heterotrofe

Heterotrophs are organisms that cannot synthesize all of their organic compounds from inorganic sources and therefore must obtain energy and carbon from preformed organic molecules produced by other organisms. In contrast, autotrophs, such as plants and many bacteria, fix carbon dioxide into organic matter using light energy or inorganic chemical energy.

Heterotrophs obtain energy by degrading and assimilating organic matter, typically through respiration. Their carbon source is organic molecules like sugars, amino acids, and fats. They include animals, fungi, and many bacteria and archaea. Some organisms are mixotrophic, capable of both autotrophic and heterotrophic nutrition depending on environmental conditions. Others are heterotrophic saprotrophs that decompose dead organic material by external digestion, as seen in fungi and certain bacteria, or detritivores that ingest particulate matter.

Ecologically, heterotrophs function as consumers that feed on living organisms and detritus, as well as decomposers that recycle nutrients. The energy and carbon flow in ecosystems generally proceeds from autotrophs to heterotrophs and finally to decomposers. Parasitic heterotrophs derive nutrients from hosts, while predatory heterotrophs actively consume other organisms. Some protists are heterotrophic, whereas many algae are capable of photosynthesis or mixotrophy. Understanding heterotrophy helps explain trophic dynamics, nutrient cycling, and the evolution of diverse energy strategies in life.