What is the primary source of energy for ecosystems?

The primary source of energy for ecosystems is the sun. Solar energy drives the process of photosynthesis, which is essential for the growth of plants and other photosynthetic organisms. These organisms, known as producers, convert solar energy into chemical energy stored in glucose, which then becomes the foundation of the food web. Herbivores consume these plants, transferring energy to higher trophic levels like carnivores and omnivores. This flow of energy is crucial for maintaining the structure and function of ecosystems.

The sun's energy is not only vital for photosynthesis but also influences climate and weather patterns, which in turn affect the distribution of ecosystems. Without solar energy, life as we know it would not exist, making it the cornerstone of ecological processes. While other options like geothermal processes, fossil fuels, and nuclear reactions can provide energy, they do not serve as the primary energy source that drives the fundamental biological processes in ecosystems.