What is Energy: The ability or capacity to do work, Radiant, Chemical, thermal, mechanical, nuclear, electrical. What is Energy Flow: The existence of flora and fauna in ecosystem depends upon the cycle of minerals and flow of energy. Energy is needed for all the biotic activities. The only source of this energy is the sun. The entrance, transformation and diffusion of energy in ecosystem are governed by laws of thermodynamics.

1. Topic:-
EnergyFlowinEnvironment:Ecologicalenergetics
Submitted to:- Presented by:-
Department of Zoology Kamlesh Patel
St. Aloysius College Jabalpur M.P. M.Sc. Zoology 3rd Sem

2. Synopsis
Introduction
The Laws of Thermodynamics
Photosynthesis
Cellular Respiration
10% Law of Energy Transfer
Y-Shaped Energy Flow Model
Food Chain
Food Web
Ecological Pyramid Models

3. Introduction
What is Energy:
• The ability or capacity to do work
• Radiant, Chemical, thermal, mechanical, nuclear, electrical.
What is Energy Flow:
The existence of flora and fauna in ecosystem depends
upon the cycle of minerals and flow of energy. Energy is
needed for all the biotic activities. The only source of this
energy is the sun. The entrance, transformation and
diffusion of energy in ecosystem are governed by laws of
thermodynamics.

5. The Laws of Thermodynamics
 First Law of Thermodynamic:
Energy can be transformed from one form into another,
it can neither be created nor destroyed.
 Second Law of Thermodynamic:
During the process of transformation of energy, some of
the transformed energy is diffused from the ecosystem in
dispersed form.

6. Energy Flow Through Ecosystems
R = Energy loss
through Respiration
E = Energy loss from Grazing food chain to Detrivores
and Decomposers Through Excretion and Egestion
C = Consumption by Organism
at the higher Trophic Level
R R R R
C C C
E E E E
Photosynthesis

7. Photosynthesis
The process where the Sun’s energy is converted into chemical energy
(Glucose/Sugar).
Occurs in PLANTS!!
Producer – an organism that makes its own energy-rich food compounds using the
Sun’s energy.
Energy captured by plants via photosynthesis is transferred to the organisms that
eat the plants.
oxygensugarwaterdioxidecarbon energylight
 
6 CO2 + 12 H2O + radiant energy
C6H12O6 + 6 H2O + 6 O2

8. Cellular Respiration
The process where the chemical energy captured in
photosynthesis is released within cells of plants and animals.
This energy is then used for biological work
Creating new cells, reproduction, movement, etc.
C6H12O6 + 6 O2 + 6 H2O
6 CO2 + 12 H2O + energy

9. 10% Law of Energy Transfer
The Ten percent law for the transfer of energy from
one trophic level to the next was introduced by Lindemann
(1942). According to this law, During the transfer of energy
from organic food from one trophic level to the next, only
about ten percent of the energy from organic matter is
stored as flesh.
The remaining is lost during transfer, broken down in
respiration, or lost to incomplete digestion by higher
trophic levels.

10. Energy flow in different trophic levels of Lindeman’s Ecosystem

11. “Rule of 10” Only ~10% passes to next level.
Therefore, ~90% LOSS at each Trophic Level.
10

12. Y-Shaped Energy Flow Model
According to E.P. Odum (1983), naturally, two types of food chain
function in ecosystem.
1. Grazing food chain - Which begins from green plants and proceeds
towards herbivores and then towards carnivores
2. Detritus food chain - Which starts from rotten organic substances
and proceeds towards carnivores thought detrivores.

13. Food Chain
Food chain – Shows one path of the flow of energy in an ecosystem.
Energy from food passes from one organisms to another
◦ Each “link” is called a trophic level
Order of the food chain:
1.Sun – energy source
2.Producer
3.1st level Consumer –
eats producers
4.2nd level Consumer –
eats 1st level consumers
5.Decomposer –
recycles materials for
use by producers

14. Food Web
A model that shows the
energy flow through
different organisms in
an ecosystem.
Consists of many
overlapping food chains
in an ecosystem

15. Ecological Pyramid Models
The idea of Ecological pyramids
was given by Charles Elton (1927)
The graphical representation of
number, biomass and stored energy
of various trophic levels of food
chain in an ecosystem is called
Ecological pyramid.
Three types of ecological
pyramids:
1. Pyramid of Numbers
2. Pyramid of Biomass
3. Pyramid of Energy
Energy Loss

16. Pyramid of Numbers
•Compares the number of organisms at each trophic level in a food chain.
•Typically pyramid shaped, with the largest number of organisms at the
producer level:
Inverted Pyramid of Numbers in ForestUpright Pyramid of Numbers in
an Aquatic Ecosytem

17. Pyramid of Biomass
•Shows the amount of living matter in a food chain.
•Total dry weight (without water) of organisms in a food chain
•Mass/Area
• Example: g/m2

18. Pyramid of Energy
 Energy pyramid - Energy
loss and transfer between
trophic levels; the size of
each layer represents the
amount of energy
available at that trophic
level.
 Only about 10% of the
energy taken in by the
individuals at one trophic
level is passed on to
individuals at the next
level.

19. References
www.google.co.in
https://www.slideshare.net/
https://en.wikipedia.org/wiki/Energy_flow_(ecology)
Fundamentals of Ecology – M. C. Dash
Fundamentals of Environmental Biology – S. Arora