Which statement is true about autotrophs in ecosystems?

Which statement is true about autotrophs in ecosystems?

• A. They are the base of the food chain because they produce food energy for others
• B. They rely on other organisms for energy
• C. They require external food sources
• D. They decompose dead matter

Answer: (A)

Autotrophs are producers in ecosystems. They capture energy from the environment—usually sunlight, though some use chemical energy from minerals—and convert inorganic carbon dioxide into organic molecules that store that energy. Because they generate the organic matter that other organisms rely on for energy and carbon, they form the base of the food chain. The idea that autotrophs rely on other organisms for energy isn’t correct, since their energy comes from sunlight or chemical sources themselves. Requiring external food sources describes heterotrophs, not autotrophs. Decomposers, meanwhile, break down dead matter rather than produce new organic energy-rich compounds, so they aren’t autotrophs either. Examples of autotrophs include plants, algae, and certain bacteria. In some ecosystems, like deep-sea vents, chemotrophic autotrophs use chemical energy to make organic matter, illustrating the same producer role in different environments.

Autotrophs are producers in ecosystems. They capture energy from the environment—usually sunlight, though some use chemical energy from minerals—and convert inorganic carbon dioxide into organic molecules that store that energy. Because they generate the organic matter that other organisms rely on for energy and carbon, they form the base of the food chain. The idea that autotrophs rely on other organisms for energy isn’t correct, since their energy comes from sunlight or chemical sources themselves. Requiring external food sources describes heterotrophs, not autotrophs. Decomposers, meanwhile, break down dead matter rather than produce new organic energy-rich compounds, so they aren’t autotrophs either. Examples of autotrophs include plants, algae, and certain bacteria. In some ecosystems, like deep-sea vents, chemotrophic autotrophs use chemical energy to make organic matter, illustrating the same producer role in different environments.