INFORMATIVE AND PRESENTABLE..!! HOPE IT PROVES HELPFUL FOR YOU..

1. ENERGY FLOW IN
ECOSYSTEM

2. An “Ecological System?”
In the discipline of ecology, the word
Ecosystem is an abbreviation of the term, Sir Arthur Tansley (1871-1955)
ecological system – the basic unit in ecology. It first
appeared in a 1935 publication by the British ecologist Arthur
Tansley (Tansley, 1935). However, the term had been coined
already in 1930 by Tansley's colleague Roy Clapham, who was
asked if he could think of a suitable word to denote the physical
and biological components of an environment considered in
relation to each other as a unit.
Tansley, A., 1935, The use of vegetational concepts and terms. Ecology, v. 16, p. 284-307.

3. An “Ecological
System?”
Components of an Ecosystem:
Sir Arthur Tansley (1871-1955)
Abiotic (non-living) and
Biotic Components Physical Components
Species Water
Populations Nutrients
Communities Topography
Weather
Competition and Predation Disturbances

4. What Keeps Us and Other
Organisms Alive?
• One-way flow of high-quality energy from the sun
(returned as low quality heat)
• Cycling of matter or nutrients through parts of the
biosphere (closed system applies; law of conservation
of matter; time frame of seconds to centuries)
• Gravity (maintains atmosphere, enables movement &
cycling of air, water, nutrients)

5. Energy and the Laws of
Thermodynamics
20.1 – The Laws of Thermodynamics Govern Energy Flow.
Energy exists in many forms, such as heat, light, chemical
energy, and electrical energy. Energy is the ability to bring
about change or to do work. Thermodynamics is the study
of energy.
Kinetic
energy
Entropy Entropy
Potential
energy

6. Energy and the Laws of
Thermodynamics
The 1st Law of Thermodynamics:
Energy can be changed from one form to
another, but it cannot be created or
destroyed. The total amount of energy
and matter in the Universe remains
constant, merely changing from one form
to another. Isaac Newton (1643-1727)

8. Energy and the Laws of
Thermodynamics
The 2nd Law of
Thermodynamics: "in all energy
exchanges, if no energy enters or leaves the
system, the potential energy of the state will
always be less than that of the initial state." In
energy transfer, some energy will dissipate
as heat. The flow of energy maintains Isaac Newton (1643-1727)
order of life.

9. Second Law of Thermodynamics
• - Scientists have studied many ecosystems and have concluded
that this energy loss is a constant pattern. In fact, scientists have
calculated that the percentage (%) of usable energy transferred
from one organism to another is 10%.
• !! - That means that 90% of energy is lost as heat!!!
• So…. if producers captured 10,000 calories from the sun, then
only bout 1,000 calories will be available to support primary
consumers (herbivores), and only about 100 calories to support
secondary consumers (carnivores or omnivores).

10. 10% LAW.. !!
• In the Arctic, Eskimos hunt whales for food.
Whales eat tons and tons of microscopic
plankton. This plankton in turn eats microscopic
algae. It requires 1,000 units of energy (calories)
of algae to produce 100 calories of plankton
which is what a whale uses to produce 10
calories of blubber (fat) to its body. Finally
these 10 calories of whale blubber contains
enough energy to give the Eskimo one calorie of
energy.

11. Trophic Levels
• Producers – autotrophs
-Photosynthesis
• Consumers – heterotrophs
-Primary
-Secondary
-Third-level
• Omnivores
• Detritus feeders / Decomposers

12. Trophic Levels
Trophic Level =
Feeding Level
20 energy
10 consumer energy
Producers energy
- Just like a skyscraper
has floors, or levels, an
energy Pyramid has
distinct levels, called
TROPHIC LEVELS.

13. 4th Tr. Level
1 calorie
eskimos
3rd Trophic Level
10 calories
whales
2nd Trophic Level
100 calories
plankton
1st Trophic Level
1000 calories
algae
A healthy ecosystem will always have
the most energy available in the first trophic
level.

14. Ecosystem Energetics
- Energy Decreases in Each Successive Trophic Level.

16. Ecological pyramids
• The standing crop, productivity, number of organisms, etc. of an
ecosystem can be conveniently depicted using “pyramids”, where
the size of each compartment represents the amount of the item
in each trophic level of a food chain.
carnivores
herbivores
producers
Note that the complexities of the interactions in a food
web are not shown in a pyramid; but, pyramids are often
useful conceptual devices--they give one a sense of the
overall form of the trophic structure of an ecosystem.

17. Pyramid of energy
• A pyramid of energy depicts the energy flow, or
productivity, of each trophic level.
• Due to the Laws of Thermodynamics, each higher level
must be smaller than lower levels, due to loss of some
energy as heat (via respiration) within each level.
carnivores
herbivores
producers

18. Pyramids of Energy Suggests:
• The number of trophic levels are limited. At each
trophic level, there is a dramatic reduction in energy.
• Eating at lower trophic levels means more
resources available.
• Movement up the pyramid explains the problems
of Biological Magnification (DDT, PCBs, etc.)

20. Food Chains
and
Food Webs
How energy moves in an ecosystem
OR
who eats who!? ;)

21. • Food Chain: A food chain shows one path of
how energy moves through an ecosystem
• Food Web: A food web shows many paths of
how energy moves through an ecosystem. A
food web is made up of many different food
chains.

22. FOOD CHAIN

23. F
O
O
D
W
E
B

24. Primary productivity
• Primary productivity is the rate of energy
capture by producers.= the amount of new
biomass of producers, per unit time and space

25. • Gross primary production (GPP)
= total amount of energy captured
• Net primary production (NPP)
= GPP - respiration
• Net primary production is thus the amount of energy
stored by the producers and potentially available to
consumers and decomposers.

26. • Secondary productivity is the rate of production
of new biomass by consumers, i.e., the rate at
which consumers convert organic material into
new biomass of consumers.

27. CONCLUSION
• Energy flow follows the second law of
thermodynamics
• Biomass decreases with increasing trophic level
• Ecological efficiency – typically 10%

28. CREDITS:
-PARTH - PRAFFUL
-SUMIT -SHUHUL
-VERNIKA - KOMAL
-LAKSHYA - PRANSHU
-RISHABH -ROHAN