Florida Biology EOC Practice Test

An autotroph is distinguished from a heterotroph primarily by its ability to produce its own food. Autotrophs, such as plants, algae, and some bacteria, utilize processes like photosynthesis or chemosynthesis to convert inorganic substances (like carbon dioxide and water) into organic compounds (such as glucose), which serve as their energy source. This self-sufficiency in food production is a defining characteristic of autotrophs.

While some autotrophs do require light for their energy needs—such as those performing photosynthesis—this is not a universal requirement for all autotrophs since some can obtain energy through chemical reactions in environments devoid of light. Moreover, the ability to photosynthesize is not found in heterotrophs, which depend on consuming other organisms or organic matter for their nutritional needs. Therefore, the unique capability of autotrophs to synthesize their own food clearly differentiates them from heterotrophs, who lack this ability and must obtain energy by ingesting other forms of life.