If 50,000 J energy is available to the primary producer, then the energy available to the tertiary consumer will be:
(b) 50 J
Understanding Energy Transfer in Food Chains
In any ecosystem, energy flows from one trophic level to the next. The primary producers (like plants) capture energy from the sun. This energy is then consumed by primary consumers (herbivores), which are eaten by secondary consumers (carnivores or omnivores), and so on, up to tertiary or quaternary consumers.
The Ten Percent Law of Energy Transfer
A fundamental principle governing energy flow in ecosystems is the Ten Percent Law, proposed by Raymond Lindeman. This law states that only about 10% of the energy from one trophic level is transferred to the next trophic level. The remaining 90% of the energy is lost as heat during metabolic processes, used for life activities (like respiration, movement), or remains unconsumed or undigested.
Calculating Energy Available to Tertiary Consumer
We are given that the energy available to the primary producer is 50,000 J.
Let's calculate the energy available at each subsequent trophic level using the 10% law:
- Primary Producers: Energy available = 50,000 J
- Primary Consumers (Herbivores): Energy available = 10% of energy available to primary producers.
Calculation: \( 50,000 \, \text{J} \times \frac{10}{100} = 5,000 \, \text{J} \)
- Secondary Consumers (Carnivores/Omnivores): Energy available = 10% of energy available to primary consumers.
Calculation: \( 5,000 \, \text{J} \times \frac{10}{100} = 500 \, \text{J} \)
- Tertiary Consumers (Top Carnivores/Omnivores): Energy available = 10% of energy available to secondary consumers.
Calculation: \( 500 \, \text{J} \times \frac{10}{100} = 50 \, \text{J} \)
Therefore, if 50,000 J of energy is available at the primary producer level, the energy available to the tertiary consumer will be 50 J.
Summary of Energy Flow Calculation
| Trophic Level | Available Energy | Calculation |
|---|---|---|
| Primary Producer | 50,000 J | Given |
| Primary Consumer | 5,000 J | \(50,000 \times 0.10\) |
| Secondary Consumer | 500 J | \(5,000 \times 0.10\) |
| Tertiary Consumer | 50 J | \(500 \times 0.10\) |
Revision Table: Energy Transfer in Food Chain
| Trophic Level | Description | Energy Transfer Efficiency (approx.) |
|---|---|---|
| Primary Producers | Organisms that produce their own food (e.g., plants, algae). | Capture solar energy. |
| Primary Consumers | Herbivores; feed on primary producers. | ~10% of producer energy. |
| Secondary Consumers | Carnivores or omnivores; feed on primary consumers. | ~10% of primary consumer energy. |
| Tertiary Consumers | Carnivores or omnivores; feed on secondary consumers. | ~10% of secondary consumer energy. |
| Quaternary Consumers | Top carnivores; feed on tertiary consumers. | ~10% of tertiary consumer energy. |
Additional Information on Energy Flow in Ecosystems
The 10% law is an approximation, and the actual energy transfer efficiency can vary between 1% and 20% depending on the ecosystem and organisms involved. However, 10% is a widely used average for ecological calculations.
This significant energy loss at each level explains why food chains typically have only 4 or 5 trophic levels. There is simply not enough energy left to support higher levels of consumers.
Energy flow in an ecosystem is unidirectional, meaning it moves from producers to consumers and is eventually lost as heat. Nutrients, on the other hand, cycle within the ecosystem.
Ecological pyramids, such as the pyramid of energy, graphically represent the decrease in energy at each successive trophic level. The pyramid of energy is always upright because energy is lost at each step, meaning there is less energy available at higher levels.
Important Questions from Ecosystem
The process of mineralisation by microorganisms helps in the release of:
In which ecosystem is the biomass of primary consumers greater than producers?
Choose the correct statements with respect to decomposition from the following:
(A) Decomposition is an anaerobic process.
(B) Decomposition rate of detritus depends upon the chemical nature of it.
(C) Water-soluble organic nutrients go into the soil and get precipitated in the process of leaching.
(D) Humification follows mineralisation.
Match List-I with List-II:
List-I (Concepts)
List-II (Explanation)
List-I List-II (A) Standing state (I) Available biomass for the consumption of heterotrophs (B) Secondary productivity (II) Rate of formation of organic matter by consumers (C) Standing crop (III) Mass of living matter in a trophic level at a given time (D) Net primary productivity (IV) Amount of mineral nutrients in the soil at a given time Choose the correct answer from the options given below:
Which of the following is not a characteristic of a stable biological community?
