Prevention and control of bacteriophage saprophy: a nutritional way for organisms to absorb nutrients from animal and plant residues or soluble organic matter to maintain their normal life activities. Get nutrition
1.*** Life means that two creatures * * * live together, depend on each other and benefit from each other; If separated, the two sides or one side can't live independently, and there are synchronous changes between * * * creatures, that is, "the same life and death, the same honor and disgrace."
2. Parasitism means that one organism parasitizes on the body or surface of another organism, from which it absorbs nutrients to maintain life. Parasitic living organisms are called parasites, and infringed organisms are called hosts or hosts. Parasitic life is beneficial to parasites, but harmful to them. If the two are separated, it is difficult for parasites to live alone, but the host can grow healthily, and there is no necessary quantitative relationship between them.
3. Competition refers to the phenomenon that two creatures live together and compete for resources and space. The quantitative relationship between them, that is, the mathematical model, is generally represented by figure C. As can be seen from the figure, at the beginning, the two species A and B increased at the same time, and the competition at this time was not fierce. However, when they increase to a certain extent, due to the limitation of space and food, the two species have undergone a "life and death" change, resulting in "the strong is stronger and the weak is weaker", and even the weak is finally eliminated. If the viability of the two species is equal, due to the dual adjustment of competition and intraspecific struggle, the two species can rise and fall with each other and exist in the same environment for a long time, showing convergent evolution.
Predator-prey relationship means that one organism feeds on another. Generally speaking, it is an asynchronous change of "those who increase first decrease, those who decrease then increase and then decrease", that is, "this is a long time, this is a long time." Predators first increase and then decrease, and predators then increase and then decrease.