Healthy ecosystems maintain this balance via limiting factors

So why does this keep happening?Most of the world's ecosystems are the result of millennia of coevolution by organisms,adapting to their environment and each other until a stable balance is reached.Healthy ecosystems maintain this balance via limiting factors,environmental conditions that restrict the size or range of a species.These include things like natural geography and climate,food availability,and the presence or absence of predators.For example, plant growth depends on levels of sunlight and soil nutrients.The amount of edible plants affects the population of herbivores,which in turn impacts the carnivores that feed on them.And a healthy predator population keeps the herbivores from becoming too numerous and devouring all the plants.