PPT ON ECOSYSYTEM

2. Ecosytem
 The term Ecosystem was first proposed by ecologist
A. G. Tansely who defined ecosystem as “ the
system resulting from the integration of all the living
and non living factors in the environment”
• A community of living organisms interacting with
one another and with its non-living physical and
chemical environment.
 Or
• An Ecosystem is a region in which living organism
interact with their environment and these
interactions perpetuate the community and retain
stability under varying conditions.

3. Classification of ecosystem

4. Natural vs Artificial
Ecosystem

5. Structure of ecosystem:
Components

6. Producers
 Producers make their
own food
 Green plants use
energy from the sun
to make food
 Producers are on the
bottom of the food
chain

7. Consumers
 Consumers hunt, gather, and
store food because they cannot
make their own.

8. Three Types of Consumers
Herbivores
Carnivores
Omnivores

9. Herbivores
 Animals who eat plants such as:
 grasshoppers
 rabbits
 squirrels
 deer
 pandas

10. Carnivores (secondary
consumers)
 Meat eaters and feed on herbivores
are known as secondary consumers
 Eg dog, fox, wolf etc.

11. Carnivores (tertiary
consumers)
 Carnivores which prey upon other
carnivores but are not eaten
themselves. They constitute the
terminal end of predator of grazing
food chain
 tigers
 lions
 hawks

12. Omnivores
 Animals who eat both plants
and animals such as:
 humans
 bears

13. Decomposers
 Organism that feed on dead and decaying
matter and convert the organic material in to
organic material are called decomposers
 They help in nutrient recycling and known
as recycling agent of the nature
 In absence of recycling nutrients earth
would be converted in to a vast dump of
dead organism
 Microorganisms that are able to break down
large molecules into smaller parts

14. Abiotic components
 Physical factors: Sunlight, shade, intensity of
solar flux, length of day , temperature, annual
rainfall (precipitation), latitude, altitude, soil
type, water availability
 Chemical factors: Availability of essential
nutrients such as carbon, nitrogen, phosphorous,
potassium, oxygen, sulfur, percentage of water
and air in soil, salinity of water, oxygen dissolved
in water

15. Functioning of Ecosystem
 The function of ecosystem can be studied in
following terms
 Food chain
 Mineral nutrient cycle
 Energy flow

16. Food chain
 The transfer of food energy from the source
through a series of organism by regular
eating and eaten up
 In food chain each stage of transfer of food
energy is known as trophic level
 Therefore trophic level refers to successive
levels of energy flow that form the link of
food chain

17. Types of Food Chains
 Aquatic- Water-related food
chains with sea plants and
animals
 Terrestrial- Land-related food
chains with land plants and
animals

18. Type of food chain
 Grazing food chain: Common in nature. Producer form the
first link , herbivores as second and secondary consumer as
the third
 Detritus food chain: The organic waste and dead matter
derived from grazing food chain is termed as detritus.
Detrivores are the animal that consume detritus and in
doing so contribute to decomposition and recycling of
nutrient
 Eg algea, bacteria, earthworms, millipedes
 Organism in this food chain are generally smaller, and
functional role do not fall in catagories
 However grazing and detritus food chain are interlinked

22. Food webs
 It is not possible to depict the real world by
means of simple food chain, because the
interconnection between different trophic
level in real world are extremely complex
 Various food chain are interlinked with each
other and these interlocking pattern formed
by several food chain linked together are
called food web

25. Ecological Pyramids
 An ecological pyramid is a diagram that
shows the relationship amounts of energy or
matter contained within each trophic level in
a food web or food chain.
 Energy Pyramid only 10% of the energy
available within one trophic level is
transferred to organisms at the next trophic
level.

26. Pyramids Continued
 Biomass pyramids show the total amount of
living tissue available at each trophic level. This
shows the amount of tissue available for the next
trophic level.
 Numbers pyramid shows the number of species
at each trophic level.
 Because each trophic level harvests only about
one tenth of the energy from the level below, it
can support only about one 10th
the amount of
living tissue.

27. PYRAMID OF NUMBERS
 Shows the number of organisms at each
trophic level per unit area of an ecosystem.

28. Pyramid of Numbers
Pyramid of numbers displays the number of individuals
at each level.
1 owl
25 voles
2000
grass plants

29. PYRAMID OF BIOMASS
The total amount of matter present in
organisms of an ecosystem at each trophic
level is biomass.
Biomass is preferred to the use of numbers of
organisms because individual organisms can
vary in size. It is the total mass not the size
that is important.
Pyramid of biomass records the total dry
organic matter of organisms at each trophic
level in a given area of an ecosystem.

30. Biomass PyramidsBiomass Pyramids
Displays the biomass at each trophic level.

31. PYRAMID OF ENERGY
 Shows the amount of energy input to each
trophic level in a given area of an ecosystem
over an extended period.
1. Why will this type of pyramid never be
inverted?

32. Energy PyramidEnergy Pyramid
Fig. 4–19
In nature, ecological
efficiency varies from
5% to 20% energy
available between
successive trophic
levels (95% to 80%
loss). About 10%
efficiency is a general
rule.