Unit 5, Lesson 4- Energy Flow in Ecosystem Lesson Outline: 1. Energy Flow 2. Energy-Flow Pyramids and Food Pyramids 3. Food Chain and Food Web

1. Energy Flow in
Ecosystem
UNIT FIVE, LESSON 5.4
BY MARGIELENE D. JUDAN

2. LESSON OUTLINE
Energy Flow
Energy-Flow Pyramids and Food Pyramids
Food Chain and Food Web
Short Quiz (10 items)

3. All organisms require energy,
for growth, maintenance, reproduction,
locomotion, etc.
Hence, for all organisms there must
be:
1. A source of energy
2. A loss of usable energy

4. Life on earth depends largely on the flow of energy
coming from the sun.

5. 34% solar radiant energy reaches the earth
Much of the energy is immediately reflected by the atmosphere,
clouds and the Earth’s surface that
ONLY 1% REMAINS FOR THE ORGANISMS THAT LIVE ON
EARTH.

6. Of this 1%, only 3% (0.03) or less is captured by the
green plants and used in the process of
photosynthesis
to produce compounds such as
carbohydrates, lipids (fats), and proteins.

7. Consumers obtain energy by eating and then
oxidizing (using) all organic materials
Decomposers obtain energy by acting on organic
waste materials/

8. ENERGY FLOW
The passage of
energy from one
organism to another

9. Energy Flow Diagram
Note that heat is always released, proving that not all energy are used..

10. Energy
Flow
Pyramids
and Food
Pyramids

11. Terminology of Trophic Levels
Producers - capture energy,
produce complex organic
compounds
Primary consumers-feed on
producers (herbivores)
Secondary consumers-feed on
primary consumers (carnivores)
Tertiary consumers-feed on
secondary consumers (carnivores)

14. The SUN is present at all trophic
levels.
Note that only 10% of the original
energy is left to feed the next level.
This 10% is stored in the tissues of
the organism in the form of ATP
(adenosine triphosphate). The 90% is
lost as heat.

15. kJ stands for
kilojoule, a unit of
energy
1000 kJ
100 kJ
10 kJ
1 kJ
10% loss of energy
producers
primary consumers
secondary consumers
tertiary consumers

17. An average human
needs about 2000
calories per day.
So if you want more
energy next time, eat
plants!
Note: The more we go up a
food chain/web/pyramid, the
less energy becomes.

18. This is why we have so
much plant life at the
bottom of each food chain
yet so few consumers at
the top of each food chain.
So the next time you take
a car ride, you’ll know why
there’s so many green
plants and so few animals.
It’s all about energy!

19. Food Chain and Food Web
Together, these groups (consumers, producers, etc.)
make up a food chain.
Food chains in both land and aquatic ecosystems
always begin with the producers and are eaten by
one or several consumers, and finally end with the
decomposers.
(producers > consumers > decomposers)

20. HerbivoreCarnivore Producer
100%
10%
1%

21. Problems
Too simplistic
No detritivores
Chains too long

22. Food Web
More typically, food chains
interact to form a food web.
A food web is a
combination of two or more
food chains.

24. Plants have
the most
energy.

25. Several food chains
also exist:
Plant > rabbits > foxes
Plant > squirrels >
hawks and owls
Plant > herbivorous
insects > predaceous
insects > toads >
snakes
And many more…

26. Short Quiz tomorrow about this lesson.

27. Sources:
Science Links 7
https://www.csun.edu/science/scale/4th.../ppt/energy_ec
osystem.ppt
http://shawmst.org/biology/chapter/how_do_living_things
_get_energy/