Q. How do populations of predators and prey vary in predatism?

Whenever a predator population enhance at the first moment the prey population tends to reduce. At a second moment the diminish of the prey population and the bigger population density of predators cause the predator population to decrease. The prey population then reverts the tendency to reduce and begins to grow.

If the variations in the size of populations take place in an unexpected intensity (different from the usual intensity of the ecological interaction) for instance, due to ecological accidents killing many prey, the prey-predator equilibrium is disturbed and both species can be harmed. The existence of the predator sometimes is fundamental for the survival of the prey population, since the absence of predatism favors the proliferation of the prey and, in some cases, when the excessive proliferation creates a population size over the sustenance capacity of the ecosystem, environmental degradation occurs and the entire prey population is destroyed.