Which of the following best defines primary production in the context of photosynthesis?

• A. The transfer of energy from one trophic level to another in a food web
• B. The synthesis of organic compounds from atmospheric CO\(_2\) through photosynthesis by autotrophs
• C. The absorption of sunlight by chlorophyll without any chemical transformation
• D. The breakdown of organic matter by decomposers to release energy

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of primary production. Primary production refers to the process by which autotrophs, such as plants, algae, and cyanobacteria, synthesize organic compounds from inorganic substances, primarily atmospheric CO₂, using energy from sunlight through photosynthesis.
2. Step 2: Recognize the role of autotrophs in ecosystems. Autotrophs are organisms that produce their own food and serve as the base of the food web, supporting all other trophic levels by providing energy in the form of organic compounds.
3. Step 3: Eliminate incorrect options. For example, the transfer of energy between trophic levels describes energy flow in a food web, not primary production. Similarly, the absorption of sunlight without chemical transformation does not involve the synthesis of organic compounds, and the breakdown of organic matter by decomposers is related to decomposition, not primary production.
4. Step 4: Focus on the correct definition. Primary production specifically involves the synthesis of organic compounds from atmospheric CO₂ through photosynthesis by autotrophs, which is the foundation of energy flow in ecosystems.
5. Step 5: Relate this concept to photosynthesis. Photosynthesis is the biochemical process where chlorophyll absorbs sunlight, enabling autotrophs to convert CO₂ and water into glucose (C₆H₁₂O₆) and oxygen (O₂), which are essential for primary production.