The interaction among organisms when they hunt, kill, and eat other organisms which are called predators . The animals that are eaten by predators are called prey . Thorn on a rose. In response to predation, organisms have evolved a number of defense. For example, horses can run away quickly and roses have thorns that discourage herbivores.
Predators help to reduce the size of prey populations.
This way, predators help to maintain the diversity in an ecosystem. When predators are absent, prey species can become too numerous and crowd out other organisms.