Question

In the equation, GPP−R=NPP R represents :

• A. Respiration losses
• B. Radiant energy
• C. Retardation factor
• D. Environment factor

Answer 1

The Correct Option is A

The equation given is GPP - R = NPP, which stands for Gross Primary Productivity (GPP), Net Primary Productivity (NPP), and R. In this context, we need to identify what 'R' represents. Let's break down the terms to understand the equation:

• Gross Primary Productivity (GPP): It is the total amount of organic matter or biomass produced by producers (like plants) through photosynthesis over a given period.
• Net Primary Productivity (NPP): It is the amount of organic matter available to herbivores and decomposers after respiration loss. It represents the energy that is stored as biomass and is available for the next trophic level.
• Respiration (R): It represents the energy or organic matter consumed by plants during respiration. This is a loss in potential energy from the GPP that is not available for the next trophic level. Hence, 'R' in this particular equation represents the "Respiration losses" of the plants.

Therefore, the term 'R' in the equation GPP - R = NPP refers to "Respiration losses". This matches with the correct option given:

• Respiration losses: This is the correct answer because in the context of ecological productivity, respiration is a key factor.
• Radiant energy: While important in photosynthesis, it is not represented by 'R' in this equation.
• Retardation factor: Not relevant in the context of primary productivity equations.
• Environment factor: While important in ecology, it is not represented as 'R' here.

So, by understanding the definition and context of the terms involved, we conclude that 'R' stands for "Respiration losses".