"On Heterotrophs and Organic Carbon Sources"

The origin of all things is different. In the field of biology, there is a class of organisms that live on ready-made organic carbon sources, which are called heterotrophs. Heterotrophs cannot use light or chemical energy to synthesize the organic matter they need from inorganic carbon sources like autotrophs, but need to ingest the organic carbides formed in the outside world to fill their energy and constituents.

Organic carbon sources are as important to heterotrophs as water is to fish. They can come in various forms, such as sugars, fats, and proteins. Sugars are common and efficient energy donors. After a series of biochemical changes, they can provide energy for the activities of heterotrophic organisms. Fats are very high in energy and rich in energy storage. When nutrients are sufficient, heterotrophic organisms often store them for emergencies. Protein is not only a structural substance, but also can decompose and supply energy when necessary, and provides nitrogen sources and other raw materials for biosynthesis of many important molecules.

Heterotrophic organisms consume organic carbon sources in different ways. Animals mostly feed on plants or other animals, and digest and absorb them to obtain organic carbon sources. For example, tigers and leopards eat meat, cattle and sheep eat grass. The content of their food mostly contains organic carbides, which are processed through the stomach and intestines, and nutrients enter the body to maintain the movement of life. Among microorganisms, some bacteria or fungi can secrete extracellular enzymes to degrade macromolecular organic carbon sources in the environment into small molecules and then absorb them; some parasitize in other organisms and directly obtain organic nutrients from the host.

The relationship between heterotrophs and organic carbon sources is a key part of the ecosystem. The distribution and amount of organic carbon sources affect the type and quantity of heterotrophs. The activities of heterotrophs, in turn, act on the cycle of organic carbon sources. Their respiration converts organic carbon into carbon dioxide and other inorganic substances, returning to the environment and participating in a new round of carbon cycle. This cycle is repeated to maintain ecological balance and stability. Heterotrophs depend on organic carbon sources, and organic carbon sources circulate because of heterotrophs. The two are interdependent and co-constitute a wonderful picture of life.