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Class 10  »  Biology  »  Our Environment

Energy Flow in Ecosystem Ten Percent Law_Unsolved Paper

Class 10

Chapter: Our Environment | Topic: Energy Flow in Ecosystem Ten Percent Law

Unsolved Paper
Study Material.
Class 10

ENERGY FLOW IN ECOSYSTEM TEN PERCENT LAW_UNSOLVED PAPER

Topic: Energy Flow in Ecosystem Ten Percent Law

Time: 90 mins | Marks: 45 | Difficulty: Medium
multiple choice question

Q1. The ultimate source of energy for most ecosystems is:

  1.  Soil   
  2. Water
  3. Decomposer
  4. Sun

Q2. According to the Ten Percent Law, approximately how much energy is transferred from one trophic level to the next?

  1. 1%
  2. 10%
  3. 50%
  4. 90%

Q3. If plants in an ecosystem contain 10,000 J of energy, approximately how much energy would be available to the primary consumers?

  1. 10 J
  2. 100 J
  3. 1,000 J
  4. 9,000 J

Q4. Why does the amount of available energy generally decrease at higher trophic levels?

  1. Organisms stop consuming food
  2. Energy is used for life processes and much of it is lost as heat
  3. Producers receive no sunlight
  4. Consumers produce their own food

Q5. Consider the food chain:

Grass --> Grasshopper --> Frog --> Snake

Which organism would generally have the least available energy among the organisms shown?

  1. Grasshopper
  2. Grass
  3. Snake
  4. Frog

Q6. A student observes that a food chain usually contains only a limited number of trophic levels. Which concept best explains this observation?

  1. Energy decreases at successive trophic levels
  2. Producers cannot reproduce
  3. Consumers do not require energy
  4. All organisms receive equal energy

Short questions

Q1. What is meant by the flow of energy in an ecosystem? In which direction does energy generally move through a food chain?

Q2. State the Ten Percent Law of energy transfer. Why is it important when studying food chains?

Q3. Why does energy flow in an ecosystem differ from the cycling of materials such as carbon and nutrients?

Q4. A school garden contains grass, insects, frogs and birds. Explain why the birds at a higher trophic level generally receive less energy than the grass at the producer level.

Q5. Why is energy lost between successive trophic levels? Mention the role of life processes in this energy loss.

Q6. Consider the food chain:

Crop plants --> Rat --> Snake --> Eagle

Why would the eagle receive much less energy than the crop plants? Relate your answer to the Ten Percent Law.

long questions

Q1. Explain how energy enters an ecosystem and passes through different trophic levels. Describe the role of producers, primary consumers and higher-level consumers in this flow of energy.

Q2. Explain the Ten Percent Law with the help of a suitable food chain. Discuss why only a small fraction of the energy available at one trophic level becomes available to the next trophic level.

Q3. A farmer observes the following food chain in a field:

Green plants --> Insects --> Frogs --> Snakes --> Birds of prey

Explain how the amount of available energy changes as energy moves through this chain. Why would the organisms at the highest trophic level generally receive much less energy than the organisms at the producer level?

application-based questions

Q1. In a grassland ecosystem, producers store 20,000 J of energy.

Using the Ten Percent Law, calculate the approximate energy available at:

(a) Primary consumer level
(b) Secondary consumer level

Q2. A food chain in a pond is represented as:

Algae --> Small fish --> Large fish --> Fish-eating bird

Suppose the algae contain 50,000 J of energy.

Using the Ten Percent Law, determine the approximate energy available at the large fish level.

Q3. During a biology activity, a student records the following energy values:

Trophic Level

Energy Available

Producers

80,000 J

Primary Consumers

8,000 J

Secondary Consumers

800 J

Tertiary Consumers

80 J

Based on the data:

(a) Calculate the percentage of energy transferred from the primary consumers to the secondary consumers.
(b) What pattern in energy availability across the trophic levels can be observed from the table?

Total: 45 Marks | Time: 90 mins

Explore more topics in Our Environment

Ecosystem Components and Types Food Chain and Food Web Trophic Levels Biodegradable vs Non Biodegradable Waste Ozone Layer Formation and Depletion Managing Garbage and Waste Disposal Environmental Impact of Human Activities