Tag: energy flows

Questions Related to energy flows

About how much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 10%

  2. 1%

  3. 30%

  4. 50%

Show answer
Correct Option: A
Explanation:

According to the 10%  law, in a terrestrial ecosystem during the transfer of energy from one trophic level to the next, about ten percent of the energy in the form of organic matter is eaten and digested and stored as flesh. The remaining is lost during transfer in the form respiration or incomplete digestion. Thus the correct answer is option A.

10% law of energy transfer was given by

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. Lindemann

  2. Tansley

  3. Stanley

  4. Darwin

Show answer
Correct Option: A
Explanation:

Lindemann (1942) put forth ten percent law for the transfer of energy from one trophic level to the next. According to the law, during the transfer of organic food from one trophic level to the next, only about ten percent of the organic matter is stored as flesh. The remaining is lost during transfer or broken down in respiration.

Plants utilise sun energy for primary production and can store only 10% of the utilised energy as net production available for the herbivores. When the plants are consumed by animal, about 10% of the energy in the food is fixed into animal flesh which is available for next trophic level (carnivores). When a carnivore consumes that animal, only about 10% of energy is fixed in its flesh for the higher level.

So at each transfer 80 - 90% of potential energy is dissipated as heat (second law of thermodynamics) where only 10 - 20% of energy is available to the next trophic level.

Therefore, the correct answer is option A.

Which of the following is the correct order of flow of energy?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. Plants--> tigers--> microbes--> goats

  2. Plants--> goats--> tigers--> microbes

  3. Tiger--> plants--> microbes--> goats

  4. Microbes--> tigers--> goats--> plants

Show answer
Correct Option: B
Explanation:

The flow of energy is always unidirectional. The energy passes from primary producers to primary consumers. From the primary consumers, the energy is passed to secondary consumers and then to tertiary consumers. Thus the energy pyramid is always upright.

If first trophic level represent 100,000 kcal of energy. According to Lindman's law, how much energy is available to the fourth trophic level?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 10 kcal

  2. 100 kcal

  3. 1,000 kcal

  4. 10,000 kcal

  5. 100,000 kcal

Show answer
Correct Option: B
Explanation:
If first trophic level represents 100,000 kcal of energy, in second level it will have 10% of 100000 = 10000 kcal.
In third level, 10 % of 10000 = 1000 kcal
In fourth level, 10% of 1000 = 100 kcal
The Ten percent law is the transfer of energy from one trophic level to the next was introduced by Raymond Lindeman (1942). According to this law, during the transfer of energy from organic food from one trophic level to the next, only about ten percent of the energy from organic matter is stored as flesh.

Autotrophic species produce 400,000 kJ of energy in a tropical food web. The amount of energy at the level of secondary consumers is

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 40 KJ

  2. 400 KJ

  3. 4000 KJ

  4. 40, 000 KJ

  5. 4000, 000 KJ

Show answer
Correct Option: C
Explanation:

Energy transfer along each trophic level of a food chain exhibit loss of 90% energy as heat and transfer of only 10% energy to the next trophic level. The energy is lost in metabolic activities. According to this, out of 400,000kJ energy of primary producers, 40000kJ will be transferred to primary consumers and 4000kJ will be transferred to the secondary consumer. Tertiary consumers will obtain only 400kJ energy from secondary consumers while top consumers will obtain as little as 40kJ energy. Correct answer is option C.

Find the incorrect statement about the energy flow through an ecosystem?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. Energy is conserved and stays in an ecosystem, to be used by organisms again and again.

  2. Solar radiation is the original energy source for the vast majority of organisms on earth.

  3. Energy flow is one-way, from autotrophs to progressively higher trophic levels.

  4. Energy flow is inefficient; a lot is lost in each transfer from one organism to another.

  5. All solar radiation used in photosynthesis will eventually be lost as heat.

Show answer
Correct Option: A
Read the passage and answer the following question.

Assume you had a 10m$^2$ pond to study. You measured the amount of light energy bathing the water surface at 1,000kcal.


Based on the energy captured, about what percentage of that would be transferred to higher trophic levels?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 1.65 percent

  2. 16.5 percent

  3. 33 percent

  4. 3.3 percent

  5. 66 percent

Show answer
Correct Option: B

If the energy produced by plants is 800,000 kJ, then how much energy will exist at the level of secondary consumers?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 80 kJ

  2. 800 kJ

  3. 8,000 kJ

  4. 80,000 kJ

  5. 800,000 kJ

Show answer
Correct Option: C
Explanation:

According to the 10 percent law, when energy is passed in an ecosystem from one trophic level to the next, only ten percent of the energy will be passed on.  The remaining is lost during transfer, broken down in respiration, or lost to incomplete digestion by higher trophic levels.

As per this rule, if the plant produces 800,000kJ of energy then only 10% of this is passed to the next trophic level which is the primary consumers. So, the energy obtained by the primary consumer will be 80,000kJ.
Now, only 10% of this 80,000kJ is passed on to the next trophic level (secondary consumers) which is 8,000KJ.
So, the correct answer is option C.

Read the passage and answer the following question.

Assume you had a 10m$^2$ pond to study. You measured the amount of light energy bathing the water surface at 1,000kcal.


About how much of that available energy would be expected to be converted into producer biomass?

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. $100$ kcal

  2. $1,000$ kcal

  3. $2,000$ kcal

  4. $10$ kcal

  5. $200$ kcal

Show answer
Correct Option: D
Explanation:

Plants absorb 1% of sun energy for photosynthesis. With each trophic level, only 10% energy is transferred and 90% is lost as heat in respiration. Here, the total available sunlight is 1000kcal, the producers will get 1% i.e. 10kcal. Correct answer is D.  

According to Lindeman's 10% law, only 10% energy is transferred to the next trophic level. If the plants produce 100 units of energy, the amount of energy at the level of secondary consumers would be

zoology meaning of life energy flow and loss energy flow in a food chain energy flows

  1. 1 unit

  2. 25 units

  3. 50 units

  4. 70 units

  5. 80 units

Show answer
Correct Option: A
Explanation:

10 percent Law introduced by Lindeman states that only 10% of energy is transferred from one trophic level to another and 90% of the energy is lost during transfer, respiration and digestion processes. Therefore if plants (present at producers level) produces 100 units of energy, 10% of it will be transferred to primary consumers (10 units of energy) and 10% of the subsequent energy is transferred to secondary consumers (1 unit of energy). Hence, the correct answer is option A.