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How does photosynthesis provide energy for food webs?

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Diagram of a tree leaf illustrating photosynthesis, with arrows showing sunlight, water, and carbon dioxide entering the leaf and sugars and oxygen being produced. A person is shown beside the tree to demonstrate the exchange of oxygen and carbon dioxide between plants and animals. — Photosynthesis Diagram of photosynthesis showing how water, light, and carbon dioxide are absorbed by a plant to produce oxygen, sugars, and more carbon dioxide.

Photosynthesis is the fundamental process by which solar energy is converted into chemical energy, providing the primary source of nutrition for nearly all life on Earth.12

Through this process, photosynthetic organisms—such as plants, algae, and certain bacteria—act as primary producers at the base of food webs. They capture light energy and store it in energy-rich molecules like glucose, which are then consumed by heterotrophs (consumers).1324

This energy flows through the ecosystem via trophic levels:
* Primary Producers: Convert solar energy into biomass.35
* Consumers: Herbivores and carnivores derive energy by consuming producers or other consumers.35

Because energy is lost as heat during metabolic processes at each transfer, the amount of available energy decreases as it moves up the trophic pyramid. Consequently, the entire structure of biological communities and the availability of food energy depend on the initial conversion of light into chemical energy by photosynthetic organisms.3415