1, energy source:
Autotrophic organisms can convert solar energy into chemical energy and inorganic matter into organic matter through photosynthesis to meet the needs of their own growth and maintenance of life activities. Autotrophic organisms such as green plants and cyanobacteria can use light energy for photosynthesis to convert carbon dioxide and water into organic substances such as glucose.
In contrast, heterotrophs cannot obtain energy and nutrition by synthesizing organic matter by itself, but maintains its life activities by ingesting ready-made organic matter. These organics may come from decaying organics, animals or plants. Therefore, heterotrophs's energy source mainly comes from organic matter.
2. Carbon source:
The carbon source of autotrophs is mainly carbon dioxide, which is converted into organic matter through photosynthesis. There are various carbon sources in heterotrophs, which can be rotten organic matter, animals or plants. Therefore, heterotrophic bacteria will produce carbon dioxide when decomposing organic matter, and carbon dioxide can be reused by autotrophic bacteria.
Classification of autotrophs
1, photosynthetic bacteria
Photosynthetic bacteria are a kind of prokaryotes that can carry out photosynthesis. They can use light energy to synthesize organic matter and release oxygen at the same time. Photosynthetic bacteria include Rhodosporium, Rhodococcus, Thiobacillus, etc. They are widely distributed in every corner of nature, such as oceans, rivers, lakes, ponds and other waters, as well as soil, rocks, plant rhizosphere and so on.
2. Green plants
Green plants refer to organisms that carry out photosynthesis and convert carbon dioxide and water into organic substances. They include terrestrial plants and aquatic plants, such as various herbs, woody plants, algae and so on. Green plants absorb carbon dioxide and release oxygen through photosynthesis, providing necessary gas and food for other organisms.
3. Chemical synthesis of bacteria
Chemosynthetic bacteria refer to organisms that use chemical energy to synthesize organic matter, including nitrifying bacteria and hydrogen bacteria. Nitrifying bacteria can oxidize ammonia into nitrate, and use the chemical energy released in this process to synthesize organic matter from carbon dioxide and water. Hydrogen bacteria use the chemical energy released by hydrogen oxidation reaction to synthesize carbon dioxide and water into organic matter.