The primary source of energy for most ecosystems is solar energy. Through the process of photosynthesis, plants, algae, and some bacteria convert sunlight into chemical energy stored in the form of glucose. This primary production forms the foundation of the food web, as it provides energy for herbivores (primary consumers) and, subsequently, for carnivores (secondary and tertiary consumers). Additionally, decomposers recycle nutrients back into the ecosystem, ensuring that energy flows sustainably through different trophic levels, contributing to the balance of ecosystems.