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What is 10% Law of Energy Transfer?
Grade Level:
Class 7
Space Technology, EVs, Climate Change, Biotechnology, HealthTech, Robotics, Chemistry, Physics
Definition
What is it?
The 10% Law of Energy Transfer states that when energy moves from one living thing to another in a food chain, only about 10% of that energy is transferred. The remaining 90% is lost as heat or used up for life activities like breathing and moving.
Simple Example
Quick Example
Imagine you have 100 rupees. If you give 10% of it to your friend, they get 10 rupees. Similarly, if a plant has 100 units of energy, the animal that eats it only gets about 10 units of that energy.
Worked Example
Step-by-Step
Let's see how much energy a tiger gets if the grass it indirectly relies on has 10,000 units of energy.
1. Start with the energy at the producer level (grass): 10,000 units.
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2. Calculate energy transferred to the primary consumer (deer that eats grass): 10% of 10,000 units = (10/100) * 10,000 = 1,000 units.
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3. Calculate energy transferred to the secondary consumer (tiger that eats deer): 10% of 1,000 units = (10/100) * 1,000 = 100 units.
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So, the tiger gets 100 units of energy.
Why It Matters
Understanding this law helps scientists plan how to grow enough food for everyone and design sustainable ecosystems. It's crucial for careers in environmental science, agriculture, and wildlife conservation to manage resources effectively and protect our planet.
Common Mistakes
MISTAKE: Thinking 90% of energy is transferred to the next level. | CORRECTION: Only 10% of energy is transferred; 90% is lost.
MISTAKE: Believing the 10% loss applies only to animals. | CORRECTION: The 10% transfer rule applies to all levels of a food chain, from plants to animals.
MISTAKE: Confusing energy transfer with biomass transfer. | CORRECTION: The 10% law specifically refers to the amount of energy that moves up the food chain, not the total amount of living matter (biomass).
Practice Questions
Try It Yourself
QUESTION: If a plant has 500 units of energy, how much energy will the grasshopper that eats it get? | ANSWER: 50 units
QUESTION: A hawk eats a snake, which eats a frog, which eats an insect. If the insect got 2000 units of energy from plants, how much energy would the hawk get? | ANSWER: 2 units
QUESTION: A farmer wants to raise chickens for meat. If the grains fed to the chickens contain 10,000 units of energy, and humans eat the chickens, how much energy will the humans get from eating the chickens? | ANSWER: 100 units
MCQ
Quick Quiz
What percentage of energy is typically transferred from one trophic level to the next in a food chain?
1%
10%
50%
90%
The Correct Answer Is:
B
The 10% Law of Energy Transfer states that only about 10% of energy is transferred to the next trophic level. The rest is lost as heat or used for life processes.
Real World Connection
In the Real World
This law helps us understand why there are fewer tigers than deer in a forest, or why it's more energy-efficient to eat plants directly than meat. It's applied in farming to calculate how much land is needed to produce food for a certain population, like how much rice or wheat is needed to feed a city like Mumbai.
Key Vocabulary
Key Terms
FOOD CHAIN: A sequence showing how living things get food and energy | TROPHIC LEVEL: Each step or level in a food chain or food web | PRODUCER: Organisms, like plants, that make their own food | CONSUMER: Organisms that get energy by eating other organisms | ENERGY TRANSFER: The movement of energy from one organism to another
What's Next
What to Learn Next
Next, explore 'Food Chains and Food Webs' to see how different organisms are connected and how energy flows through entire ecosystems. This builds on the 10% Law by showing the bigger picture of energy movement in nature.
