ecosystem

1. ECOSYSTEM

2. TABLE OF CONTENTS
 CONCEPT OF ECOSYSTEM
ECOSYSTEM AND ECOLOGY
LAWS OF THERMODYNAMICS
TROPHIC LEVELS
 PRODUCERS , CONSUMERS,DECOMPOSERS
 ENERGY FLOW IN ECOSYSTEM
ENERGY FLOW
OXYGEN,CARBON AND NITROGEN CYCLE
 FOOD CHAIN , FOOD WEBS & ECOLOGICAL PYRAMIDS
FOODCHAIN:FOOD WEBS
PYRAMID OF BIOMASS
PYRAMID OF NUMBERS

3. 1.
CONCEPT OF ECOSYSTEM
Ecosystem : Defined area in which a community lives with interactions taking place among
the organisms between the community and its non-living physical environment
• Ecology is the study of ecosystem formed by the interactions between all living and non-living
things
• Nonliving components include sunlight, rainfall, silica and clay particles in the soil, the air, etc
• Thus, an ecosystem encompasses all aspects of a biological community, in addition to factors
such as rates of CO2 uptake, rates of nitrogen fixation from the atmosphere etc.

4. “The greatest threat to our planet is the
belief that
“ Someone Else Will Save It”
:- Robert Swan

5. Laws Of Thermodynamics
▪ The first law known as law of conservation of energy.
“ Energy can neither be created nor be destroyed”
We can potentially trace all the energy from its solar input its
release as heat by organisms.
▪ The Second law
“ When energy is transferred from one form to another only
lesser quantity is available at the end of transfer process”
The second law of thermodynamics allows us to measure the
efficiency of the energy conversions.

6. TROPHIC LEVELS
▪A trophic level is the position occupied by an organism in a food chain.
▪Trophic levels can be analyzed on an energy pyramid.
▪Producers are found at the base of the pyramid and compromise the first trophic
level.
▪Primary consumers make up the second trophic level.
▪Secondary consumers make up the third trophic level.
▪Finally tertiary consumers make up the top trophic level.

7. The
efficiency of
energy
transfer
between
trophic
levels is
usually less
than 20%

8. 2.
PRODUCERS , CONSUMERS AND DECOMPOSERS
▪ Ecosystem characterized based on Structure
▫Living (biotic)
▫Nonliving (abiotic)
BIOTIC
Biotic part includes
Producers ,consumers and
decomposers
ABIOTIC
•Solar energy provides practically all the
energy for ecosystems.
•Inorganic substances, e.g., sulfur, boron,
tend to cycle through ecosystems.
•Organic compounds, such as proteins,
carbohydrates, lipids, and other complex
molecules, form a link between biotic and
abiotic components of the system.

9. PRODUCERS
Producers make their own food. They do
not have to obtain energy from other
organisms. They obtain their energy from
the sun and make food with that energy
through the process of photosynthesis.
Producers may also be called autotrophs
Most producers are plants, but there are
some small organisms that produce food
through photosynthesis as well. Producers
are at the beginning of any simple food
chain

10. Most of the
energy
originally
fixed by
autotrophs are
lost in the
form of heat

11. An
ecosystem’s
energy budget
depends on
primary
production

12. CONSUMER
SConsumers cannot make food.
They must find food and eat it to
obtain energy. Consumers may also
be called heterotrophs. There are
both primary and secondary
consumers. Primary consumers are
the next link in a simple food
chain. These are the plant eaters,
or herbivores. They do not eat
other animals. examples of primary
consumers would be a wild boar or

13. Secondary consumers follow
primary consumers in a simple food
chain. Secondary consumers eat the
primary consumers. Secondary
consumers can be
carnivores or omnivores. Carnivores
eat only meat, while omnivores eat
both meat and plants. In addition to
the cheetah, secondary consumers
can include a lion who kills and eats
the giraffe, or a human who kills and
eats the wild boar

14. DECOMPOSER
SDecomposers are the waste managers of
any ecosystem. The are the final link in a
foodweb breaking down dead organic
matter (DOM) from producers and
consumers and ultimately returning
energy to the atmosphere in respiration
and inorganic molecules bake to the soil
during decomposition
Decomposers can be divided into two
groups based on their mode of nutrition.
•Detritivores
•Saprotrophs

15. • Detritivores are an organisms
that ingest non-living organic
matter. These can include
earthworms, beetles and many other
invertebrates.
•Saprotrophs are organism that
lives on or in non- living organic
matter, secreting digestive enzymes
into it and absorbing the products of
digestion. These include Fungi and
bacteria.

16. 3
ENERGY FLOW IN A ECOSYSTEM
Biological and geologic processes move nutrients between organic and inorganic
compartments
BIOCHEMICAL CYCLE
It is a biological pathway in which chemical elements or molecules moves through both
biotic and abiotic components of an ecosystem.
So by this process an element is recycled in the ecosystem.

17. TYPES OF BIOCHEMICAL CYCLES
Carbon
cycle
Oxygen
cycle
Nitrogen
cycle

18. OXYGEN
CYCLE

19. CARBON CYCLE
Carbon exists in
the non-living
environment as
carbon dioxide in
the atmosphere,
dissolved carbon
dioxide (HCO3-,
etc.) in the ocean,
and as
carbonates in the
Earth’s crust.

20. NITROGEN CYCLE
The process of
converting
atmospheric
nitrogen into
forms that
organisms can
use is called
nitrogen
fixation.

21. 4
FOOD CHAIN , FOOD WEBS & ECOLOGICAL PYRAMIDS
FOOD CHAINS
•The producers, consumers, and decomposers of each ecosystem make up a food
chain.
•There are many food chains in an ecosystem.
•Food chains show where energy is transferred and not who eats who.
FOOD WEBS
•All the food chains in an area make up the food web of the area.
ECOLOGICAL PYRAMIDS
An ecological pyramid (also trophic pyramid energy pyramid,
or sometimes food pyramid) is a graphical representation designed to show
the biomass or bio productivity at each trophic level in a given ecosystem.

22. BIOMASS
▪Energy is sometimes considered in terms of biomass, the mass of all
the organisms and organic material in an area.
▪Biomass can be defined as the weight of living matter (usually
measured in dry weight per unit area).
▪There is more biomass at the trophic level of producers and fewer
at the trophic level of tertiary consumers. (There are more plants on
Earth than there are animals.)
▪Bio=life Mass=weight
▪Bio + Mass = Weight of living things within an ecosystem.

23. PYRAMID OF BIOMASS
•A pyramid of biomass is a figure that quantifies the relative amounts of living
biomass found at each trophic level.
•In most ecosystems, the amount of biomass found in each trophic level decreases
progressively as one moves from the bottom to the top of the food chain.
•Primary consumers eat producers.
•They generally possess significantly less biomass than producers.

24. Distribution
of biomass
for various
levels
in a forest
community

25. PYRAMID OF NUMBERS
•Pyramids of numbers show the relationship between
producers, herbivores and carnivores at successive trophic
levels in terms of their number. In grassland the producers,
which are mainly grasses are always maximum in number.
•This number then shows a decrease towards apex, as the
primary consumers like rabbits, mice etc. are lesser in
number than the grasses; the secondary consumers, snakes
and lizards are lesser in number than the rabbits and mice.

26. PYRAMID OF NUMBERS
IN
DIFFERENT ECONOMIES

27. Thanks
!!
Any questions?