From the mathematical model in (1) diagram, it can be seen that when the number of predators decreases in the section of N 1 ~ N2, the number of predators also decreases, and the number of predators will not increase with the increase of the number of predators; From N3 to N4, when the number of prey increases, the number of predators also increases. However, when predators reach a certain level, the number of prey is decreasing. This trend reflects the widespread negative feedback regulation in the ecosystem.

(2) When the number of prey population increases, the number of predator population increases, so that the number of prey population decreases, so that the number of predator population decreases, and finally the number of prey population increases. In this way, the number of the two populations can be kept relatively stable through continuous circulation.

(3)K value refers to the maximum population that can be tolerated in a specific environment. It can be seen that the data most likely to represent the K value of prey and predator is N2? And p2.

(4) The relationship between predator and prey is gradually formed through long-term co-evolution; At the same time, some individual behaviors and population characteristics provide a lot of useful information to each other, indicating that the role of information transmission in the ecosystem is to adjust the interspecific relationship of organisms in order to maintain the stability of the ecosystem.

So the answer is:

(1) Mathematics? Negative/reverse/reverse feedback

(2) The increase of prey population → the increase of predator population → the decrease of prey population → the decrease of predator population → the increase of prey population, and the cycle is repeated.

③N2？ And P2.

(4)*** use? Regulate the interspecific relationship of organisms and maintain the stability of the ecosystem.