Purves, W.K., G.H. Orians and H.C. Heller. The Science of Biology . These linkages are the prime movers of energy through food chains. They are an important factor in the ecology of populations, determining mortality of prey and birth of new predators.
Predation is widespread and easy to observe.
Neither its existence nor its importance is in doubt. The development of predation theory Mathematical models of predation are amongst the oldest in ecology. The Italian mathematician Volterra is said to have developed his ideas about predation from watching the rise and fall of Adriatic fishing fleets. When fishing was good, the number of fishermen increased, drawn by the success of others. After a time, the fish declined, perhaps due to over-harvest, and then the number of fishermen also declined.