With reference to 'Ecosystem', which of the following statements is/are correct?

Question

With reference to 'Ecosystem', which of the following statements is/are correct?

1. Green plants in terrestrial ecosystem capture about 1% of energy of the sunlight that falls on their leaves.

2. Around 10% of organic matter reaches to the next higher level of consumers.

Select the correct answer from the code given below:

1. A. Only 2
2. B. Neither 1 nor 2
3. C. Both 1 and 2 (Correct answer)
4. D. Only 1

Correct Answer

Option C — Both 1 and 2

Detailed Solution & Explanation

The correct answer is Both 1 and 2.

Key Points

• Statement 1 is correct. Green plants in a terrestrial ecosystem fix only about 1% of the photosynthetically active radiation falling on their leaves into chemical energy. The rest is reflected, transmitted or lost as heat.
• Statement 2 is correct. This is the 10% law of Lindeman (1942) — roughly 10% of the energy or organic matter at one trophic level is transferred to the next higher level; the other 90% is lost in respiration, movement and heat.
• Both hold, so the answer is option (c).

Additional Information

• The 10% law is why food chains rarely exceed four or five trophic levels — too little energy remains to support another level.
• Pyramid of energy is always upright; pyramids of number and biomass can be inverted (for example, the biomass pyramid in an ocean, where phytoplankton biomass is less than that of the zooplankton they support).
• Terms to keep straight: GPP (gross primary productivity), NPP (net primary productivity, = GPP minus respiration) and secondary productivity (at consumer level).