Autotrophs make their own food using energy from sunlight or inorganic chemical reactions. Most autotrophs, such as plants, algae, and cyanobacteria, use sunlight energy to convert carbon dioxide and water into organic compounds like glucose through photosynthesis. Some autotrophs, called chemoautotrophs, use energy from chemical reactions involving inorganic compounds to produce food.

Key Points

• Autotrophs are organisms that synthesize their own food from inorganic substances.
• Photoautotrophs use light energy (usually from the sun) to perform photosynthesis.
• Chemotrophs (chemoautotrophs) use energy from inorganic chemical reactions.
• Autotrophs are primary producers in ecosystems and form the base of the food chain.
• Examples include green plants, algae, cyanobacteria (photoautotrophs), and some bacteria near hydrothermal vents (chemoautotrophs).

Thus, autotrophs primarily use energy from sunlight or inorganic chemical sources to make their own food.