Which type of organisms forms the base of the food chain in an ecosystem?

The organisms that form the base of the food chain in an ecosystem are autotrophs. These are primarily plants and some types of algae and bacteria that can produce their own food through the process of photosynthesis or chemosynthesis. Autotrophs are essential because they convert solar or chemical energy into organic compounds that can be used as food by other organisms in the ecosystem, such as herbivores or primary consumers, which rely directly on autotrophs for their energy needs.

By forming the foundational level of the food chain, autotrophs provide the necessary energy that supports the entire ecosystem. Without them, higher trophic levels, including primary consumers and secondary consumers, would not have a food source, leading to a breakdown in the ecosystem's energy flow. This interdependence highlights the critical role of autotrophs as the primary producers in the ecological pyramid.