Which statement best explains the relationship between gross primary production (GPP), net primary production (NPP), and energy conversion in an ecosystem?

• A. GPP is the total energy captured by producers through photosynthesis, and NPP is the energy available to consumers after subtracting the energy used by producers for respiration.
• B. GPP and NPP are equal because all energy captured by producers is available to consumers.
• C. NPP is the energy lost as heat during energy conversion, while GPP is the energy stored in consumer biomass.
• D. NPP represents the total amount of energy captured by producers, while GPP is the energy remaining after producers use some for respiration.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the key terms involved in the problem. Gross Primary Production (GPP) refers to the total amount of energy captured by producers (like plants) through photosynthesis in an ecosystem. Net Primary Production (NPP) is the portion of this energy that remains after producers use some of it for their own metabolic processes, such as respiration.
2. Step 2: Clarify the relationship between GPP and NPP. GPP represents the total energy input into the ecosystem via photosynthesis, while NPP is the energy available to consumers (herbivores, decomposers, etc.) after subtracting the energy used by producers for respiration.
3. Step 3: Eliminate incorrect statements. For example, the statement 'GPP and NPP are equal because all energy captured by producers is available to consumers' is incorrect because producers use some energy for respiration, so GPP is always greater than NPP.
4. Step 4: Address the statement 'NPP is the energy lost as heat during energy conversion, while GPP is the energy stored in consumer biomass.' This is incorrect because NPP is not energy lost as heat; it is the energy available to consumers. GPP is not stored in consumer biomass; it is the energy captured by producers.
5. Step 5: Confirm the correct explanation. The correct statement is: 'GPP is the total energy captured by producers through photosynthesis, and NPP is the energy available to consumers after subtracting the energy used by producers for respiration.' This accurately describes the relationship between GPP, NPP, and energy conversion in an ecosystem.