What is the primary source of energy for Earth’s ecosystems?

The primary source of energy for Earth's ecosystems is the Sun. This is because solar energy drives the process of photosynthesis in plants, which forms the foundation of most food webs. Through photosynthesis, plants convert sunlight into chemical energy, producing glucose and oxygen, which are essential for life on Earth. This energy is then transferred throughout the ecosystem via various trophic levels as organisms consume plants and each other.

Solar energy also influences climate patterns, weather, and the Earth's various biomes, creating the conditions necessary for diverse ecosystems to thrive. Without this consistent input of energy from the Sun, life as we know it would not be sustainable.

In contrast, while internal geothermal energy does contribute to some ecosystems, particularly in extreme environments, it is not the primary source. The Earth itself and the Moon do not provide the necessary energy for sustaining ecosystems; rather, they play roles in gravitational effects and geological processes. Therefore, the Sun is unequivocally the central driver of energy in Earth's ecological systems.