What is the primary source of energy for most ecosystems?

The primary source of energy for most ecosystems is the sun. Solar energy is captured through the process of photosynthesis by plants and other photosynthetic organisms, which convert sunlight into chemical energy in the form of glucose. This energy then flows through the ecosystem as organisms such as herbivores consume plants, and carnivores consume herbivores, creating complex food webs.

In addition to being the initial energy source, sunlight also drives climate and weather patterns, influencing various ecological processes. Without the sun, photosynthesis would not occur, and thus the primary energy source that supports life and sustains ecosystems would be absent.