Final answer:
Three groups of autotrophs important for ecosystem energy supply are plants, algae, and photosynthetic bacteria. These organisms use photosynthesis to produce organic compounds needed by themselves and other species.
Step-by-step explanation:
Three groups of autotrophs are:
- Plants: These are the most common autotrophs that use photosynthesis to convert sunlight into energy, in the form of carbohydrates like glucose.
- Algae: Like plants, algae are photosynthetic organisms that are capable of producing their own food using sunlight.
- Photosynthetic bacteria: Some bacteria also have the ability to perform photosynthesis and are thus considered autotrophs, using solar energy to make organic compounds.
Autotrophs such as these play a critical role in ecosystems, essentially serving as the foundation of food webs by producing the energy that is then consumed by heterotrophic organisms.