lying in india.
These are present in little away from the equator
∑ These are characterised by warm climate
∑ Deciduous means which loss there leaves during day season anually
These are present in areas where dry conditions are longer
Eg:-deciduous trees& shurbs.
These are present with area in sufficient rainfall.
Eg:-coniferous tree ,pine tree ,fir tree
They are found in area with moderate temperature summer season
is long .
Eg:-desciduous trees like Oak & popular (soft wood) (hard wood)
These are found in archetic region winter are long & cold
Eg:- pine, fir, ceelar-a sweet smelling wood tree
These are found along with coast they grow In muddy region they
have breeding roots
Grass land are grousy,windy , party drybiome almost1/4 of the
earths land area is covered by grass land most of the grassland are found in
the interiors of continents & rain shadows
Grass lands are generally called”meadon”. They have enough
average rainfall for growing of grass. Natural grassland occur where rainfall is
intermediate between that of desert & a forest where rainfall is roughly
between 10-30 inches a year
Deep routed grasses are the dominated type of flora in the
grassland biomee They have very few trees & shurbs.
Charasteristics of grass land ecosystem.
∑ It is a plain land occupied by grasses
∑ Soil is very rich in neutrients & organic matter
∑ Since it has tall gasses it is ideal place for grazing animals
∑ It characterised by low rainfall
Grass land ecosystem
Abiotic components
Biotic components
Minerals, organic substance are
Present in soil
Producers
Eg:-grasses, sherbs
Ground, vegetation
consumers
Primary consumers
Eg:-cow,deer,sheep,
Rabbit, mouse, insects
termites
decomposers
Eg:-actino mycetes,
algae, bacteria
2 consumers
eg:- snakes, lizeards,
fox, wolf,birds
3 consumers
Eg:-fox, jackals,
lion,tiger
They include neutrients present in soil, the atmosphere . Thus the
elements like C,H,O,N,P, S etc are supplied by co2, H2o, Nitrares , sulphates
present in air & soil of the area
:The grasslands are characterised by treeless herbaceous
plant. Cover dominated by a wide variety of grass species like
dichanthimum, cynodon, important etc besides there a few herbs are
present
Eg:-Greenplants
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The herbivores feeding on grasses are mainly such grazing
animals as cow, sheep, deer, buffaloes, rabbit, mouse etc
Some inseet species as termites, millepeds etc they feed on the
leaves of grass (herbivores)
Snakes , lizards, birds , jackel, fox etc are feed on the
herbivores(carnivores)
Tertiary consumers:They include hawks which feed on secondary consumers
Several fungi acetomycetes, bacteria decay the dead organic
matter of different forms of higher life. Thay bring about mineral back into the
soil, thces making them available to the producers.
Grass lands in different continents are given different names as follows.
Between the forest to the south of Artic ocean &North pole ice
caps region, “treeless” are called ‘Artic tundra’.
These are the grass lands of Eurasia.
These are grass lands of North America.
These are grass lands of South America.
These are grass lands of South Africa.
These are grass lands of Australia.
It occur on hill-slopes aiongside of extremelymoisi moist
evergreen forest in south India. This consists of pastures of grass along with
coniferous forest.
Found in himalayan foot hills. The teril consists of tall
grasslands interlink with a sal forest ecosystem.
It is found in western & central India part of it
consists of pastures of gasses with thory trees several mammals such as the
wolfs, black bucks, &birds such as the bustards & floricans are adopted to
these arid conditions.
∑
∑
∑
∑
It provides food for herbivores cattle feeding
It also used in medicines
It also used to thatch houses &farm-sheds.
The thorny shes & branches of few tree that are seen in grassland are
used as a major source of fuel wood.
Desert occupies about 35% of our worlds land area, in which
less than2 inches of annual rainfall is recorded.
The climate in these area is extremely dry
∑ Deserts are seen in the rain shadow area in the temperature zone of
world
∑ Rain shadow is the region of earth which does not receive rain either
due to non-interception of clouds caused by lack of mountains
1.
2.
3.
4.
5.
They are mainly located in western india & deccan plateates.
Characteristics of desert ecosystem
The desert air is dry & the climate is hot
Nights are cold & days are very hot with temperature reaching
50-600c
The soil is very poor in nutrients & organic matter
Annual rainfall is less than 2 cm
Vegetation is poor
Depending upon the temperature deserts are of to types they
are:1. Cold desert
2. Hot desert
1. It can be observed in north american continents
2. It have good rainfall xerophytic plants grow very well
3. These contain micro-flora such as lichener , mosses, blue green algae are
present abundantly.
4. Tall trees are generally absent
Example:-Gobi
1. In the state of Arizona in U.S.A there is a large desert which is generally
called “hot deserts”.
2. It is located in a temperature area it contains sandy soil with low eater
content.
3. Some short lived plants & insects occur during the rainy seasons Eg:Boerhaavia repents of 10-14 days.
4. Few plants live for 2-6 months because they are ab to cut down water
loss.Eg:hardy grasses.
5. Amongest highest animals only can survive desert conditions since it
body cells can endure a loss of 40% water while in man 15% loss causes
death
Most deserts have a considerable amount of specialized
vegeatation as well as speciallised vertebrictes & invertebrate animals
the variuous components of deserts bioms are
The temperature is very high & the rainfall is very low the nutrient
cycle is very low
These are shurbs , especially bushes some grass & a few trees some times
a few succutents like cacti are also present some lower plants like lichens and
xerophytic mosses are present
Insects, reptiles, noctural radents, birds, camel etc are the main
consumers.
These are very few as due to poor vegetation. The amount of dead
organic matter is correspondingly less. These are some fungi & bacteria most
of them are thermophilic.
producers
biotic
components
desert ecosystem
temperature is
high and very low
rainfall organic
substance are
poorly present in
soil
abiotic
components
eg:- shurbs, bushes
succulant plants,
xerophytic grasses&
trees,tichens
consumers
eg:-insects,
reptiles,
noctumal,radents,
birds,camels
decomposers
eg:-fungi,
Bacteria
An aquatic ecosystem is a group of interacting organism dependent on
one another & their water environment for nutrients & shelter
Eg:-ponds, lakes & rivers
Depending upon the quality & nature of water the aquatic ecosystem
are categorized into
1. Fresh water ecosystem
2. Marine ecosystem
3. estuarine
It occupy a small portion of the earth surface fresh water is
defined as water with less than 1%salt concentration
Fresh water ecosystem can further be devidedinto catagories
1. .standing water(or)lentic ecosystem (lake, pond, swamp)
2. Running water (or) lotic ecosystem (River, spring ,stream)
Pond (or) lake is agood ex. Of a self-suffierence & self regulation of
ecosystem
Location sizedepth & substratum of a pond (or) lake constitute the
biology of the ecosystem
A pond has defined as a body of standing water which
hes no connection with other water bodies
It includes in organic as well as organic substances such as water ,o2,
co2, phosphorous, calcium, amino acids & nitrogen present in the bottom soil
& disorganic materials also present
It includes submerged free-floating plants are present they also called
photo planktons
Eg:-hydrilla , utricularia, wolfia, eichhornia, typha etc minute floating &
suspended lower phytoplanktons
Eg:-ulothrix, spirogyra, oedogonium etc.
These are zoo planktons & benthas
Eg:-ciliants, flagellants, other protozones, small cr
These are the carnivores like insects & fishes feeding on the
herbivores
Large fishes feeding on small fishes
Eg:-Leeches, fishes ,water snake
Lakes are usually big fresh water bodies with standing water
they have a shallow water zone called liltoral zone an open water zone where
effective penetration of solar light takes place called limnetic zone & a deep
bottom area where light penetration is negligible known as prafundal zone
That float on surface of water
Eg:-phyto planktones like algae,zoo planktons like rotifers
Eg:-fish
That swims on the surface of water
That rest (or) swim on the surface
Eg:-snails
That are attached to bottom sediments
That are attached conclinging to other plants (or) any other surface
eg:-crustaceans.
Ocean cover more than 1/3rd of the earth’s surfaces It
characterised by its high conc of salts and minerals the ocean represent a very
large & stable ecosystem
marine/ocean
abiotic components
biotic
conponents
high Na, ca, Mg,k-saltscons dissolved oxygen
contents,light &temperature
consumers
producers
eg:phytoplanktons(
diatoms)Rhodop
hycaar,angiosper
ms,
Ruppia,Rhizopho
ra
primary consumers
eg:-crustaceansmollluska
fish
secondary consumers
eg:-carnivores smallfishes
30 consumers
eg:fishes cod,haddock etc
decomposers
eg:-bacteria
,fungi
light.
Physio-chemical factors such as dissolved oxygen,temperature,
It includes photo planktons & large marine plants
Eg:-diatoms & dinoflagelletes
The lather group includes sea water (algal),belongs to chlorophycal
& angiosperms
These are heterotropic macro consumers being depended for their
nutrition on the producers
The herbivores that feed directly on producers are chiefly
crustaceans olluses, fish etc.
Carnivores ,fishes, such as herring sand
Fishes like cod haddock etc are the tertiary consumers
They are chiefly bacteria & some fungi which participate actively
in decomposition of dead organic matter
Estuarine ecosystem
biotic
conponents
abiotic components
mixture of fresh marine eco system
producers
eg:macrophytrs,gras
ses,seaweeds,se
agrasses,Benthic
algae
consumers
eg:-oysters ,crashs,several
kinds shrimps&many
commercial sport fish
decomposers
eg:-bacteria
fungi
An estury is a semi closed coastal body of water that has a free
connection with sea . it is strongly affected by tidal action & with in this sea
water is mixed with fresh water from land drainage
Ecosystem have some functional attributes which keep the
component parts running together. The majorfunctional attributes of the eco
system are
1. Productivity and decomposition
2. Energy flow
3. Nutrient cycling
4. Development and stabilization
The rate of organic matter or biomass production is called
productivity the productivity of an ecosystem is of two types .
1. Primary productivity
2. Secondary productivity
The rate at which radiant energy is captured by producers for
synthesis of organic compound through photosynthsis is called primary
productivity. It is expressed as gm-2 year-1 for dry matter kcalm-2 year -1 for
energy.
The primary productivity is further distingushed as Groiss primary
product(G.P.P)& Net primary product(N.P.P)
The rate of total capture of energy or the rate of total production of
organic matter /biomass by the producers per unit area and time
The rate at which energy or organic matter stored the producers
after resperation and maintenance per unit area and time
Net primary product=Gross primary product-loss due to resperation and
maintenance
The rate of increase in the biomass of consumers perunit area and
tlme is called “secondary productivity”.
It refers to the process by which complex organic materials are
broken down by the decomposers to in organic raw materials like co2 ,H2o and
various netarients
Decomposition makes in organic raw materials available for
reutilization by the plants
The ability to do work is called energy
The functioning of eco system depends on the flow of energy through
matter
Energy enters the eco system from the solar radiation and is converted
into chemical energy . it is stored in the form of sugars
∑ From there the energy passes fromone tropic level to the next tropic
level through food the flow of energy in the ecosystem is governed by
the basic laws of thermo dynamicsi.e
1. Energy that can neither be created nor destroyed but can be transferred
from one state to another or transferred from one component to
another
2. Every transformation or transferrfer of energy is accompanied by its
dispersion that means one hundred per unit of energy transfer is not
possible some amount of energy transfer is not possible some amount of
energy loss occur in the form of heat and resperation
There are two aspects with to energy flow in ecosystem
3. There is undirectional or one way of flow of energy in the eco system i.e.
the energy captured by the autotrophy doesnot revert back to solar
input or the energy which passes to the herbivores does not pass back
to autotrophy
4. The amount of energy flow decreases with successeive tropic levels
Producers capture only a small fraction of solar energy
(only1%) and remaining 99% of energy loss occurs in the form of heat
only 10% of energy from producers will be avilable for herbivores
The energy assimilated by the herbivores is used in resperation
about 10% herbivores productivity is used to support carnivore
productivity in the same way the energy avilable at carnivore tropic
level is again divided leaving a very small fraction to support the next
tropic level i.e. top carnivore.
With increasing tropic levels the resperation cost also
becomes sparply thus there is a tremendous loss of energyat successive
higher tropic level as a result the residual energy is decreased to such as
exrtent that no further tropic level can be supported therefore there can
be3-5 trophic levels in the food chains of an eco system
The substances which are present in biotic components came from
abiotic components (air,water,soil)
Eg:-photosynthesis
After the death of the living organisms decomposers detritivores act
on them to get their energy . they decompose the complex molecules to simple
inorganic neutrients like co2, H2o and various neutrients
∑ In this way minerals which are utilized by plants returning back to the
soil which will again available to the plants for reutilization.
∑ In this way minerals circulating between biotic & abiotic components in
a circular form these cycles are called nutrient cycle /Bio geo chemical
cycle
consumers
decomposers
Nutrient
cycle
producers
nutrient
pool
(soil)
An eco system is not static in nature. It is dynamic and changs
occur in its structure and function with time. These changes are orderly
and can be predicted. It is observed that one type community is totally
replaced by another community over a period of time. This process is
known as ecological succession.
Ecological succession is defined as an orderly process of
changes in the community structure and function with time mediated
through modification in physical environment and ultimately
culminating in a stabilized ecosystem is known as “climax”.
The whole sequence of commmunities which are transitory
are known as seral stages/ seres where as the community establishing
first of all in the area is called a “poineer community”
Ecological succession starts on different types of area
depending on area in which ecological succession started are named as
follows.
1. Hy drarch/Hydrosere: starts in water areas like ponds swamp bog
etc
2. Mesarch : starting in an area of adequate moisture
3. Xerarch/xerosere: starting in a dry area with title moisture.
These can be of the following types
1. Lithosere: starting on a bare rock
2. Psammosere: starting on sand
3. Halosere: starting on saline soil
Ecological succession is characteristised by the following
features
1. It tends to progress from un stable biotic community to stable
biotic community i.e complete adjustment with the environment.
2. Its seral stages are so regular and directional
3. In succession several stages there is tendency towards increase in
species diversity total biomass niche specialization and humans
content of the soil.
4. It tends to progress from simple food chains to complex food
webs.
5. The habitat tends to modify from aquatic or dry conditions to
mesic (moderately wet) conditions.
6. Succession of plant and animal communities occurs side by side
However plant successsion is easily visible
Ecological succession takes place in asysttametic order of
sequential steps.
It is development of bare area without any life from
the bare area mey be caused due to land slides, volcanoic, eruptions
(tropographic factors) or due to drought, glaciers, frost etc (climatic
factors) or due to over grazing disease out break agriculture/
industerial activities (bioticfactors).
The seeds spores or rther propagule the organism reach the
bare area. This process is called migration. It is generally brought about
by air, water, animal and man. The first arrivals in a bere area called
pioneers or poineer colonisers.
The successful establishment of a species after reaching to
new area as a result of adjustment with the conditions prevailing there
is known as ecessis/establishment. Only few of them are capable of
doing this under primitive harsh conditions and most of them disappear
as a result the individual species become established in the area.
After ecesis the increase in no. of colonising individuals
is called aggregation
Migration does not ends with the establishment of poineers
from time to time pioneers of new species continue to reach the area
under colonisation. This process is called invasion and the new
organisms are called invaders. Invaders are able to establish themselves
only if they are more aggressive than the colonisers.
After sggregation of a large no. of the species at the
limited place there develops competetion (both intra species) mainly
for space & nutrition.
A.
v
v
v
v
It is the change brought about by colonisers in the habitats. The
changes take place in soil, water, light conditions temperature etc. of the
environment .due to all of these environment is modified becoming
unsuitable for existing community which sooner or later is replased by
another community.
:Continuoues competion invasion and reaction give rise
to continuous changes in the environment and structure of vegeatation.
Aafter a long interval some individuals a rise which are , no further
change occur in the vegetation. This vegetation is called climax stage/
climax community.
The sequence of succession originates on a bare rock. The bare rock is
deficient of water hence the sequence of saral stages of succession is
also called “xerosere”.
The climax community is a forest intermediate stages are different
Pioneer community consists of crustore foliose & lichanes.
Lichans produces some weak acids. These acids disintegrate the rock
forming humans & soil.
Soil will be the source for various communities
Lichen stage
moss stage
herb stage
sherb stage
forest
B.
The succession starts in water body like pond
v A no of intermediate stages come & ultimately it cuminates in a climax
community i.e. forest
v Poneer communityis phytoplanktons. By the death & decay of these
organisms it forms a layer of soil & shollowing of water takes place
phytoplanktons
free floting
floting plants
marshystage
forest
woodland
sedagemeadom
1. It provides information which help to have a controlled
growth of one or more species in a forest preventing the in
vasion of other species in the area.
2. Pastures can be maintained by not allowing biotic
succession to processed further through grazing or fire
3. It also helps in reforestation & forest managemant
programmes