Autotrophic organisms, also known as producers. It mainly includes green plants and many microorganisms. They can make use of sunlight, carbon dioxide in the air, water and inorganic salts in the soil to produce organic matter through biological processes such as photosynthesis, and provide material and energy for the lives of various organisms in the ecosystem.

Nepenthes is a very peculiar insect-eating plant. The difference between it and other green plants is that it does not directly absorb and manufacture the nutrients needed to sustain life from the inorganic world, but lives by catching small animals such as insects. This kind of plants are called carnivorous plants by botanists, such as pitcher plants, flytraps, pitcher plants, sage and other insect-eating plants. From the appearance, they seem to be preying on insects, but in fact, they can't directly swallow and digest insect carcasses. They can only degrade insect carcasses by secreting highly corrosive substances (acid, alkali or enzyme), and obtain a very small amount of organic matter from the degraded substances. The main elements needed for their growth are still obtained through photosynthesis. Judging from the energy flow direction, they also did not absorb the energy released by insect carcasses. Strictly speaking, they don't eat meat. They are all green plants, so they are autotrophs.

Autotrophic organisms generally have no digestive function and cannot swallow other organisms. Therefore, autotrophs use other methods to maintain life, such as photosynthesis used by plants. However, plants still need water, visible light and carbon dioxide in the process of photosynthesis, which does not mean that plants are autotrophic biota, because these three conditions are the basic conditions of life.

In the process of assimilation, organisms cannot directly use inorganic substances to make organic substances, but can only convert ready-made organic substances absorbed from the outside into their own components and store energy. This metabolic type is called heterotrophy.