Ecological Succession�&�Ecological Pyramids

introduction, description, examples and explanation of ecological succession and ecological pyramids.
Lots of images and diagrams to make it easy to understand for you

1. Ecological Succession
&
Ecological Pyramids
PPT Prepared by
Mr. NiladriSekharRoy
Asst. Professor
Department of Environmental Science
AKS University, Satna, M.P.
Email [email protected]

2. Ecological Succession & Ecological Pyramids
Ecological Succession
•Introduction
•Definition
•Types
•Stages\Process of succession
Ecological Pyramids
•Introduction
•Definition
•Types

3. Ecological Succession
Introduction:
Every place in the world did not evolve suddenly, it took a long
time and process to look like as it is today.
Ecological successionis the process of change in
thespeciesstructure of anecological communityover time.
The time scale can be decades (for example, after a wildfire),
or even millions of years after amass extinction.
In 19
th
century, the French naturalistAdolpheD. Mallewas the
first to make use of the wordsuccessionconcerning the
vegetation development after forest clear-cutting.
Definition:
•Ecological Succession is the gradual process by which
ecosystems change and develop over time.
•In a place, the changes and development of biotic and abiotic
components is called as Ecological Succession.

4. Types:
Ecological Succession can be categorized as,
According to the formation on different types of areas
1.Hydrachor Hydrosere
2.Mesarch
3.Xerachor Xerosere: Starting in dry area or areas
without adequate moisture. Xerachhas following
types,-
•Lithosere:
•Psammosere:
•Halosere:
According to the causes of occurrence
1.Primary Succession
2.Secondary Succession

5. According to the formation on different types of areas
1.Hydrachor Hydrosere: Starting in watery areas like
pond, swamp etc.
2.Mesarchor Mesosere: Starting in areas with
adequate moisture.
3.Xerachor Xerosere: Starting in dry area or areas
without adequate moisture. Xerachhas following
types,-
•Lithosere: Starting in a bare rock.
•Psammosere: Starting on sand.
•Halosere: Starting on saline soil.

7. Hydrosere

8. Mesarchor MesosereSuccession

9. LithosereSuccession

10. PsammosereSuccession

11. HalosereSuccession

12. According to the causes of occurrence
1.Primary Succession: occurs in essentially lifeless
areas—regions in which thesoilis incapable of
sustaininglifeas a result of such factors aslavaflows,
rocksleft from a retreatingglacier etc.
2.Secondary Succession: occurs in areas where
acommunitythat previously existed has been
removed; it is typified by smaller-scale disturbances
that do not eliminate all life andnutrientsfrom
theenvironment.

13. Primarysuccessionbeginsinbarrenareas,suchasonbarerockexposed
byaretreatingglacier.Thefirstinhabitantsarelichensorplants—those
thatcansurviveinsuchanenvironment.Overhundredsofyearsthese
“pioneerspecies”converttherockintosoilthatcansupportsimple
plantssuchasgrasses.Thesegrassesfurthermodifythesoil,whichis
thencolonizedbyothertypesofplants.Eachsuccessivestagemodifies
thehabitatbyalteringtheamountofshadeandthecompositionofthe
soil.Thefinalstageofsuccessionisaclimaxcommunity,whichisavery
stablestagethatcanendureforhundredsofyears.

14. Secondarysuccessionfollowsamajordisturbance,suchasafireora
flood.Thestagesofsecondarysuccessionaresimilartothoseofprimary
succession;however,primarysuccessionalwaysbeginsonabarren
surface,whereassecondarysuccessionbeginsinenvironmentsthat
alreadypossesssoil.Inaddition,throughaprocesscalledold-field
succession,farmlandthathasbeenabandonedmayundergosecondary
succession.

15. Stages\Process of succession
Ecological Succession has five stages, they are-
Nudation: It is the development of a bare area without any life form.
The bare area may be caused due to landslides, volcanic eruption
etc. (topographic factor), or due todrought, glaciers, frost etc.
(Climatic factor), or due to overgrazing, disease outbreak,
agricultural/ industrial activities(biotic factors).
Invasion: It is the successful establishment of one or more species on
a bare area through dispersal or migration. Dispersal of the seeds,
spores etc. is brought about by wind, water, insects or birds. Then
the seeds germinate and grow on the land.

16. Stages\Process of succession
Competition and coaction: As the number of individuals grows there
is competition, both inter-specific (between different species) and
intra-specific (within the same species), for space, water and
nutrition. They influence each other in a number of ways, known
as coaction.
Reaction: The living organisms grow, use water and nutrients from
the substratum, and in turn, they have a strong influence on the
environment which is modified to a large extent and this is known
as reaction.
Stabilization: The succession ultimately reaches to a climax or point
of highest development. (more or less stable community) called
climax which is in equilibrium with the environment.

17. Ecological Pyramids
Introduction: Every food chain or ecosystem shows
different characteristics such as number of organisms,
weight (biomass) and energy level. Every trophiclevel
differs from each other in relation with numbers,
biomass and energy.
The concept of Ecological Pyramid was developed
byCharles Eltonin 1927.
TrophicLevel: Trophiclevel is the position of an organism
in a food chain or ecosystem.
Trophiclevels can be represented by numbers, starting at
level 1 with plants. Further trophiclevels are numbered
subsequently according to how far the organism is
along the food chain.
Cont...

18. Level 1: Plants and algae
make their own food and
are called producers.
Level 2: Herbivores eat
plants and are called
primary consumers.
Level 3: Carnivores that
eat herbivores are called
secondary consumers.
Level 4: Carnivores that
eat other carnivores are
called tertiary consumers.
Apex predators by
definition have no
predators and are at the
top of their food web.

19. Ecological Pyramid-Definition
Anecological pyramidis a graphical representation designed
to show the number,biomassand energy at eachtrophic
levelin a givenecosystem.
An Ecological Pyramids are graphic pictures of food chain in
relation with the number, biomass and energy level of
organisms.
The base of every Ecological Pyramids consists of producers
and apex of every Ecological Pyramids consists top
carnivores.
Ecological Pyramids may be up right or inverted or semi
inverteddepending on increasing or decreasing of
numbers, biomass and energy level.
There are three types of Ecological Pyramids,
•Pyramids of Numbers
•Pyramids of Biomass
•Pyramids of Energy

20. Pyramids of Numbers
•It shows the relationship
between the producers,
herbivores and carnivores
in terms of their
numbers.
•This indicates the number
of organisms at every
trophiclevel
Pyramids of Number are
graphic pictures those
represent total number
of organisms at various
trophiclevel in a food
chain.

21. Pyramids of Numbers (Examples)
Forest Ecosystem
Pyramid of numbers of a tree (Parasitic food chain)Grassland Ecosystem
Pond Ecosystem

22. Pyramids of Biomass
The amount of living
material in an organism is
called biomass.
Pyramid of biomass shows
quantitative relationship
existing at various trophic
levels.
Pyramids of Biomass are
graphic pictures those
represent total biomass
at each trophiclevel in a
food chain.

23. Pyramids of Biomass (Examples)
Forest Ecosystem
Pyramid of biomass of a tree (Parasitic food chain)Pond Ecosystem
Grassland Ecosystem

24. Pyramids of Energy
Pyramids of energy show
the amount of total
energy trapped by the
organism at each
trophiclevel.
Energy pyramid is always
upright in all
ecosystems.
Pyramids of Energy are
graphic pictures those
represent the energy
level of organisms at
each successive trophic
level.

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