heterotrophic hypothesis

The heterotroph hypothesis suggests that the earliest life forms were heterotrophic, meaning they obtained nutrients by consuming pre-existing organic matter. This contrasts with autotrophs, which can produce their own food from inorganic sources.12

This idea is a key component of the Oparin-Haldane theory, which proposes that life originated on early Earth from non-living materials. This theory posits that Earth's primitive atmosphere was reducing (low in oxygen) and contained gases like ammonia and water vapor. Energy sources, such as ultraviolet radiation, could have driven chemical reactions to form organic molecules. These molecules may have then aggregated into precursors of cells, such as coacervates, which could have functioned as early metabolic units.3

The Miller-Urey experiment in 1953 provided experimental support for this theory by successfully creating organic molecules from inorganic components thought to be present on early Earth. This research laid the groundwork for modern abiogenesis hypotheses, which explore how life could have arisen from non-biological processes.34