The primary role of a producer in an ecosystem is to convert solar energy into chemical energy through the process of photosynthesis. Producers, primarily plants, algae, and some bacteria, utilize sunlight, carbon dioxide, and water to create glucose and oxygen, serving as the foundation of the food chain. By generating organic matter, producers support herbivores, which in turn are preyed upon by carnivores, thereby establishing complex food webs. This role is vital for sustaining biodiversity and maintaining the balance of ecosystems.