- Producers: Producers are organisms that make their own food from inorganic matter. Plants are the primary producers in most ecosystems, using sunlight, water, and carbon dioxide to produce food through photosynthesis. Some other producers include algae and certain bacteria.
- Consumers: Consumers are organisms that cannot make their own food and must eat other organisms to obtain energy. Animals are the primary consumers in most ecosystems, feeding on plants or other animals. Consumers can be further classified into primary, secondary, and tertiary consumers based on their position in the food chain.
- Decomposers: Decomposers are organisms that break down dead plants and animals, returning nutrients to the environment. Fungi and bacteria are the primary decomposers in most ecosystems. Decomposers play a vital role in the cycling of nutrients and the maintenance of ecosystem health.