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Energy Flow in Food Chains

The document discusses the flow of energy through ecosystems and the 10% law of energy transfer between trophic levels. It provides an example food chain of sun -> grass -> rabbit -> snake -> eagle. Grass receives 30,000 J of energy from the sun. Based on the 10% law, only 10% of energy is transferred to the next trophic level. In this example, the snake at the third trophic level receives 300 J of energy, which is 10% of the 3000 J received by the rabbit at the second trophic level.

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84 views2 pages

Energy Flow in Food Chains

The document discusses the flow of energy through ecosystems and the 10% law of energy transfer between trophic levels. It provides an example food chain of sun -> grass -> rabbit -> snake -> eagle. Grass receives 30,000 J of energy from the sun. Based on the 10% law, only 10% of energy is transferred to the next trophic level. In this example, the snake at the third trophic level receives 300 J of energy, which is 10% of the 3000 J received by the rabbit at the second trophic level.

Uploaded by

Admn Tagore
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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in

Exercise 15: Flow of energy and Ten percent law

Aim:
To understand the unidirectional flow of energy
in an ecosystem and transfer of energy follows the
10% law.
Principle:
The student studies about flow of energy and that
only about 10% of energy is made available to the
next trophic level. Large amount of energy about
90% is lost at each trophic level in a food chain.
Requirements:
Problems to be given to students based on different examples with alternating food chain and amount
of energy.

The teacher must train the student by giving them various kinds of food chain with different
values.

Problem
Analyse the food chain given below and find out the amount of energy received by the organism in
third trophic level.
Sun

l
Grass
Grass receives 30,000. J of energy from sun
-----+ Rabbit -----+ Snake -----+ Eagle
Given: The amount of energy in the producers, i.e. grass = 30,000 J.
Solution:
Grass -----+ Rabbit -----+ Snake Eagle
Tl T2 T3 T4

Producer Primary Consumer Secondary Consumer Tertiary Consumer

T1 - Grass (Producer)
= 30,000 J of energy
T2 - Rabbit (Primary Consumer)
=
T3 - Snake (Secondary Consumer)
= ?
According to the ten percent law, during the transfer of energy, only about 10% of the energy flows
from each trophic level to the next lower trophic level. So 10% of energy from T1 gets transferred to T2

So T2 10
- Rabbit (primary consumer) receives 30000 X = 3000 J
00
Similarly, 10% of energy from T2 gets transferred to T3 1
So T3 - Snake (Secondary consumer) receives 10
3000 X l00 = 300 J
Answer:
1. The third tropic level T3 - (Snake) receives 300 J of energy.

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